CONTRIBUTION OF FRUITING POSITION ON GROWTH,YIELD, QUALITY OF COTTON AND THEIR RELATIONSHIP WITH NITROGEN

A field experiment was conducted on the experimental farm of the Dept. Field Crop Sci.-Coll. of Agriculture-University of Baghdad during summer seasons of 2011 and 2012. That was to determine the contribution of each fruiting position in the yield of cotton of lashata cultivar and the effect of nitrogen in this contribution. The study included two factors, the first one nitrogen with three levels (150, 200 and 250) kg N.ha(-1) as main plots, and the second factor was the technique of fruiting form removal with four levels (Rm(0); control without removal, Rm(1); keeping on first fruiting position and remove all the others, Rm(2); keeping on second fruiting position and remove all the others and Rm(3); keeping on third fruiting position and remove all others sites) as sub-plots. Complete randomized block design was used under split plots with four replications. Increasing nitrogen level to 250 kg N.ha(-1) led to the highest average of number of total boll (11.79 and 13.59) boll.plant(-1), number of open boll (5.67 and 6.66) boll.plant(-1), boll weight (3.53 and 3.86) gm, therefore, the yield of plant was increased (19.79 and 25.88) gm, seed cotton yield (995.63 and 1332.75) kg.ha(-1), lint cotton yield (348.12 and 473.55) kg.ha(-1), lint length (28.20 and 27.60) mm, lint strength (19.33 and 20.73) gm.tex(-1) for both season, respectively, as well as gave highest average of micronare of lint (4.36) in the first season in comparison with the treatments 150 and 200 kg N.ha(-1). While the level fertilizer 150 kg N.ha(-1) gave the highest ratio of shedding (17.42 and 15.71) % for both season, respectively. The results showed a significant effect of bud removal in all characteristic studied. The Rim treatment gave highest average for boll weight (3.56 and 3.88) gm and lint length (28.18 and 27.27) mm, while the control treatment Rm o gave highest average for number of total boll (27.99 and 32.01) boll.plant(-1), ratio of shedding (34.16 and 32.80)%, number of residual boll (18.49 and 21.50) boll.plant(-1), number of open boll (10.04 and 13.05) boll.plant(-1), cotton yield per plant (37.80 and 49.01) gm, seed cotton yield (1853.81 and 2482.75) kg.ha(-1), and cotton lint (621.02 and 845.52) kg.ha(-1), and there are non-significant effect of removal treatment in lint strength and micronaire. There are significant interactions between nitrogen and removal treatment. The levels of fertilizer level 150 kg N.ha(-1) with Rm(0) gave highest ratio of shedding (37.10 and 34.30) %, while the level of fertilizer 250 kg N.ha(-1) with Rim gave highest average for yield per plant at second season (52.56) gm, seed cotton yield (2012.00 and 2680.56) kg.ha(-1) and lint cotton yield (694.94 and 938.19) kg.ha(-1) for both seasons, respectively. We can conclude that the first fruiting site contributes about 61-64% from the yield and gave best properties for lint quality in comparison with the others fruiting position and the nitrogen addition led to increase contribution ratio and improve the quality. So, we recommend the breeder to take this concept in confederation in order to produce cotton cultivars having one or two fruit positions on plant with high quality of fiber properties,