Reaction of spring barley genotypes on nitrogen fertilization in grain yield and quality traits in generations F3, F4 and F5

Spring barley lines F2.3, F2.4, F2.5 originating from six parents (Amos, Stabil, Kosan, Progres, Galan, SK-13-9) and from five hybrid crossings were evaluated jointly with parents in the years 2000, 2001, 2002 on two levels of N-fertilization (N1 - unfertilized control, N2 - 120 kg/ha). In F3 generation plant offspring (135 lines) were evaluated in rows and in F4 (42 lines) and in F5 (14 lines) on plots 5 and 10 m2, respectively. In all generations grain yield, quality traits by NIRS instrument (protein content, starch content, extract content, diastatic power, Kolbach number, and test weight) were evaluated. In F4 and F5 generations the protein content in grain and straw were determined. Crossings responded in grain yield on N-fertilization slightly. In F5 generation higher N-fertilization reduced grain yield. Only three crossings from evaluated set Progres/Kosan, Progres/Galan and SK-13-9/Stabil responded on higher N-fertilization by increasing of grain yield in two generations, and crossing SK-13-9/Stabil in three generations. N-fertilization increased grain protein content, nitrogen content in grain and in straw and diastatic power and on the other side decreased starch and extract content. Protein content determined by NIRS analysis was in comparison to direct determination of nitrogen content higher by 1.87%, however correlation coefficient between them was 0.90++ in both generations. Among hybrid combinations were differences in nitrogen uptake and utilization. Effective nitrogen uptake, but low responsibility on N-fertilization characterized crossing SK-13-9/Stabil, on the contrary crossing Progres/ Kosan was high responsible on N-fertilization. From varieties high nitrogen content in straw (maximum 0.912%) and in grain (maximum 2.026 %) had varieties Stabil and Galan. Variety Progress had only 0.676% and 1.726 Vo, respectively. Differences among generations in quality traits and in grain yield were conditioned by years, with different length of vegetative period up to 12 days, (difference in the year 2000 in comparison to the year 2002 in the vegetative period from sowing to heading was 19days). Protein content in grain and in straw (average of F4 and F5 generations) was higher at higher N-fertilization; however in F5 generation was higher nitrogen content in straw and lower in grain than in F4 generation, which was conditioned by different period of nitrogen accumulation and translocation in respective years. Low responsibility of spring barley on N-fertilization is explained by low tolerance to lodging and low nitrogen uptake and utilization. Among protein content and starch content, and extract content correlations were negative and positive between protein content and diastatic power. Among generations were medium even high correlations at the most quality traits, weaker and variable in nitrogen content in grain and in straw and none at grain yield. Selection of spring barley genotypes with higher effectivity of nitrogen uptake and utilization is discussed.