Yield, Water‐Use Efficiency, and Oil Concentration and Quality of Dryland Sunflower Grown in the Southern High Plains1

Abstract

AbstractFor oilseed sunflower (Helianthus annuusL.) to develop as a competitive crop on the drylands of the Southern High Plains, information is needed concerning the effects of various agronomic practices on sunflower production in this area. The objectives of the research were to determine the effects of seeding date, plant population, and soil water content at time of seeding on dryland sunflower seed yield, water‐use efficiency (WUE), and oil concentration and quality. The study was conducted from 1975 through 1979 on Pullman clay loam (fine, mixed, thermic Torrertic Paleustoll). Seeding date had the greatest effect on seed yield and WUE and reflected the effects of seasonal precipitation patterns. Yield response to increased soil water content at seeding was 0.70 kg seed/m3water. Plant populations in the range of 2.5 to 4.5 plants/m2resulted in similar seed yields and WUE , but high populations (>3.5 plants/m2) tended to increase oil concentration. Seeding date significantly influenced oil concentration and quality with April seedings having a 50 to 80 g/kg greater oil concentration than July seedings. Oleic acid concentration in sunflower oil decreased, and conversely, linoleic acid concentration increased as seeding dates became later. Thus, by manipulating seeding dates, oil of a quality suited to a particular need (margarine, cooking or salad oil) may be produced. Yield potential was enhanced when soil water content at seeding was increased, indicating that sunflower is adapted for use on water conservation systems or after fallow where additional soil water may be available.