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ROLE OF HONEY BEES ON SEED PRODUCTION OF RADISH

Thesis submitted to theUniversity of Agricultural Sciences, Dharwad

In partial fulfillment of the requirements for theDegree of

MASTER OF SCIENCE (AGRICULTURE)

In

AGRICULTURAL EMTOMOLOGY

By

G.S. CHANDRASHEKAR

DEPARTMENT OF AGRICULTURAL ENTOMOLOGYCOLLEGE OF AGRICULTURE, DHARWAD

UNIVERSITY OF AGRICULTURAL SCIENCES,DHARWAD 580 005

OCTOBER, 2005

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ADVISORY COMMITTEE

DHARWADOCTOBER, 2005 (H.N. SATTIGI )

MAJOR ADVISOR

Approved by:Chairman: __________________

(H.N. SATTIGI)

Members:1. _________________(R.K. PATIL)

2. _________________(C.P. MALLAPUR)

3. _________________(R.V. PATIL)

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CONTENTS

Chapter

No.Title

Page

No.

I. INTRODUCTION

II. REVIEW OF LITERATURE

III. MATERIAL AND METHODS

IV. EXPERIMENTAL RESULTS

V. DISCUSSION

VI. SUMMARY

VII. REFERENCES

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LIST OF TABLES

TableNo.

TitlePageNo.

1. Pollinator fauna of radish

2. Foraging activity of A. floreaon radish

3. Foraging activity of A. dorsataon radish

4. Foraging activity of A. ceranaon radish

5. Foraging activity of other pollinatorson radish

6. Comparative foraging behaviour of different pollinator species

7. Influence of attractants on visitation of A. florea

8. Influence of attractants on visitation of A. cerana

9. Influence of attractants on visitation of A. dorsata

10. Influence of attractants on visitation of other pollinatorson radish

11. Influence of bee pollination on quantitative parameters of radish

12. Influence of bee pollination on qualitative parameters of radish seed

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LIST OF FIGURES

Figure

No.

TitleBetween

Pages1. Pollinator fauna of radish

2. Foraging activity of bees and other pollinators at different times ofobservation

3. Foraging activity of different honey bees

4. Influence of bee pollination on quantitative parameters of radishseed

5. Influence of bee pollination on qualitative parameters of radishseed

LIST OF PLATES

PlateNo.

TitleBetweenPages

1. General view of radish seed production experimental plot withcages

2. Close view of bee box placed on one border of cage with bothside entrance

3. Apis floreaon radish flower

4. Apis dorsataon radish flower

5. Eumenissp. on radish flower

6. Danaus chrysippuson radish flower

7. Chrysomyasp. on radish flower

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I. INTRODUCTIONRadish (Raphanus sativusL.) is one of the important vegetable crops grown in India.

India is next only to China in area and production of vegetables. India contributes about 13per cent to the world vegetable production (Smita, 2005).

Radish is a quick growing and short duration vegetable crop. It belongs to familyBrassicaceae (Cruciferae), originated in Europe and Asia (Thompson and Kelly, 1957). In

Karnataka, radish is grown in an area of 6035 ha with the production of 11 tones/ha (Anon,2001)

Hundred gram leaves of radish contain 89 per cent water, 3.9 per cent protein, 0.6per cent fat, 4.1 per cent carbohydrate, 31 mg calcium, 6 mg phosphorus, 8 mg iron, 8 I.U vit-A, 21 mg Vit-B, 21 mg Vit-C, 1.4 mg nicotinic acid and 2.7 mg riboflavin (Singh et al., 2004).

The tender tuberous roots of radish used raw as salad and cooked as vegetable.Seeds are used for obtaining non-drying fatty oil, which is suitable for soap making,illuminating and also for edible purposes. Radish has got several medicinal properties. Itincreases appetite, prevent constipation, beneficial for the patients suffering from piles, livertrouble, enlarged spleen, jaundice, gall bladder and urinary disorders.

Radish plants had an average of ten branches, each with 155.2 18.3 flowers, 14.1 1.3mm in diameter. It bears white to lilac flowers. Flowers opened in the morning andremained open for two to three days. The flowers are rich in pollen and nectar. All the

essential floral parts are enclosed in long tubular corolla (Uma Partap and Verma, 1994)

The leaves of radish are rosette covered with stiff bristles. The fleshy root of radish ismodified root (fusiform) developed from both the primary root and the hypocotyls. The skincolour of radish is white, pink, red, black and various other shades. The flesh of radish isalways white in all varieties.

Radish is grown by sowing seeds. The seed production of radish is done by twomethods. (1) seed to seed and (2) root to seed method (Singh, 2001).

Radish is a good source of Vit-A, Vit-C and the minerals like calcium, potassium, ironand phosphorus. Pink skinned radish is generally richer in Ascorbic acid than white skinned(Prasad and Kumar, 2003).

The seed set, numbers of seeds per siliqua and test weight were significantly higherin open pollinated radish plants compared to wind and self-pollinated plants (Verma andPhogat, 1994).

Radish is a cross-pollinated vegetable crop due to sporophytic system of self-incompatibility. It shows considerable inbreeding depression upon selfing. It is entomophilous,pollinated by wild honey bees, wild-flower flies, bumble bees, some Hymenopterans,Dipterans, Coleopterans, Lepidopterans etc.

Any material to increase the honeybees visits to specific crop would be of greatpractical value to harness the benefits of cross-pollination. Commercial and local beeattractants viz., Bee line, Bee here, Bee scent, Bee scent plus, fruit boost and Bee-Q arebeing used to boost the yield of pear, peach, blue berries, watermelon and apple in the UnitedStates, Spain and Canada.

However, in India, the studies on the use of bee attractants are meager. And noattempts have been made for exploring the possible use of bee attractants to boost theproduction of radish seeds in India and role of different species of honeybees in quantitativeand qualitative improvement of radish crop is very much limited. Hence, the present

investigation was undertaken with the following objectives.

1. To study the pollinator fauna of radish

2. To know the foraging activity of bees and other pollinators in radish ecosystem

3. Effectiveness of different bee attractants in attracting the bees

4. Effect of bee pollination on quantitative and qualitative parameters of radish seed.

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II. REVIEW OF LITERATURE

The review of literature pertaining to pollinator fauna of radish, foraging activity ofbees in radish ecosystem, effectiveness of different bee attractants in attracting the bees andeffect of bee pollination on qualitative and quantitative parameters of radish seed arepresented here under. Since, literature on various aspects of radish is scanty, hence theliterature on related crops is also being reviewed and presented.

2.1 POLLINATOR FAUNA OF RADISH

Radechenko (1964) reported that honey bees were the dominant pollinators of winterrape. They comprised of 88.00 to 97.40 per cent from the beginning of bloom to the end ofblooming. The other pollinators were Andrenidae, Halictidae and Bombicidae.

Kapil et al. (1971) reported that Apis florea (Fabraceous) was found to be principalvisitor of mustard flowers. The other species associated with this crop were Andrena ilerada(Cameron), Apis dorsata(F.) and Halictine bees.

Muhammad et al., (1973) reported that honey bees comprised 77 to 94 per cent ofpollinators of radish. Among the honey bees, A. dorsatawas the highest (41%) followed byApis cerana(F.) (32 %) and lowest with A. florea(F.) (21%).

Langdridge and Goodman (1975) observed that oil seed rape (Brassica compestris)was visited by many insect species, of which honey bees were major visitors ( 32.9 %)followed by hover fly ( 30.7 %), blowflies ( 22.9 %), native bees ( 4.9 %) and others ( 8.8 %) atVictoria.

Mesquida (1978) observed that honey bees were the most frequent visitors ( 83 %)on Kale (Brassica oleracea L. ) and other pollinators were bumble bees (5.4%) mainlyBambus terrestris(Linnaeus),B. lapidarius (L.) and other wild bees ( 7.2 %)

Kakar (1980) reported that the highest population of A. cerana(42.1%) on Cauliflowerbloom followed by Eristalis sp. (20.9%), Ceratina sp. (15.1%), Halictus sp. (5.3 %),Lasioglossumsp. (4.7 %) and other insects (10.9 %)

Hussein and Abdel- Aal (1982) reported the solitary bees (Amegilla spp., Halictusspp., Nomiaspp., Nomiodesspp., Megachilespp and Prosopisspp.) comprised 85 per cent

of flower visitor on radish and only 15 per cent were honey bees in Egypt.

Bhalla et al. (1983) recorded 7 species of insect pollinators viz.,A. indica,Andrenareticulata(F.), Lasioglossumsp., Eristalis polymacharusand E. tenax(L.) on mustard bloom.Among these, Dipteran were found most abundant visitors (47.08%) followed by honey bees(33.75 %), other insects (9.93 %) and wild bees (9.11 %)

Sihag (1986) reported that nine species of Hymenopterans (Andrena ileradaiCameron, A. leaena, A. florea, A. dorsata, Apis mellifera L., Halictus sp., Melisodes spp.,Xylocopa fenestrata F. and Pithtus smargdulaI) were abundant visitors of radish for bothpollen and nectar collection and six Lepidopterans (Euploea core, catopsilia crocaleCramer,Papilio sp., Delias sp., Pontia sp. and Dannus sp.) and two Dipterans (Eristalis sp.,Sarcophaga sp.) were the visitors of radish flowers only for nector collection.

Goyal et al. (1989) reported that Diptera was the most dominant group visiting carrot

followed by Hymenoptera. In Diptera the family Syrphidae was predominant and in theHymenoptera, Apidae was most abundant. A. florea (10.74%) was the most common,followed by A. melliferaand A. cerana indica.

Panda et al. (1989) reported that mustard (var.M- 27) was visited by seven species ofinsects. Of which, 4 species were members of Apidae (A. dorsata, A. florea, A. cerana indicaand Trigonasp.,) two species of Anthoporidae (Xylocopa sp. and Ceretina hieroglyphicaL.)and one species of Andrenidae (Andrena ilerada).

Apoidea were most prominent flower visitors of radish constituting 73.82 per cent oftotal insect visitors. Among Apoidea, Indian bee, A. ceranawas most predominant (47.94%)

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visitor followed by rock bee, A. dorsata (31.17%) and little bee, A. florea (20.89%) (Vermaand Poghat, 1994).

Sinha et al. (1994) reported that mustard flowers were visited by many insectpollinators. Of these, honey bees like A. dorsata, A. cerana indica and A. florea togetherconstituted 49 per cent and Dipterans 49.5 per cent and other pollinators such as solitarybees and Lepidopterans were less than one per cent.

Priti and Sihag (1998) reported that the blossoms of carrot, Daucus carotaL. werevisited by twenty insect species during its flowering period. Hymenopterans and Dipteransconstituted 57.66 and 33.31 per cent of total population respectively. The abundance of A.floreawas maximum followed by flies and other species of honey bees.

