Arizona has experienced a trend toward increasing fiber micronaire values in recent years resulting in substantial discounts on fiber value. There is some evidence to suggest management can influence fiber micronaire. Approximately 560 cases were identified in cotton production areas in Arizona ranging from the lower Colorado River Valley to near 2,000 ft. elevation with grower cooperators in the 2000-2002 seasons. Field records were developed for each field by use of the University of Arizona Cotton Monitoring System (UA-CMS) for information such as variety, planting date, fertility management, irrigation schedules, irrigation termination, defoliation, etc. Routine plant measurements were conducted to monitor crop growth and development and to identify fruiting patterns and retention through the season. As the crop approached cutout and the lower bolls began to open, open boll samples were then collected from the lowest four, first position bolls (theoretically the bolls with the highest micronaire potential on the plant) from 10 plants, ginned, and the fiber was then analyzed for micronaire (low 4). From that point forward, total boll counts per unit area and percent open boll measurements were made on 14-day intervals until the crop was defoliated. Following defoliation, final plant maps were performed. Relationships among low 4 sample micronaire, irrigation termination (IT), defoliation, and final crop micronaire were analyzed. Results indicate strong relationships with final fiber micronaire for factors such as total heat units (HU) accumulated by the crop from planting to IT, variety, region of production (environment), and green boll load at cutout. Results showed that as total HU accumulated from planting to IT exceeded 2945 that micronaire levels increase significantly, especially for some districts (Paloma and Maricopa) and producers.

Messenger® was applied ar various growth stages of cotton to ascertain effects upon yield and quality. Plant mapping data indicated that treated cotton aborted lowest developing fruits when temperatures caused stress during experiment, untreated cotton did not. Lack of Messenger® after first bloom resulted in lower lint quality. Untreated cotton had highest yields and value/ acre from the Nov. 9 harvest date, although Messenger® applied at both first bloom and three weeks after first bloom had highest yields and value/acre when harvested on October 15.

Upland cotton advanced strains, commercial check comparison varieties, and national standard comparison varieties were evaluated in replicated field studies at three locations in 2002. The test sites include Safford, AZ, Maricopa, AZ., and Yuma, AZ. Six seed companies submitted a maximum of five advanced strains entries per location. Three commercial check varieties were used at each site for comparison purposes and included SG747, DP33B, and ST474. Four National Standard varieties were used at the Safford and Maricopa sites for comparison purposes and included Acala 1517-99, Atlas, DP458BR, and ST4892BR.

A series of studies were conducted around the southeastern region of the state during the 2002 cotton growing season to evaluate the effects of a twin-line (TL) planting configuration on fiber quality and lint yield. Two of the three studies were conducted on grower cooperator fields with large block comparisons or demonstrations of TL versus single-line (SL) configurations. Fiber quality was essentially the same for both demonstration locations. Yield differences were observed in both locations with the Graham County location experiencing a 130 lb lint yield decrease in the TL plots. The Cochise County location experienced a 328 lb lint yield increase in the TL plots. The third study was a split plot within a randomized complete block design with planting configuration (TL or SL) as the main effect and variety as the sub-unit effect. . No significant differences were detected in the main effect, sub effect or the interaction with respect to yield. Trends were observed however, indicating less difference between the TL and SL with respect to yield for varieties with a more columnar growth pattern. Fiber quality results indicated no significant differences among any of the treatments

A field experiment was conducted during the 2002 growing season to evaluate a central Arizona grower’s method of addressing cotton fiber micronaire based on the management and timing of his agronomic inputs. The success of his inseason management, irrigation termination decision combined with his method of defoliation has led to a consistent production of premium fiber micronaire in recent years. Steps to accomplish crop defoliation and the subsequent mixing of seed cotton from the top (younger) and lower (older) bolls achieved at harvest are intended to keep the micronaire at premium levels and further prevent discounts on the crop. A companion study was conducted at the University of Arizona Maricopa Agricultural Center (MAC-1,175 ft. elevation) in an effort to duplicate the grower’s late season crop management operations. This study consisted of two treatments, a control (conventional) which received an application of 10 oz. Ginstar combined with ½ pt. surfactant in 20 gal./acre carrier and a treatment which received the conventional treatment in addition to a pre-defoliation Accelerate and a post-defoliation Gramoxone applications consistent with the grower’s methods. Plant growth and development measurements taken inseason revealed that height to node ratio (HNR) and fruit retention (FR) levels estimates were similar for both sites (grower fields and MAC study). Lint yield estimates indicated no difference between the conventional defoliation and the treatment receiving additional compounds at MAC. Results of the analyses performed on final micronaire data also indicated no significant difference in micronaire values between the two methods of defoliation and late season management at MAC. Fiber micronaire values exceeded the premium level (>5.0) for both treatments at MAC. However, results obtained from the cooperator-grower gin records revealed that average fiber micronaire for all of the fields monitored in this project were at premium level (<5.0).

Each year the University of Arizona conducts variety trials across the state to evaluate the performance of upland cotton varieties. These tests provide unbiased data on the performance of varieties when tested side-by-side under typical production practices. In 2002, we planted a total of 9 trials, two in the Yuma region (Yuma County), four in the central region (Maricopa and Pinal counties), one in the southern region (Pima county), and two in the eastern region (Graham, Greenlee, and Cochise counties). We tested nine to twelve commercially available varieties at each test site. The purpose of this report is to present the results of the 2002 tests conducted in the Yuma, western, central, southern, and eastern regions of Arizona.

A field trial was established during the 2002 growing season as part of the statewide Upland Cotton Variety Testing Program. This trial was located in Thatcher with Dennis Layton Farms as the cooperator. The location was one of eleven around the state. Nine varieties from 5 different participating seed companies were evaluated in this study. Several varieties performed well including Deltapine DP555BR, a new variety from Deltapine, DP655BR, Fiber Max 989BR and 991R. Results indicate that DP655BR, which has traditionally been grown in this valley, continues to be an excellent choice. However, there are several other varieties that have recently come onto the market that provide very strong alternatives for cotton production in the Upper Gila Valley.

Twelve 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.

Twelve 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.

Five New Mexico and three California acala varieties along with twelve upland varieties of interest to the area were tested in a replicated small plot trial on the Safford Agricultural Center in Graham county at an elevation of 2950 feet. The highest yielding variety in this study was DP 655BR with a yield of 1552 pounds of lint per acre. It was followed closely by FM 989BR. These same two varieties were also the highest yielding varieties in this study in 2001 (1). Riata, a roundup resistant cultivar from CPCSD, was the highest yielding acala variety in the study. In addition to the yield and other agronomic data traditionally reported, fiber quality data and estimated values per pound of lint and per acre are contained in this paper.