Grain Yield Components of Winter Wheat New Cultivars in Correlation with Sowing Rate

During the process of plant breeding and selection of new winter wheat cultivars a lot of attention is paid to the improvement of the main components of grain yield-number of ears/m2, number of grains per ear and 1000 seed weight. Production of cultivars that achieve a large number of fertile ears per unit area, a large number of grains per ear and a heavy 1000 seed weight, even with a lower density, would mean that a high grain yield is achieved with lower costs. It is of great importance for wheat production in Croatia. Along with the research on sowing rate influence (400, 500, 600 and 700 germinable seeds/m2) on winter wheat grain yield, other trials were done on the grain yield components (number of ears per unit area, number of grains per ear and 1000 seed weight) during periods 1996–1997 and 1997–1998 both on three AG cultivars of winter wheat Lara, Kruna and Lenta and on the check cultivar Ẑitarka. The trial was done according to the split-plot method in 4 replications. Statistically speaking, various sowing rates had a very significant influence on the number of ears per unit area. The largest number was achieved with the sowing rate of 700 germinable seeds/m2 (783,38 ears/m2). This number of ears is statistically more significant (P<0,05) in relation to the sowing rate of 600 germinable seeds/m2, and statistically very significant (P<0,01) in relation to the sowing rates of 400 and 500 germinable seeds/m2. On the grounds of the results obtained by a statistical analysis it was established that the sowing rate did not have a statistically significant influence on the other two grain yield components — number of grains per ear and 1000 seed weight. The investigated cultivars had a statistically very significant influence (P<0,01) on the number of grains per ear, and a statistically significant influence on 1000 seed weight, whereas there were no statistically significant differences between the investigated cultivars in relation to the number of ears per unit area. The largest grain number was achieved with the cultivar Lenta (46,36 grains) and the heaviest 1000 seed weight with the cultivar Lara (45,72 g). The year of research had a very significant influence on the height of all investigated yield components in terms of statistics; the first year of research is characterized by better results, unlike the second. On the grounds of the obtained results it may be concluded that production of the investigated cultivars with lower density is possible, despite the fact that two out of three main yield components were not under influence of the sowing rate.