Browsing Cotton Report 2003 by Title
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Short Staple Variety Trial in Cochise County, 2002Twelve varieties were tested including two New Mexico Acalas, two California Acalas from CPCSD, the new Arizona Cotton Grower’s variety and seven other upland varieties. Among the twelve varieties, eight contained the roundup resistant gene, which is very important for the high elevation trials. Four of these roundup resistant varieties were stacked gene varieties also containing the Bollgard trait. The highest yielding variety in the trial was 1517-99, with a yield approaching 800 pounds of lint per acre. This yield was lower than seen in 2001. In addition to the plant mapping data and HVI data which are provided, estimates of the crop values are also included in this report.
Short Staple Variety Trial in Virden, NM, 2002Twelve varieties were tested including two new herbicide resistant entries from California, Riata and Nova, two New Mexico Acalas, seven roundup resistant entries from Delta and Pine Land Co., Stoneville, SureGrow and FiberMax, and the new variety developed for the Arizona Cotton Grower’s Association, AG 3601. The highest yielding variety in the trial was FM 989 with a yield of 1045 pounds of lint per acre. It was also the highest yielding variety at this location last year. The Acala 1517-99 placed second in yield at 1039 pounds of lint per acre. HVI data are also included in this report.
Susceptibility of Arizona Pink Bollworm to Cry1Ac Following Six Years of Intensive Use of Transgenic Bt Cotton in ArizonaWe summarize information on the performance of Bt cotton against pink bollworm (PBW), Pectinophora gossypiella, in Arizona following six years of use of this new technology. Monitoring of PBW susceptibility to Bt toxin Cry1Ac was conducted annually since 1997 by collecting insects from ten to 17 cotton fields, culturing strains in the laboratory, and measuring susceptibility to Cry1Ac in diet-incorporation bioassays. Based on survival in discriminating concentration bioassays of 10 μg Cry1Ac/ml of insect diet, resistant PBW were detected in low frequencies at 10 out of 17 Arizona locations sampled in 2001 and ranged from 0.0 to 4.0%. Though significantly more abundant than in the previous three seasons, resistant PBW were statistically less abundant in 2001 than they were in 1997. One collection from Paloma, AZ, had 4.0% survivors (uncorrected, actual survival) in bioassays of 10 μg/ml and samples from Coolidge, Maricopa, and Parker Arizona yielded • 1.0% survivors of this concentration. Susceptibility of a limited numbers of 2001 collections of PBW from California, New Mexico and Texas is also reported. Bioassays of 2002 collections are underway at the time of this writing. In a parallel effort, field efficacy of Bt cotton against PBW was documented at five to 39 Arizona locations per year since 1995 by collecting cotton bolls at seasons’ end and counting PBW and exit holes. In 39 pairs of adjacent Bt and non-Bt fields evaluated in 2001 by the Arizona Cotton Research and Protection Council, mean end-of-season pink bollworm infestation levels were > 15% for non-Bt fields and were < 0.15% in adjacent Bt fields. Thus, field observations indicated that performance of Bt cotton continued to be excellent throughout Arizona in the 2002 season.
Twin-Line Per Bed Plant Population and Variety EvaluationTwo experiments were conducted at the University of Arizona Maricopa Agricultural Center in 2002 designed to evaluate cotton yield and fiber quality at various plant populations and to test cotton variety performance in a twinline per bed cotton production system. The plant population experiment consisted of four target populations which included 60, 80, 100, and 120,000 plants per acre (PPA) and two varieties, Stoneville 4892BR and AG3601. The resulting plant populations were 52800, 69200, 82800 and 96200 for ST4892BR and 54800, 70800, 90500 and 104500 for AG3601. The two lowest plant populations resulted in the highest lint yields for both varieties and were similar but there was a significant linear of decreasing yield with increasing plant population. The highest lint yields in the twin line variety experiment were DP449BR (1743 lb/acre) and DP5415R (1702 lb/acre) which were not statistically different.