Parental Polymorphic Marker Survey and Genetic Diversity Studies among the Popular Maintainer Lines of Hybrid Rice (Oryza sativa L.) for Stigma Exsertion Trait

Parental polymorphic survey using rice satellite (RM) simple sequence repeats (SSR’S) is a pre-requisite for genotypic screening to identify the loci associated with trait of interest among mapping population. In the present study, eight popularly used rice maintainer lines viz., APMS-6B (Improved for Bacterial leaf blight. [1], IR58025B, IR68897B, IR79156B, DRR-6B, DRR-9B, BF-16B and BF2096B were used to study stigma exsertion trait as a single, double and total stigma exsertion. A total of 630RM markers were used to study parental polymorphism among eight maintainer lines and also to map their association with stigma exsertion trait. Among 630, 253 RM markers showed polymorphism with 635 alleles among the eight maintainers which were distributed across twelve chromosomes of rice. The overall parental survey revealed 40.18 per cent of polymorphism among the maintainer lines with a maximum and minimum frequency of 5 and 2 alleles, respectively. The genetic similarity coefficient for the most number of pairs ranged between of 0.2-0.9 with the average value of 0.60 for all possible combinations, indicating moderate genetic diversity among the chosen genotypes. The genotypes grouped according to their place of origin and represents genetic closeness between them. The identified RM polymorphic markers could be used to construct the linkage map and subsequently, to identify the stigma exsertion related QTLs from mapping population developed from different combinations of the rice maintainer lines.