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Planting date effects on growth, yield, and oil of irrigated sunflower

Unger, P.W.
Agronomy journal 1980 v.72 no.6 pp. 914
Helianthus annuus, planting date, plant growth, plant development, soil temperature, crop yield, sunflower oil, fatty acid composition, linoleic acid, oleic acid, irrigated farming, Texas
In 1975-8 sunflower Hybrid 896 was sown at 2-wk intervals from late March to late July or early Aug. on clay loam. Time from sowing to emergence was influenced by soil temp., and ranged from 19 to 5 days with early to late sowings, resp. The time from sowing to the 50% ray flower stage decreased with delay in sowing, except for the last 4 sowings for which the av. was 59 days. Seed yields were not significantly different with sowings from late March to mid-June. Yield decreased with sowings after 21 June. Oil yield/ha decreased with sowings after 29 May. The oleic and linoleic acid conc. of the oil were strongly affected by sowing date because of seeds developing during periods of different temp. Early-sown sunflower matured during hot weather, and the oil had oleic and linoleic acid conc. of 43 and 45%, resp. Oil from late-sown sunflower, which matured during cooler weather, had oleic and linoleic acid conc. of c. 15 and 75%, resp.