Barley adaptation. Lessons learned from landraces will help to cope with climate change

Abstract

27 Pags., with Figs. y Tabls.Adaptation of crops to temperate climates depends to a large extent on plants having the appropriate combination of genes to respond to environmental cues. Global warming poses new challenges to plant breeding. In many places, current cultivars will no longer be suited for cultivation. We present several findings on barley adaptation to Mediterranean climates, which resulted from the study of adaptations presented by local landraces. Winter barley is widely grown in the Mediterranean region. We found that local winter landraces have some degree of vernalization requirement, tuned to respond to the winter temperatures typical for each region. Our results demonstrate that the allelic series of the main vernalization gene, VrnH1, is essential to determine the length of the cold period needed to promote flowering in barley. The presence of photoperiod gene HvFT3 in most Mediterranean landraces is presented as a safety mechanism to promote flowering, which comes into play at least when vernalization conditions are not optimum (rather often in some areas). This mechanism is coordinated with the vernalization pathway through repression by VrnH2. A latitudinal pattern of distribution of HvFT1 in Spanish barleys suggests a role in adaptation. This gene integrates the photoperiod and vernalization pathways in barley, and seems to present an allelic series of at least five functionally different alleles. We present evidences from several independent sets of materials that demonstrate the effect of three of these alelles, in accordance with the latitudinal distribution observed. A combination of these three mechanisms optimizes the growth cycle of Mediterranean landraces. These mechanisms have a wider interest in a climate change scenario, as temperatures in most of Europe will increase, and may become beneficial in higher latitudes. Cultivars with new combinations of vernalization, photoperiod and frost tolerance alleles will have to be bred for the upcoming conditions.Funded by Spanish Ministries of Economy and Competitiveness (former Science and Innovation) and Agriculture.Peer reviewe