Cold injury causes severe losses in wheat production and restricts varietal planting.
Winter wheat cultivars are vulnerable to cold temperatures and spring wheats are vulnerable to late spring freezes. Cold hardiness loci exhibit both dominant and additive effects between spring and winter wheats. The NILs were derived from six backcrosses between a hardy winter wheat recurrent parent 'Daws' to 'Triple Dirk' NILs, each containing a different Vrn gene, and then selecting for growth habit starting in the BC2. Spring NILs carrying either Vrn2, Vrn3, or Vrn4 had a significantly more cold hardiness compared to the Vrn1 NILs. This cold tolerance was similar to winter habit NILs with the same Vrn genes.