Bhatia et al. (1999) reported 12 species of insects on radish flowers. Of whichHymenopterans (5 species) were the most abundant group followed by Dipterans (4 spp.,)and Lepidopterans (2 species)

Thakur et al. (2000) reported that the most frequent visitor of turnip was Eristalistenax, followed by Episyrphus balteatusDegeer and A. cerana. E. tenaxalso spent less timeper flower and was rated as the most efficient pollinator of the crop.

Chaudhary (2001) reported the predominance of Apoideavisiting flower of rapeseedand mustard constituting 98.5 per cent of total visitors. Among Apoidea, the social honey

bees constituted 59.5 per cent. The little bee, A. florea was the most abundant (42.8%)followed by rock bee, A. dorsata (16.6%). Solitary bees constituted 39 per cent of totalvisitors.

Priti et al. (2001) reported that the pollinators of radish included A. florea, A. mellifera(most dominant due to proximity of the area to an apiary). A dorsata, Halictussp. ChrysomyabezzianaVilleneuve, Gasterophilussps. Sarcophagasp.

2.2 FORAGING ACTIVITY OF BEES AND OTHERPOLLINATORS IN RADISH ECOSYSTEM

Kapil et al. (1971) observed that A. dorsata, A. florea, and A. cerana indica beganforaging at 0700 to 1000 hr on rape seed and mustard. Peak foraging activity was recordedbetween 1230 to 1400 hr and ceased by 1700 hr.

Kakar (1981) observed the commencement of foraging activity of honey bees onCauliflower at 0800 hr and was highest between 1200 and 1400 hr of the day. A. dorsataforaged most rapidly visiting on an average 9.95 flowers per minute, followed by 8.05 and7.60 by A. melliferaand A. cerana indica, respectively.

Landridge and Goodman (1982) showed that bees worked readily on rape seedflower. A single bee worked on as many as 90 flowers in 47 inflorescence in 7 min 12 sec.The average time spent by single bee on one inflorescence was 8.8 sec. In 126 counts, beesvisited a mean of 2.0 flowers per head with a range of 1 to 5.

Thakur et al. (1982) studied the foraging activity of A. melliferaand A. cerana indicaon mustard at Kangra valley. A. cerana indica colonies, considerable activity was built up at0900 hr when compared to A. mellifera which continued till 1000 hr. A decline in foragingactivity was noticed soon after 1030 hr in both the honey bee species. However, there was a

marginal increase between 1500 to 1530 hr, followed by gradual decline. It was observed thattotal foraging work was at its peak at 1200 hr. There were smaller peaks at 1400 and 1500 hr.

Sinha and Chakrabarti (1985) reported that honey bees were the major pollinators ofcauliflower. Maximum activity of pollinators occurred during 1200 to 1400 hr. A. dorsataandA. cerana indica remained for longer period (1200 to 1600 hr) on the crop than A. florea,even with the temperature between 21.12 to 24.7

0C.

Mishra et al, (1988) reported that the peak foraging activity of A. mellifera, Eristalissp. and other Dipterans were observed between 1200 to 1300 hr, where as A. cerana indicaand syrphids were observed between 1300 to 1400 hr on mustard flower at Solan, India.

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Rana et al. (1993) conducted studies on foraging activity of A. melliferaand A. ceranaindicaat the hive entrance during rape seed bloom. The results revealed that the returned

foragers were significantly maximum in A. cerana indica (22.22 0.82) compared to A.

mellifera(17.59 0.82) at hive entrance. In both species, highest peak foragers wee recordedat 1200 hr and there was no much difference in the number of foragers at 0900 and 1500 hr.

Chand et al, (1994) recorded that the foraging activity of A. cerana indicaincreased at1000 hr and reached peak at 1100 hr on mustard bloom. Similarly, the activity of A. dorsatawas increased from 1400 hr and reached the peak at 1600 hr. The number of visits perminute by A. ceranawas positively correlated with maximum relative humidity and minimumtemperature.

Uma and Verma (1994) made observations on A. ceranaforaging on radish flowersfrom 0640 to 1839 hr with peak foraging between 1100 and 1400 hr. Workers spent on anaverage of 4.5,5.3 and 12.8 sec. per flower, visited 8.0,9.0 and 5.0 flowers per minute andcollected 11,10 and 7 mg of pollen at 0900, 1200 and 1500 hr, respectively.

Verma and Phogat (1994) reported that the foraging activity of A. cerana, A. dorsata,A. florea and other insects were found on radish from morning to evening with peak foragingactivity of A. cerana , A. dorsata , A. floreaand others were observed between 0800 to 1000hr, respectively. There after the activity declined as the hours of the day progressed.

Rush et al, (1995) reported that pollen removal by pollinators in wild radish(Raphanus raphanistrum L.) was extremely high with a minimum of 84 per cent of pollenproduced was removed in one hour. Pollen removal increased with increasing number ofvisits by honey bees and small native bees, but increased numbers of syrphid fly visits had noeffect

Sattigi et al. (1996) noticed the foraging activity of A. ceranathroughout the day but itwas at its peak between 0800 to 1100 hr in winter and 0600 to 1100 hr and 1600 to 1800 hr insummer and 0800 to 1400 hr in monsoon. The foraging activity was low during other timing ofthe day in different seasons.

Rana et al. (1997) reported that the foraging activity of A. cerana and A. melliferawere significantly higher on rape seed bloom at 1200 hr compared to 0900 hr. However, boththe species were found on the crop in equal proportion from 1200 to 1500 hr. The meannumbers of A. ceranaforagers were significantly higher than the A. melliferaforagers.

Peak abundance and activity of all the insect pollinators were observed during midflowering period and at 1200 to 1400 hr. Population of A. floreawas maximum and remainedactive for a long duration on the biomass of carrot (Priti and Sihag, 1998).

Sharma and Singh (1999) reported that the A. florea, was most dominant visitor ofcarrot blossom compared to A. dorsata. A. florea, has taken maximum time for foragingcompared to A. dorsata

Sihag et al. (1999) studied the foraging pattern of A. dorsata, A. mellifera and A.florea on eight cultivars of oil seed crop and reported that in oil seeds, the honey beevisitation frequency was low in the morning and reached peak between 1100 to 1300 hr andagain declined in the evening.

Chandel et al. (2000) reported that A. cerana was observed to start its foragingactivity at 0625 hr and A. melliferaat 0720 hr on toria. A. ceranaceased its foraging at 1730

hr and A. melliferaat 1740 hr. Thus, the average duration of foraging was 1118 hr and 1012hr in A. ceranaand A. mellifera, respectively. The highest number of incoming foragers of A.mellifera(90.7) and A. cerana(274.3) was recorded at 1000 to 1030 hr at a temperature of25

0C.

Sharma and Singh (2001) noticed the foraging time of A. florea and A. dorsata incarrot ecosystem. A. florea spent more time (37.09 sec/flower) and visited less number offlowers (2.20/min) as compared to A. dorsatathat visited more number of flowers (4.31/min)and spent less time (9.20 sec/flower).

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Shivaramu and Chithiraichelvan (2002) recorded A. florea, Trigonasp., A. cerana,A.melliferaand waspon radish flower with peak activity between 1300 hr to 1600 hr at chettalli

Pandey and Tripathi (2003) reported that A. cerana indicashowed the highest frequency ofvisits followed by A. dorsata, A. melliferaand A. floreain mustard. Regarding the time spentof A. dorsata worker took the least time followed by A. mellifera, A. cerana indica and A.florea.

2.3 EFFECTIVENESS OF DIFFERENT BEE ATTRACTANTS INATTRACTING THE BEES

Woodrow et al. (1965) screened the natural and synthetic materials as attractantsand repellents of A. mellifera by observing response of bees to their vapours. Out of 195formulations tested, four were rated as weak to moderate attractants and 19 were moderateto very strong repellents (materials viz., alcohols and one fatty acid having more carbonatoms).

Williams et al. (1981) reported that nasonov pheromone of honey bee comprised ofseven components, among these, the presence of 'foot print pheromone' enhanced theattractiveness of synthetic nasonov pheromone. They opined that this could prove useful inattracting the honey bees to the crops, needing pollination.

Marglith et al.(1984) revealed that Bee line was totally ineffective in attracting bees tomaternal parent of Dallia under summer conditions in coastal plain of Israel.

Bee scent and Bee scent plus when applied on blooming pear, plum and appleincreased the number of foraging honey bees (Apis mellifera) and fruit set in treated plots asreported by Mayer et al. (1989a).

Looper and Rossette (1991) conducted the field trials on two adjacent fields ofCitrullus lanatus L. in Arizona, USA, in which honey bees were introduced at a stockingdensity of two colonies/acre. Bee-scent was sprayed over alternate strips of 18 row in onefield and the other field without spray. Though, bee visitation was high on the day ofapplication but did not reflected in yield

Allsopp and Cherry (1991) studied the attraction of A. melliferato volatile compoundsand they concluded that anetholes and commercial traces of Japanese beetle lure (10:22:11,

2 phenyl ethyl propionate:eugenol:geraniol) exposed in trace in Japanese beetle trapsattracted A. melliferabut other floral lures and fatty acids did not attract the bees.

Two application of Bee-scent (a liquid formulation containing 9.00 per centpheromone and 40.00 per cent other natural attractants) on watermelon cultivars in Florida,increased total fruit yield in one farm with the treatment up to 3000 fruits/acre compared to1500 fruits/acre without treatment and there was apparent increase in early yield in threefarms. The soluble solid contents of fruit were not affected by the treatment. The number ofseeds per fruit was higher with treatment on three frames (Elmstorm and Maynard, 1991).

Henning et al. (1992) studied behavioural responses of A. melliferato primary alfalfafloral volatiles in a screened flight chamber. They found that linalool was the only compoundattractive to honey bees at the optimised concentration. Two other compounds, 3-octanoneand methyl salicylate were repellents. The remaining two compounds cis-3-hexenyl acetoneand ocimine were neither attractive nor repellent.

Ortiz-Sanchoz (1993) reported that the efficacy of Bee-here (Nasonov pheromoneother honey bee attractant and control release formulation aids) as honey bee attractant tomarrow crop (Cucurbita pepoL.) grown in greenhouse conditions in Almeria, Spain. Honeybee counts were made on plants sprayed with recommended dose of attractant (3.00 ml/lit),plants sprayed with half the dose, plants sprayed with water and untreated plants. The beesdid not exhibit preference for any experimental treatment indicating that this product beingineffective as a honey bee attractant to marrow flowers

Schultheis et al. (1994) evaluated two commercial bee attractants like Bee-scent andBee-line on cucumber and watermelon. They found that these attractants did increase the

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yield and also bee visitation. Similarly, Ambrose et al. (1995) evaluated Bee-line as honeybee feeding stimulant on watermelon and Bee-scent as worker bee attractant on bothcucumber and watermelon. They found that these attractants neither increased the beeactivity on vine crop when compared to untreated control nor they increase the value ofsubsequent harvest.

