Utilising genetic variability and diversity analysis as a tool to identify drought tolerant pre-breeding genetic materials in rice (Oryza sativa L.)

Abstract

Rice (Oryza sativa L.) is the main cereal crop cultivated throughout the globe the importance of rice can be judged by finding that rice alone caters to around half of the world's population. Therefore, studying rice in different environments is a need of time because of climate change which severely hampers crop production. Hence the study was carried out in 50 rice landraces to observe their phenotypical variability and diversity under a drought environment. Analysis of variance shows that a wide range of variability is present among the genotypes so further analysis of PCV (phenotypic coefficient of variance) and GCV (Genotypic coefficient of variance) was calculated to show the environmental effect on traits which was maximum in leaf area (46.66 and 45.55) total leaves per plant (39.88 and 37.45) and number of panicles (38.39 and 35.40). Correlation studies revealed that the drought scores, tip drying score and leaf rolling scores are significantly correlated to each other as well as to total leaves per plant (0.491), leaf area (0.491), number of tillers (0.6244) and number of panicles (0.8003); which are in turn significantly correlated to single plant yield. By clustering, all the 50 genotypes were placed in 11 clusters. Among all clusters, the cluster three is major cluster which contains a total of 18 genotypes. Maximum intracluster distance was found in cluster IV (929.08). Cluster V (90.25) observed the highest cluster mean for single plant yield. Drought score ranking method revealed that the cluster number seven has a genotype which is tolerant to drought. Based on the study the variability and the diversity among the genotypes were assessed under drought environment. Cluster number seven contains a genotype IC 216378 which has superior in performance under drought situation and selected as a best pre-breeding material for drought breeding programme.