Systems Agronomic and Economic Evaluation of Transgenic and
Conventional Varieties in the Texas High Plains
Dr. Randy Boman, Extension Agronomist-Cotton
Mr. Mark Kelley, Extension Assistant-Cotton
Mr. Alan Helm, Extension Assistant-Cotton
Texas Agricultural Extension Service
Medium Weed Control Input Site – Muleshoe
The early season performance and growth characteristics are presented in Table 4, Table 5, Table 6, and Table 7. Plant stands averaged about 70,000 plants per acre. The Stoneville varieties had significantly lower stand counts than other types. Some varieties exhibited significantly lower early season plant height, total nodes, and height to node ratio. No apparent trends were noted between Roundup Ready, BXN, Bollgard, stacked gene (Roundup Ready with Bollgard) compared to conventional varieties. FiberMax 819 had a greater number of mainstem nodes per plant than most varieties by early August, however, the corresponding height and height to node ratio indicated shorter internodes. Mid-season first position fruit retention for PM 2200RR was significantly lower than some other varieties. Final plant height ranged from about 20 to 24 inches, and indicated that PM 2326RR had significantly larger plant size than most varieties. Final total mainstem nodes ranged from 15 to nearly 19, and height to node ratios indicated that PM 2326RR and BXN 16 had larger overall internode length than most other varieties. Final first position fruit retention ranged from 36 to over 51%. The PM 280 background varieties (PM 2200RR, PM 2280BG/RR, and PM 280) had lower retention than PM 2145RR.
Commercial turnouts of harvested material ranged from 22.81% for PM 280 to 26.35% for FiberMax 819 (Table 8). Bur cotton yields per acre ranged from 4158 lb/acre for All-Tex Xpress RR to 5165 lb/acre for PM 2280BG/RR. This resulted in lint yields ranging from 969 lb/acre for All-Tex Xpress RR to 1254 lb/acre for PM 2145RR. Lint loan values derived from USDA-AMS classing results of the bales obtained in the project show that values ranged from $0.3603 for Stoneville X9904R to $0.4651 for FiberMax 819 (Table 9). After totaling lint and seed value per acre and subtracting out ginning costs and system-specific costs, the net value per acre ranged from a low of $335.53/acre for All-Tex Xpress RR to $501.14/acre for FiberMax 819. Statistically, the PM 2326RR produced the same net value as the FiberMax 819, even though it numerically produced less lint (45 lb/acre). 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 economics of production. However, the conventional okra-leaf FiberMax 819 produced higher net value than all varieties except PM 2326RR.
High Weed Control Input Site – Ralls
Early season agronomic data show that lower stand counts were noted for the Stoneville 4892BR variety when compared to others (Table 10 and Table 11). Plant height differences were noted on June 12, and the PM 2200RR variety had the largest plants. Stoneville BXN 47 had the smallest plant size on June 12. No differences were observed in early season total nodes. Early season height to node ratio data indicated only minor differences in average internode length. No significant differences were noted for final plant height, however, the BXN 47 had somewhat larger plants in early August and 12 oz/acre of Pix was applied to this variety to reduce vegetative growth. Final total node numbers ranged from 15.1 to almost 16.8. Only minor differences were noted for final height to node ratio. No significant differences were found for final fruit retention.
Commercial turnouts ranged from 24.08% to 26.10% (Table 12). Bur cotton yields ranged from 3016 for BXN 47 to 3951 lb/acre for PM 2326BG/RR. The corresponding lint yields ranged from 764 lb/acre for BXN 47 to 968 lb/acre for FiberMax 989. Loan values were lowest for Stoneville 4892BR ($0.4614) and highest for PM 280 ($0.5321) (Table 13). After calculating total value per acre and then subtracting ginning costs and systems costs, net value per acre ranged from a low of $291.03 for Stoneville BXN 47 to a high of $454.48 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.
Low Weed Control Input Site – Tokio
Agronomic characteristics of varieties at this site are found in Table 14, Table 15, and Table16. Both Stoneville varieties produced significantly lower stand counts than other varieties. Early season plant height indicated that PM 2200RR had larger plant size than several other varieties. Total nodes and height to node ratios indicated significant, but minor differences among varieties. By mid-season, FiberMax 989 and DP 237B had greater plant height than several other types. Mid-season total nodes indicated that the PM 2326RR, PM 2326BG/RR, and PM 2200RR had lower numbers of mainstem nodes than other varieties. Mid-season plant height to node ratio was not different among varieties. First position fruit retention at mid-season was significantly greater for the Stoneville BXN 47 and 4892BR than several other varieties. Final plant height was greatest for BXN 47 (23.9 inches) and lowest for PM 2280BG/RR (19.4 inches). Stoneville BXN 47 also had the highest number of mainstem nodes (18.1) whereas DP 237B had the lowest (16.1). Final fruit retention ranged from a low of 29.6 for Atlas RR to a high of 47.9% for PM 2280BG/RR.
Economic results for this site are presented in Table 17. Commercial turnouts ranged from a low of 22.38% for FiberMax 989 to a high of 26.30% for PM 2326BG/RR. Bur cotton yields varied considerably from a low of 2616 lb/acre for Stoneville BXN 47 to 3752 lb/acre for DP 237B. Lint yields ranged from 698 lb/acre for Stoneville BXN 47 to 980 lb/acre for DP 237B. Loan values also varied considerably from a low of $0.4032 for BXN 47 to a high of $0.4878 for PM 2200RR (Table 18). Deltapine 237B produced significantly greater net value per acre than all other varieties at this site. PM 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, several transgenic varieties produced economically competitive net value results, even when considering increased 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.