RESPONSE OF SUNFLOWER (HELIANTHUS-ANNUUS) TO PLANTING PATTERN AND POPULATION-DENSITY IN A DESERT CLIMATE

The effects of three planting patterns (ridge, furrow and flat) and th ree population densities (31 800, 47 600 and 71 400 plants/ha) on the growth and yield of three sunflower hybrids, Flamme, Upsolveraflor and Isostar, were investigated at the Sultan Qaboos University Experiment Station, 1990-93. Seed and oil yields were higher in the ridge-plante d sunflower than those planted in furrow or flat patterns, the order b eing ridge > flat > furrow. However, the magnitude of yield difference s between ridge-planted and flat-planted sunflower was not sufficientl y high to compensate for the additional labour and materials required for making ridges. Based on this, planting in the flat was recommended . Although increased population density resulted in taller plants, lod ging was generally low and did not constitute a serious problem. Bioma ss/plant, head weight, receptacle weight, head diameter, number of see ds/head and 1000-seed weight decreased with increase in plant populati on density. Flamme had its highest seed and oil yield at 71 400 plants /ha, while Isostar attained its highest yield at 47 600 plants/ha. Iso star outyielded the other two hybrids and appeared to have a potential for commercial production in a desert climate.