Helianthus annuus L. hybrid ideotype

The issue of determining the ideotype of sunflower varieties and hybrids is relevant not only for breeding but also for cultivation in new environmental conditions. The aim of our research was to evaluate the genotypes according to ecological adaptability and establish the parameters of the sunflower ideotype for the arid conditions of the Crimean steppe zone. The studies were conducted in 2017-2020 at the Field Crop Department, FSBSI “Research Institute of Agriculture of Crimea” (village of Klepinino). Soil – chernozem southern low humus. Materials for the research – sunflower hybrids: ‘Garant’, ‘Komandor’, ‘Signal’, ‘Paritet’, ‘Prestizh’ (standard), ‘Sprint’, ‘Sprint 2’, ‘Gorstar’, ‘Kometa’ (bred in the All-Russian Scientific Research Institute of Oil Crops by the name of Pustovoit V.S.” (VNIIMK)). The experiment was replicated four times. The total area of the trial plot is 56 m2, the accounting area – 28 m2. Plant density – 40 thousand plants per ha. The harvest was brought to 100% purity; the seeds – to 10% moisture content. The linear regression coefficient (plasticity) of the yield of hybrids (bi) and the standard deviation (stability) (Ϭd2) were calculated according to S. A. Eberhart and W. A. Russell. Favourable weather conditions were in 2017 (Ij = +0.21) and 2019 (Ij = +1.04). Hybrids ‘Komandor’, ‘Garant’, ‘Sprint 2’ and ‘Gorstar’ are more responsive to the improvement of growing conditions (bi>1); variety ‘Kometa’ – weakly responsive (bi<1). When cultivation conditions changed, the yield of the hybrids ‘Signal’, ‘Paritet’, ‘Prestizh’ and ‘Sprint’ varied (bi = 1). In terms of yield, the most stable is ‘Kometa’ (Ϭd2 = 0.48); the most unstable – ‘Komandor’ (Ϭd2 = 2.19). According to the long-term field research, we have identified the parameters of the optimal model of a sunflower hybrid for cultivation in the Crimea: growing season length – 92–98 days, plant height – 161–166 cm, 1000-seeds weight – 69.5–83.0 g, productive area of the capitula (flower head) – 313–379 cm2, yield – 2.26–2.49 t/ha, oil content – 45–47%, as well as god responsiveness to the growing conditions improvement.