Abstract

Grain quality is an essential component in wheat breeding programs since influences the commercial value of wheat. This study was conducted to determine the effects of genotype, season and sowing date on quality parameters of seventeen bread wheat commercial varieties and three advanced lines from Portuguese Wheat Breeding Program (Plant Breeding Station, Elvas, Portugal) under irrigated Mediterranean systems. Field experiments were conducted at two locations of Southeast Portugal (Elvas and Beja), during two growing seasons. At Elvas, results showed that environment (season) had highest contribution on variation of quality traits. At Beja experiments, the level of environment (season) influence decreased in relation to Elvas experiments: season was the most important factor to explain the variation of protein content and test weight, but for alveograph parameters (W and P/L ratio) it was found that genotype had higher influence. Sowing date was ever the most important factor to explain thousand kernel weight. The results confirmed that genetic potential is crucial to obtain high quality wheat but it is necessary a good environment to promote its expression.

Key words: Bread wheat, Environmental constraints, Genetic improvement, Quality traits, Sowing date