Molecular mapping of quantitative trait loci for stigma exsertion trait in rice (Oryza sativa L.)

Stigma exsertion is the most important floral trait of female parent/cytoplasmic male sterile (CMS) line for out crossing which increases hybrid seed production at farmer’s field. The present study was aimed to map the genomic regions controlling the stigma exsertion in F2 mapping population derived from IR68897B, a recipient maintainer line of IR68897A with low stigma exsertion (36.78 %) and BF-16B, a donor parent for high stigma exsertion (80.25%). Phenotyping and genotyping of stigma exsertion trait was done for 188 individuals of F2 population developed from IR68897B X BF16B. Frequency distribution of F2 population showed continuous variation which indicated polygenic nature of inheritance. Phenotypic evaluation revealed that significant variation for stigma exsertion trait and transgressive segregation was observed. A total of 15 QTLs were identified for total stigma exsertion rate (TSE) which includes single and dual stigma exsertion distributed on chrm 2, 3, 4, 5, 6, 8, 11 and 12 through QTL mapping. The phenotypic variance and LOD value explained by each QTL ranged from 1.19 to 5.83% and 2.54 to 9.29 respectively. In the present study, total 15 QTLs were minor effect QTLs s