Protein concentration inheritance and selection in durum wheat

Grain protein concentration is important in the determination of the value of durum wheat (Triticum turgidum L. var. durum) for pasta manufacture. This study was undertaken to investigate the heritability and inheritance of protein concentration in seven genetically diverse durum populations, and to determine if the precision of this information could be improved by adjustment for micro-environmental trends. Grain protein and grain yield were measured at multiple locations and years. The Papadakis method was used to adjust for environmental trends in these replicated trials, and the moving mean was used for confimation in a sample of 19 un-replicated breeding trials. Environmental trends were substantial, and trend adjustment improved both correlations among locations and precision. Consequently, trend adjustment may be useful for genetic studies to improve trial precision, but would be of questionable merit in early-generation breeding trials due to the cost of additional protein measurements and marginal improvement in selection response. Grain yield was negatively correlated with grain protein concentration in all trials. Protein concentration was moderately heritable and complexly inherited in these populations, with the number of estimated effective factors ranging from 5 to 17 for the majority of trials. The complexity of inheritance and interactions of protein with yield and environment makes early-generation selection for protein difficult.Key words: Grain protein concentration, heritability, inheritance, semi-dwarf