Interaction hybrid × planting date for oil yield in sunflower

The aim of the study was to assess the effects of hybrids and planting dates as well as their interaction on oil yield in sunflower for three-year experiment (2005, 2006, 2007). Three sunflower hybrids (Miro, Rimi and Pobednik) and eight planting dates were included in the experiment. AMMI (Additive Main Effects and Multiplicative Interaction) analysis is one of the mainly used multiplicative models, which evaluates main effects and also interaction. The interaction was detected by using AMMI1 biplot. Oil yield was predominantly influenced by the year of growing (58.9%), then by planting date (12.9%) and by hybrid (10.7%). All interactions were significant as well. AMMI ANOVA showed high significance of both IPC1 and IPC2. The contribution of IPC1 was 77.5%. Hybrids Miro and Pobednik showed no significant differences in the mean values, which were higher than average. However, the hybrid Miro showed the highest stability for oil yield. Hybrid Rimi, with the lowest mean value, was the most unstable for the examined character. Oil yield was higher in earlier than in later planting dates. Graphical presentation of AMMI1 in the form of biplot could facilitate the choice of stable hybrids and planting dates for desired characters in sunflower.