| This experiment was carried out during the growing season of 2001-2002 and repeated in 2003-2004 in Mosul to investigate the effects of plant populations and intervals of flowering stalk removal on growth , dry bulbs and green yields of onions grown under irrigated and non-irrigated cultivations. The results of 2001-2002 growing season showed that supplementary irrigated onions significantly increased leaf fresh weight (14.4%), root dry matter percentage (7%), as compared to these of rainfalls. Low onion plant population (18 plants.m‾²) was superior over high onion plant population (36 plants. m‾²), as it substantially increased leaf numbers per plant (27.3%), leaf fresh weight (19.7%), fresh weight of dry bulb (25.9%), and yield of dry bulbs (62%). Moreover, this population significantly exceeded high population in 2003-2004 growing season in leaf fresh weight per plant (27.2%), bulb: leaves ratio (7.7%), and fresh weight of individual plant (6.7%). Weekly eradication of flowering stalks in 2001-2002 growing season appeared to be the most potent treatment, as it highly increased leaf numbers per plant (28.6%), bulb: leaves ratio (219%), bulb fresh weight (265%), yield of dry bulbs (263%), and root fresh weight (15.1%), in relation to that of no flowering stalk elimination which resulted in profound dry bulb yield reductions. On the other hand in 2003-2004 growing season, treatment of no flowering stalk eradication was superior on others, particularly on weekly eradication of flowering stalks, as it significantly increased the plant height (6.9%), leaf fresh weight (52.6%), and green onion yield (26.3%). The highest dry onion bulb yield (3.1 kg.m‾²) and green onion yield (6.64 kg.m‾²) were obtained from supplementary irrigated high onion population of weekly flowering stalk eradication, respectively, during 2001-2002 and 2003-2004 growing seasons. |