Development of Pearl Millet Minicore Collection for Enhanced Utilization of Germplasm

Abstract

Pearl millet [Pennisetum glaucum (L.) R. Br.] exhibits enormous genetic diversity in the global germplasm collection. The pearl millet core collection (~10% of the entire collection), with 2094 accessions, is still large for precise evaluation to identify parents for a genetic improvement program. A minicore collection of pearl millet comprising 238 accessions was constituted by using data on 10 qualitative and 8 quantitative traits of 2094 core collection accessions. The hierarchical cluster analysis of data using a phenotypic distance matrix resulted in 136 clusters. A proportional sampling strategy with 10% or a minimum of one accession from each cluster was used to form the minicore collection. The comparison of data in the minicore and core collections using various statistical parameters, such as homogeneity of distribution for geographical origin and frequency classes of qualitative traits, means, median, within and between-accession variances, diversity index, and phenotypic correlations, indicated that almost the entire genetic variation present in the core collection was captured in the minicore collection. The possible impact of high between- and within-accession variability in pearl millet on maintenance of genebank accessions is discussed. With its greatly reduced size, the pearl millet minicore collection can be used for precise evaluation of traits of agronomic importance and biotic and abiotic stresses as well as mapping with molecular markers for identifi cation of trait-specifi c germplasm and discovery of new genes