Systems Agronomic and Economic Evaluation of Transgenic and
Conventional Varieties in the Texas High Plains
February, 2001
Dr. Randy Boman, Extension Agronomist-Cotton
Mr. Mark Kelley, and Mr. Alan Helm, Extension Assistants-Cotton
Texas Agricultural Extension Service
Lubbock, TX
Small-plot cotton variety testing generally includes evaluation of genetic components but not genetics in concert with management programs. Characteristics commonly evaluated in small-plot testing include lint yield, turnout percentages, fiber quality, and earliness. Over the last 3 years, High Plains cotton producers have increased planted acres of transgenic cottons (Roundup- and Buctril-herbicide tolerant and Bt insect-resistant types) from approximately 300 thousand in 1997 to over 2 million in 1999. Industry continues to increase the number of herbicide-tolerant, insect-resistant, and “stacked gene” varieties. Current small-plot variety testing programs are generally inadequate in scale and design to investigate the economic impact of new transgenic varieties with value-added traits. The objective of this project was to evaluate the profitability of various transgenic cotton varieties when compared to conventional types in producer’s fields. Three replications of each variety were included at each location. Plot size was of sufficient size to enable the compositing of all replications of each individual variety into a single module at harvest. Each individual variety had at least three acres total (approximately one acre per plot with three replications = three acres total). Plot weights were determined at harvest using a boll buggy with integral electronic scales. Modules were followed through the ginning process to determine lint turnout, USDA fiber quality, and loan value. Three producer-cooperator locations were utilized for this project, including medium, high, and low weed control input sites. Insect control measures were uniform across varieties at all locations. At the medium weed control input location at Muleshoe, PM 2326RR produced the same net value as FiberMax 819, even though it numerically produced less lint. The BXN 16 variety and system produced significantly lower net value per acre than several of the Roundup Ready varieties and the conventional FiberMax 819. The main economic components resulting in similar net value were the cultivation, hoeing and graminicide costs. These results indicate that in this medium weed control input production scenario, many of the transgenic Roundup Ready varieties competed very well with existing conventional varieties in terms of overall production economics. However, the conventional okra-leaf FiberMax 819 produced higher net value than all varieties except PM 2326RR. At the high weed control input site at Ralls, net value per acre was lowest for Stoneville BXN 47 and highest for FiberMax 989. No statistically significant differences were noted for net value per acre for FiberMax 989, PM 280, PM 2280BG/RR, PM 2326RR, and PM HS 26. These data indicate that some transgenic Roundup Ready and stacked gene varieties were competitive with conventional types in terms of production economics. The BXN 47 variety and system resulted in lowest numerical net value at this site. Results from the low weed control input site at Tokio indicated that Deltapine 237B produced significantly greater net value per acre than all other varieties. Paymaster 2200RR, PM 2326BG/RR, and PM HS 26 produced statistically similar net values per acre. These data indicate that even though additional post-emergence applications of herbicides were not required at this site, several transgenic varieties produced economically competitive net value, even when considering higher seed and technology fee costs on a per acre basis. Due to the fact that the recurrent parent of DP 237B, DP 2379, was not in this test, the impact of the Bollgard gene on the overall higher profitability of this background type cannot be determined. This site had considerable beet armyworm pressure over an extended period of time and the Bollgard gene in DP 237B may have contributed to increased yield. When comparisons were made between PM 2326BG/RR and PM 2326RR (same recurrent parent), yields were about 135 lb/acre greater for the Bollgard type. However, when comparing the PM 2200RR and the PM 2280BG/RR (same recurrent parent), there was only a 7 lb/acre advantage for the Bollgard type. Results from the 2000 production season at three varying locations in the Texas High Plains indicate that some transgenic Roundup Ready and Roundup Ready/Bollgard stacked gene varieties can be competitive with standard conventional varieties in terms of production economics. However, at two of three locations, conventional FiberMax varieties numerically produced the highest net values on a per acre basis.