According to Higo et al. (1995) a combination of increased recruitment of foragersand greater time spent by foragers with increased flower visitation contributed to theenhanced pollination of blooming crops treated with Fruit boost.

Evans et al. (1995), reported that lure (contain liver and sodium sulfide) had nosignificant effect in improving carrot seed weight.

Singh and Sinha (1996) reported that Bee-Q failed to attract additional honey bees tothe treated plots compared to the untreated plots on sunflower in Haryana.

Zvendenok (1996) treating the onion with secondary attractants viz., citral, geranoil,limonene and carrot seed extract can significantly improve pollination in which citral 0.100.30 per cent having the greatest effect.

Nakamura (1997) reported that bee line and bee scent could be used to attract beesto areas small enough to be sprayed with effective of them. However, attempts by Tsirakoglouet al. (1997) to direct honey bee to kiwi flowers by spraying bee-here showed no difference in

bee visit between sprayed and control treatments.

Viraktamath and Patil (1999) studied the influence of bee-Q and bee-here on beevisitation and yield parameters of sesamum at Dharwad. Bee visitation increased significantlyon the sprayed crop up to 5

thday after 1

stand 2

ndsprays

Lingappa et al. (1999) reported that an increases of 21.80 and 31.80 per cent in thenumber of fruits formed and total yield, respectively when Bee-Q was sprayed twice onwatermelon.

Tew and Ferree (1999) studied over 4 years (1991-1994) in Ohio, USA anddetermined that Bee scent is a effective synthetic foraging attractant for bees. Treated appletrees showed a significantly larger number of bees compared to the control trees in 1991,1993 and 1994.

Application of Bee-Q @ 12.50 and 15.00 g/l resulted in higher yield (19.56 and 19.45t/ha respectively), maximum good fruits, minimum malformed fruits and higher size andweight in watermelon (Sattigi et al., 2001a). Spraying of Bee-Q (12.5 g/l) and bee-here (4 ml/l)on sesamum increased bee visitation on sprayed crop up to 5

thday, resulted in significantly

higher yield at Dharwad (Patil, 1999 and Patil et al., 2000).

Application of Bee-Q (12.50 g/l) on niger increased the number of seeds/ capsule(ranged from 24.41 to 29.26) and oil content (38.10%) as compared to control (Sattigi et al.,2001b).

Kalmath and Sattigi (2002) reported that spraying of Cacambe (10 %) and jaggery(10%) attracted maximum number of A. dorsataup to 15 days after first and second sprayBee-Q (1.25%) and sugar solution were the next best attractants.

Application of Fruit boost and Bee-Q attracted more bees to sunflower than

unsprayed crop (Viraktamath and Patil, 2002).A wide range of pollinators including A. melleferavisited umbles sprayed with rose

water and spent more time for foraging than they did in unsprayed umbels . (Alshaff, 2002)

Viraktamath and Anagoudar (2002) reported that two applications of Bee-Q (12.5g/l), Bee-here (4 ml/l) and sugar solution (10 %) on staminate flowers of Cucumis sativaL.noticed more number of bees (4.01 to 4.97 bees/flower.5 min.) up to 5 days after first andsecond sprays compared to unsprayed crop (3.25 to 3.59 bees). Similarly, higher visitationwas recorded on pistillate flowers on the sprayed crop.

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Naik et al., (2003) reported that sugar syrup containing extract of dried fruits ofFagara budrunga plant were more attractive to A. cerana than sugar syrup. According toManjunath (2003) spraying of fruit boost and Bee-Q significantly enhanced visitation by A.dorsata, A.cerana, A. mellifera and other pollinators.However, attractants lost their efficacyafter 5 days of spraying in sunflower.

Malerbo Souza et al. (2004) reported that Bee here, eugenol, geranol, citral, andlemon grass extracts diluted in water were effective in attracting bees to sweet orangeorchards.

Nidagundi (2004) reported that spraying Cacambe @ 10 per cent , Bee-Q @ 1.25 percent and jaggery solution @ 10 percent enhanced bee visitation to the flowers of bitter gourd.

2.4 EFFECT OF BEE POLLINATION IN RELATION TOQUANTITATIVE AND QUALITATIVE PARAMETERS OFRADISH SEED

Kermer (1945) reported that radish crop within 3.2 km from honey bee coloniesyielded about 448 to 673 kg per hectare whereas, crop which was 3.2 km away from beecolonies yielded 224 to 336 kg per hectare.

Olsson (1952) recorded flower set of 64.7 per cent of cauliflower with 2.46 seeds per

pod and 1.75 gram per pod with bees excluded plots whereas bees included plots thesevalues were increased to 95.3, 4.08 and 2.69, respectively.

Froster et al. (1973) observed that caging Brassica oleracea during flowering toexclude honey bees and bumble bees had the lower seed yield, half the weight of seeds perplant and reduced number of flowers per plant by fifth.

Landridge and Goodman (1975) observed that the open pollinated plot of oil seedrape produced 50 per cent more seeds and 46 per cent more seed weight per plant than plotsfrom which these insects had been excluded. The weight of 1000 seeds was significantlygreater in the enclosed plots than in the opened ones.

Lerin (1982) reported that the number of pods and seeds per pod on the main shootof rape was greatly increased by insect pollination. Insect pollination reduced variability inyield components on a whole plant basis and increases homogeneity of maturity.

Verma and Joshi (1983) reported that the comparison of honey bee pollination withother insects pollination on mustard bloom, the honey bee pollination increased the pod setby 74.30 per cent and number of seeds by 4.07 per pod. The weight of single seed increasedby 0.19 mg.

Bisht et al. (1983) reported that the rape plants visited by insect pollinators yielded472 pods per plant and 14 seeds per pod. Whereas, plants caged to exclude insects yielded37 pods per plant and 3 seeds per pod.

Sihag (1986) noticed that the pod length, number of pods per plant, number of seedsper pod, weight of the seeds per plant and seed yield per hectare were significantly higher inopen pollinated plots of Brassica compesris var.toria, Brassica var.prakash, Brassica rapa,

Brassica oleracea var.botrytisand eruca sativa(6.92 0.85 cm, 9.71 73.39, 15.01 3.96,

354.75 80.31 g and 1219 394 kg respectively) compared to caged plots (2.16 0.35 cm,

26 5.88, 3.03 0.27, 2.42 1.03 g and 10 1 kg respectively ) at Hissar.

Khan and Chaudhary (1988) reported that sarson plants pollinated by A. ceranahadhigher seed weight per plant (67.2 to 90.02 g) followed by other insect pollinators (41.72 to56.35 g) and lowest was record in self pollination (20.46 to 34.34).

Goyal et al. (1989) opined that intensive bee pollination in carrot increased the yieldfrom 59.95 to 64.42 per cent in inter-varietal trials and 70.33 to 73.62 per cent in intra-varietaltrial over the control. The number of seeds per flower (2.36) per cent seed set (90.47) and percent seed germination (77.79) in bee pollinated onion crop was significantly higher than thenet caged and muslin cloth caged flowers. Seed yield was 83.81, 29.71 and 2.23 times higher

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under bee pollinated, open pollinated and net caged umbels; respectively than under clothbagging (Kumar et al., 1989).

Prasad et al. (1989) reported that the plots without any pollinator had the lowestsiliqua per cent (48.3%), which obtained the maximum siliqua length (92.65 mm) ascompared to other treatments. The plots access to all the pollinators showed the maximumsiliqua per plant (75.8%), which is closely followed by plots caged with honey bees (72.3%).The open pollinated plots had the maximum number of seeds per siliqua (10.58) with highesttest weight.

Singh and Chamotre (1992) reported that average number of pods per plant, seedsper siliqua and seed yield per plant was maximum in open pollinated plants of radish (375.55,6.15and 26.20 g respectively) compared to hand pollinated (222.60, 4.96 and 15.65respectively) and naturally selfed (90.50, 3.99 and 5.77 g respectively) 1000 seeds weightwere maximum in hand pollinated (20.64 g) compared to naturally selfed (20.44g) and openpollinated plants (15.75 g)

Verma and Poghat (1994) revealed that seed set, number of seeds per pod and 100seed weight were maximum in open pollinated radish, intermediate in wind-pollinated plotsand minimum in self-pollinated plots.

Uma and Verma (1994) reported that pod set per plant (44.9%), number of seeds perpod (42.3%), 1000 seeds weight (44.5 g) and germination rate (72.7%) were significantly high

in bee pollinated radish plants over open-pollination. There was no pod set in control plot.

Chand and Singh (1995) reported that the mustard plots caged without any pollinatorhad lowest seed yield (966 kg / ha). Whereas, the free access to all the pollinator showed themaximum yield (1620 kg / ha) followed by plots caged with honey bees (1160 kg / ha)

Priti et al. (2001) reported that fruit set was 81 per cent and 56.55 per cent, siliqualength 13.2 and 6.8 cm, number of seeds per pod was 8.6 and 4.8 and seed weight 1.5 and0.9 grams in bee pollinated and self pollinated radish, respectively.

Kapila et al. (2002) reported that open pollinated plants of radish and greater numberof grains per siliqua, seed yield per plant, 100 seed weight, seed set. And root length than thecaged plants, indicating the positive effects of insect pollination on seed production andquality.

Abel et al. (2003) observed that in Brassica rapaaccession PI 392025 and Brassicanapusaccession PI 469944, produced significantly more seeds when pollinated by Osmialanigera sub sp. Lignariathan Osmia cornifronsRadoszkowski.

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III. MATERIAL AND METHODS

The present investigations were carried out in farmers field at Marewada village nearby University of Agricultural Sciences, Dharwad.

Marewada is located 10 km from Dharwad, just interior to Bijapur Dharwad road.Dharwad is located 1526 North latitude, 7507 East longitude and at an altitude of 731.80

meters above the mean sea level (MSL). This lies in the northern transitional zone, whichreceives an average annual rainfall of 751 mm distributed well over the season. The averagetemperature and relative humidity ranges from 11 to 37C and 40 to 85 per cent, respectively.


The study was made on crop raised during rabi-summer season of 2004-05.The experimental plot was kept free from any spray during flowering period. Five spots of 1m

2area were selected randomly for observation.

