Investigation of rice recombinant inbred lines based on drought tolerance using tolerance indices and SSR markers

Drought stress is considered as one of the most important limiting factors in plant production. In the present study, 142 recombinant inbred lines (RILs) derived from IR28 and Shahpasand were investigated in Faculty of Agricultural Sciences University of Guilan during spring and summer 2015. After recording of yield under normal and drought stress conditions, in order to determine the drought tolerant lines were used tolerance indices and microsatellites markers that identified as linked to drought stress. According to the cluster analysis results, all of lines were divided to four groups. In this grouping two lines (37 and 144) a long with another sub group with 11 lines were most tolerant lines based on tolerance indices (GMP, STI and MP). Average yield of these 13 lines under normal and drought stress condition were 5.086 and 4.678 t/ha respectively. In order to validate identified markers for drought stress identified in previous studies, a stepwise regression was performed. The marker RM7 for all dependents variables, RM231 for yield under two conditions, STI and RM302 for yield under two conditions, GMP, and MP were significant and thereafter RM12091, RM19367 and RM10793 were the next important markers. Association analysis revealed 51.4% of variation of yield under drought stress was explained by RM7, RM231, RM302, RM12091 and RM19367 markers that can be indicative a confirmation of these markers importance in present genetic background.