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

Wide crosses for pod borer resistance in pigeonpea: To transfer the pod borer resistant gene(s) from
C. scarabaeoides to cultigens, biparental mating between 38 Helicoverpa-resistant F 6 interspecific single plant
progenies were attempted, and 17 F 1 ’s were advanced to F 2 generation. A total of 78 F 2 single plant progenies of the
cross ICPW 94-P1 x ICP 28-P1 were evaluated under controlled environment facilities.
HD Upadhyaya
Output target 6A.2: Promising transgenic events of pigeonpea with proven resistance to Helicoverpa available
for commercialization and introgression in locally adapted germplasm
Activity 6A.2.1: Develop transgenic events of pigeonpea for resistance to Helicoverpa armigera and evaluate
their performance under contained greenhouse and field conditions
Milestone: 80 transgenic events of pigeonpea with Bt genes developed and screened in contained greenhouse
(KKS/HCS/KBS) 2008
Transgenic pigeonpea plants were developed through Agrobacterium tumefaciens-mediated transfer of the Bt cry1Ac
gene, and were evaluated for resistance to H. armigera under contained greenhouse and field conditions. Using
seedling leaf petiole as the explant, a total of 50 independent transgenic events; 20 events of ICPL 88039, 25 of ICPL
87, and 5 of LRG 41 were produced and successfully transferred to the greenhouse. All these plants were
characterized for the presence, integration, and expression of the cry1Ac gene by PCR, RT-PCR, Southern, IPCR and
ELISA. A total of 35 (16 of ICPL 88039, 14 of ICPL 87, and 5 of LRG 41), and 20 (12 of ICPL 88039 and 8 of ICPL
87) events were advanced to T 1 and T 2 generations, respectively. These transgenic plants were evaluated for resistance
to H. armigera in contained greenhouse conditions using leaf and pod bioassays. Larval survival and weights were
found to be significantly less on 18 independent transgenic events in leaf bioassays. A contained field trial was
conducted by using nine events of ICPL 88039 and nine events of ICPL 87 during the 2005 rainy season. In the leaf,
pod, and inflorescence bioassays of the field grown transgenics, 5 events showed significant effect on weight gain by
H. armigera larvae, but no significant effects on mortality were observed.
More events of pigeonpea transgenics with cry1Ab and cry1Ac genes are being produced using Agrobacteriummediated
transformation. Ten independent transgenic events with the cry1Ab gene have been transferred to
greenhouse and are being characterized for the integration and expression of the transgenes. Over the course of next
year, the development of at least 75 transgenic events with each gene are planned.
KK Sharma and HC Sharma
Milestone: Three promising Bt-transgenic events of pigeonpea identified and insect resistance characterized under
contained field conditions (KKS/HCS/KBS) 2009
Putative transgenic pigeonpea plants carrying cry1Ab, and cry1Ac genes evaluated for resistance to
Helicoverpa armigera under greenhouse conditions: Transgenic pigeonpea plants developed by introducing the
synthetic cry1Ac gene through Agrobacterium tumefaciens-mediated genetic transformation were bioassayed for
resistance to H. armigera using detached leaf assay. Each fully expanded leaf embedded in 3% agar-agar was
infested with 10 neonate larvae of H. armigera. Data were recorded on leaf damage, larval survival, and weight gain
at 5 days after initiating the experiment. The leaf damage rating ranged from 5.5 to 8.4, and larval survival from 70
to 86%. The weight gain by the larvae was 0.96 mg to 1.71 mg on 723 Bt 1-2-1-2, 723 Bt 2-1-1-1, 723 Bt 11-19, 723
Bt 1-2-1-2, 2310 Ac-0-3, 2310Ac-10-3, 2310Ac-20-1, and 2310Ac-15-4 compared to 2.41 mg on the nontransformed
control plants of ICPL 88039. In case of transgenic plants derived from ICPL 87 using cry1Ac gene,
the larval weights were 8.99 to 9.76 mg on the ICPL 87-12-1, ICPL 87-14-3, ICPL 87-23-3, ICPL 87-25-5, ICPL
87-12-1, and ICPL 87-3-2 transgenic plants compared to 9.48 mg on the non-transgenic ICPL 87 control plants and
13.69 mg on ICPL 87-5-1, suggesting that the effect of Bt protein on H. armigera was lower in plants derived from
the susceptible cultivar ICPL 87 than the ones derived from the relatively less susceptible cultivar, ICPL 88039.
HC Sharma and KK Sharma
Progress reported towards the achievement of milestone for 2008 will contribute towards achievement of the
milestones listed below.
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