| Abstrakt: |
Lint yield losses can be directly attributed to the storm tolerance of a cotton variety. Combined losses including pre-harvest loss and losses through machine harvest inefficiency can be as high as 20%. Two new varieties with potential for higher yields, DP 555 BG/RR and DP 444 BG/RR, have lower storm tolerance than many other commercially available varieties. The study was conducted to determine the difference in yield loss of varieties with varying degrees of storm tolerance, and whether higher potential yield can compensate for lower storm tolerance. Six locations in 2003 and five locations in 2004, all in the eastern US cotton belt, were used to compare DP 555 BG/RR, DP 451 B/RR, and DP 458 B/RR. Three and four locations in 2003 and 2004, respectively, were used to compare DP 444 BG/RR, DP 451 B/RR, and DP 458 B/RR. Sample areas within strips of each variety were hand-harvested prior to machine harvest with lint from the plant and ground kept separately. After machine harvest, adjacent samples were hand-harvested, again maintaining ground and plant cotton separate. DP 555 BG/RR produced numerically higher actual and potential yield than did DP 451 B/RR and DP 458 B/RR. Pre-harvest yield loss for DP 555 BG/RR (66.4 lbs/a) was significantly greater than DP 458 B/RR (23.5 lbs/a), but percent of potential yield lost was similar (4.5 % and 2.0%, respectively). DP 458 B/RR (13.4%) lost a numerically greater percent of potential yield through all forms of yield loss than did DP 555 BG/RR (12.4%). DP 444 BG/RR produced significantly greater actual yield than did DP 451 B/RR. Potential lint yield was greater (1350 lbs/a) for DP 444 BG/RR than both DP 451 B/RR (1193 lbs/a) and DP 458 B/RR (1207 lbs/a). Pre-harvest losses for DP 444 BG/RR (86.9 lbs/a) and DP 451 B/RR (68.3 lbs/a) were significantly higher compared to DP 458 B/RR (19.5 lbs/a). Numerically, DP 444 BG/RR lost more actual yield and percent of potential yield (231 lbs/a and 16.8%) than did DP 451 B/RR (165 lbs/a and 14.1%) and DP 458 B/RR (142 lbs/a and 12.0%), however the differences were nonsignificant. When all forms of yield loss are accounted for, there were no significant differences in yield loss due to storm tolerance. [ABSTRACT FROM AUTHOR] |
