RESPONSE OF SESAME CULTIVARS TO PLANT-DENSITY AND NITROGEN IN THE SUDAN CENTRAL RAINLANDS

Field experiments were conducted for 3 years to determine the effects of cultivar, nitrogen and plant population on seed yield and other pla nt characteristics under the conditions of limited water supply in rai nfed areas of the central Sudan. Seed yield and its components were ad versely affected by delayed sowing and inadequate water supply. Cultiv ar, unlike nitrogen and inter-row spacing, had a significant effect on seed yield, plant height and number of capsules plant-1 under favoura ble environments (i. e. early sowing and adequate moisture). In the dr y season, cultivars differed significantly in days to flowering wherea s nitrogen significantly increased number of days to onset of flowerin g and increased number of capsules plant-1. Cultivar x nitrogen and cu ltivar x spacing interactions varied with the season and the plant par ameter but they were both significant for number of plant ha-1 in the dry and moderate seasons. Interactions of cultivar x nitrogen were als o significant for seed yield in both favourable and moderate seasons a nd for number of capsules and plant height in the former. In the favou rable environment cultivars UCR 76202 (1388 kg ha-1) and UCR 75370 (97 9 kg ha-1) had their highest seed yields (71 and 56% over the control) at 40 kg N ha-1; whereas the local cultivars A/5/9 (1183 kg ha-1) and A/1/9 (1057 kg ha-1) had their highest yields (22 and 14% over the co ntrol) at 20 and 80 kg N ha-1, respectively.