Variety responses to vernalization and photoperiod in double purpose wheat varieties

Abstract

The wheat vernalization response is controlled by three recessive alleles identified and located, that allows to characterize varieties through genetic analysis. However, it is unknown whether the same genetic constitution at a loci scale in different varieties implies the same (1) requirement of cold hours, and (2) interaction with the photoperiod for induction. Therefore, we conducted an experiment with varieties carrying the alleles (vrn-A1, vrn-B1 vrn-D1), extreme condition of vernalization requirements, to compare the duration of the vegetative phase under different photoperiods. The study was conducted in a greenhouse with four varieties of double purpose wheat. The treatments were 8, 6, 4, 2 and 0 weeks of vernalization, and two photoperiods: natural - Fn - (approximately 10 h), and extended - Fe - (18 h). At the time of anthesis the number of days to flowering (DaF) since transplantation date was determined. We demonstrated that: (1) the presence of the three recessive alleles does not guarantee an identical performance in the varieties under the tested light regimes; (2) all varieties saturated their requirements with comparable amounts of chilling hours. However, shortening of the flowering period did not determine the same response in all varieties, and (3) our results suggest potential complementary effects of vernalization and photoperiod. However, some regulation coming from the residual genotype of each variety should not be overlooked on genes accountable for responses to vernalization.