Proceedings of The Fourth International Iran & Russia Conference 941

Redescription of the Pigeon Pea Cyst Nematode, Heterodera cajani Majid Olia 1 and Mohammad Ali Alaeddini 2 1 Crop Protection Dept. & 2 English Dept. Shahrekord University, Shahrekord, Iran Olia100@yahoo.com Abstract Cyst forming nematodes are a major group of plant pathogens of economic importance in many countries all around the world and considerable yield losses have been attributed to them attacking potato, sugar beet, cereals and pulses. Some of the cyst nematode species have been completely morphologically studied, but number of others await full taxonomic study and description. Soil samples collected from the infested pigeon pea field, air dried and Heterodera cajani cysts extracted by Fenwick can method. Freshly isolated cyst crushed and second stage juvenile and eggs obtained and vulval cone prepared from the cyst mounted in glycerin gelly. All the measurements were taken with an ocular micrometer, drawing with the help of camera lucida. Cysts are lemon-shaped, ambifenestrate and encircled by more or less circular basin, 6-13 µm wide; 6-9 µm vulval bridge with 31-46 µm long vulval slit. Each semifenestrae 31-48 µm long and 22-41 µm wide. Underbridge well developed, 42-58 µm long and 11-16 µm wide. Bullae present, peripheral and may present at different levels. In this communication, second stage juvenile, cyst and eggs of the pigeon pea cyst nematode, Heterodera cajani Koshy, 1967 have been measured, drawn, microphotographed and redescribed . Keywords: cyst nematode, description, Heterodera cajani, taxonomy Introduction Pigeon pea cyst nematode, Heterodera cajani was first described in 1967 by Koshy. During the course of study on species diversity of soil inhabiting nematodes in Aligarh Dist., UP, India, soil samples collected from various localities yielded populations of the pigeon pea cyst nematode, which is being redescribed, illustrated and microphotographed here. Soil collected from the infested pigeon pea field, air dried and cysts extracted using Fenwick can method. The freshly isolated cysts crushed and suspension of second stage juvenile and eggs obtained, fixed in hot TAF, dehydrated and permanent slides were made. Posterior part of the cysts cut, trimmed, mounted in glycerin gelly in lateral as well as top view and gently covered by a cover slip to form the vulval cone. Measurements were taken with an ocular micrometer and drawings were made using a drawing tube attached to the microscope equipped with camera. Descriptions Second stage juvenile: Dimensions: See Table 1. Body small, straight to slightly curved ventrally upon fixation, narrow at head end and distinctly tapering at posterior end. Cuticle finely striated, each stria 1.5 µm at midbody. Lateral field each with 4 incisures, 1/3-1/4 body width at midbody. Lip region slightly offset, with 3-4 annules, well sclrotized, 3.5-4.5 µm high and 8-9.5 µm wide. Stylet well developed, conus about half of stylet length, knobs anteriorly directed. Dorsal oesophageal gland opening 3-4.5 µm behind the spear base. Procorpus 30-32 µm long. Metacorpus slightly oval. Oesophageal glands overlapping ventrally. Nerve ring 75-89 µm from anterior end. Excretory pore near cardia. Hemizonid two annules wide anteriorly adjacent to excretory pore. Tail long conoid 40-50 µm long with 23-29

Proceedings of The Fourth International Iran & Russia Conference 942

µm long hyaline portion. Phasmids at the level of anus or or 2-3 annules behind it; lateral lines invisible on hyaline portion. Cyst : Dimensions : See Table 2. Lemon shaped, with protruding neck and vulval cone, dark yellowish to light or dark brown in color. External pattern on cyst cuticle zigzag. Egg sac sometimes present. Vulval cone structure: Dimensions : See Table 2. Ambifenestrate, encircled by more or less circular basin, 6-13 µm wide. The semifenestrae semicircular in shape, separated by a 6-9 µm wide vulval bridge. Vulval slit 31-46 µm long. Each semifenestrae 31-48 µm long, 22-41 µm wide, with a thin transparent circular mass, attached in the center of underbridge at the base. Bullae present, peripheral and many present at different levels. Egg: Dimensions : See Table 3. Generally ovoid to oblong in shape, 100-120 µm long and 38-50 µm width. Egg shell hyaline, without visible markings, punctation absent. Second stage juvenile in 3-4 folds inside the egg. Selected References Koshy, P. K. (1967) A new species of Heterodera from India. Indian phytopathology, 20: 272-74. Mulvey, R.H. (1972) Identification of Heterodera cysts by terminal and cone top structures. Canadian

