Identification of QTL for seed yield and agronomic traits in 944 soybean (Glycine max) RILs from a diallel cross of early-maturing varieties

Increasing soybean yield plays a key role in meeting the high demand for protein in Europe and other countries. The aim of this study was to dissect the genetic architecture underlying seed yield, plant height, protein yield and thousand-seed weight in early-maturing soybean. To this end, we performed QTL mapping based on 944 RILs derived from a half-diallel crossing design of five parents. We identified five to eight QTL for each of the four agronomic traits and some explained a considerable proportion of the genotypic variance. The three major QTL showed pleiotropic effects on two or more traits. Fine characterization revealed the maturity genes E1 and E3, and the stem growth habit gene Dt2 as likely candidates underlying these QTL. In general, the allele increasing seed yield also resulted in taller plants, which needs to be considered during selection due to an increased risk of lodging. Collectively, our results underline the strong effect of some loci like the E1 gene on a range of traits including seed yield, making them attractive targets for a marker-assisted selection.