Observations were made for different groups of pollinators visiting the radish fieldduring peak flowering at 0600, 1000, 1200, 1400 and 1600 hr of the day for five minutes ineach of the five spots. So also, unidentified pollinators were collected by using standardinsect collecting hand net. The collected pollinators were pinned, labeled and later identifiedwith the help of specialists. The collected data were later averaged time wise and group wiseto infer the pollinator fauna as well as the dominance of particular group. The weather datalike temperature, humidity and rainfall were also recorded to correlate with the presence ofpollinators.

3.2 FORAGING ACTIVITY OF BEES AND OTHERPOLLINATORS IN RADISH

The study was made on crop raised during rabi-summerseason of 2004-05 in theunsprayed plots of the crop raised for studying pollinator fauna.

The observations were made at two hourly intervals from 0600 to 1800 h. Ten spotsof 1 m

2area were selected randomly and number of different species of bees visiting were

counted for five minutes. Such observations were taken from 5 per cent flowering at 4 daysinterval for 5 times. Further, the data were averaged time wise and species wise to assess

most favourable period of the day for bee species to visit the radish flower and most dominantspecies in a day and at particular time of the day.

3.3 EFFECTIVENESS OF DIFFERENT BEE ATTRACTANTS INATTRACTING THE BEES

The experiment was laid out in Randomised Block Design (RBD) with seventreatments replicated thrice. The variety used was Pusa Chekti. The treatment details are asfollows;

T1 - Crop sprayed with Cacambe @ 10%

T2 - Crop sprayed with Bee-Q @ 1.25 %

T3 - Crop sprayed with Sugarcane juice @ 10%

T4 - Crop sprayed with Sugar solution @ 10%

T5 - Crop sprayed with Jaggery solution @ 10%

T6 - Crop sprayed with Molasses @ 10%

T7 - Crop without any spray

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Plot size : 4.2 X 3 m

Spacing : 30 X 10 cm

Treatments : 7

Replications : 3

Design : Randomized Block Design (RBD)

Crop was raised by following recommended package of practices in RBD having 4.2x 3m plot size, which was replicated thrice. The crop was sown with spacing of 30 x10 cm between rows and between plants, respectively. Later, all the attractants were sprayedat 5 per cent flowering of the crop. The attractants were sprayed twice at an interval of 15days starting from 5 per cent flowering of the crop. In each plot, one square meter area wasrandomly selected and number of different species of pollinators visiting these flowers per fiveminute were recorded at 0800, 1000, 1200, 1400 and 1600 hr. Such observations were madea day before the spray and 1, 3 and 5 days after each spray. Mean of all the observationswere pooled for different bee pollinators separately. The data were subjected to suitable

statistical analysis for inference after (+1) transformation.

3.4 EFFECT OF BEE POLLINATION ON QUANTITATIVE AND

QUALITATIVE PARAMETERS OF RADISH SEED

The experiment was laid out in RBD with nine treatments and replicated thrice. Thevariety used was Pusa chekti. The treatment details as below

T1 - Crop caged with bees

T2 - Crop caged without bees

T3 - Crop sprayed with Cacambe @ 10%

T4 - Crop sprayed with Bee-Q @ 1.25 %

T5 - Crop sprayed with Sugar solution @ 10%

T6 - Crop sprayed with Jaggery solution @ 10%

T7 - Crop sprayed with Molasses @ 10%

T8 Crop sprayed with Sugarcane juice @ 10%

T9 - Crop without any spray

This study was carried out in rabi summer 2004-05 and experiment was laid out asmentioned in 3.3 with addition of two treatments (T1 and T2), T1 and T2 were caged before thestart of flowering during night to eliminate natural pollinators (Plate ). Later all the treatments(T3-T8) were imposed at 5 per cent flowering of the crop. Spraying of attractants was done twotimes at fifteen days intervals starting from 5 per cent flowering of the crop. Bee hive withback and front entrance was kept open in one boundary of cage to facilitate the bees to movein and out of the cage (Plate ). The cage was removed after completion of flowering. In order

to study the effect of bee pollination in enhancing the productivity and quality of radish seeds,the following quantitative and qualitative parameters were recorded from each treatment.

3.4.1 Quantitative parameters

3.4.1.1 Number of seeds per siliqua

The number of seeds present in the siliqua were counted and expressed as seedsper siliqua. Observation was made on 10 randomly selected plant per treatment.

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3.4.1.2 Number of siliqua per plant

The observations made by selecting ten plants at random from each treatment. Andnumber of siliqua in each plant was recorded and expressed as mean number of siliqua perplant

3.4.1.3 Thousand seed weight (Test weight)

The observation was made by weighing 1000 dried seeds drawn randomly from eachtreatment using a electronic balance. The data were subjected to statistical analysis

3.4.1.4 Percent filled and unfilled seeds

The observation is made by collecting ten randomly selected pods were separatedfrom plots. The total numbers of filled and unfilled seeds in each siliqua were counted. Theratio of filled seed to the number of unfilled seeds per siliqua was calculated and expressed inper cent.

3.4.1.5 Seed yield per plant

After maturity, the pods of ten plants in each treatment were removed. The seedswere separated by thrashing the siliqua and weight was recorded by using electronic balancewhich expressed in grams per plant. The seed yield obtained from the plots was laterconverted into qtls per ha basis.

All the data were subjected to statistical analysis after suitable transformations (+1for numbers and A sine for per cent)

3.4.2 Qualitative parameter

3.4.2.1 Germination percentage

Hundred seeds obtained from the different treatments were taken and were placed ongermination paper in germination chamber at 27.60

oC and 80 per cent relative humidity. The

germination count was made 6 days after incubation. The seedlings were classified intonormal, abnormal, dead and diseased seedlings. The germination percentage was expressedbased on the number of seedlings obtained in the test out of total seed yield. The data weresubjected to statistical analysis after A sine transformation to draw the inference

3.4.2.2 Seedling vigour

For evaluating the vigour of seedling, all the seedlings were considered from eachtreatment and length of shoot and root were measured. The data was averaged per treatmentafter totaling. The data was subjected to statistical analysis

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Plate 1: General view of radish seed production experimental plot withcages

Plate 2: Close view of bee box placed on one border of cage with bothside entrance

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IV. EXPERIMENTAL RESULTS

The results of the present investigation carried out on pollinator fauna of radish,foraging activity of bees, effectiveness of different bee attractants and their effect onquantitative and qualitative parameters of radish seeds are presented here under.


List of pollinators that visited radish flowers is presented in Table 1.

As many as 16 species of pollinators were recorded during present study, of these 7belonged to Hymenoptera, 4 to Diptera, 4 to Lepidoptera and 1 to Coleoptera. Among thetotal of 461.01 (Table 5) pollinators recorded, A. floreawas most dominant constituting 42.20per cent followed by A. cerana(27.60%), A. dorsata(14.62%) and others (15.57%).

4.2 FORAGING ACTIVITY OF HONEY BEES AND OTHERPOLLINATORS ON RADISH

4.2.1 Foraging activity of A. floreaon radish

The foraging activity of A. floreaon radish was observed from 0600 to 1800 hr from 5

per cent flowering i.e., at 4 days after flowering to 20 days after flowering. On 4

th

day afterflowering, foraging activity commenced from 0800 hr with 3.55 bees/sq. m/5 min (Table 2).The activity of bees was not seen at 0600 hr. It attained a peak (5.23/bees/sq. m/5 min) at1200 hr however it remained more or less uniform up to 1400 hr and there after it decreased.The lowest foraging activity was noticed at 1800 hr with 2.80/bees/sq. m/5 min.

On 8th

day after flowering, the activity of bees was noticed from 0800 hr with4.62/bees/sq. m/5 min. However, there was no bees activity observed at 0600 hr. The peakactivity of bees with 8.20 bees/sq. m/5 min was observed at 1000 hr and it remained more orless uniform up to 1400 hr and there after it decreased gradually to reach the lowest activity at1800 hr which recorded 4.67 bees/sq. m/5 min. Similar trend was observed on 12

thday after

flowering and 16th

day after flowering. However, on 20th

day after flowering the peak activity ofbees with 7.13 bees/sq. m/5 min was observed at 1000 hr and remained more or less uniformeven upto 1400h. Later the activity gradually decreased and reached minimum of 4.48 to 4.79bees/sq. m/5 min between 1600 to 1800 hr and there was no activity observed at 0600 hr.

The highest activity was recorded (6.83 to 8.62 bees/sq. m/5 min) between 1000 to 1400 h,there after the activity was almost decreased.

The comparative foraging activity of little bee during different days from 5 per centflowering indicated that the total number of little bees that visited the radish during theflowering period were 194.55 bees/sq. m/5 min from five observation. On 4

thday after

flowering, (5% flowering), little bees visited the radish with an average of 3.68 bees/sq. m/5min and it increased gradually and attained peak on 16

thday after flowering with an average

of 7.79 bees/sq. m/5 min, there after, it reduced to an average of 4.83 bees/sq. m/5 min on20

thday after flowering.

Similarly, when the bee foraging activity was compared between different hours of theday, the little bee started visiting the radish at 0800h with an average 5.72 bees/sq. m/5 min.It suddenly increased and peak activity was observed at 1000 hr with an average of 8.62

bees/sq. m/5 min. The activity of bees was almost same up to 1400 hr and than decreased.The lowest activity was observed at 1800h with an average of 4.67 bees/sq. m/5 min (Table2).

4.2.2 Foraging Activity of A. dorsataon radish

The foraging activity on 4th

day after flower (5% flowering) started at 0600 hr with 0.40bees/sq. m/5 min and maximum activity was attained at 1400 hr (2.08 bees/sq. m/5 min) thanthe activity decreased suddenly at 1600 and 1800 hr with 1.84 and 1.37 bees/sq. m/5 min,respectively (Table 3).

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Table 1. Pollinator fauna of radish

SL. No. Pollinator Systematic position

1. Apis floreaF. Apidae : Hymenoptera

2. A. ceranaF. Apidae : Hymenoptera

3. A. dorsataF. Apidae : Hymenoptera

4. Halictussp. Halictidae : Hymenoptera5. Nomiasp. Halictidae : Hymenoptera

6.

7.

8.

9.

10.

11.

12.

13.

14.

15.

16.

Eumenissp.

Bombus terrestrisL.

Musca domesticaL.

Eristalissp.

Helophilaus qaudrivittatus(Widermann)

Chrysomyasp.

Coccinella septumpunctata

Pieris brassicaeL.

Maruca testulalisGeyer

Danaus chrysiphusL.

Lampides boeticusL.

