SUNFLOWER AGRONOMIC TRAITS IN FIELD IRRIGATION CONDITIONS

Multi-year studies are crucial for the evaluation of sunflower hybrids and quantifying the environmental effect in the expression of genetic potential. In order to assess the adaptation of eight hybrids and test the impact of water availability on plant height (PH), head diameter (HD), 1000-grain weight (TWG), hectolitre mass (HM), seed yield (SY), oil content (OC) and oil yield (OY), a two-year study was conducted with irrigation as treatment. Analysis of variance (ANOVA) and principal component analysis (PCA) confirmed the year influence on all tested agronomic traits. According to the three-way ANOVA, irrigation significantly affected all tested traits except HD, OC and OY. All agronomic traits had lower values in both rainfed and irrigated treatment in 2014, confirming the influence of the environment. The hybrid was a significant source of variation for all traits. ANOVA and PCA grouped hybrids 1, 7, and 8 in one group and 2, 3, 4, 5, and 6 in another. The first group had lower PH, HD, TGW and SY values and higher HM, OC and OY values, and the second group had reversed traits values. Furthermore, the PCA biplot indicates SY was positively correlated with PH, HD, TGW and OY and HM was positively correlated with OC. This facilitates the breeding process because it enables indirect breeding for economically important traits such as seed yield, oil content and oil yield. As treatments were significant sources of variation for PH, HM, TWG and SY, sunflower irrigating is considered justified and can be used as an additional agrotechnical measure to target the agronomic traits. Understanding the expression of traits under rainfed and irrigation conditions will greatly help design effective breeding programs by creating hybrids suitable for cultivation in semi-arid environments.