Dynamics of nitrogen content and chlorophyll content (SPAD-values) in spring barley parental genotypes (Hordeum vulgare L.) and F1 offsprings

In pot experiments with five spring barley genotypes (Orbit - released in 1986, Proskovcuv Hanacky - 1882, Amulet - 1995, Slovensky Dunajsky Trh - 1946, SK-4410-2000), evaluated on two levels of N-fertilization (N0, N40) and with their fourteen F1 offsprings SPAD-meter readings (chlorophyll content) and nitrogen content in leaves, straw and grain were taken. SPAD-values (chlorophyll content) varied independently on growth stages (GS) from 40.44 (GS 32) to 44.87 (GS 70) whereas nitrogen leaf content decreased with increased growth stage from 3.578% (GS 32) to 1.579% (GS 70). In spite of interaction term with genotype the highest SPAD-values had genotypes Orbit and Proskovcuv Hanacky and the lowest ones Amulet and SK-4410. Older genotypes responded to higher N-fertilization by higher straw yield and higher grain nitrogen content, modern genotypes by higher grain yield without increasing grain nitrogen content. Chlorophyll content (SPAD-values) was more conditioned genetically than nitrogen content in leaves was. With respect to dependence of variability of chlorophyll content (SPAD) not only from growth stage, but leaf insertion and point of measurement on leaf, SPA-meter readings were taken from three leaves (the first to the third leaf measured downwards) and three points of measurements on leaf (2-4 cm from the leaf base, in the midpoint of leaf, 2-4 cm from the leaf tip). Results showed as the most advisable to take SPAD-meter readings from the second leaf and in its centre. Among SPAD-values measured in four terms and nitrogen yield and dry matter per plant in heading (experiment 2) were negative genetic correlations, in spite of positive genetic correlations between SPAD and nitrogen content in leaves (r = 0.4 - 0.6). In experiment 1, positive correlations were among SPA-values and nitrogen content in leaves and grain, too, but negative with grain yield per plant. Among average value of parents and their F1 hybrids in chlorophyll content (SPAD) no correlations were found, however among average values of maternal genotype and offsprings in GS 49 (booting, first awns visible) were significant correlations. Reasons of these correlations are discussed