Evaluation of rice hybrids and their parents for drought tolerance

A study was carried out to assess the drought tolerance ability of 39 rice genotypes (12 parents and 27 hybrids) using PEG-6000 induced moisture stress, on the basis of morphological, physiological, biochemical and histological parameters such as germination percentage, shoot length, root length, seedling dry weight, promptness index (PI), germination stress index (GSI), protein fraction and root anatomy. In vitro screening revealed that morphological and physiological characters were reduced significantly at −0.75MPa compared to control (0.00MPa). Among the genotypes, Nootripathu, Norungan, PMK 2, Norungan x PMK 2 and Nootripathu x PMK 2 performed better under stress in terms of morphological and physiological characters. SDS-PAGE analysis revealed prominent expression of 65 kDa and 78 kDa proteins in stressed parents, viz. Norungan, and Nootripathu and hybrids Norungan x PMK 2 and Nootripathu x PMK2. The expression was totally absent in PMK 2 stressed plants. These proteins could possibly be responsible for the development of water stress tolerance. Root anatomy of Norungan x PMK 2 and Nootripathu x PMK 2 grown under control and stress situation was studied. Increase in the number of xylem vessels of varying diameter, wider pith and compact cell arrangement was noticed in roots under stress.