University of Agricultural Sciences,GKVK Bangalore-65

Project report On

Flower visitors in pollination and pod set of Pigeonpea, Cajanus cajan L. Millsp

Submitted by: Batch III1. Subhash B Kandakoor (PALB 1021)2. Rajendra Prasad B S (PALB 1017)3. Sanjaya C Topagi (PALB 1023)4. Murali S (PALB 1015)5. Ajit kumar M A (PALB 1007)

Submitted to: Dr. N. S. BHAT

Professor

DEPARTMENT OF APICULTUREUNIVERSITY OF AGRICULTURAL SCIENCE

GKVK, BANGALORE- 65

Flower visitors in pollination and pod set of Pigeonpea, Cajanus cajan L. Millsp

Pigeonpea, Cajanus cajan L. Mill sp is one of the major grain legume crops grown in the

tropics and subtropics. Although pigeonpea flowers are self compatible and are believed to be

self-pollinated and very little information exists on the relationships between flowering insects

and many plants species. Nevertheless, it is known that generally anthophilous insects and bees

in particular usually increase the fruit and seed yields of many plants species, through

pollinisation provision C. cajan flowers have bright corollae and produce nectar and pollen.

These traits suggest that C. cajan would be attractive and possibly be pollinated by bees .The

pollen and nectar in its flowers are however accessible to insects other than bees, requiring the

separation of pollinators from other visitors. Though insects visited flowers, it was not known

whether they increased seed yield. Further, there is no information on the need for pollinating

agents in the production of seeds, as seeds set even when insects are excluded from visiting

flowers the present study provide information on the role played by flower visitors in pollination

and their foraging activity and also podset of pigeonpea.

Ten species of insects visited flowers of pigeonpea during the study period. Of these,

majority species belonged to the order Hymenoptera (Apidae, Megachilidae, Chrysididae and

Scoliidae) (Table 1). Megachile spp, Apis spp, Xylocopa spp were frequent visitors of pigeonpea

flowers.

Table1: Flower visitors of pigeonpea

Sl.No Flower visitors Family

1 Apis dorsta Fab.

Apidae2 Apis florea Fab.

3 Apis cerana Fab.

4 Trigona spp.

5 Xylocopa spp1Xylocopinae

6 Xylocopa spp2

7 Megachile spp Megachilidae

8 Cuckoo wasp Chrysididae

9 Scolia spp Scolidae

10 Amegilla spp Halictidae

Peak activity period was observed for 3 days and result showed two peak (Fig1.) periods

in a day. Honey bee species were observed from morning to evening with peak from 10.00 h to

12.00 h and from 12.00 h to 14.00 h Megachile spp was more active. Along with these some

Amegilla spp and vespidea are active. Before 10 h and after 16 h the pollinator activity was very

low (Table 2 & 3).

Table2 : Peak activity of pollinators in a day

TimeNo. of pollinators visited / plant

I II III Mean

8:00 - 10:00 26 24 22 24.00

10:00-12:00 37 33 34 34.67

12:00-14:00 32 33 29 31.33

14:00-16:00 23 22 23 22.67

16:00-18:00 13 15 12 13.33

Table3: peak activity of different species

Timings (h) Apis spp Megachile spp Others

8:00 - 10:00 11.00 7.00 6.00

10:00-12:00 17.33 12.00 5.33

12:00-14:00 12.33 15.67 3.33

14:00-16:00 9.33 7.33 7.00

16:00-18:00 6.00 4.00 3.33

The importance of pollination by the pollinators was assessed by caging the plants to avoid

pollination by pollinators and in another set the plants were allowed for open pollination. The results

showed there were significant differences between plants that were allowed for open

pollination (Uncaged) and those that were prevented from bee visits (Caged) in some of

the parameters observed. The Differences between Uncaged and Caged plants with

respect to pod and seed characters are given in (Table 4 and 5).

The per cent flower drop was calculated in both open pollination and caged condition and

results showed that 64.37 ± 21.25 in open condition where 79.16 ± 28.90 in caged plants.The

number of pods set in inflorescence was 26.67 ± 2.08 in open pollination whereas 14.33 ± 2.08

in caged plants. Similarly there was significant increase in the pod weight 14.99 ± 0.7 in open

condition and 8.21 ± 1.23 in caged condition. Seeds per pod in open condition 3.67 ± 0.14 and

3.42 ± 0.05 in caged condition.

Table4: Flower drop in uncaged (cross pollination) and caged (self pollination) plants**

Replication

Cross pollination Self pollination

Totalno. of

flowers

No. of final pod set

Total flower drop

% flower drop

Total no. of

flowers

No. of final

pod set

total flower drop

% flower drop

RI 80 26 54 67.50 77 12 65 84.42

RII 76 29 47 61.84 62 16 46 74.19

RIII 69 25 44 63.77 71 15 56 78.87

Mean 75 26.67 48.33 64.37±21.24 70 14.33 55.67 79.16±28.90

** Values presented in the table indicates per inflorescence

Table5: Differences between Uncaged and Caged plants with respect to pod and seed characters.Characters Cross pollination Self pollination

RI RII RIII Mean RI RII RIII Mean

No. of flowers/inflorescence

80 76 69 75.00±5.57 77 62 71 70.00±7.55

No. of pods/ inflorescence

26 29 25 26.67±2.08 12 16 15 14.33±2.08

Pod weight/inflorescence

14.82 16.03 14.12 14.99±0.97 6.84 9.23 8.56 8.21±1.23

No. of seeds/pod 3.82 3.64 3.55 3.67±0.14 3.45 3.36 3.45 3.42±0.05

The results of the present study have clearly shown that flower visitors are important in

pod set of Pigeonpea and that there is a significant increase in the per cent pod set and yield by

encouraging flower visitors. Hence, there is a need to conserve the populations of Apis spp and

non-Apis bees, especially, Megachile, Amegilla and Xylocopa spp to realise higher production.

Cuckoo wasp Megachile sp.

Apis dorsata Amigella sp.

Trigona sp. In caged conditon

Fig2: Different pollinators of pigeonpea

Fig1: Activity of pollinators during different hours