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

UAS Dharwad-ICRISAT collaborative research on wilt resistance in chickpea: Ninety-six single plant
progenies (SPP) of the cross F 3 Bheema x ICCV 10, 106 SPPs of the cross F 3 M 2 Bheema x ICCV 10, 113 SPP of
M 3 Bhima, five susceptible populations of the cross Bheema x ICCV 10, five resistant populations of Bheema x
ICCV 10, five heterozygous populations of the cross Bheema x ICCV 10, and both the parents (Bheema and ICCV
10) were evaluated for wilt resistance under controlled environment conditions in the greenhouse. Susceptible
cultivar JG 62 was included for comparison. High levels of resistance to wilt were observed in F 3 and M 3
populations, while no resistance was observed in susceptible, resistant, and heterozygous populations of the cross
Bhima x ICCV 10.
Suresh Pande and PM Salimath
Milestone: Identification, characterization and resistance screening of potentially important diseases (DRR, BRR,
CR) of chickpea (SP) 2008
Standardization of screening technique for collar rot (CR) resistance: Pure culture of collar rot fungus,
Sclerotium rolfsii, was multiplied on three media; sterilized groundnut shells, sterilized sorghum straw (2 - 3 cm
long pieces), and potato dextrose broth, and incubated at 25 0 C for 20 days. Sclerotial production was estimated from
100 g ml -1 from each medium. About 10,245 sclerotia from groundnut shells, 5,074 from sorghum straw, and 1,853
from potato dextrose broth were recorded. Since the sclerotia are the main disease producing bodies in CR,
groundnut shell medium was selected for further standardization of the screening technique. Thirty grams of
inoculum (multiplied on groundnut shells) was mixed with 1 kg sterilized top 15 cm soil and filled in metal trays (70
x 30 x 16 cm). Light irrigation was given to make the soil moist and was left undisturbed for three days for the
establishment of the fungus. Susceptible chickpea cultivar Annigeri was planted in rows in the trays and observed
for 21 days for seed and seedling (collar) rot symptoms. About 21% of seed rotting and 79% collar rot was recorded
at 21 days after sowing. Since the seed and seedling rots were consistent in three screenings in Annigeri, these trays
were used for routine evaluation for collar rot resistance.
Evaluation of wilt promising selections for resistance to CR: Eighty-nine wilt promising advanced breeding and
germplasm selections were evaluated for CR resistance following standardized sick tray technique under controlled
environment conditions. None of the lines tested was found to be resistant CR. Therefore, we initiated systematic
evaluation of germplasm accessions for CR resistance.
Suresh Pande
Milestone: Basic and strategic research on succession of Fusarium wilt and root rots of chickpea (SP) 2009
Threshold and quantification of fungal pathogens of chickpea in wilt and multiple disease sick plots:
Quantification of fungal pathogens of chickpea wilt complex was carried out for the third year in the wilt sick plot
(BIL 3 C), and the multiple disease sick plot [(MDSP) (BIL 1)] at ICRISAT, Patancheru, India. Collection of soil
samples before planting and after harvesting of the crop and processing of soil was done as in the previous year.
Number of fungal colonies g -1 soil was estimated using synthetic media (PDA and CDA) at 48 to 96 h after
incubation. Number of sclerotia of S. rolfsii was quantified by using the rapid floatation technique.
Unlike previous years, the number of colonies of all the wilt complex pathogens was greater in the samples taken
before sowing than after harvesting of the crop in both the fields. Fusarium oxysporum f.sp. ciceris (FOC) colonies
were around 1,700 g -1 soil before planting and up to 4,150 g -1 soil after harvest of the crop in both fields. FOC
colonies were recovered up to 80 cm depth before planting and up to 100 cm depth after harvest. In the wilt sick
plot, in addition to FOC, other root rot causing pathogens (Fusarium solani, Rhizoctinia bataticola, and Sclerotium
rolfsii) were negligible. This observation was in agreement with that of previous season.
Additionally, soil collected from MDSP was also assessed for root rot pathogens, Fusarium solani (black root rot),
Rhizoctonia bataticola (dry root rot), and Sclerotium rolfsii (collar rot). About 475 colonies of F. solani and 220
colonies of R. bataticola g –1 soil, and four sclerotia of S. rolfsii 10 g -1 of soil were recovered from surface soil,
which was collected before sowing of chickpea crop. These root rot pathogens multiplied during the cropping period
and their population was almost double after crop harvest. Further, F. solani and R. bataticola were recovered up to
50 cm depth before planting and up to 65 cm depth after harvesting of the crop, while S. rolfsii was recovered up to
20 cm depth before sowing and 25 cm after harvest of the crop. Number of colonies of all these pathogens decreased
as the depth increased. Lower number of propagules of the pathogens before sowing of the crop (October) may be
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