ABSTRACT

Field studies were conducted at one hundred six locations in eleven states comparing the fruit retention of five Bollgard II, eleven Bollgard and nine non-Bollgard varieties. Bollgard II fruit retention on DPL 50 BIIR has been compared to Deltapine 50 BR and Deltapine 50 from 2000 until 2002. Bollgard II was deregulated and launched in 2003. This enabled Bollgard II to be tested in more diversified genetic background across a broad geography. All comparisons were made under large plot or field-size, grower conditions in LA, MS, AR, TN, AL, GA, NC, SC, OK and TX. All locations compared Bollgard II with Bollgard or non-Bollgard varieties. Most locations included comparisons of a Bollgard II, Bollgard and a non-Bt variety. Each technology was managed for heliothine pest using IPM established thresholds. Ten to twenty plants were selected from each treatment at each location. Boll retention after physiological cutout was recorded by node and position on each plant. Locations and plants were used as replicates. ANOVA was conducted for boll retention least square means at each node and position for each technology to determine differences (p>0.05). Fruit retention comparisons were made for nodes six though fifteen due to the relative importance of these nodes in contribution to lint yield.