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Weather played a major part in the production of cotton in the Safford valley in 1991. A cool spring and early summer slowed the development of cotton and gave an advantage to varieties that could produce quickly in the warm late summer months. Three Stoneville varieties came to the top of the test with Stoneville 506 producing the highest yield of over 4000 pounds of seed cotton per acre. The New Mexico acalas, 1517-91 and 1517-88 also produced well, and depending on the premium, could produce more income per acre than the top varieties. Fifteen varieties were tested at this site and all produced over 2 bales per acre.

Forty one short staple varieties and Pima S-6 were grown in a replicated field trial on the Safford Agricultural Center in Graham county. Most of the varieties were commercially available in the cotton belt, however, a few experimental varieties from the New Mexico acalas, ChemBred and from Delta Pines were included. Yields were 15 to 30% lower than the yields in this trial in 1990, with only one variety producing more than 4000 pounds of seed cotton per acre. The top variety was CB (ChemBred) 407 with a yield of 4177 pounds per acre. HS Sal 10, which was number two last year, retained that position in 1991. Newcomers to the top ten were: S1001, HS 46, CBX 1210, DP 5690, STV 506 and DP 5415. Heat unit data from the past couple of years are given in this report along with the average heat unit accumulation.

Three new California acala varieties are evaluated in this field trial along with nine New Mexico acalas. The highest yielding variety was New Mexico's 1517-88 with a yield of 2.8 bales per acre. California's MAXXA came in number 3, but not very far behind, yieldwise. Nazas 77, a rust resistant variety from Mexico,was evaluated in a second trial at this same location. Rust was not a problem at this site in 1991 so its rust- resistance could not be evaluated, but it yielded within 5% of the yield of 1517-88.

Short staple variety trials have been conducted for three years on the demonstration farm, at the Maricopa Agricultural Center. Twenty varieties, received from various seed companies, were entered into the test in 1989, 19 varieties in 1990, and 10 varieties in 1991. Yields ranged from 3353 to 4679 lbs. seedcotton/acre in 1989, 829 to 1428 lbs. lint/acre in 1990 and 1099 to 1246 lbs. lint/acre in 1991. Results form the statistical analysis showed significant differences among varieties for all three years. Differences among varieties in 1989 showed no clear trends with respect to maturity types. In 1990, those varieties that were medium to early season maturity types yielded higher than full season maturity types. The results in 1991 showed medium maturity types yielding in the highest ranking of the test without exception, while the performance of the full season maturity types was mixed. An additional test with narrow row spacing (30 inches) was included in 1991 with 5 varieties. Yields ranged from 947 to 1117 lbs. lint/acre. No significant differences were detected among varieties.

Short staple variety trials were conducted for four years at Prechel Farms near Coolidge Az. Six varieties were included in 1988, twelve in 1989, eight in 1990, and eight in 1991. Results from the statistical analysis showed significant differences among varieties in each of the four tests. Lint yields ranged from 908 to 1313 lbs. lint acre⁻¹ in 1988, 2844 to 4827 lbs. seedcotton acre⁻¹ in 1989, 695 to 1059 lbs. lint acre⁻¹ in 1990, and 1065 to 1286 lbs. lint acre⁻¹ in 1991. Those varieties that were medium to short- season maturity types yielded higher than long season maturity types in the 1988 and 1990 seasons. The reverse was true in the 1989 season and results were mixed in 1991.

Fourteen acala and four delta varieties were tested in two separate field trials in Greenlee county in 1991. Yields at both sites were about 1000 pounds per acre (seed cotton yields) than the 1990 yields. Cool weather and wet grounds delayed planting one to two weeks compared with 1990. The highest yielding varieties, both acala and delta type, produced around 2300 pounds per acre of seed cotton. An experimental New Mexico acala, B510 and Stoneville 506 were the top varieties.

Twelve upland cotton varieties were compared in an on farm trial in Graham county. The highest yielding variety was Stoneville 324, a relatively new semi-smooth- leafed variety from Stoneville with fiber qualities that approach those of DPL 90. Stoneville 324 yielded 4226 pounds of seed cotton with HS Sal 10 following closely behind at 4158 pounds per acre.

Eight field experiments were conducted across the cotton growing areas of Arizona in 1992 for the purpose of evaluating Upland cotton varieties in terms of adaptability and performance. Five commercial cottonseed companies participated in the program. Two varieties were submitted from each company at each location. Experiments were conducted on grower-cooperator fields in each case except one, which was conducted on a University of Arizona Agricultural Center. Locations used in the program spanned the range of conditions common to cotton producing areas of the state from about 500ft. to 3,000ft. elevation. Results indicated a broad range of adaptability and competitiveness on the part of each of the participating companies and their representative varieties. Each of the companies offers a compliment of varieties that can serve to match various production strategies commonly employed in the state as well as showing a strong capacity to be regionally adaptive.

Eighteen short staple varieties were grown in a replicated trial at the Maricopa Agricultural Center as part of the National Cotton Variety Testing Program.