A Rice Diversity Panel Evaluated for Genetic and Agro‐Morphological Diversity between Subpopulations and its Geographic Distribution

Abstract

A diverse collection of 409 Asian rice (Oryza sativa L.) accessions originating from 79 countries was fingerprinted with 36 simple sequence repeat (SSR) markers and evaluated for 18 agro‐morphological traits. Genetically, the accessions clustered into five ancestral groups (subpopulations), indica, aus, aromatic (Group V), tropical japonica, and temperate japonica, based on model‐based structure analysis. Thirty‐three accessions with less than 60% ancestry from any single group were identified as admixtures. Canonical discriminant analysis identified eight agro‐morphological traits (panicle number per plant, panicle length, plant height, flag leaf width, grain length, width, length:width ratio, and volume) as the main discriminatory characters among the rice accessions and between the subpopulations. Both SSR allele‐ and phenotypic trait‐based analyses indicated a close relationship between aus and indica and similarly between temperate japonica and tropical japonica. The aromatic (Group V) rice represents a distinct small group that is more closely related to tropical japonica based on SSR alleles but to aus and indica based on phenotype. A strong relationship between subpopulations and geographical distribution was observed. This rice diversity panel with the accompanying genetic and phenotypic information provides a valuable foundation for association mapping, understanding the basis of both genotypic and phenotypic differences within and between subpopulations, and rice improvement programs.