Evaluation of rice (Oryza sativa L.) germplasm for biotic and abiotic stresses and their genetic diversity using SSR markers

The present study was carried out to screen the rice germplasm for biotic and abiotic stress tolerance. Fifty genotypes were screened using 18 microsatellite marker pairs distributed throughout the genome. Blast resistance alleles were observed in the genotypes viz., SYE -8, IRBLSH - KU (CO), TN1, Pusa Sugandha, B40, IPN - 12, IRBLZ - FU/RL, IR09L324 and IR10L139. Brown plant hopper resistance genotype includes; IRBLB -ITB (CO), IRBLK - KA (CO), IRBLKS -CO (CO), IRBLTA - ME (CO), IRBLSH -KU (CO), IR09L204, IR10A314 and IR10F221. Bacterial Blight resistant genotypes were; Basmati 370, SYE - 6, SYE - 7, SYE - 75, IRBLK - KA (CO) IRBLKS - CO (CO), IRBLSH - S (CO), IRBLT - K59, IRBLZ5 - CA (CO) and IRBLTA - 2 IR 64 (CO). Gall midge resistant genotypes are CT 186 14-4-1-2-3-2, SYE-4, SYE-5, SYE-6, IR09N251, IR09N516 and IR10A237 observed in the present studies. Four genotypes viz., IR10A237, IR10A314, IR10F221 and IR10A237 were observed tolerant to drought condition, since it showed amplification at specific base pair. Salt tolerant genotypes include; Ajaya, Durai, SYE-4, SYE-7, SYE-8, IRBLK-KU (CO), IRBLKP-K60, IRBLKS-CO (CO), IRBLTA-ME(CO), IR09N501, IR09N516, Basmati 370, TN1, Pusa Sugandha, B40, IPN-12, K90San, CT 186 14-4-1-2-3-2, IRBLSH-B(CO), IRBLSH-S(CO), IR05A272, IR09L324, IR09N251 and IR10A231. Out of total 18 SSR primers used in this study, 14 primers amplified and showed the polymorphism with357 loci. Each primer thus produced on an average 25.5 loci in the size ranging from 164.28 bp to 292.85 bp in the 50 rice genotypes in relation to diversity assessment. UPGMA grouped 50 rice genotypes into two main clusters, which were further divided into two subclusters. This study will be helpful for selection of parental lines and development of new breeding population tolerant to specific traits through marker assisted selection.