Morpho-physiological and biochemical attributes as tools to screen tolerance and susceptible rice cultivars for drought stress

Present research work was aimed to observe possible changes in the metabolism of rice plants (Oryza sativa L.) through drought stress. Rice belongs to the family Poaceae.  It is considered as a vital food crop across all the major countries worldwide. Rice is prone to be affected by drought stress. Therefore, developing the drought tolerant cultivars of cereal crops assumed considerable importance. This work was carried out with an objective to study the Screening of rice cultivars against water stress and compare biochemical characteristic among different drought tolerant and sensitive rice cultivars. A set of 25 cultivars of rice were screened against drought stress at vegetative stage through various morpho-physiological characters such as moisture, relative water content (RWC), membrane stability index(MSI), membrane injury(MI), seedling length and seedling weight. The RWC is a best criterion for plant water status. The osmotic adjustment is a influential mechanism of conserving cellular hydration under water stress and RWC expression also affects osmotic adjustment in this respect. Thus, it can be considered that the higher RWC having cv. GAR-13 and NWGR-16026 were tolerant and lower RWC having cv. NWGR-16009 and NWGR-16019 were susceptible. Hence, cv. GAR-13 & NWGR-16026 was used as tolerant and NWGR-16009 & NWGR-16019 were used as susceptible. On the basis of first experiment total four cultivars (Two tolerant NWGR-16026 & GAR-13, two susceptible NWGR-16009 & NWGR-16019) were selected for various biochemical analysis. The results indicated that total soluble sugars (TSS), glycine betaine and ascorbic acid content were found significantly higher in cultivar NWGR-16026. The proline content was found significantly higher in cultivar GAR-13. So, RWC and some biochemical parameters are best indicators for selection regarded as potentially useful for drought tolerant rice cultivars and targets for development through transgenic approaches.