Development of Laos Khao Kai Noi rice landrace (Oryza sativa L.) core collection as a model for rice genetic resources management in the Laos National Genebank

Abstract

Khao Kai Noi rice is considered as an elite quality landrace in Laos, which has led to its germplasm conservation in the Laos National Genebank. As happens with other germplasm collections, a manageable yet representative sub collection has become an essential element for researchers and breeders to simplify many activities, including those related to crop improvement, phenotype-genotype correlation and determination of diversity hotspots. In this study, 109 accessions were used as a test collection for core collection development to determine the feasibility of collection reduction in a closely related rice group. Three core collections were developed by two established methodologies and evaluated by diversity indexes, allele retention, phylogenetic distribution and geographical location. Based on SSR molecular markers and PowerCore, a reduction to 24 accessions was achieved with the conservation of complete genetic diversity. A K-means based on reduction to 24 accessions rendered slightly lesser results while based on 12 accessions resulted in a 17% diversity loss. These core collections may be useful for genebank management, research and breeding activities in the future. Also, they may as well serve to estimate core collection development behavior in other landraces and cultivars, which is fundamental in genetic resources management and utilization.