ICRISAT Archival Report 2006 - The seedlings of success in the ...

that the Helicoverpa-resistant chickpea genotypes are compatible with this parasitoid. Larval weight of H. armigera
showed a significant and positive association with C. chlorideae cocoon formation and adult emergence, and
weights and size of male and female parasitoids (r = 74* to 99**), while significant and negative association was
observed with larval period of C. chlorideae (r = -0.70*). The ELISA test indicated the presence of Bt protein in the
H. armigera larvae fed on Bt treated chickpeas, while no Bt protein was detected in the larvae, cocoons, and adults
of the parasitoid, C. chlorideae reared on Bt intoxicated H. armigera larvae, suggesting that lower survival of the
parasitoid was due to poor quality of the host.
In another experiment, we studied the effects of cotton aphid, Aphis gossypii fed on Bt-transgenic and nontransgenic
cottons on development and survival of the coccinellid, Cheilomenes sexmaculatus. The larval period of
C. sexmaculatus reared on A. gossypii fed on Bt-transgenic cotton was prolonged by 1.5 to 2.0 days. The weight of
C. sexmaculatus larvae was reduced by 3 to 4 mg when fed on A. gossypii reared in Bt-transgenic cotton plants.
There was no effect of Bt-transgenic cotton fed aphids on larval survival, pupal period, and sex ratio of C.
sexmaculatus. However, adult emergence decreased by 20 to 30% in coccinellids fed on Bt-RCH 2 and Bt-Mech 12
cotton hybrids as compared to those reared on non-transformed controls. The ELISA test indicated the presence of
Bt protein in aphids, and the larvae and adults of the C. sexmaculatus fed on aphids obtained from Bt-transgenic
cotton.
HC Sharma and MK Dhillon
Pigeonpea
Output 6A: Improved germplasm and varieties of sorghum, pearl millet, pigeonpea, chickpea and groundnut
with pro-poor traits and associated advanced knowledge of selection tools and breeding methods made
available to partners internationally
MTP Output Target 2006: New knowledge synthesized on seed production systems of improved lines, wild relatives
and putative transgenics of pigeonpea, published and disseminated globally
Output target 6A.1: About 5 - 6 pigeonpea varieties with stable resistance to Fusarium wilt, sterility mosaic
and Helicoverpa made available to NARS
Activity 6A.1.1: About 15 new genetically diverse germplasm sources/ breeding lines resistant to wilt and
sterility mosaic diseases identified
Milestone: 25 - 30 pigeonpea lines tested multilocationally for their stability to wilt and sterility mosaic resistance
in India (Annual) (SP)
Identification of stable sources of resistance to Fusarium wilt and sterility mosaic (SM): Pigeonpea lines found
resistant to wilt and SM at ICRISAT, Patancheru were tested for wilt and SM resistance at different locations in
India through the pigeonpea wilt and sterility mosaic disease nursery (PWSMDN) to identify stable and broad-based
resistance to both these diseases. Thirty entries (28 wilt and SM resistant lines, and a susceptible check for each of
the two diseases) were evaluated in 20 locations in India(Akola, Badnapur, Bangalore, Berhampore, Coimbatore,
Dholi, Faizabad, Gulbarga, Hazaribagh, Hisar, ICRISAT, Patancheru, Kanpur, Khargone, Rahuri, Raipur, Sehore,
SK Nagar, Pudukottai, Varanasi, and Warangal) during the 2005/06 cropping seasons. The experiment was planted
in a wilt sick plot and inoculated with SM infested pigeonpea leaves using the leaf staple technique at two leaf stage
or spreading SM infested twigs on test entries wherever possible. Data on wilt and SM was recorded twice, at
flowering and at maturity stages of the crop.
Data was received from 13 locations. Wilt incidence in the susceptible check, ICP 2376 was high (> 60%) at Akola,
Badnapur, Gulbarga, ICRISAT-Patancheru, Kanpur, Rahuri, and Sehore; while it was moderate at Bangalore and
Warangal (~ 38%); and low in Khargoan (13%). There was no incidence at Berhampur, Hazaribagh, and Pudukottai
(Vamban). Incidence of wilt in the local check was 83% (TTB 7) at Bangalore, 54% (LRG 30) at Warangal, 50% at
Pudukottai, 10% at Hazaribagh, and no infection at Berhampur. The differential reaction of susceptible checks at
different locations indicated the possible presence/existence of races/pathotypes of the wilt pathogen. This
phenomenon needs detailed investigations to resolve the race scenario of Fusarium udum in India.
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