RESPONSE OF EARLY-MATURING SUNFLOWER HYBRIDS TO ROW SPACING AND PLANT DENSITY

Two early-maturing sunflower hybrids, Sunwheat 101 and MRS 34, with shorter than normal height and a narrower growth habit were grown at 30- and 60-cm row spacings and three plant densities at each row spacing in the 1986 and 1987 seasons at Morden, Manitoba. There were no differences in achene yield or oil content between row spacings. Plant height and oil content of achenes increased with increase in plant density, while achene weight decreased. Achene yield of both hybrids increased as plant density increased from 55 000 to the 74 000 plants ha−1 density, then remained relatively constant to 148 000 plants ha−1.Key words: Oilseed sunflower, Helianthus annuus L., plant row spacing, plant density