The impact of planting dates and hybrid selection on sunflower seed yield and oil content

Abstract

Suitable planting dates and hybrid selection are crucial in optimising yield, component traits and oil production in sunflower (Helianthus annuus L.). In South Africa, there is limited information on the effects of planting dates on currently available sunflower hybrids in the marketplace. This study aimed to investigate the impact of planting dates on sunflower seed yield, oil content and oil yield, and to discern optimal planting dates for selected sunflower hybrids. Nineteen commercial sunflower hybrids were evaluated at three planting dates and three consecutive seasons in Potchefstroom, South Africa. The study used a complete block design with three replicates, and the standard analysis of variance was conducted. Significant differences were detected among seasons, planting dates, hybrids, and their interactions. The mean seed yield varied from 1.86 (LG 5678 CLP) to 2.50 tonnes ha−1 (PAN 7160 CLP). The oil content varied from 37.23 (P 65LP 54) to 53.16% (SY 3970 CLP), and the oil yield ranged from 0.74 (AGSUN 5101 CLP) to 1.25 tonnes ha−1 (LG 5710). Planting sunflowers in November and December resulted in the highest seed yield, oil content and oil yield, while planting in January and early February showed linear declines. January planting reduced 1 to 20%, 2 to 10%, and 3 to 26% in seed yield, oil content and oil yield, respectively. February planting significantly reduced seed yield by 72%, oil content by 20% and oil yield by 77%. The study recommended November and December as optimal sunflower planting dates in South Africa.