The correlations between some main agronomy practices (type of previous crop and mineral fertilization norm) and the year conditions with grain yield from a group of common winter varieties were investigated. According to the yield obtained, the genotypes were divided into two groups. The varieties with yield significantly higher than the mean were referred to the first group and the varieties with yield significantly lower than the mean - to the second group. A three-year field trial was carried out, in which the investigated genotypes were grown after three previous crops (bean, sunflower, maize) at three levels of mineral fertilization. Fertilization depended on the previous crop: T1 - check variant without fertilization, T2 - N6P6 after bean and N10P10 after sunflower and maize, T3 - N10P10 after bean and N14P14 after sunflower and maize. The independent effect of the main agronomy practices (variety, previous crop, fertilization) was much higher on the formation of productivity of the high-yielding varieties from the first group. The low-yielding varieties of the second group were most affected by the changeable environments, which made them more variable. Mineral fertilization was the main factor which contributed to the formation of yield and related higher productive tillering; the year had the highest significance for the formation of more grains per spike in both groups.
Correlations between some main agronomy practices and grain yield from winter wheat varieties