Augmenting the pearl millet core collection for enhancing germplasm utilization in crop improvement

Developing a core collection that represents the diversity of entire collection is an efficient approach to enhance the use of germplasm in crop improvement. Core collections are dynamic and need to be revised when additional germplasm and information become available. In the present study, the pearl millet [Pennisetum glaucum (L.) R. Br.] core collection, consisting of 1600 accessions selected from about 16,000 accessions characterized at the International Crops Research Institute for the Semi-Arid Tropics Genebank by 1998, was augmented by adding 501 accessions representing 4717 accessions assembled and characterized in the past 9 yr. The revised core consists 2094 accessions. (Five duplicate and two male sterile accessions were deleted from original core collection.) A comparison of mean data using Newman-Keuls test, variance using Levene's test, and distribution using χ2 test indicated that the variation in the entire collection of 20,766 accessions was preserved in the revised core collection. A few important phenotypic correlations that may be under coadapted gene complexes were preserved in the revised core collection. The Shannon-Weaver diversity index for different traits was similar in the revised core and entire collection. The revised core collection was observed to be more valuable than the original core as it has sources of resistance for important diseases such as downy mildew. The revised core collection could be a point of entry to the proper exploitation of pearl millet genetic resources for crop improvement