Journal of Zoology, 50 : 1277-92. Mulvey, R.H. & Stone , A. R. (1983) An illustrated key to the cyst forming genera and species of

Heteroderidae in the western hemisphere with species morphometrics and distribution. Journal of Nematology, 15: 1.

Rajan & Swarup, G. (1985) Evaluation of cyst extraction techniques and their effects on biology of Heterodera cajani. Indian Journal of Nematology 15: 75.

Sharma, S. B. & Swarup, G (1984) Cyst Forming Nematodes of India. Cosmo Publications, New Delhi, India.

Sharma, S. B. (1998) The Cyst Nematodes. Kulwer Academic Publishers, The Netherlands. Figure legends: Fig. 1: Cysts of Heterodera cajani . Fig. 2: Second stage juvenile of H. cajani. A) Oesophageal region B) Anterior end. C) Lateral field. D) Entire. E &G) Posterior ends showing phasmid portion. F&H ) Posterior ends showing hyaline portion. Fig. 3: Eggs of H. cajani. Fig. 4: Second stage juvenile of H. cajani. A)Anterior end. B)Posterior end. Fig. 5: Cone top of H. cajani. A) View showing vulval-bridge and fenestrae. B) View showing under-bridge

Proceedings of The Fourth International Iran & Russia Conference 943

Table 1 - Measurements (µm ) of H. cajani second stage juveniles (n=19)

Table 2 – Measurements (µm ) of H. cajani cysts

Character Range Mean S.D. C.V. (%)

Length 350-510 456.2 40.7 8.9

Width 16.8-19.9 18.4 1.1 5.7

a 20.1-26.5 24.5 1.8 7.5

Oes. Int. Jun. 80-95 93.4 9.5 10.1

b 3.6-5.7 4.9 0.7 14.1

Oesophagus 110-118 111 5.8 5.3

b´ 3.1-4.5 40 0.4 1.1

Tail 45-50.5 47.2 2.6 5.5

C 9.3-10.3 9.8 1.1 11.1

ABD 9.1-13 11.3 1.2 10.4

C´ 3.6-5 4.2 0.4 9.6

Lip width 8.4-9.8 9.2 0.5 5.4

Lip height 3.6-4.6 4.2 0.4 8.8

Stylet length 20-25 23.4 1.4 0.1

DGO 3-4.6 4.4 0.4 9.5

Nerve ring 75-88 78.5 5.2 6.6

Excretory pore 89-92 90.9 1.3 0.1

Median bulb 64.3-76 69.2 4.9 7.1

Hyalin portion 22-28.5 26.8 3.1 11.3

Proceedings of The Fourth International Iran & Russia Conference 944

(n=15)

Character Range Mean S.D. C.V. (%)

Cyst length (L) 500-650 579.6 50.6 8.7

Cyst width (W) 280-400 343 41.7 12.1

Vulval slit 31-46 42.2 6.7 16

Fenestral length 31-48 38.5 6.1 15.7

Fenestral width 22-41 28.8 4.7 16.3

Vulval bridge width

6-9 7.8 1.4 17.6

Under-bridge length

42-58 52.5 4.7 8.9

Under-bridge width

11-16 12.5 1.5 12.1

Basin width 6-13 9.8 2.4 24

Cyst L / W 1.4 – 2.2 1.7 0.3 15.5

Table 3 – Measurements (µm ) of H. cajani eggs

(n=15)

Character Range Mean S.D. C.V. (%)

Length (L) 100-120 108 7.9 7.3

Width (W) 38-50 43.3 3.6 8.4

Egg L /W 2.2-3 2.5 0.3 11.4

Proceedings of The Fourth International Iran & Russia Conference 945

Proceedings of The Fourth International Iran & Russia Conference 946