Linkage analysis for drought tolerance in kharif rice of Assam using microsatellite markers

Drought stress in rainfed ecosystem significantly limits the production of Ranjit, the most predominant high yielding rice variety of Assam. A mapping population comprising 85 F-4 individuals between Ranjit and a drought tolerant cultivar, ARC10372 was developed and genotyped with 80 microsatellite markers in order to understand the genetic basis of drought tolerance. The linkage map constructed based on a framework linkage map using these markers showed that the marker loci were distributed across 12 chromosomes spanning a distance of 273.4 cM with an average interval of 3.41 cM between marker loci. Most of the marker loci were found to be in good fit with the expected Mendelian segregation ratio; however, thirteen marker loci in total showed segregation distortion on six chromosomes. The linkage map generated in the study will facilitate mapping of quantitative trait loci imparting drought tolerance in rice of Assam and their map-based cloning.