QSY-3 CONTROLS MULTIPLE MORPHOLOGY, PHENOLOGY AND GRAIN YIELD TRAITS IN RICE (ORYZA SATIVA L.) UNDER SALINITY STRESS

Rice (Oryza sativa L.) production, all over the world, is affected by salinity stress. A major quantitative trait locus (QTL), qSY-3, linked to rice straw yield was identified in our previous study. Nearest marker to this QTL was RM473D located on rice chromosome 3. Present study was designed to validate this QTL. A representative panel of twenty four rice varieties was used in this study. Panel consisted of salt-susceptible, as well as, salt-tolerant varieties. Panel was cultivated under saline, as well as, normal conditions and traits related to morphology, phenology, and grain yield were scored. Genotyping of the panel was done with 111 polymorphic simple sequence repeats (SSR) markers. Genotypic data were analyzed by STRUCTURE software to identify subpopulations in the panel and TASSEL software for marker-trait association assessment. Marker RM473D was found associated with eight traits including straw yield per plant (SY). Probability (P) and phenotypic variance explained (R-2 ) values for these associations ranged from 0.0001-0.0427 and 23.39%-54.86%, respectively. It appeared that qSY-3 is a major locus controlling morphology and grain-yield in rice. In future, this locus can be exploited through marker-assisted breeding approach for the development of rice cultivars with good yield potential under salt stress conditions. Our study demonstrated potential of association mapping approach in validating previously identified QTLs.