Effects of environment on optimizing nitrogen nutrition on content of first-class seeds in winter barley cultivars

In this paper was investigated variability of percentage content of seeds first-class (thickness of seeds >2.5mm) in four divergent barley cultivars (Jagodinac, Premium, NS 489 and NS 495) originated from different breeding centres in Serbia. These cultivars investigated during two years on experimental field on plots 5m2 and four replications under four different rate of nitrogen treatments (control N0=0, N1=20, N2=40 and N3=60 kg ha-1). The variability of content of seeds first-class was established in both years of experiment and under all nitrogen rate of supplied N fertilizer. According to percentage of content first-class (thickness of seeds >2.5mm) were found differences among the cultivars in each years of experiment and all variant of nitrogen nutrition. In average, content of seeds first-class for all cultivars and all treatments was higher in second year 82.34% than in first experimental year 80.03%. The average value of percentage content of seeds first-class in both growing seasons and under N treatment was the highest in barley cultivar NS 595 (82.70%) and the lowest in barley cultivar Premium (78.79%). For all investigated cultivars, content of seeds first-class increased with increasing nitrogen rate. This indicate that content of seeds first-class mostly affected by mineral nitrogen nutrition and to a much lesser degree by cultivar