Effects of N and K fertilizers on durum wheat quality in different environments

• Nitrogen fertilizers increased protein content and gluten content.
• Potassium contributed to protein and thousand kernel weight increase.
• Landraces showed superior quality traits expression over high yielding varieties.
• Semi-arid areas valorized the fertilizers use and quality expression.
• Gluten elasticity was reduced in the semi-arid areas with excessive rainfall.

Eight genotypes from two different genetic pools (high yielding varieties and landraces) were assessed for grain yield (GY) and for five quality traits: protein content (P), thousand kernel weight (TKW), yellow berry (YB), gluten content (Gc) and gluten index (Gi) in sub-humid and semi-arid areas using four combinations of nitrogen and potassium fertilizers during two cropping seasons. Genotype × Environment × Fertilizers (G × E × F) was significant only for protein content (p < 0.05); and E × F was found significant (p < 0.05) for all parameters. Greater quality related traits expression was noted in the semi-arid areas for both genetic pools. Excessive rainfall in semi-arid areas resulted in gluten elasticity reduction. N-fertilizers seemed to enhance protein content and to reduce thousand kernel weight. K-fertilizer, might enhance the increase in both proteins and thousand kernel weight in favorable growing conditions of water availability. Semolina yielding ability was higher in landraces as compared to high yielding varieties particularly using recommended fertilizer management. This group of cultivars showed superiority over high yielding cultivars for quantitative quality parameters.