IDENTIFICATION OF TRADITIONAL RICE (Oryza sativa L.) GENOTYPES TOLERANT TO COLD AND HEAT STRESS
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Date
2019-11-27
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UNIVERSITY OF AGRICULTURAL SCIENCES GKVK, BENGALURU
Abstract
Rice is susceptible to a variety of abiotic stresses including cold and heat stress
that affects the grain yield. Genetic resources for tolerance of these stresses are available
in indigenous races. 60 rice landraces and two aerobic rice varieties were evaluated under
summer, kharif and late kharif, 2016 representing heat stress, control and cold stress
situation during reproductive stage of the crop respectively. Evaluation at germination
stage was done at 28±3°C and 42±3°C for heat tolerance. Similarly, for cold tolerance
seeds were germinated at 28 ºC for 7 days (control) and 13 ºC for 15 days (cold).
Fourteen stress indices were computed to quantify the response to both germination and
reproductive stage cold and heat stress. Geometric mean and arithmetic mean were found
effective for selection of genotypes for grain yield plant-1 under reproductive stage-cold
and heat stress respectively. At germination stage, stress tolerance index was found best
for germination per cent, shoot length and root length under both cold and heat stress.
Marker validation was done using fourteen cold-tolerance and seven heat-tolerance
specific SSR markers in the genotypes identified based on the effective indices giving
more reliable result. At reproductive stage, Jeerigebattha and Sampige battha 2 and at
germination stage, Marabattha and Puttabattha were tolerant to both stresses. These
genotypes in future can serve as elite genetic material for developing suitable varieties for
cold and heat stress situations.