Registration of Near-Isogenic Lines for Photoperiod Response in Hard Red Spring Wheat

Alleles at photoperiod response loci Ppd-B1 and Ppd-D1 affect the adaptation of wheat (Triticum aestivum L.) genotypes to specific latitudes. Near-isogenic lines (NILs) were developed in five hard red spring wheat backgrounds for alleles at the Ppd-B1 and Ppd-D1 loci and tested for five location-years in Montana. Lines homozygous for the insensitive allele at Ppd-D1 (Ppd-D1a) headed earlier than lines with the insensitive allele at Ppd-B1 (Ppd-B1a). Lines homozygous for alleles for photoperiod sensitivity (Ppd-B1b and Ppd-D1b) were the latest to head. There were no differences in grain yield among the NILs based on means over the environments and parents. The lines have utility to assess the impact of photoperiod response at varying latitudes and conditions. This provided rationale for the release of 15 NILS (Reg. No. 975, PI 673428-Reg. No. 989, PI 673442), 3 NILs for each of the 5 parents, including lines with the insensitive allele at either Ppd-B1 or Ppd-D1, and photoperiod sensitive lines with the allele for sensitivity at both Ppd-B1 and Ppd-D1.