Phenotypic Diversity of US Proso Millet (Panicum miliaceum L.) Core Collection.

Proso millet (Panicum miliaceum L.) is the lowest water-requiring cereal and increasingly being used for human consumption. It can play a critical role in global food security especially in dryland production regions. It is the best rotational crop for a wheat-based dryland production system in the semi-arid High Plains of the USA.  This crop has a limited breeding history. The genetic base of six commonly grown US cultivars is very narrow. Assessment of proso millet germplasm for agronomic traits is essential for its efficient utilization in the genetic improvement of this crop. Objectives of this study were to (1) characterize the US proso millet germplasm for nine morpho-agronomic traits and (2) to cluster the germplasm based on these traits. A total of 77 genotypes from 24 different countries were evaluated in the field during 2014 at two locations. Data and cluster analysis were done using SAS. The genotypes showed a wide range of variation and were significantly different for all the traits across locations. Many traits showed genotype by environment interactions and were highly correlated. Several genotypes were identified as sources of important traits such as maturity, lodging, and grain shattering. The genotypes formed six clusters based on phenotypic data. Principal component analysis revealed that eight of the nine traits explained maximum phenotypic variance and could be used as selection indices in proso millet breeding. This is the most comprehensive genetic diversity analysis of the US proso millet germplasm based on morpho-agronomic traits and would be useful for developing improved proso millet cultivars.