Authors:I. Liović, A. Mijić, M. Krizmanić, P. Pepó, V. Kovačević, A. Markulj, T. Duvnjak and G. Krizmanić
Environmental conditions (soil, weather) have the greatest impact on the production of all crops, so it is necessary to check the behaviour of new hybrid combinations under diverse environmental conditions. In 2009 and 2010, field trials were sown at various locations in Croatia to test new sunflower hybrid combinations bred at the Agricultural Institute in Osijek. In both years, the trials were conducted in Beli Manastir (BM09 and BM10), Nova Gradiška (NG09 and NG10) and Osijek (Os09 and Os10), while in 2010, a trial was also sown in Vukovar (Vu10). The genotypes included three cytoplasmic male sterile lines (cms 1–3) as female parent with a set of 8 fertility restorer lines (four branching restorers: oG1–4 and four single-headed restorers: oM5–8). The grain yield data were processed for years and locations (7 environments) using analysis of variance (ANOVA) and Additive Main effects and Multiplicative Interactions (AMMI) analysis with the SAS for Windows 9.1 statistical software. To obtain a better picture of the grain yield stability of the hybrid combinations in different environments, AMMI1 and AMMI2 biplots were made using IRRISTAT for Windows 5.0 software. No significant differences were found between the hybrid combinations of the female lines (cms 1–3). Among the environments, the significantly highest grain yield was recorded in the environment Os09 (4.220 t ha−1), followed by BM09 and Os10. As regards the restorers the highest grain yields (statistically on par with each other) were found for hybrid combinations involving oG2 and oM7 (3.726 and 3.666 t ha−1). Together, the first two interaction principle components (IPC) explained 85.4, 76.6 and 64.8% of the variability for crosses involving cms1, cms2 and cms3, respectively. The AMMI1 and AMMI2 biplots showed that the highest yielding hybrid combinations did not have the most stable grain yield. The greatest stability was shown by restorer line oM7 in cross combinations with inbred lines cms1 and cms2, while the same restorer line exhibited a large genotype × environment interaction and low stability when crossed with cms3.