The influence of different soil types on rainfed wheat varieties for grain and protein yield

Twenty-three winter wheat (Triticum aestivum L.) varieties were tested in randomized complete blocks for four seasons in two fields (sandy and loamy soil), of the Mendel University in Brno, Czech Republic. Objectives were to find genotypes combining high grain with protein yield and cover the protein content standards. Stability was assessed on the coefficient of variation (CV) of grain yield and plant height (plot-to-plot variability), the level a variety lagged behind the maximum yield attained within a block (yield-gap index), and the GGE biplot analysis. Sandy and loamy fields simulated low- and high-input agroecosystems, respectively. The sandy field averaged 5.47 t/ha grain yield and 15.25% grain protein content, while the respective values for the loamy field were 10.4 t/ha and 13.17%. In the loamy field, nine varieties failed to meet the protein content benchmark of 13% for the breadmaking industry. The CV of plant height rather than of grain yield was a good criterion to show the effects of crop variation on yield and stability. The yield-gap index constituted a good measure of general adaptability to fluctuating conditions. Some varieties showed specific adaptation to sandy or loamy soil. On basis of CV of plant height, yield-gap index and GGE biplot, there were also varieties with general adaptability. Genotypes were found to have high protein content irrespective of grain yield, so selection of varieties with good yielding performance and protein concentration appears to be a sound pursuit.