Vespidae : Hymenoptera

Bombicidae : Hymenoptera

Muscidae : Diptera

Syrphidae : Diptera

Syrphidae : Diptera

Callliphoridae : Diptera

Coccinellidae : Coleoptera

Pieridae : Lepidoptera

Pyraustidae : Lepidoptera

Danidae : Lepidoptera

Lycaenidae : Lepidoptera

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Plate 3: Apis floreaon radish flower

Plate 4: Apis dorsataon radish flower

On 8th

day after flowering, foraging activity started at 0600 hr with 0.70 bees/sq. m/5min and gradually increased to 2.17 bees/sq. m/5 min at 1200 hr and reached maximum at

1400 hr (2.42 bees/sq. m/5 min). Later, it gradually decreased and reached minimum activityof 1.44 bees/sq. m/5 min at 1800 hr.

Similar trend was observed on 12th

day after flowering. The rock bee activitycommenced at 0600 hr with 0.80 bees/sq. m/5 min and maximum activity was recorded (2.47to 3.08 bees/sq. m/5 min) between 1000 to 1400 hr.

On 16th

day after flowering, foraging activity started at 0600 hr with 0.20 bees/sq. m/5min and less activity of 2.10 bees/sq. m/5 m was found at 0800 hr. The activity graduallyincreased and reached to 3.94 bees/sq. m/5 min at 1400 hr. Later, it suddenly decreased andrecorded minimum activity of 1.70 bees/sq. m/5 min at 1800 hr.

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Plate 5: Eumenissp. on radish flower

Plate 6: Danaus chrysippuson radish flower

Plate 7: Chrysomyasp. on radish flower

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Table 2. Foraging activity of A. floreaon radish

Number of bees/sq mt/5 minTime of observation(hours) 4 DAF 8 DAF 12 DAF 16 DAF 20 DAF

0600 0.00 0.00 0.00 0.00 0.00

0800 3.55 4.62 6.80 7.43 6.20

1000 4.81 8.20 10.43 12.55 7.13

1200 5.23 6.56 8.43 10.64 5.98

1400 5.12 6.28 7.84 9.68 5.24

1600 4.28 5.16 6.45 8.16 4.48

1800 2.80 4.67 4.98 6.06 4.79

Total 25.79 35.49 44.93 54.52 33.82

Average 3.68 5.07 6.41 7.79 4.83

DAF Days after flowering

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Table 3. Foraging activity of A. dorsataon radish


0600 0.40 0.70 0.80 0.20 0.30

0800 1.18 1.84 1.95 2.10 1.98

1000 1.96 2.27 2.47 3.45 2.16

1200 1.98 2.17 2.86 3.10 2.52

1400 2.08 2.42 3.08 3.94 2.30

1600 1.84 1.68 1.98 2.64 1.46

1800 1.37 1.44 1.67 1.70 1.43

Total 10.81 12.52 14.81 17.13 12.15

Average 1.54 1.78 2.11 2.44 1.73


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Table 4. Foraging activity of A. ceranaon radish


0600 0.00 0.80 1.20 0.40 0.20

0800 1.95 3.08 3.80 4.10 3.24

1000 2.75 3.18 5.16 5.80 3.40

1200 5.18 6.42 7.95 8.32 3.35

1400 4.10 5.80 7.10 7.80 3.40

1600 2.48 2.80 4.18 5.95 2.68

1800 1.25 1.64 2.15 3.82 1.80

Total 17.71 23.72 31.54 36.19 18.07

Average 2.53 3.38 4.50 5.17 2.58


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Table 5. Foraging activity of other pollinatorson radish

Other pollinators/sq mt/5 minTime of observation(hours) 4 DAF 8 DAF 12 DAF 16 DAF 20 DAF

0600 1.58 2.16 2.76 2.28 2.38

0800 2.28 2.44 2.88 2.58 1.98

1000 1.65 2.84 2.53 2.56 2.18

1200 1.48 1.64 1.42 1.80 1.72

1400 1.14 0.84 1.38 1.61 1.70

1600 1.74 2.14 2.34 2.48 2.10

1800 1.81 2.20 2.42 2.63 2.14

Total 11.68 14.26 15.73 15.94 14.20

Average 1.67 2.03 2.25 2.78 2.02


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Table 6. Comparative foraging behaviour of different pollinator spec

Number of different pollinators species/sq mt/5 mTime of observation(hours)

A. florea A. dorsata A. cerana Others To

0600 0.00 2.40 2.60 11.16 16

0800 28.60 9.05 16.17 12.16 65

1000 43.12 12.31 20.29 11.76 87

1200 36.84 12.88 31.22 8.06 89

1400 34.16 13.57 28.20 6.67 82

1600 28.53 9.60 18.09 10.80 67

1800 23.30 7.61 10.66 11.20 52

Total 194.55 67.42 127.23 71.81 461

Average 27.80 9.63 18.17 12.26 65

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Table 7. Influence of attractants on visitation of A. florea

Bee visits/sq mt/5 min

1st spray (5% flowering) 2nd spray flowerin

Sl.No

Treatments

1 DBS 1 DAS 3 DAS 5DAS 1 DBSS 1 D

1Crop sprayed with Cacambe(10%)

3.90a 14.78a 26.58a 17.16a 8.30a 27

2Crop sprayed with Bee-Q(1.25%)

4.20a 9.26c 17.56c 15.90b 7.06a 18

3Crop sprayed withSugarcane juice (10%)

4.40a 7.82cd 10.41d 7.76c 6.24ab 17

4Crop sprayed with Sugarsolution (10%)

3.75a 7.55cd 11.63d 11.13b 5.93b 18

5Crop sprayed with Jaggery(10%)

3.97a 11.57b 20.63b 12.84b 8.29a 21

6Crop sprayed with Molasses(10%)

3.85a 6.57d 8.27e 6.38c 6.01b 10

7 Crop with out any spray 3.66a 4.88e 5.62f 5.76c 5.30b 7

DBS Day before spray : DAS Day after spray Means followed by same letter in the column do not differ sig

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On 20th

day after flowering, activity started at 0600 hr with 0.30 bees/sq. m/5 min andpeak activity was noticed at 1200 hr (2.52 bees/sq. m/5 min) and there after it graduallydecreased and least activity was observed at 1800 hr (1.43 bees/sq. m/5 min).

Further, on an average total of 67.42/rock bees/sq. m/5 min visited the radish duringa period of 5 days in the present study. The comparative study indicated that the averageforaging activity of rock bees in a day was 1.54 bees/sq. m/5 min on 4

thday after flowering

and peak activity was attained on 16 days after flowering (2.44 bees/sq. m/5 min) anddecreased to 1.73 bees/sq. m/5 min on 20th

days after flowering i.e., at the end of flowering.

When foraging activity of rock bee was compared between different hours of the day,the activity began with an average of 0.48 bees/sq. m/5 min at 0600 hr and increasedgradually reaching its peak at 1400 hr with 2.76 bees/sq. m/5 min and decreased to 1.52bees/sq. m/5 min at 1800 hr (Table 3).

4.2.3 Foraging activity of Indian bee, A. ceranaon radish

The foraging activity on 4th

day after flowering started at 0800 hr with 1.95 bees /sq.m/5 min, which indicated that there was no activity at 0600 hr. Later, it gradually increasedand reached the peak at 1200 hr (5.18 bees/sq. m/5 min). Further, the activity decreasedsuddenly to 2.48 and 1.25 bees/sq. m/5 min at 1600 and 1800 h, respectively.

On 8

th

day after flowering, the bee activity started earlier at 0600 hr with 0.80 bees/sq.m/5 min. It gradually increased and reached the peak at 1200 hr (6.42 bees/sq. m/5 min) andmore or less uniform activity was observed at 1400 hr. Further, it suddenly decreased (2.80and 1.64 bees/sq. m/5 min) at 1600 and 1800 h, respectively.

On 12th

day after flowering, the foraging activity started at 0600 hr with 1.20 bees/sq.m/5 min. It suddenly increased to 5.16 bees/sq. m/5 min at 1000 hr and attained a peakbetween 1200 to 1400 hr (7.10 to 7.95 bees/sq. m/5 min). Thereafter, activity decreased andlowest activity was observed at 1800 hr (2.15 bees/sq. m/5 min).

On 16th

day after flowering, foraging activity was observed throughout the day, whichranged from minimum of 0.40 and maximum of 8.32 bees/sq. m/5 min at 0600 and 1200 h,respectively. Thereafter, activity decreased to 7.80 to 3.82 bees/sq. m/5 min at 1400 to 1800h, respectively. On 20

thday after flowering, once again activity was observed throughout the

day with peak activity at 1000 hr of the day (3.40 bees/sq.m /5 min) and more or less same

activity was observed up to 1400 hr and then decreased gradually.

The foraging activity gradually increased from 4th

day after flowering and activity waspeak on 12

thand 16

thday after flowering and then declined on 20

thday after flowering.

The foraging activity at different hours of the day indicated that the activitycommenced at 0600 hr with an average of 0.52 bees/sq. m/5 min. The maximum activity wasfound between 1000 to 1200 hr which ranged with an average of 4.05 to 6.24 bees/sq. m/5min. Foraging activity at 1400 hr was almost similar with 5.64 bees/sq. m/5 min and thereafterdecreased to 2.13 bees/sq. m/5 min at 1800 hr (Table 4).

4.2.4 Foraging activity of other pollinators on radish

On the 4th

day after flowering, foraging activity of other pollinators (other than honeybees) was observed throughout the day with the peak activity at 0800 hr (2.28 pollinators /sq.m/ 5 min) and thereafter it started decreasing and reached the lowest of 1.14 pollinators /sq.m/ 5 min at 1400 hr. Once again the activity was regained slightly with 1.74 and 1.81pollinators /sq. m/5 min at 1600 and 1800 h, respectively.

On 8th

day after flowering, foraging activity of other pollinators observed from 0600 to1800 hr. The peak activity was observed at 1000 hr (2.84 pollinators /sq. m/5 min) andthereafter decreased gradually and least pollinators were observed at 1400 hr (0.84pollinators /sq. m/5 min) and than activity was regained at 1600 and 1800 hr (2.14 to 2.20pollinators /sq. m/5 min).

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On 12th

day after flowering, other pollinators started visiting the radish at 0600 hr with2.76 pollinators /sq. m/5 min, the activity was attained peak at 0800 hr (2.88 pollinators /sq.m/5 min) and it gradually decreased to 1.38 pollinators /sq. m/5 min at 1400 h, but at 1600 to1800 hr again activity was regained which ranged from 2.34 to 2.42pollinators /sq. m/5 min.Similar trend in the activity of pollinators was observed on 16

thday after flowering with a peak

at 0800 (2.58 pollinators /sq. m/5 min). However, on 20th

day after flowering, the activity ofother pollinators started at 0600 hr with 2.38 pollinators /sq. m/5 min which was the peak

activity and at 1200 hr once again the activity gradually increased and formed second peak at1800 hr (2.14 pollinators /sq. m/5 min).

