Effect of Genes Governing Photoperiod and Vernalization Response on Wheat Phenology and Adaptation

Photoperiod–Vernalization Gene Interactions in Wheat

Abstract

Flowering time in wheat is a complex trait that significantly influences total yield and adaption of wheat to different niches, and is primarily under the control of vernalization genes (VRN genes) and photoperiod sensitivity genes (PPD genes). Strategic changes in these alleles have yielded substantial gains in productivity. In the present study, different allelic combinations of vernalization (Vrn) and photoperiod sensitivity (Ppd) genes were identified in two back cross populations derived from winter wheat x spring wheat crosses and were evaluated under various sowing regimes. The BC1 F6 progenies for the crosses Chianti/WH1105//PBW698 and Aciento/2*PBW683 showed wide variation for days to flowering, ranging from 95 to 125 days and 90-115 days, respectively. Screening of parental lines for the Vrn1 and Ppd-D1 genes revealed that the parents of the cross Aciento/2*PBW683 were polymorphic for two Vrn1 genes viz. Vrn-B1 and Vrn-D1, while,those of the cross Chianti/WH1105//PBW698 were polymorphic for these loci as well as for the Ppd-D1 gene. The identified allelic haplotypes of Vrn and Ppd genes were evaluated for productivity and phenology across three sowing regimes. Different allelic combinations of Vrn and Ppd genes affected days to flowering, tiller number per plant, and thousand-grain weight. Spikelets per spike were not affected by allelic variation in Vrn1 gene. However, this trait was influenced by allelic variation at the Ppd-D1 gene. These findings provide valuable guidance for wheat breeding programs in India to strategically deploy Vrn and Ppd alleles for developing varieties with improved phenological adaptation and higher productivity under diverse sowing environments.