GENETIC DIVERSITY AMONG INDONESIAN RICE (Oryza Sativa L.) GENOTYPES FOR DROUGHT TOLERANCE

Rice is one of the most important staple foods for most people in the world. However, worldwide rice production is threatened by abiotic stress caused by global climate change. Drought is the most extensive abiotic stress for rice, because compared with the other cereal crops rice needs a vast amount of water for growth and development. The breeding of rice cultivars for drought stress is indispensable. The availability of broad genetic diversity, including drought tolerance, in rice is essential in crop genetic improvement programs. Thus, the evaluation of genetic diversity is a critical step in a breeding program. We report a genetic diversity analysis of Indonesian rice germplasm based on Simple Sequence Repeat (SSR) markers linked to drought tolerance traits in rice. Forty-five rice germplasm consisting of 41 genotypes and four check cultivars were used in this study. Nine markers consisting of eight SSR markers and one custom marker designed based
on the deeper rooting gene were used to analyze rice germplasm. Results showed a low number of alleles and moderate genetic diversity. An unweighted pair group
method with an arithmetic mean dendrogram generated by cluster analysis revealed four major clusters. A biplot generated via principal coordinate analysis divided rice germplasm into two major groups and confirmed the cluster analysis results. Rice genotypes in clusters I and II belonged to the first group. Similarly, the members of clusters III and IV belonged to the second group. The members of cluster I were predicted to be tolerant of drought stress because they belonged to the same cluster as the drought-tolerant check. This finding will be useful for theacceleration of rice breeding programs for drought stress tolerance.