On an average, the total number of other pollinator was 71.81 pollinators/sq. m /5 minfor observation period of 5 days. The foraging activity at different hours of the daycommenced at 0600 hr with an average of 2.23 pollinators/sq. m/5 min. The maximum activitywas found between 0800 to 1000 hr which ranged with an average of 2.35 to 2.43pollinators/sq. m/5 min. Thereafter, it decreased to reach a minimum activity at 1400 hr (1.33pollinators /sq. m/5 min), but once again the activity gradually regained with 2.16 and 2.24pollinators /sq. m/5 min at 1600 to 1800 h, respectively. On an average, 1.67 pollinators /sq.m/5 min were observed during 4

thday after flowering and pollinators activity increased

gradually and attained maximum on 12th

and 16th

day after flowering with 2.25 and 2.78pollinators /sq. m/5 min respectively and activity decreased to 2.02 pollinators /sq. m/5 minon 20

thday after flowering (Table 5).

4.2.5 Comparative foraging Activity of different bees species

The comparative foraging activity of different honey bees species indicated thatamong the 4 groups, A. florea was more predominant as bees visited with an average of27.80 bees /sq. m/5 min followed by A. cerana(18.17 bees /sq. m/5 min) and other pollinators(12.26 bees/sq. m/5 min). Least was A. dorsatawith 9.63 bees/sq. m/5 min, no A. melliferaand T. iridipenniswere observed visiting the radish during the study period.

Among different honey bees species the foraging activity of A. floreawas maximumbetween 1000 to 1400 hr (34.16 to 43.12 bees /sq. m/5 min). Whereas, A. ceranaactivitystarted at 0600 hr but the peak activity was noticed at 1200 hr (31.22 bees/sq. m/5 min).Further, foraging activity of A. dorsatawas more between 1000 hr to 1400 hr (12.31 to 13.57bees/sq. m/5 min). Similarly, the foraging activity of other pollinators was maximum between0600 to 1000 hr and 1600 to 1800 hr which ranged from 10.80 to 12.16 pollinators/sq. m/5min. It was less between 1200 to 1400 hr with 6.67 to 8.06 pollinators/sq. m/5 min. On anaverage, the overall foraging activity of bees was maximum between 1000 to 1400 hr (Table6).

4.3 EFFECTIVENESS OF DIFFERENT BEE ATTRACTANTS INATTRACTING THE BEES TO RADISH

4.3.1 Influence of attractants on visitation of A. florea

Observations were recorded on A. florea visitation to radish sprayed with differentbee attractants at 5 per cent flowering and 15 days after 1

stspray are presented here under

(Table 7).

4.3.1.1 First spray

A day before the first spray, the number of bees visiting the radish flowers rangedfrom 3.66 to 4.40 bees/sq. m/5 min and did not differ significantly among treatments. A dayafter first spray, cacambe @ 10 per cent attracted more number of bees (14.78 bees/sq. m/5min) and was significantly superior over rest of the treatments and sprayed with 10 per centjaggery solution recorded 11.57 bees/sq. m/5 min which was the next best treatment and wason par with Bee-Q @ 1.25 per cent. This was followed by 10 per cent sugar solution, sugarcane juice (10%) and molasses (10%) which recorded the bees which ranged from 6.57 to7.82 bees/sq. m/5 min. However, least number of bees were observed in untreated control(4.88 bees/sq. m/5 min).

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On 3rd

day after first spray, 10 per cent cacambe recorded maximum number of bees(26.58 bees/sq. m/5 min) followed by jaggery @ 10 per cent (20.63 bees/sq. m /5 min).Further, Bee-Q @ 1.25 per cent was next best (17.56 bees/sq. m/5 min) treatment inattracting bees. This was followed by 10 per cent sugar solution which recorded.11.63bees/sq. m/5 min and 10 per cent sugarcane juice (10.41 bees/sq. m/5 min). Whereas,molasses @ 10 per cent recorded 8.27 bees/sq. m/5 min which found superior over untreatedcontrol which recorded 5.62 bees/sq. m/5 min.

On 5th day after first spray, once again cacambe (10%) recorded significantly highernumber of bees (17.16 bees/sq. m/5 min).. The next best treatments were Bee-Q @ 1.25 percent, jaggery solution (10%) and sugar solution (10%) which recorded 15.90, 12.84 and 11.13bees/sq. m/5 m, respectively. This was followed by sugarcane juice (10%) and molasses(10%) which recorded 7.76 and 6.38 bees/sq. m/5 min, respectively and these two treatmentsfound superior over untreated control which recorded 5.76 bees/sq. m/5 min.

4.3.1.2 Second spray

One day before second spray, cacambe (10%) was superior over untreated control,sugar solution (10%) and Molasses (10%) which were on par with jaggery (10%). Bee-Q(1.25%) and sugar cane juice (10%) which recorded bees visitation ranging from 5.30 to 8.30bees/sq. m/5 min.

A day after second spray, treatment with cacambe @ 10 per cent (27.95 bees/sq. m/5

min) proved significantly superior over rest of the treatments. The next best treatment was 10per cent jaggery (21.21 bees/sq. m/5 min) and was on par with Bee-Q @ 1.25 per cent (18.99bees/sq. m/5 min) and sugar solution (10%) (18.43 bees/sq. m /5 min). However, 10 per centsugarcane juice and molasses were less effective which recorded 17.25 and 10.80 bees/sq.m/5 min, respectively and least number of bees were found in untreated control (7.75bees/sq. m/5 min).

On 3rd

day after second spray, once again 10 per cent cacambe (20.85 bees/sq. m/5min) and jaggery @ 10 per cent (19.75 bees/sq. m/5 min) recorded higher number of beesand these were on par with Bee-Q @ 1.25 per cent and sugar solution (10%) which recorded18.70 and 17.57 bees/sq. m/5 min, respectively and were equally effective. These werefollowed by sugarcane juice (10%) and 10 per cent molasses (15.35 and 13.70 bees/sq. m/5min, respectively) and least was in untreated control with 9.40bees/sq. m/5 min.

On 5

th

day after second spray, 10 per cent cacambe recorded 18.98 bees/sq. m /5min was significantly superior over other treatments. The next best treatments were jaggerysolution (10%) and Bee-Q (1.25%) which recorded 15.07 and 15.01 bees/sq. m /5 min,respectively followed by sugar solution (10%) and sugarcane juice (10%). The least beeswere found in molasses (10%) which was on par with untreated control (7.37 bees/sq. m/5min).

4.3.2 Influence of attractants on visitation of A. cerana

4.3.2.1 First spray

A day before spray, there was no significant difference in bee visitation amongvarious treatments which ranged from 1.74 to 2.10 bees/sq. m/5 min (Table 8).

On one day after 1st

spray, treatment with cacambe @ 10 per cent (9.32 bees /sq.m/5 min) was significantly superior in attracting more bees and was on par with jaggery @ 10per cent (7.75 bees/sq. m/5 min). Further, Bee-Q @ 1.25 per cent was next best treatmentwhich recorded 6.41 bees/sq. m/5 min. This was followed by 10 per cent sugar solution (4.88bees/sq. m/5 min). The remaining treatments attracted the bees ranging from 2.53 to 3.31bees/sq. m/5 min which were significantly inferior to above treatments but attracted morenumber of bees than control (1.17 bees/sq. m/5 min).

On 3rd

day after first spray, the treatment sprayed with cacambe @ 10 per cent (17.23bees/sq. m/5 min) was significantly superior in attracting more bees which was on par withjaggery @ 10 per cent (15.58 bees/sq. m/5 min) and Bee-Q @ 1.25 per cent and sugarsolution (10%) were the next best treatment that recorded 14.25 and 12.98 bees /sq. m/5 min,

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Table 8. Influence of attractants on visitation of A. cerana



Sl.No

Treatments



2.10a 9.32a 17.23a 13.41a 6.31a 16


1.92a 6.41b 14.25bc 12.48a 6.23a 12


1.87a 3.31d 9.62d 8.36bc 5.51a 10


1.98a 4.88c 12.98c 9.77b 5.86a 11


1.80a 7.75ab 15.58ab 12.18a 6.32a 15


1.74a 2.53d 8.59d 7.59c 5.52a 8

7 Crop with out any spray 1.99a 1.17e 5.21e 5.35d 5.54a 6

DBS Day before spray : DAS Day after sprayMeans followed by same letter in the column do not differ significantly by DMRT (P = 0.05)

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respectively which was followed by sugarcane juice (10%) (9.62 bees/sq. m/5 min) andmolasses @ 10 per cent (8.59 bees/sq. m/5 min) and were superior over untreated control(5.21 bees/sq. m/5 min).

On 5th

day after first spray, treatment cacambe (10%), jaggery (10%) and Bee-Q(1.25%) were significantly superior in attracting more number of bees that ranged from 12.18to 13.41 bees/sq. m/5 min. This was followed by 10 per cent sugar solution (9.77 bees/sq.

m/5 min). Whereas, molasses @ 10 per cent (7.59 bees/sq. m/5 min) was found on par withsugar cane juice (10%) and least number of bees recorded in untreated control (5..35bees/sq. m/5 min).


One day before second spray, all the treatments recorded on par results. The beevisitation ranged from 5.51 to 6.31 bees/sq. m/5 min. One day after second spray, treatmentcacambe @ 10 per cent (16.52 bees/sq. m/5 min) attracted higher number of bees, whichwas on par with jaggery @ 10 per cent (15.26 bees/sq. m/5 min), Bee-Q @ 1.25 per cent(12.98 bees/sq. m/5 min) were the next best treatments. This was followed by sugar solution(10%) sugarcane juice (10%) and molasses (10%) which attracted bees ranging from 8.71 to11.69 bees/sq. m/5 min.

On 3rd

day after second spray, cacambe @ 10 per cent (14.69 bees/sq. m/5 min) and

jaggery @ 10 per cent (15.19 bees/sq. m/5 min) were significantly superior and were on parwith Bee-Q @ 1.25 per cent (13.28 bees/sq. m/5 min) followed by 10 per cent sugar solutionwhich attracted 10.95 bees/sq. m/5 min. However, sugarcane juice (10%) and molasses(10%) which attracted 9.81 and 8.76 bees/sq. m/5 min, respectively were on par with eachother and were superior over untreated control (6.88 bees/sq. m/5 min).

On 5th

day after second spray cacambe (10%) jaggery (10%) and Bee-Q (1.25%)attracted maximum number of bees ranging from 8.51 to 9.44 bees/sq. m/5 min, foundsignificantly superior over the other treatments and were on par with each other. The nextbest treatment were sugar solution (10%) and sugar cane juice (10%). However, molasses(10%) (5.50 bees/sq. m/5 min) also found successful in attracting more bees over control(3.45 bees/sq. m/5 min) (Table 8).

