Differences in Tolerance to Water Deficiency at Vegetative Stage among Wild Upland Rice, Lowland Rice Landrace, their Inter-Specific Hybrids and Lowland Rice Varieties

摘要

Rice germplasm comprising wild species, low land and upland genotypes and 7 progenies of their inter-specific hybrids were tested under water levels of field capacity (100% moisture) and 75, 50 and 25% of field capacity. The objectives were to identify i) most water stress tolerant genotype, ii) characters associated with that genotype and iii) its ability to contribute water deficiency tolerance to lowland rice varieties. Experiment was conducted in potted soil with Randomized Complete Block two-factor factorial design and three replications. Different growth parameters were studied at tillering stage. Within an entry, reduction due to water level was significant in all the parameters. The interaction between various water levels and rice entries was also highly significant. We observed six parameters (shoot length, root length, shoot and root dry weight, number of tillers and leaf area) that were comparatively less affected in some of the progenies such as WAB-56-50 (shoot dry weight and root length), WAB-56-104 (root dry weight and tillers), WAB-272-H3 (leaf area) and WAB-272-H2 (shoot length) when tested under water level which is only 25% of the field capacity. This indicated that using these progenies as donor; water deficiency tolerance in lowland rice cultivars can be improved.