Agronomic Performance of Spring Wheat as Related to Planting Date and Photoperiod Response

Abstract

ABSTRACTPhotoperiod response impacts the adaptation of spring wheat (Triticum aestivum L.) to specific areas of the world. Both photoperiod sensitive (PS) and photoperiod insensitive (PI) cultivars are grown successfully in the northern regions of the western United States and the Canadian plains. The goal of the present experiment was to determine the relative performance of PI and PS genotypes as related to planting date and to interpret results in view of climate trends for the region. Three sets of near‐isogenic lines that differed for alleles at the Ppd‐D1 locus for photoperiod sensitivity were tested at three planting dates in 15 environments in Montana, Washington, Saskatchewan, and Alberta. Results showed that PS lines headed later than PI lines at all planting dates. Grain yield was significantly greater for PS lines at the first two planting dates although no difference between PS and PI lines occurred for the latest planting date. Our results suggest that PS lines are superior to PI lines for this region. This difference is likely to be significant for regional adaptation as planting date becomes earlier due to increasing spring temperatures.