Grain protein quality in response to changes in pre-anthesis duration in wheats released in 1940, 1964 and 1994

Grain protein content is one of the most important attributes in bread making quality. Several studies have reported that the type of, and the balances between, storage protein (i.e. gliadins and glutenins) are also relevant. Generally, the modern cultivars present less grain protein content than their predecessors, suggesting that breeding may have reduced baking quality while improving yield. Furthermore, there is little information on whether, and eventually how, breeding influences the types of protein synthesized in the grains, and the sensitivity of the type of protein and baking quality to changes in the environment. This study aimed to determine the stability in baking quality in wheat cultivars released at different eras to variation in the duration of the pre-anthesis period without changes in the sowing date. The experiment studied the combination of three cultivars released in 1940, 1964 and 1994 at two different durations from sowing to anthesis (because of exposure to different photoperiods during stem elongation in the field). Modern cultivars showed lower grain protein content than the oldest ones (11 vs. 14 %). There were no correlation between grain protein content and baking quality (assessed by Zeleny test), indicating that protein type is more important than grain protein content. Gliadins were more variable than glutenins because of differences between cultivars and flowering dates. Wheat breeding also seemed to have improved the stability of quality variables in response to environmental variation during the pre-anthesis period (when yield potential is being determined).