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Planting date effects on sunflower head and seed development
- Unger, P.W., Thompson, T.E.
- Agronomy journal 1982 v.74 no.2 pp. 389
- Helianthus annuus, planting date, flowering, seed development, crop yield, fatty acid composition, oleic acid, linoleic acid, yield components, desiccation (plant physiology), environmental factors, solar radiation, air temperature, Texas
- In field trials in 1977-80 in Texas, sunflower cv. Hybrid 896 was sown at 2-wk intervals from 23 March to 1 Aug. and after anthesis head wt. and diam. were measured together with seed DM, seed wt., oil percentage and oleic and linoleic acid contents of the oil. All characteristics were significantly affected by sowing date, sampling date and position of seeds in the head. Seed DM and seed wt. increased throughout sampling but not at the same rate for all sowing dates. Oil content of seeds increased for 3 wk after anthesis and seeds from late sowing generally had a low oil content. Conc. of oleic and linoleic acids decreased and increased, resp., in plants from later sowing dates. Multiple regression showed that air temp. significantly affected changes in seed oil content but not in oil composition, the conc. of oleic and linoleic acids being dependent on total solar radiation and daylength.