Effect of Variation for Major Growth Habit Genes on Maturity and Yield in Five Spring Wheat Populations

Segregation at major genes controlling plant height, photoperiod response, and vernalization response in wheat (Triticum aestivum L. em. Thell.) may have pleiotropic effects on several traits. Allelic variation at these loci can be monitored using polymerase chain reaction (PCR) markers. The effect of segregation at these loci on maturity and agronomic traits was measured for sets of recombinant inbred lines (RIL) developed from five crosses between spring wheat lines adapted to Montana and the Northern Great Plains. Results from field trials grown in multiple years in Bozeman, MT, showed that variation at Rht-B1 and Rht-D1 had large effects on most agronomic traits in two populations, including grain yield, grain protein concentration, and test weight. Variation at photoperiod response loci Ppd-B1 and Ppd-D1 influenced both heading date and date of flag leaf senescence under field conditions for two of three populations in which they were segregating. The insensitive allele at Ppd-B1 was associated with higher grain yield in one population. Variation at Vrn-B1 had a significant effect on heading date in the field for both populations in which it was segregating, with spring allele lines being earlier. Our results suggest that variation at Rht loci impacting plant height had large pleiotropic effects. Variation at photoperiod and vernalization loci impacted maturity characteristics but had less consistent effects on economic characteristics such as grain yield, test weight, and grain protein concentration.