Simple sequence repeat (SSR) markers for assessing genetic diversity among the parental lines of hybrid rice (<i>Oryza sativa</i> L.)

Abstract

The present scientific study was carried out at Tamil Nadu Rice Research Institute, Aduthurai with the objective of studying the genetic divergence among 51 restorer and five maintainer lines in terms of grain quality and fertility restorer genes (Rf3, Rf4 and Rf7) using 55 primers of simple sequence repeat (SSR) markers. Among them, 37 SSR markers were found to be polymorphic and the number of amplified fragments ranged from one to five. The highest polymorphic information content (PIC) value (more than 0.60) was observed for eight primers viz., AB 443, RM 3, RM 29, RM 226, RM 228, RM 304, RM 1812 and RM 3873 and average PIC value was 0.444. Cluster analysis using NTSYS generated dendrogram divided all the 56 parental lines into two distinct groups viz., maintainer line (Group I) and restorer line (Group II) at 76% coefficient of similarity. Maintainer line group consisted of five genotypes (COMS 23B, COMS 24B, COMS 25B, CRMS 31B and CRMS 32B) and restorer line group had 51 genotypes. Further, at 80% similarity, all fifty one restorer lines were again grouped into nine clusters. With higher polymorphism revealed by SSR markers, parental lines having the similar genetic background from pedigree information were grouped into different clusters. The combination of pedigree analysis and SSR markers could be a more reliable method to study the diversity and grouping of parental lines of hybrid rice. Hybridization between diverse restorer and CMS groups identified from this study would be expected to yield hybrid combinations with premium grain quality and good fertility restoration.

Keywords: Simple sequence repeat (SSR), maintainer and restorer genetic diversity, grain quality, fertility restoration

African Journal of Biotechnology Vol. 12(33), pp. 5105-5116,