Authors:A. Mijić, I. Liović, V. Kovačević and P. Pepó
Oil crops constitute the second most important field crops worldwide and are important both in Hungary and Croatia. Among the oil crops, sunflower has a significant role in Hungary (∼550,000 ha) and Croatia (∼30,000 ha). The main aim of this study was to compare sunflower yields and their variation over years (2000–2007) in the eastern parts of Hungary and Croatia, with the emphasis on the impact of rainfall and temperature regime, and using a rain factor (RFm) calculated monthly as the quotient of precipitation (mm) and mean air temperatures (°C). The results showed that the year had a different effect on the yield of sunflower in the different counties of eastern Hungary and Croatia, because of their different soil conditions. The results proved that the highest yields of sunflower (2140–2710 kg ha−1) were obtained in years when the rainfall before and during the vegetation period was 110–130 mm and 350–420 mm, which was very similar to the 30-year mean data (82–108 mm and 305–346 mm, respectively). The strongest correlations (positive and negative r values) between meteorological data and sunflower yields were found in counties with unfavourable soil conditions. In counties with better soil fertility the correlation coefficients were smaller, indicating that better soil conditions can compensate for unfavourable year effects (especially temporary shortage of rainfall or unfavourable rainfall distribution).
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.