Genetic and Phenotypic Variability of Grain Mass per Spike in Wheat under Different Dose of Nitrogen Nutrition

Variability of grain mass per spike was investigated in four wheat genotypes: G-3052, G-3625, G-3004 and G3617, grown under application of four nitrogen nutrition treatments: 0, 30, 60 and 90kg N ha-1 in field experiment during two years. The experiment was designed by randomised block system on plot 5m2 in four replications. Obtained results indicate differences in average values of grain mass per spike among tested cultivars were determined in both years and under all variant of nitrogen fertilization. In average for all cultivars grain mass per spike was higher in the first year than in second year of experiment. In average the highest grain mass per spike expressed the wheat genotypes G-3625 in the first year (2.85g) as well as in the second experimental year (2.35g) while the least value of grain mass in the first year had G-3617 (2.20g) and in the second year G-3004 (1.94g). On average, for all genotypes, grain mass per spike increased by increasing nitrogen rate in both years, it mean that variability of grain mass per spike was affected by nitrogen nutrition. The genetic components of variance showed that environmental factor (61.49%) had the higher influence than genetic factor (19.26%) on the expression the grain mass per spike