ABSTRACT
Field studies were conducted to find the effects of Paclobutrazol (Pb) and row spacing on drip-irrigated cotton (var. SJ-2). Two levels of Pb )12.5 and 37.5 g a.i. ha-1) were applied through the driplines on different dates (first bloom, 2 and 4 weeks later) on narrow-row and standard cotton (72.5 and 96.5 cm.). Pb treatments caused significant reduction in several vegetative parameters (plant height, number of mainstem nodes, dry weight of stems and leaves) in both row spacings. Early application and high level of Pb had stronger effects on growth than the late applications. Ph had a stronger effect on narrow-row plants although the growth difference among treated plants of the different spacings was not significant. The reduction in plant height of treated plants was in the range of 10%, whereas the reduction of stem dry weight was in the range of 20%. Ph treatments did not affect the flowering rate, yield and fiber properties. Narrow-row plants were compact and had a 16% yield increase over the standard row spacing plants (7.22 vs. 6.27 ton ha-1 of seed cotton).
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