In-vitro screening and field validation of rice (Oryza sativa L.) genotypes for drought tolerance

In vitro screening using polyethylene glycol (PEG) was performed with matured seed-derived callus from six elite rice varieties and eight advanced cultures to understand the response to drought stress. Murashige and Skoog medium supplemented with 2 mg l-1 of 1-napthaleneacetic acid and 5, 10, 15 and 20 g l-1 of PEG 6000 were used to induce drought stress in callus. Significant differences were observed among the genotypes, treatments and their interactions for callus morphology and fresh weight. The genotypes PMK3, RMD(R)1, ARB6 , ARB7 and ARB8 were identified as the most tolerant to drought stress using principal component analysis (PCA). A total of 48 crosses made from these genotypes showed significant yield increase over their respective parents. The hybrids RMD(R)1/ARB7, PMK3/ARB7 and PMK3/ARB8 were identified as drought tolerant using PCA analysis. From the study it is proved that in vitro screening method can be used to identify drought tolerant rice genotypes