A study of the yield stability of winter wheat varieties

In our long-term experiment the analyses of stability were conducted in one shorter (years 2001-2003) and one longer (years 1994-2003) periods by using different numbers (2-6) of varieties in each one of the periods. The results of our research proved that the method, applied can be efficiently used to analyse the environmental responses, the behaviour under varying environmental conditions of different varieties. Varieties can adapt themselves differently to favourable and unfavourable environmental conditions. In general, varieties (e.g. older varieties, like Mv 15, Mv 20, and new varieties, like Lupus, Mv Emese) that give relatively good yields under unfavourable conditions (2-3 t. ha(-1) environmental average) will utilise improving environmental conditions (7-8 t. ha(-1) environmental average) to a. lesser extent and vice versa. Varieties Mv 21, GK othalom and Mv Palotas (a currently cultivated variety) made good use of intensive growing conditions. The data in this paper may assist in choosing varieties best suited to the production and cultivation conditions of the production site. By applying stability analyses we proved that the stability of the control treatment was the most favourable over the investigation period, which good yield stability, however, manifested at very low yield levels. Our findings showed that under more intensive environmental conditions (7-9 t. ha(-1) yield level) appropriate and optimum fertilizer application was very effective and in comparison to the control treatment the yield differences between optimal fertilizer treatments were up to as much as 1-6 t. ha(-1). Under favourable environmental conditions the highest yields were obtained when a. fertilizer ratio of N-120+PK was applied. Under unfavourable conditions (these may be either or both ecological and cultivation conditions), however, only retrained, moderate fertilizer doses are recommended. Under extremely unfavourable conditions (very dry cropping year) the linear regression curves for fertilizer treatments were below those of the control treatments, which referred to yield depressions due to water deficiency.