ÃÞ »¨ ѧ ±¨ Cotton Science 2010£¬22£¨3£©£º224-230
Interaction of Plant Density with Retention of Vegetative Branches on Yield and Earliness of Cotton ( Gossypium hirsutum L.) Abstract: Optimum plant density and retention of vegetative branches(VB) have been widely studied as a single practice in cotton production, but their combination to approach better yields and benefits was less studied. Since effective combination of plant density and VB retention may further reduce cost and increase yield, it is very important to conduct profound studies on interaction of plant density and VB retention. Using upland cotton Lumianyan 28, a multi-site field experiment was conducted in Linqing City , Xiajin County and Huimin County of Shandong Province respectively, to study interaction of plant density and VB retention on yield, yield components, earliness, and economic index in 2008. A split-plot design with four replications was used for the study. The main plot was plant pruning(removal and retention of VB), while plant density(3.00, 5.25, 7.50 and 9.75 plants¡¤m-2) constituted the subplots. Significant interaction was detected between plant density and plant pruning. Plants without VB produced the lowest and highest cotton yield at 3.00 plant¡¤m-2 and from 5.25 to 7.50 plants¡¤m-2 respectively, while those with VB produced the highest and lowest cotton yield from 3.00 to 5.25 plants¡¤m-2 and from 7.50 to 9.75 plants¡¤m-2 respectively. Under VB removal cotton yield at 5.25 plants¡¤m-2 was 9.7% higher than at 3.00 plants¡¤m-2, but under VB retention cotton yield at 3.00 plants¡¤m-2 was similar to that at 5.25 plants¡¤m-2 and 15.3% higher than that at 9.75 plants¡¤m-2. Both plant pruning and plant density significantly affected yield components. Boll weight was higher under VB removal than retention, and the number of boll per m2 increased as plant density raised. There existed significant interaction among site, plant density and plant pruning. Earliness under VB removal was higher than under VB retention, while earliness at 5.25~7.50 plants¡¤m-2 was better than at 3.00 and 9.75 plants¡¤m-2. No interaction of plant density and plant pruning on ratio of seedcotton to stalk, but VB retention and elevated plant density significantly increased biological yield and decreased ratio of seedcotton to stalk. Plant density and plant pruning affected biological yield, economic index and yield components individually or interactively, thus resulting in a significant interaction on economic yield. VB retention can compensate for yield loss due to lower population under low plant density£¬while VB removal is still beneficial to yield increase under middle and high plant density in Shandong Province.
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