Mapping QTLs for Morpho-Agronomic Traits in Proso Millet (Panicum miliaceum L.).

Proso millet (Panicum miliaceum L.) is the lowest water-requiring cereal and increasingly being used for human consumption. It is the best rotational crop for a wheat-based dryland production system in the semi-arid High Plains of the USA. No genetic linkage map and QTL mapping for proso millet are available. Objectives of the present study were to (1) construct a genetic linkage map and (2) map and identify DNA markers linked of QTLs for morpho-agronomic traits. A total of 93 recombinant inbred lines derived from a single F1 (‘Huntsman’ x ‘Minsum’) were genotyped with GBS-SNP markers and phenotyped for nine morpho-agronomic traits in the field during 2013 and 2014 at Scottsbluff and Sidney, NE. IciMapping v.4.0.6.0 was used for genetic linkage map construction and QTL mapping.  The RILs were significantly different for many traits and several traits showed genotype x environment interactions. A total of 833 GBS-SNP markers formed 18 major and 84 minor linkage groups, whereas 519 markers remained ungrouped. A total of 117 GBS-SNP markers on the 18 major linkage groups spanning a genome length of 2137 cM of proso millet with an average distance of 18 cM between markers. The length and number of markers in each of the 18 major linkage groups ranged from 54.6 cM to 236 cM and four to 12, respectively.  A total of 17 QTLs for seven morpho-agronomic traits were detected on 14 linkage groups, which explained 13.6 to 34.7% phenotypic variance.  DNA markers flanking the QTLs were identified, which would be useful in marker-assisted selection of these traits. This is the first genetic linkage map and QTL mapping in proso millet, which would be useful for further genetic analysis and map-based cloning the genes.