Identification of trait-specific germplasm and developing a mini core collection for efficient use of foxtail millet genetic resources in crop improvement

Abstract

Foxtail millet is an important staple crop in some parts of China, India and Japan, and a potential bioenergy source. The grains are rich source of protein, fiber, minerals and vitamins. We had earlier reported the development of a core collection (155 accessions) of foxtail millet. This study was initiated to identify trait-specific germplasm for agronomic and nutritional traits, and to develop a mini core through multilocational evaluation of the foxtail millet core collection. One hundred and fifty-five accessions together with five controls (four common and one location-specific control) were evaluated for 21 descriptors at five agro-ecologically diverse locations in India during the 2008 rainy season. The experiment was conducted in an alpha design with three replications at Patancheru, and in an augmented design with one of the five controls repeated after every nine-test entries at other locations. A number of diverse germplasm accessions with agronomically (earliness and high grain yield) and nutritionally (high seed protein, calcium, iron and zinc) superior traits were identified for use in foxtail millet breeding. The hierarchical cluster analysis of data using phenotypic distances resulted in 25 clusters, from each cluster, ∼10% or a minimum of one accession was selected to form a mini core, which comprised of 35 accessions. The comparison of mean, variance, frequency distribution, diversity (H’) and phenotypic correlations revealed that the mini core indeed captured adequate variability from the core collection. This mini core collection is an ideal pool of diverse germplasm for studying population structure and diversity, and identifying new sources of variation for use in breeding and genomics studies in foxtail millet.