Establishment of a pearl millet [Pennisetum glaucum (L.) R. Br.] core collection based on geographical distribution and quantitative traits

ICRISAT conserves a large collection of pearl millet [Pennisetum glaucum L. R. (Br.)] comprising of 21,392 accessions. This includes landraces, cultivars, genetic stocks, breeding lines, and wild relatives from 50 countries. However, only a small fraction of this huge collection has been exhaustively used in the pearl millet improvement program. The objective of our research was to develop a core collection of pearl millet to enhance utilization of genetic resources in improvement programs and simplify their management. For this purpose, accessions were initially stratified according to geographical distribution followed by hierarchical clustering on 11 quantitative traits using Ward's method. This resulted in 25 distinct groups. Approximately 10% accessions were then randomly selected from each of these 25 distinct groups to form a core collection of 1,600 accessions. Different statistical methods like comparison of mean using Newman-Keuls test, variance using Levene's test, frequency distributions using Chi-square test, and Wilcoxon's rank-sum non-parametric test for the traits validated that the variation present in entire collection had been preserved in the core collection. The important phenotypic correlations among different traits that may be under the control of co-adapted gene complexes were also preserved in the core collection. The diversity represented in the core collection will therefore, be a guideline to breeders for a wider use of the pearl millet genetic resources available in the genebank.