Plant Genome IV Conference Plant Genome IV Conference
Results are presented from a study in maize designed to evaluate several aspects of quantitative trait locus (QTL) mapping under both optimum and stress environments. Experimental materials were derived from a set of 208 RI lines developed from the maize single cross, B73 x Mo17, which were then backcrossed to the parental lines. Backcross progenies were evaluated in several field environments with a 2 x 2 x 2 factorial arrangement of soil moisture levels, soil nitrogen levels, and planting densities. The study was conducted over three years in two locations and involved nearly 13,000 experimental plots. Discussion will focus on how mapping results differ under different types of stress, on differences between vegetative and reproductive traits, on differences between results using RI lines versus F3 lines in an earlier study, and on possible effects on breeding strategies. For example, it was found that under optimum environmental conditions, QTL maps generated from F3 line backcross date were very similar to those generated from RI line backcross data.