Multi-population QTL Detection for Flowering Time, Stem Elongation and Quality Traits in Medicago truncatula

Medicago truncatula, as a model species, is useful to study the genetic control of flowering time, stem elongation and quality (protein content and digestibility) in legume crops. These traits were measured in four mapping populations originating from five parental lines. Single and multi-population quantitative trait locus (QTL) detections were carried out. A large variation was observed within populations and transgressive segregations were noted. On average, genotypes with long primary branches and a high branch elongation rate showed an early flowering date and a long main stem and had lower digestibility and protein content. Ninety QTLs for morphogenesis and 27 QTL for quality were identified and localized over all eight chromosomes. All QTLs for quality traits were located in genomics regions showing QTL for morphogenesis, suggesting common regulation and/or colocation of genes responsible for their variation. Using genomic resources publicly available, a list of candidate genes that could control variation for aerial morphogenesis and quality was established.