4.3.3 Influence of attractants on visitation of A. dorsata

4.3.3.1 First spray

A day before spraying of attractants, number of bees varied from 0.82 to 1.90bees/sq. m/5 min (Table 9).

Treatment with cacambe @ 10 per cent (5.21 bees/sq. m/5 min) was significantlysuperior in attracting more bees and was followed by jaggery solution (10%) on first day afterfirst spray. Further, Bee-Q @ 1.25 per cent (3.19 bees/sq. m/5 min) was the next besttreatment which was followed by sugar solution @ 10 per cent (2.39 bees/sq. m /5 min). Theremaining treatments attracted the bees ranging from 1.53 to 1.93 bees/sq. m/5 min, whichwere found inferior to above treatments but significantly superior in attracting more number ofbees than control (0.78 bees/sq. m/5 min).

On 3rd

day after first spray, the treatment cacambe @ 10 per cent (10.82 bees /sq.m/5 min) was significantly superior in attracting more bees which was on par with jaggery @

10 per cent (8.28 bees/sq. m/5 min). Bee-Q (1.25%) was next best treatment which recorded5.64 bees/sq. m/5 min. This was followed by sugar solution (10%) which was superior oversugarcane juice @ 10 per cent (2.90 bees/sq. m/5 min). Whereas molasses 10 per cent (2.18bees/sq. m/5 min). Further untreated control (0.96 bees /sq. m/5 min) failed to attract morebees.

On 5th

day after first spray, cacambe @ 10 per cent (4.88 bees/sq. m/5 min) andjaggery @ 10 per cent (5.03 bees/sq. m/5 min) were equally effective and were superior overBee-Q @ 1.25 per cent (3.82 bees/sq. m/5 min) and sugar solution @ 10 per cent (3.30bees/sq. m/5 min) was next best treatment and followed by 10 per cent sugarcane juice which

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Table 9. Influence of attractants on visitation of A. dorsata



Sl.No

Treatments



1.00ab 5.21a 10.82a 4.88a 1.84a 13


1.90a 3.19c 5.64c 3.82b 1.91a 9


0.82b 1.93e 2.90d 1.83c 1.88a 3


1.04a 2.39d 4.28c 3.30b 1.82a 5


1.09a 4.10b 8.28ab 5.03a 1.88a 9


1.11a 1.53f 2.18d 1.69c 1.83a 2

7 Crop with out any spray 0.92ab 0.78g 0.96e 1.00d 1.75a 1


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was on par with molasses (10%) which recorded 1.83 and 1.69 bees/sq. m /5 minrespectively.


On one day before second spray, there was no significant difference amongtreatments. Where, the bees visitation ranged between 1.75 to 1.91 bees/sq. m/5 min.

On one day after second spray, cacambe @ 10 per cent (13.46 bees/sq. m/5 min)was significantly superior in attracting more bees. Jaggery solution @ 10 per cent (9.56bees/sq. m/5 min) and Bee-Q @ 1.25 per cent (9.34 bees/sq. m/5 min) were next besttreatments and were equally effective in attracting bees. These were followed by sugarsolution (10%), sugarcane juice (10%) and molasses (10%) which attracted bees rangingfrom 2.21 to 5.34 bees/sq. m/5 min and were inferior to above treatment but superior overuntreated control.

On 3rd

day after second spray, treatment cacambe @ 10 per cent (8.57 bees/sq. m/5min) attracted higher number of bees and was followed by jaggery (10%). Bee-Q @ 1.25 percent (4.28 bees/sq. m/5 min) was next best treatment followed by sugar solution @ 10 percent (4.28 bees/sq. m/5 min) which is superior over sugarcane juice (10%). The sugarcanejuice was on par with molasses @ 10 per cent (1.94 bees/sq. m /5 min) and was foundsuperior over untreated control.

On 5th day after second spray, cacambe (10%) was found superior (5.22 bees/sq.m/5) and next best treatment were jaggery solution (10%) and Bee-Q (1.25%) which attractedsignificantly higher number of bees that ranged from 3.34 to 3.87 bees/sq. m/5 min. Sugarsolution (10%) was next best treatment which recorded 1.91 bees/sq. m/5 min and was onpar with sugar cane juice (10%) and molasses (10%) and superior to untreated control (1.10bees/sq. m/5 min).

4.3.4 Influence of attractants on visitation of other pollinators

4.3.4.1 First spray

A day before the 1st

spray, other pollinators activity varied from 1.17 to 1.38pollinators /sq. m/5 min which did not differ significantly among the treatments (Table 10).

Higher number of other pollinators (6.13 pollinators/ sq. m/5 min) were observed in

the plot sprayed with cacambe (10%) a day after first spray. The jaggery (10%) and Bee-Q(1.25%) were next best treatment which were equally effective and attracted 4.32 and 4.26pollinators /sq. m/5 min, respectively, followed by sugar solution (10%). This sugar solutionwas on par with sugar cane juice (10%) and molasses (10%) that was inferior to abovetreatments with less number of bees (1.67 pollinators /sq. m/5 min) and superior overuntreated control (1.20 bees/sq. m/5).

On 3rd

day after first spray, cacambe (10%) remained effective in attracting morepollinators (13.05 pollinators /sq. m/5 min) which was significantly superior over othertreatments but on par with jaggery @ 10 per cent (10.80 pollinators /sq. m/5 min) followed byBee-Q 1.25 per cent (10.06 pollinators/sq. m/5 min). The sugar solution (10%), sugarcanejuice (10%) and molasses (10%) which were inferior to above treatments and attractedpollinators ranging from 4.67 to 6.95 pollinators /sq. m/5 min and superior over untreatedcontrol (2.64 pollinators /sq. m/5 min).

On 5th day after first spray, more number of pollinators were attracted in thetreatments with cacambe @ 10 per cent (10.99 pollinators /sq. m/5 min), jaggery @ 10 percent (9.80 pollinators /sq. m/5 min) and Bee-Q @ 1.25 per cent (9.38 pollinators /sq. m/5 min)which were equally effective and significantly superior over other treatments. The treatmentswith sugar solution (10%) was next best treatment followed by sugarcane juice (10%) andmolasses (10%) that attracted pollinators ranging from 5.42 to 4.96 pollinators /sq. m/5 min,respectively and superior over untreated control.

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On day before second spray, other pollinators visitation ranged from 3.37 to 4.26pollinators /sq. m/5 min. However, there was no significant difference among differenttreatments.

One day after second spray, cacambe (10%) attracted highest number of pollinators(11.21 pollinators /sq. m/5 min) and was significantly superior over other treatments but was

on par with jaggery solution (10%). The next best treatment was Bee-Q (1.25%) whichattracted 8.49 pollinators /sq. m/5 min. Followed by these were sugar solution (10%), sugarcane juice (10%) and molasses (10%) which were inferior to above treatments and attractedpollinators ranged from 3.40 to 5.49 pollinators /sq. m /5 min and were superior overuntreated control.

On 3rd

day after second spray, cacambe @ 10 per cent (9.52 pollinators /sq. m /5min) attracted significantly higher number of bees and was on par with jaggery (10%) andBee-Q (1.25%). Further, sugar solution (10%), sugarcane juice (10%) and molasses (10%)attracted pollinators ranging from 3.78 to 5.55 pollinators /sq. m/5 min and least number ofpollinators (3.08 pollinators /sq. m/5 min) was attracted by untreated control.

On 5th

day after second spray, cacambe (10%) and jaggery solution (10%) were onpar with Bee-Q (1.25%) which were equally effective and significantly superior over othertreatments that attracted bees ranging from 4.32 to 5.35 pollinators /sq. m/5 min. Sugar

solution @ 10 per cent (3.18 pollinators/sq. m/5 min) was next best treatment and was on parwith sugarcane juice (10%). However, molasses @ 10 per cent (2.40 pollinators /sq. m/5 min)was found on par with untreated control.

4.4 EFFECT OF BEE POLLINATION ON QUANTITATIVE ANDQUALITATIVE PARAMETERS OF RADISH SEED

The results of both quantitative and qualitative parameters of radish seed obtainedthrough bee pollination are being presented in the following headings.

4.4.1 Influence of bee pollination on quantitative parameters of radish seed

Data on the effect of bee pollination on quantitative parameters viz., number ofseeds/siliqua, 1000 seed weight, net plot yield and converted yield (q/ha) is presented in

Table 11 and 12.

4.4.1.1 Number of seeds per siliqua

The open pollinated crop spray with cacambe (10%) was found significantly superiorby recording highest number of seeds (7.40 seeds/siliqua) which resulted in 85.00 and 111.42per cent increase over open pollination without any spray and crop caged without any bees,respectively (Table 11). It was on par with jaggery solution (10%) and Bee-Q (1.25%) (6.36and 6.30 seeds/siliqua). The next best treatments were molasses (10%), sugarcane juice(10%), sugar solution (10%) and crop caged with bees.

However, crop caged without bees and open pollinator without spray recorded leastnumber of seeds/siliqua (3.50 and 4.00 seeds/siliqua).

4.4.1.2 Number of siliqua per plant

The open pollination plot sprayed with cacambe (10%) found significantly superior byrecording higher number of siliqua per plant. which resulted in 27.69 and 55.51 per centincrease over open pollination without spray and crop caged without bees, respectively (Table11). Further, it was on par with molasses 10 per cent (466.86), Bee-Q 1.25 per cent (460.06siliqua), jaggery solution 10 per cent (446.86), sugar cane juice 10 per cent (452.14) andcaged with bees (435.24 siliqua). Open pollination without spray was found on par with cropcaged without bees (323.70 siliqua).

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Table 10. Influence of attractants on visitation of other pollinatorson radish



Sl.No

Treatments



1.17a 6.13a 13.05a 10.99a 4.26a 11


1.17a 4.26b 10.06b 9.38a 3.88ab 8


1.17a 1.94cd 5.67cd 5.42c 3.68ab 4.


1.18a 2.83c 6.95c 6.83b 3.64ab 5


1.17a 4.32b 10.80ab 9.80a 4.12ab 9.


