Phenotypic response of rice (Oryza sativa) genotypes to variable moisture stress regimes
Sabar, M. (National Inst. for Biotechnology and Genetic Engineering, Faisalabad (Pakistan)) | Arif, M. (National Inst. for Biotechnology and Genetic Engineering, Faisalabad (Pakistan))
Water stress in a climate change scenario is one of the major threats for sustainable rice productivity. A certain level of drought can cause considerable yield losses. Combining drought resistance with yield potential is the most promising challenge for the rice breeders. The present study was conducted using eight rice genotypes of diverse origin to explore their response against variable drought stress. Two water stress treatments for one week and two weeks were given sixty days after seeding. Significant differences for genotypes and water stress levels were observed from phenotypic performance. Correlation studies indicated a positive and significant association of paddy yield with spikelet fertility and 1000 grain weight. Rice genotype IR55419-04 showed least effect of water stress treatments for 1000 grain weight i.e., 6.28% and 10.44% reduction, spikelet fertility percentage with 19.99% and 40.01% reduction and the paddy yield per plant of 24.97% and 51.35% under one week and two weeks water stress, respectively. On contrary, Basmati 2000 and Super Basmati were found to be the most sensitive to drought for paddy yield with 92.8% and 91.5% reduction under severe water stress given for two weeks, respectively. The existence of enough amount of genetic variability might be a result of diverse source of the present stock. Rice strain 'IR55419-04' showed the potential for drought stress tolerance amongst all the tested genotypes and needs attention of the breeders to explore the genetic tolerance through modern mapping techniques and then incorporating it through advance biotechnological approaches like marker assisted backcrossing into elite varieties.
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