Water-Use Efficiency and Light Interception of Semidwarf and Standard-Height Sunflower Hybrids Grown In Different Row Arrangements
- Eduardo Zaffaroni and
- A. A. Schneiter
Semidwarf sunflower (Helianthus annuus L.) may have potential for adaptation in large areas where conventional-height sunflowers are currently grown. To develop improved production practices for this plant type, a better understanding of light and water use is needed. The objective of this study was to evaluate light interception, water-use efficiency (WUE), and energy-use efficiency (EUE) of semidwarf (SD) and standard-height (SH) sunflower hybrids grown under various row spacings. Field studies were conducted at Prosper, ND during the 1984 and 1985 growing seasons. Row arrangements consisted of (i) conventional rows, spaced 0.76 m apart; (ii) solid seeding, rows spaced 0.38 m apart; and (iii) twin rows, two rows 0.19 m apart on 0.76-m centers at populations of 35 000, 50 000 and 65 000 plants ha−1. Soil-water depletion at different levels of the soil profile was similar for both plant types during 1984, but statistically greater for the SH hybrid during 1985. In general, soil-water depletion was greater under solid seeding both years. Total water use (WU) and WUE were not statistically different between hybrids or among row arrangements in combined analysis across years. In 1985, WUE was statistically higher for the SD hybrid (4.69 kg ha−1 mm−1), as a result of decreased yield in the SD hybrid caused by Sclerotinia head rot (Sclerotinia sclerotiorum). Light interception among treatments was not different in 1984, but in 1985 was higher for sunflower sown at solid seeding and twin rows than in conventional rows. Energy-use efficiency was not different among treatments in 1984, while in 1985, the SH hybrid had statistically higher values (1.29%). During this year EUE significantly increased from 0.99 to 1.33% as plant population increased.
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