Formation of spring barley genotypes with higher grain protein content

F2 generation of spring barley (9 direct and 5 reciprocal combinations) was evaluated along with parental varieties (Orbit, Proskovcuv Hanacky, Amulet, Slovensky Dunajsky Trh, Cyril) and controls (Progres, Novum) in a field experiment conducted in Piestany in 2001. The experiment was established by randomised block design in 3 replications. Average values of selected traits (SPAD, plant height, number of grains per ear and grain weight per ear) were lower in comparison to the average of parents, but with a higher variability range providing a selection among combinations. The variety Cyril had suitable general combining ability (GCA) for plant height and SPAD meter readings. The historical varieties Proskovcuv Hanacky and Slovensky Dunajsky Trh increased in F2 hybrids a number of grains per ear. The number of populations in F3 generation was reduced to 5. From each population 20 lines were selected and then evaluated in a field trial in 2002. This experiment was established by split-plot design (parcel-combination of crossing, subparcel-lines) in 2 replications. Heritability coefficients of grain formation traits and quality traits showed higher values for combinations than for lines. The grounds for indirect determination of nitrogen content in vegetative organs using SPAD index and for NIRS analysis in generative organs were confirmed. Positive correlations (r=0.306, r=0.602++) between these traits were only found in related genotypes with a similar genetic background. At the index selection using an additive index, a set of lines was selected for F4 generation. The lines showed higher average values in six out of nine traits for selection when compared to the original set of lines. With respect to the significant correlation between height and protein content (r=0.723++), only by selection according to the method of independent culling level for protein content, the selected set of 20 lines had the same value for this trait as the whole set of lines, but at a lower intensity of selection with the other traits. The selected set of lines is suitable for a selection of genotypes combining high grain yield and protein content.