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

due to absence of chickpea crop for about eight months in these fields. The phenomenal increase of the propagules
at crop harvest (February) suggested that chickpea supports the multiplication of these pathogens in the soil.
Suresh Pande and Mamta Sharma
Succession of fungal pathogens of chickpea in wilt and multiple disease sick plots: Succession of occurrence of
fungal pathogens in chickpea wilt and multiple diseases sick plots was studied during the season to confirm the
results obtained in the previous year. Methodology including check cultivars (early wilting JG 62, late wilting L
550, and FW resistant WR 315), sampling and isolations on potato dextrose agar and czepek dox agar media were
carried out as in the previous year. Isolations were made from root tip, root hair, epidermis and cortex, vascular
bundles and collar region of apparently healthy looking plants at 10-day intervals from 10 DAS in both fields.
All the plants of cultivar JG 62 wilted within 30 DAS and that of L 550 in 80 DAS, while those of WR 315
remained healthy till maturity. FOC was found in all the root parts of healthy looking early wilting and late wilting
cultivars from 20 DAS till the death of the plants. FOC was found only in root tip and root hairs in the resistant
cultivar WR 315 at 50 DAS till maturity. This late infection and restriction of the fungus at the root tips in this
cultivar may be due to its resistance to wilt pathogen. Black root rot pathogen, Fusarium solani and collar rot
pathogen, Sclerotium rolfsii attacked and killed the plants in all the three cultivars at the seedling stage (up to 30
DAS) when the soil moisture was high. Warm temperature and soil moisture stress encouraged dry root rot fungus,
Rhizoctonia bataticola (RB) to cause rotting of the roots. During the season, dry root rot appeared from 50 DAS till
maturity in both late wilting and resistant cultivars. In both these cultivars, a mixture of FOC and RB was observed
from 50 DAS till maturity indicating that interaction of both these pathogens may be responsible for death of the
plants.
The FOC was dominant in the wilt sick plot throughout the cropping season, and recovered from all the root parts of
apparently looking healthy plants of both JG 62 and L 550 from 20 DAS, and were present till the death of the
plants. Susceptible cultivar JG 62 wilted in 30 DAS and L 550 in 80 DAS as in MDSP. Resistant cultivar, WR 315
yielded FOC only from root tips and root hairs from 60 DAS as in multiple disease sick plot. Additionally, a mixture
of FOC and RB was also recovered from root tips of late wilting and resistant cultivars from 60 DAS till maturity.
These results indicated that the death of the plants may be due to interaction of both these pathogens. Though wilt
fungus is predominant in wilt sick plot, low intensities of F. solani and S. rolfsii at the seedling stage (up to 30
DAS), and R. bataticola during later stages were recorded in both L 550 and WR 315.
Suresh Pande and Mamta Sharma
Activity 6A.1.2: Develop chickpea breeding lines with, resistance to Helicoverpa.
Milestone: 5 - 10 resistance sources and advanced breeding lines tested for stability of resistance
(HCS/CLLG/PMG) 2009
Breeding chickpeas for resistance to pod borer, Helicoverpa armigera: We evaluated 1,586 segregating
progenies of chickpea during the 2005/06 season, and selected 1,161 progenies for further testing. The selection of
progenies was based on visual scoring for pod damage and yield. Subsequently, progenies having