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About 20 years ago control of early season pests generally became more aggressive in the US in an effort to obtain earliness and avoid the cost and yield loss associated with late season pests which were often difficult to control. During the past 20 years new management tools have been developed. These include early more determinate varieties, plant monitoring tools, and Bollgard varieties where control of some pests were provided without beneficial pest disruption. Delta and Pine Land Company conducted extensive variety testing and collected plant map data from field trials represented by most of the US cotton growing areas since 1994. This national data base was used to define the association between early boll retention and yield and the time required to develop yield potential. No association existed between yield and retention of the bottom 5 FP-1 unless the season length for effective flowering was restricted to approximately 17 days. Even then the association was weak. There was an association between % retention of the FP-1 positions in the 95 % zone and yield. Low retention of the bottom 5 FP-1 required more time to set the crop. As average bottom 5 FP-1 retention increased by 14 %, the node number of the 95 % zone was decreased by 1.0. |
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©National Cotton Council, Memphis TN |
Document last modified XXXXXX, XXX XX 2001
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