MOLECULAR MARKERS ASSOCIATED WITH SOYBEAN PLANT HEIGHT, LODGING, AND MATURITY ACROSS LOCATIONS

The identification of quantitative trait loci (QTL) has the potential to improve the efficiency of selection for polygenic traits in a plant breeding program. In this study a soybean, Glycine max (L.) Merr., po pulation derived from the cross of 'Young' and PI 416937 was evaluated with restriction fragment length polymorphism (RFLP) markers to ident ify QTL related to plant height, lodging, and maturity. One hundred-tw enty F-4-derived lines were evaluated for segregation at 155 RFLP loci . Field data were obtained in four different locations in 1994 (Athens and Plains, GA, and Windblow and Plymouth, NC). The genetic map consi sted of 137 RFLP loci which converged into 31 linkage groups and cover ed more than 1600 centimorgan (cM). By means of single-factor analysis of variance, 11 independent markers associated with plant height and the eight with lodging explained most of the genetic variability for t hese traits in combined analysis over locations. Of the 11 RFLP marker s associated with plant height and the eight with lodging, only two ma rkers for plant height (Blt043 and A063a) and one for lodging (A169) w ere detected in all locations, indicating either the inconsistency of these molecular markers across locations or the inability to detect pu tative QTL with the population size of 120 lines. However, good agreem ent of QTL across locations was found for maturity. Five markers were identified that explained variation in mean maturity over three locati ons, four of which were associated with maturity in all three location s. Results from this research indicate the level of consistency of QTL across environments is trait specific.