Effects of foliar zinc application at different growth stages on the antioxidant traits and the other quality parameters of grain in some winter durum wheat cultivars

In this study, it was aimed to investigate the effects of foliar applied zinc (ZnSO4.7H2O) with the dose of 0.2% on grain antioxidant activity (DPPH. and ABTS.+ radical scavencing activities and cuprac reducing capacity, the content of total phenolic and total flavonoid, total antioxidant capacity) and the other quality properties (thousand grain weight, the contents of protein, starch, cellulose, ash, grain moisture, wet gluten ratio, glüten index, sedimentation, delayed sedimentation, ADF and NDF) in different stages of grain filling (milky or dough ripeness) in durum wheat. The study was carried out in three replications according to the split plots trial design in randomized blocks; Ç.1252, Eminbey, Kızıltan-91, Meram-2002 and Selçuklu-97 durum wheat cultivars were used as material. At the end of the study, it was determined that ABTS.+, total flavonoid and zinc, which are from the antioxidant properties, were not affected by the foliar zinc application at the stage of milky or dough ripeness, but the zinc applied in one of these stages presented significantly higher values in terms of these properties compared to the non-treated control. In addition, cultivars and the interaction of zinc × variety showed significant variations in terms of DPPH. radical scavenging activity, total phenolic and total flavonoids. Variation sources showed statistical changes for some quality criteria; for instance, wet gluten ratio for zinc application stage and the cultivars; gluten index and delayed sedimentaion for the cultivars and NDF value for zinc application stage. On the other hand, cuprac reduction capacity and total antioxidant capacitiy and some quality parameters such as thousand grain weight, protein contents, starch, cellulose, oil, moisture, and values of color b, sedimentation, ADF showed non-significant differences in terms of variation sources. Within the scope of these results, it was found that zinc foliar application at different stages of grain filling in durum wheat had statistically significant effects on some antioxidant properties and quality criteria; however, in the future studies it will be more beneficial to expand the study by increasing the number of application doses and the kinds of growth stages.