Characterization of USDA Mini-core Panel of Rice Germplasm, based on Amylose Content Analysis and Waxy Gene Linked DNA Markers

Abstract

: Eating and cooking quality of rice is mainly determined by its amylose (major starch component) content. Waxy gene, located on chromosome 6 is involved in starch biosynthesis in rice endosperm. Amylose is also important to classify rice varieties and its accurate evaluation is a real challenge in development of rice varieties with desirable cooking quality. Current study aimed to characterize amylose content of USDA mini-core collection of rice germplasm by waxy gene linked molecular markers and their validation.  Biochemical analysis was performed through iodine binding method to determine amylose content of rice endosperm while genotypic analysis was performed by using microsatellite (SSR) and single nucleotide polymorphism (SNP) based molecular markers. Statistical tools were used to check the consistency of results. Results revealed that mini-core is diverse collection of rice germplasm with respect to amylose content and based on these findings accessions were classified into three groups (low, intermediate and high amylose containing rice) while most of accessions fall in intermediate amylose containing category. According to PIC value (from PowerMarker), RM190 was found to be highly informative marker for screening of mini-core panel. This study will be important in selecting and utilizing intermediate amylose containing genotypes for future breeding programs.