Growth and yield responses of spring and winter triticale cultivated under Mediterranean conditions

Eight hexaploid triticale genotypes, five of spring and three of winter growth habit were used to study biomass production, contribution of the pre-anthesis assimilates to the grain yield, and their relationship to grain yield. Genetic effects for biomass production were found at anthesis but not at maturity. Growth-habit explained most of the detected differences for biomass production: winter triticale had around 15% higher dry matter than spring triticale at anthesis. However, the higher accumulated thermal time from sowing to anthesis could explain the observed differences, since the correlation coefficient between both variables was 0.78 (P < 0.001, n = 24). Dry matter translocation (DMT) was 30% higher for winter than for spring triticales, representing a contribution to the grain yield of 60.9% for winter genotypes and 42.0% for spring ones. However, grains were 26.8% heavier in spring than in winter triticales, and, finally, spring triticales yielded around 21% more than winter types. For spring genotypes, crop dry weight at anthesis was positively related to yield, whereas for winter triticales the relationship for these two variables was negative. Highest values of triticale grain yield were reached when time from sowing to anthesis was comprised, approximately, between 1350 and 1420 growing degree-days (GDD), decreasing before and after this interval. Thus, time to anthesis for spring triticales were included into the optimum interval, which permitted to reach higher grain yield. We could conclude that spring triticales are much more adapted than winter triticales for grain production under Mediterranean conditions. (C) 2003 Elsevier B.V. All tights reserved.