The influence of Vrn-B1a and Vrn-B1c alleles on the length of developmental phases of substitution and near-isogenic lines of common wheat

The influence of Vrn-B1a and Vrn-B1c alleles on the length of developmental phases in lines of winter cv. Sava with intervarietal substitution of chromosomes 5B and near-isogenic lines (NILs) with these loci in the genetic background of winter cv. Bezostaya 1 is studied. We have confirmed, that effects of Vrn genes appear on the tillering phase and that the response to vernalization and shortening of day length can change the duration of this phase. We have shown that after vernalization and under short-day conditions the Vrn-B1a allele has the strongest effect on the length of the tillering phase. After vernalization in late substitution line Sava (Diamant II 5B) with the Vrn-B1a allele length of the tillering had decreased 6 days stronger, than in the earlier line Sava(Saratovskaya 29 5B) with the Vrn-B1c allele. After shortening of the day length in late NIL i:Bez1Vrn-B1a the length of the tillering phase and of period “stem elongation—heading” had increased stronger, for 13 and 5 days, respectively, than in the early i:Bez1Vrn-B1c line. The study of F₁ hybrids between substitution and isogenic lines, the growth habits of which are determined by both Vrn-B1a and Vrn-B1c alleles, had shown the dominance of the trait lateness, which is determined by the Vrn-B1a allele. In F₁ hybrids between substitution lines, the length of tillering was similar to that of the line with Vrn-B1a allele, and in F₁ hybrids between NILs, the length of tillering was intermediate between parental lines.