1.17a 1.67d 4.67d 4.96c 3.37b 3.4

7 Crop with out any spray 1.38a 1.20d 2.64e 2.80d 3.60ab 3


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Table 11. Influence of bee pollination on quantitative parameters of radish

TreatmentNo. ofsiliqua/plant

% increaseover cropwithoutspray

% increaseover cagedplot without

bees

No. ofseeds/siliqua

% increaseover crop

plot withoutspray

% increaseover caged

withoutbees

10w

Caged with bees 435.24ab - 34.45 6.00b - 71.42

Caged without bees 323.70c - - 3.50c - -

Crop sprayed withCacambe (10%)

500.16a 27.69 55.51 7.40a 85.00 111.42

Crop sprayed with Bee-Q(1.25%)

460.06ab 17.45 42.12 6.30ab 57.50 80.00

Crop sprayed withSugarcane juice (10%)

452.14ab 15.43 39.67 6.06b 51.50 73.14

Crop sprayed with Sugarsolution (10%)

440.40ab 12.43 36.05 6.00b 50.00 71.42

Crop sprayed withJaggery (10%)

446.86ab 14.08 38.04 6.36ab 59.00 81.71

Crop sprayed with

Molasses (10%)

466.86ab 19.19 44.22 6.13b 53.25 75.14

Crop with out any spray 391.68bc - 21.00 4.00c - 14.28

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TreatmentPer cent

filled seed



bees

Per centunfilled

seed

% ow

Caged with bees 77.27a - 38.35 22.73b

Caged without bees 55.85b - - 44.55a

Crop sprayed with Cacambe (10%) 83.36a 40.95 49.25 16.64b

Crop sprayed with Bee-Q(1.25%) 81.46a 37.74 45.85 18.54b

Crop sprayed with Sugarcane juice(10%)

78.31a32.41 40.21 21.69b

Crop sprayed with Sugar solution(10%)

76.24a28.91 36.50 23.76b

Crop sprayed with Jaggery (10%) 76.74a 29.75 37.40 23.26b

Crop sprayed with Molasses (10%) 81.41a 37.65 45.76 18.59b

Crop sprayed with out any spray 59.14b - 5.89 40.86a

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TreatmentNet yieldper plot

(kg/12 m2)



bees

Convertedyield (q/ha)

% ow

Caged with bees 2.00d - 66.60 16.06ef

Caged without bees 1.20f - - 10.19h

Crop sprayed with Cacambe (10%) 3.86a 141.25 221.66 29.25a

Crop sprayed with Bee-Q (1.25%) 2.91bc 81.87 142.50 23.12c

Crop sprayed with Sugarcane juice(10%)

2.09d30.62 74.16 17.44e

Crop sprayed with Sugar solution(10%)

2.60c62.50 116.66 21.27d

Crop sprayed with Jaggery (10%) 3.24b 102.5 170.00 25.30b

Crop sprayed with Molasses (10%) 1.84de 15.00 53.34 15.55f

Crop sprayed with out any spray 1.60e - 33.33 12.68g

Means followed by same letter in the column do not differ significantly by DMRT (P = 0.05)

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4.4.1.3 Thousand seed (Test) weight

The open pollinated crop which received cacambe (10%) spray produced significantlysuperior test weight (13.66 g/1000 seed) with an increase of 44.24 and 45.01 per cent overopen pollination without any spray and crop caged without bees, respectively, which was onpar with sugar solution @ 10 per cent (12.45 g/1000 seeds) and Bee-Q @ 1.25 per cent(12.90 g/1000 seed) which recorded 31.46, 36.21 and 32.16, 36.94 per cent increase over

open pollination without any spray and crop caged without bees, respectively. The plot cagedwith bees, sugar cane juice and molasses (10%) were next best treatments (11.57, 11.58 and11.47 g/1000 seeds). These treatments were on par with each other and superior over cropcaged without bees which recorded least test weight (9.42 g/1000 seeds).

4.4.1.4 Per cent filled and unfilled seeds

The plot sprayed with cacambe (10%) recoded significantly higher number of filledseeds/siliqua which recorded 83.36 per cent of filled seeds accounting 40.95 and 49.25 percent increase over open pollinated without any spray and caged without bees, respectively(Table 11). The next best treatments were Bee-Q (1.25%), molasses (10%), sugarcane juice(10%), sugar solution (10%). Further these were followed by open pollination without anyspray found superior recorded 59.14 per cent filled seeds over 55.85 per cent filled seeds bycrop caged without bees.

The open pollinated crop with cacambe (10%) recorded least number of un filledseeds (16.64%) which resulted maximum per cent decrease over open pollination withoutspray and caged without bees, respectively. This was on par with the remaining treatments.The treatments, crop caged without bees and open pollination without any spray recordedhighest per cent of un filled seeds which 44.55 and 40.86 per cent, respectively.

4.4.1.5 Net plot yield

The open pollinated crop sprayed with cacambe (10%) recorded significantly highernet plot (12.6 m

2) yield of 3.86 kg/plot which accounted for increase to the tune of 141.25 and

221.66 per cent over open pollinated plot without spray and caged plot without bees,respectively (Table 11). The next best treatment was open pollinated crop sprayed withjaggery (10%) (3.24 kg/plot) which recorded 102.5 and 170.00 per cent increase over openpollination without any spray and crop caged without bee, respectively. This was on par withthe treatment Bee-Q @ 1.25 per cent (2.91 kg/plot) followed by sugar solution @ 10 per cent

(2.60 kg/plot) which in turn recorded 81.87, 62.50 and 142.50, 116.66 per cent increase overopen pollination with any spray and plot caged without bees, respectively and was superiorover others. However, molasses @ 10 per cent (1.84 kg/plot) and plot caged with bees (2.00kg/plot) were on par with each other which were superior over plot caged without bees (1.20kg/plot). Whereas, open pollination without any spray recorded 1.60 kg/plot.

4.4.1.6 Yield/ha (Converted)

The converted yield per hectare based on net plot yield followed exactly the sametrend as in case of net plot yield.

4.4.2 Influence of bee pollination on qualitative parameters of radish seeds

The effect of bee pollination on qualitative parameters of radish seeds viz.,germination percentage and seedling vigour are presented here under.

4.4.2.1 Germination percentage

Significantly higher per cent germination (97.13%) was recorded in open pollinatedtreatment sprayed with cacambe (10%) which accounted for 14.93 and 18.94 per centincrease over open pollinated without any spray and caged plot without bees, respectively(Table 12). However, cacambe (10%) was on par with open pollinated plot sprayed with Bee-Q @ 1.25 per cent (95.62%), jaggery solution 10 per cent (94.55%), sugar cane juice 10 percent accounted (92.16%) and crop caged with bees (94.09%) which were next besttreatments and were on par with each other. However, these were followed by molasses

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Table 12. Influence of bee pollination on qualitative parameters of radish seed

Treatment Germination (%)% increase over

crop withoutspray


bees

Shootlength(cm)

% increaseover crop

without spray


bees

Caged with bees 94.09ab - 15.22 14.40d - 32.96

Caged without bees 81.66e - - 10.83f - -

Crop sprayed with Cacambe(10%)

97.13a 14.93 18.94 16.80a 43.50 55.12

Crop sprayed with Bee-Q(1.25%)

95.62ab 13.14 17.09 15.30b 30.70 41.27

Crop sprayed withSugarcane juice (10%)

92.16ab 9.05 12.85 14.73c 25.80 36.01

Crop sprayed with Sugarsolution (10%)

88.34cd 4.53 8.18 13.43f 14.78 29.00

Crop sprayed with Jaggery(10%)

94.55ab 11.88 15.94 15.10b 29.05 39.42

Crop sprayed with Molasses(10%)

91.21bc 7.92 11.69 14.00e 19.65 29.27

Crop sprayed with out anyspray

84.51de - 3.49 11.70g - 8.03

Means followed by same letter in the column do not differ significantly by DMRT (P = 0.05)

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(10%) which was superior over open pollination without any spray which recorded per centgermination 91.21 per cent and was on par with caged without bees that recorded leastgermination per cent (81.66%).

4.4.2.2 Seedling vigour

The seedling vigour was measured in terms of shoot and root length (Table 12).

4.4.2.2.1 Shoot length

The spraying with cacambe (10%) to open pollinated crop was found significantlysuperior over other treatments as it recorded maximum shoot length of 16.80cm with anincrease of 43.50 and 55.12 per cent over open pollinated without spray and caged plotwithout bees respectively. The next best treatments were Bee-Q @ 1.25 per cent (15.30 cm)and jaggery solution @ 10 per cent (15.10 cm) and were superior over sugar cane juice @ 10per cent (14.73 cm) and caged with bees (14.40 cm) which were on par with each other andnext best treatments. Whereas, remaining treatments except caged plot without beesrecorded shoot length ranging from 11.70 to 14.00 cm. Plots caged without bees recorded thelowest shoot length (10.83 cm)

4.4.2.2.2 Root length

Cacambe (10%) sprayed to open pollinated crop was found significantly superior as it

recorded maximum root length of 16.00 cm which resulted in 50.94 and 60.00 per centincrease over open pollination without any spray and caged plot without bees, respectively.However, this treatment was superior over open pollinated treatment with Bee-Q @ 1.25 percent (14.40 cm). Next best treatments were jaggery solution @ 10 per cent (12.20 cm),molasses @ 10 per cent (12.00 cm) and sugar solution 10 per cent (11.50 cm). Further,sugarcane juice 10 per cent (10.73 cm) was on par with the open pollination without anyspray. Finally the treatment caged without bees recorded less root length (10.00 cm).

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V. DISCUSSION

Results of the investigation carried out to know the pollinator fauna of radish, foragingactivity of bees and other pollinators, effectiveness of different bee attractants in attractingbees and its effect on yield parameters of radish are discussed in this chapter.


Investigations carried out on the pollinator fauna revealed that four groups ofpollinators visited the radish belonging to different orders of class insecta during floweringperiod.

Out of 461.01 pollinators observed belonging different insect orders, of whichHymenopterans (7 species) were the most abundant group (Fig. 1), followed by Dipterans (4species), Lepidopterans (4 species) and Coleopteran (1 species). These findings are in closeagreement with Bhatia et al. (1979) who reported 12 insect species on radish flowers, ofwhich five belong to Hymenoptera, four species to Diptera and three species to Lepidoptera.Sihag (1986) also reported nine species of Hymenopterans, six species of Lepidopterans andthree species of Dipterans as predominant visitors of radish flower. Similar results were alsoreported by Priti et al. (2001) on radish flowers.

5.2 FORAGING ACTIVITY OF BEES AND OTHERPOLLINATORS IN RADISH ECOSYSTEM

5.2.1 Foraging activity of A. florea

The foraging activity of A. florea observed throughout the day during all theobservation days except at 0600 hr.

The foraging activity of A. floreacommenced at 0800 hr on 4th, 8

th, 12

thand 16

thdays

after flowering because they may be late riser and construct comb in bushy plants.

The peak foraging activity of A. floreawas observed at 1000 hr ranging from 4.81 to12.55 bees/sq. m/ 5 min during 4

th, 8

th, 12

thand 20

thdays after flowering. The overall foraging

activity of A. floreawas maximum at 1000 hr (8.62 bees/sq. m/ 5 m) which was observed asmore or less uniform up to 1400 hr. This might be due to coincidence of peak anthesis of

flowering and presence of A. floreacolonies nearer to experimental field.

The present findings are supported by Priti and Sihag (1998) who reported that

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