Genotypic variability for drought tolerance-related morpho-physiological traits among indigenous rice landraces of Jeypore tract of Odisha, India

Abstract

ABSTRACTAssessment of genotypic variability in germplasm under different water stress conditions is one of the most challenging objectives in crop breeding programs. We evaluated responses of 130 indigenous rice (Oryza sativa L.) landraces that originated from various regions of Jeypore tract of Odisha, India, to drought stress for two years. Drought-tolerant (N22) and drought-susceptible (IR64) checks were also included in the experiment. Drought stress was induced by polyethylene glycol (PEG) 6000. The following traits were measured: seed germination, shoot and root length, fresh and dry weight, relative water content (RWC), membrane stability index (MSI), chlorophyll concentration (SPAD), and osmolyte accumulation. In principal component analysis (PCA), the first three principal components (PCs) captured 62.46% of the total variation; significant differences were detected among genotypes with respect to the studied parameters. The genetic advance (5% selection intensity) as the percentage of mean (GAM) ranged from 10.71% for RWC to 73.60% for root length. GAM was relatively high for germination percentage (42.85%), shoot length (SL) (55.14%), root length (RL) (73.60%), chlorophyll index (54.24%), proline content (56.73%), and vigor index (VI) (66.98%). Hence, these traits should be given top priority during selection for rice improvement programs using the studied landraces. Six landraces (Pandakagura, Machhakanta, Haladichudi, Mugudi, Kalajeera, and Dangarbayagundar), being more drought tolerant than N22, should be useful in rice breeding programs aimed at improving drought tolerance.