Breeding for submergence tolerance
1988
Mallik, S. | Lakhe, C.R. | Mitra, N.K. | Mandal, B.K. (Rice Research Station, Chinsurah, West Bengal (India))
FR13A, FR43B, and CN540, their two hybrids, and susceptible check IR20 were studied for submergence tolerance and recovery. Varieties differed significantly in initial height and leaf and tiller number. FR13A and FR43B were the tallest and had the most leaves in all age groups. In general, IR20 scored lowest for all characters, except it had the most tillers at 40 d old. Highest survival of 10-d-old seedlings was in FR13A and CN716 at both flooding depths, followed by FR43B and CN717. No IR20 plants survived the 60-cm water depth. All older seedlings of CN540 and FR43B survived. Only CN716 showed complete recovery of younger seedlings at both water depths; 40-d-old seedlings surpassed both parents in 60 cm water. FR43B had good overall recovery at all seedling ages. No 10 D IR20 seedlings recovered; recovery otherwise increased gradually with seedling age. Most varieties had higher elongation rates at 30 cm than at 60 cm water depth. Ten-day-old CN540 seedlings had the highest elongation rate. FR43B elongated most in 30 cm and FR13A in 60 cm. High initial height was correlated with low elongation rate in older seedlings (-0.60 and -0.70 at 30 cm, and -0.81 and -0.73 at 60 cm water) but not with survival. Initial leaf number was positively correlated with survival only in 40-d-old seedlings at 60 cm water depth (0.60). The resistant varieties can be divided into two groups: FR13A type was more resistant at the heterotrophic stage (seedling surviving on endosperm), CN540 type was more resistant at the autotrophic stage (seedling producing its food). Screening at both seedling stages could help identify resistance donors. Development of bridge parents such as CN716 (FR13A)/CN540) that combine both types of resistance should lead to the production of genotypes with better flood tolerance.
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