Planting Date Effects on Growth, Yield, and Oil of Irrigated Sunflower1
- Paul W. Unger2
Interest in sunflower (Helianthus annuus L.) as an oilseed crop has greatly increased in the Southern Great Plains since 1974. To effectively manage sunflower for oil production and oil quality, information is needed concerning the effect of various agronomic practices. The objective of this research was to determine the effect of planting date on growth, yield, oil percent, and oil fatty acid concentration of irrigated sunflower. Sunfower ‘Hybrid 896’ seed was planted at about 2-week intervals from late March to late July or early August from 1975 to 1978 on Pullman clay loam (fine, mixed, thermic Torrertic Paleustoll). Time from planting to emergence was influenced by soil temperature, and ranged from 19 days with early plantings to 5 days with late plantings. The time from planting to the 50% ray flower stage decreased with delayed plantings, except for the last four plantings for which the average was about 59 days. Seed yields were not significantly different with plantings from late March to mid-June. Yields decreased with plantings after 21 June. Seed soil percent was relatively constant with early plantings, but decreased with plantings after about 29 May; oil yield/ha also decreased with plantings after that date. The oleic and linoleic acid concentrations of the oil were strongly affected by planting date because the different planting dates resulted in seed development during periods of different temperatures. Earlyplanted sunflower matured during hot weather, and the oil had oleic and linolecic acid concentrations of 43 and 45%, respectively. Oil from late-planted sunflower, which matured during cooler weather, had oleic and linoleic acid concentrations of around 15 and 75% respectively.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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