Increasing the Yield of Sunflower Parent Components with the Help of Growth Regulators and Micro-Fertilizers

Low seed productivity of parentalal lines (sterility fixers and fertility restorers) hinders the rapid introduction into production of competitive simple sunflower hybrids. The purpose of this study was investigate the effects of combinations of growth regulators and microfertilizers of different origins on the growth, development, yield and sowing quality of new sunflower lines and to develop effective methods for their improvement. The study was conducted in the fields of the Yuriev Рlant Production Institute of NAAS in 2021-2024 were applied. The parental components of simple sunflower hybrids ‘Skh66A’, ‘Skh588A’, Kh1814V’, and ‘Kh2283V’ were studied; growth regulators AKM, Endophyte L1 and Antistress as well as microfertilizers Raycat Start, Microcat Oil Crops, Aminocat 30, Atlante, and Endobor. Pre-sowing treatment with AKM and Raycat Start was carried out simultaneously with seed dressing. Plants were sprayed with combinations of agents in the phases of 4 or 4 and 6 sunflower leaf pairs. It was found that, depending on combinations of agents and methods of their application, the leaf area in line ‘Skh66A’ increased on average by 1,500-3,600 m2/ha and the pre-harvest plant density – by 700-1,800 plants/ha; in line ‘Skh588A’, these parameters increased by 1,500-4,300 m2/ha and 1,5-2,6 plants/ha, respectively; in line ‘Kh1814V’ – by 2,000-4,100 m2/ha and 700-1,800 plants/ha, respectively; and in line ‘Kh2283A’ – by 400-1,700 m2/ha and 1,500-3,300 plants/ha, respectively. Pre-sowing treatment of seeds with AKM and Raycat Start increased the yield of the sunflower lines on average by 9-13%; pre-sowing treatment and subsequent spraying with combinations of agents in the phase of 4 leaf pairs – by 8-16%; and pre-sowing treatment with subsequent spraying in the phases of 4 and 6 leaf pairs – by 11-18%. Lines ‘Skh66А’ and ‘Kh1814V’ yielded the most when treated with AKM 0.2 L/t, Antistress 1.7 kg/ha, Endophyte L1 0.2 L/ha, and Endobor 0.48 kg/ha in two or three stages (0.84 and 0.72 t/ha, respectively). The yield of line ‘Skh588А’ reached the maximum after the application of AKM 0.2 L/t, Antistress 1.7 kg/ha, Endophyte L1 0.2 L/ha, and Endobor 0.48 kg/ha in three stages (1.26 t/ha); the yield of line ‘Kh2283V’ was maximal (1.19 t/ha) when Raycat Start 2.5 L/t, Microcat Oil Crops 0.5 L/ha, Atlante 0.5 L/ha, and Aminocat 30% 0.5 L/ha were used in three stages.