Winter survival in wheat requires programmed potential modulations to develop low temperature (LT) acclimation for its growth and yield. The purpose of the present study was to understand the relationships between developmental regulations and metabolic changes during LT acclimation and vernalization under field conditions. Six wheat recombinant inbred lines (RILs) of F8 generation resulted from cross Mironovskaya 808 (winter-habit parent) and Pishtaz (spring-habit parent) with different vernalization requirements and reproductive development, whose growth habits were determined by Vrn-1 loci, were cultivated under greenhouse and field conditions. Plants were sampled on three dates (Dec. 12, Jan. 11, and Feb. 10) as different phenological development stages. Early and rapid transition from vegetative to reproductive phase measured by double ridge (DR) formation and final leaf number (FLN) occurred in spring genotypes, including Pishtaz parent and RILs 4006 and 4014. They also had the lowest enzymatic antioxidants activity and contents of anthocyanins, total phenols, flavonoids, lignin, proline and carotenoids and the highest damage indices (H2O2 and MDA) among genotypes. RILs 4012 and 4016 had higher FLN than Pishtaz and remained in vegetative phase longer and showed higher tolerance (LT50 and metabolites) as compared to spring genotypes. In contrast, Mironovskaya 808 parent and RILs 4005 and 4003 spent the longest time in the vegetative phase and showed the highest level of LT tolerance (confirmed by LT50, damage indices and pigment contents). The highest level of LT tolerance in all genotypes, obtained at the vegetative/reproductive transition, significantly decreased with the onset of the reproductive phase. Our results suggested that LT tolerance was established from developmental regulations and potential metabolic networks following longer vegetative phase in wheat.
