The Effects of Foliar Nitrogen Treatments at Heading Stage on Grain Protein Contents of Bread Wheat Cultivars

Abstract

The studies were conducted at Transitional Zone Agricultural Research Institute in Eskisehir and Selcuk University in 2008-2010 growing seasons. Two bread wheat cultivars (Gerek 79 and Bezostaja 1) were used as plant material. Experimental treatments were 0, 30, 60, 90 and 120 kg N ha -1 applied at planting and tillering stages (early-season treatments) and 0, 20, 40 and 60 kg N ha -1 (urea form) applied at heading stage (late-season treatments) as foliar applications. A variation was created in terms of SPAD and TN at heading stage through different nitrogen rates in traditional nitrogen application time. Results under rain-fed conditions revealed that foliar nitrogen at heading stage could increase the protein content at least 1%, and the critical threshold NSPAD value was 0.96 for Bezostaja 1 and 0.94 for Gerek 79. On the other hand, the threshold TN value was 4.22% for Bezostaja 1 and 3.75% for Gerek 79 under the same conditions. The increase in grain protein content of Bezostaja 1 per 10 kg ha -1 of N was 2.0% in early-season and 3.2% in late-season treatments. The same increase rates for Gerek 79 were 1.5% in early-season and 2.7% in late-season treatments. Although both early and late-season treatments were effective on protein content and related quality traits, the application of foliar solution in heading stage was more dominant as compared to the traditional nitrogen application time.