Stability of grain yield and its traits at winter wheat cultivars at different growing conditions | Stabilita úrody zrna a jej prvkov pri odrodách pšenice letnej f. ozimnej pri rôznych pestovateľských podmienkach

In the vegetative years 2001/2 to 2004/5 winter wheat cultivars (Viginta, Vanda, Torysa, Malyska, Košútka, Estica, Astella, Veldava, Pavlina) were evaluated in long-term stationary experiment in Research and breeding station Vígľaš-Pstruša on twelve fertilization variants with increasing nitrogen doses (0 - 40 - 80 - 120 - 150 kg per ha) combined with P and K fertilizers (60 kg P2O5 and 60 kg K2O). Grain yields, one thousand grain weight (TGW) and grain number per square m were evaluated. The highest average grain yield in % of total average had cultivar Malyska (109.9%) and the lowest one cultivar Košútka (91.0%). Regression analyses of grain yield on environments detected cultivar Malyska as suitable for intensive farming system and cultivar Pavlina for low one. By polynomial regression of grain yield on N doses former results were confirmed and at the same time indicated that the most of cultivars the maximum grain yield had at the doses 80-100 kg N per ha, but at cultivars Malyska and Veldava tendency of positive reaction on higher N doses in grain yield was found out. TGW of all cultivars, with exception of cultivars Pavlina and Veldava, was decreased with increased N doses and on the contrary grain number per square m was increased with increased N doses. At the most cultivars the reason of polynomial reaction in grain yield on N doses was increasing grain number per square m and decreasing TGW at higher N doses. Potential sink capacity was not realized at high N doses due to lower TGW what was not conditioned by anatomical predisposition because it was the same at low and high N doses. It was probably caused by insufficiently effective translocation of dry matter for ensuring equally TGW at higher and at lower N doses. Possibilities of genetic advance in grain yield mainly by increasing of grain number per area unit and less by increasing of TGW were discussed. In evaluated set cultivar Malyska had high grain yield due to high grain number, while cultivar Veldava due to higher TGW.