The effect of different nitrogen and irrigation levels on grain β-glucan content in some durum wheat cultivars

β-glucan is a non-starchy, water-soluble polysaccharide component of wheat grain that positively affects grain nutrient quality. High β-glucan content in wheat grain also has a cholesterol-lowering effect in humans. The aim of this study was to evaluate the effect of nitrogen and irrigation on durum wheat grain β-glucan content. Correlations between durum wheat grain β-glucan content, and grain yield and some quality characteristics were examined. Kunduru 1149, Kızıltan 91, and Çakmak 79 durum wheat cultivars were used as material, and 0-, 75-, and 150-mm irrigation levels with 0, 40, 80, and 120 kg ha^–1 nitrogen rates were applied. Higher nitrogen levels generally increased durum wheat grain β-glucan content in both years of the study and the N3 nitrogen level had the greatest effect on the β-glucan content in durum wheat. Higher irrigation levels negatively affected the β-glucan content in the wheat grain. Non-irrigated treatments generally yielded the highest β-glucan content in both years of the study. The response of grain β-glucan content according to cultivar was significant and C1 had the best grain β-glucan content of all the cultivars. Correlations between grain β-glucan content, and grain yield, protein content, 1000-grain weight, test weight, seed vitreousness, and the SDS sedimentation were significant. With the exception of protein content in 2005, strong positive correlations were observed between β-glucan content, and grain yield and quality characteristics. These results indicate that higher irrigation levels negatively affected grain β-glucan content in durum wheat, whereas higher nitrogen rates positively affected grain β-glucan content. Moreover, the effect of cultivar characteristics on the β-glucan content in durum wheat grain was statistically significant.