The old standar4 1517-75, was the best yielding variety in 1989, yielding over three bales of lintper acre. 1517-77BR, which yielded well in 1987 and then dropped off a bit in 1988, carne in second and an experimental, 6658 came in third. The touted New Mexico star, 1517-88 came in fourth followed closely by California's Prema. Eight of the 10 varieties tested yielded over 2.5 bales per acre. More than normal heat units coupled with good management practices brought the highest yields yet recorded in a University cotton variety trial in Cochise County.

Forty-nine, short- staple varieties and Pima S -6 were grown in a replicated 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 and from Delta Pines were included. Weather conditions were favorable through most of the year and the cotton produced well. Fifteen varieties produced more than 4000 pounds of seed cotton per acre, with the highest yielding variety producing 4759 pounds per acre. Delta Pine 77 was the highest yielding commercial variety but it was topped by an experimental New Mexico acala.

Short- staple variety trials were grown in two locations in Graham County in 1989. Exceptional weather conditions, coupled with good management practices, provided record cotton yields in the Safford valley. Delta Pine 77 was the highest yielding variety in the Thatcher location with a yield of 1740 pounds of lint per acre. An experimental acala from New Mexico came in second in this triad ahead of Delta Pine 90. Delta Pine 90 was the highest yielding variety in the Eden area with a yield of 1196 pounds per acre. Data on percent first pick plant height and plant populations are presented for each variety in each location. Graphs of heat units received each day throughout the growing season at the AZMET station on the Safford Agricultural Center are presented for 1988 and 1989.

Two short staple and one long staple variety trials were implemented in Greenlee County in 1989, with new varieties topping each trial. The most exciting new discovery was HS 46, which topped the competition in the short-staple trial by nearly 200 pounds of lint per acre. In the acala trial, the top four entries were composed of three New Mexico experimentals and Prema from the San Joaquin Valley. Any one of these acalas could become the new standard for the valley. P-69 in the long staple cotton trial yielded over 850 pounds of lint per acre and topped the S-6 yield by 25%. The testing program in Greenlee County is not only of benefit to the cotton producers and related agri-businesses in southeastern Arizona, but also to southwestern New Mexico.

The standard variety DPL 61 yielded higher in this trial. M-5, a California acala type was tested for the first time.

Short staple variety demonstrations were conducted in Pinal County in 1989 at the Prechel and Benedict Farms near Coolidge Az. Twelve varieties were included in the demonstration at Prechel Farms. Results from the analysis showed significant differences among varieties. Seedcotton yields in this test ranged from 4826 to 2844 lbs. acre⁻¹ for STV BR-110 and S-55 respectively. Seven varieties were included in the demonstration at Benedict Farms. Results from the analysis showed significant differences among varieties. Seedcotton yields in this test ranged from 4127 to 3530 lbs. acre⁻¹ for STV BR-110 and DP-50 respectively.

Regional variety tests were conducted at Maricopa, and Marana Agricultural Centers in continuing cooperation with the beltwide testing program. The national standards included in this test were Coker 139, Deltapine 50, and Paymaster 145. Lint yields for each variety, at both locations, are given in Table 1.

Short staple variety trials were conducted for three years at Prechel Farms near Coolidge At. Six varieties were included in 1988, twelve in 1989, and eight in 1990. Results from the statistical analysis showed significant differences among varieties in each of the three tests. Lint yields ranged from 908 to 1313 lbs. lint acre⁻¹ in 1988, 2844 to 4827 lbs. seedcotton acre⁻¹ in 1989, and 695 to 1059 lbs. lint acre⁻¹ in 1990. 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.

A short staple variety trial was conducted on the demonstration farm, at the Maricopa Agricultural Center in 1989. Nineteen varieties, received from various seed companies, were entered into the test. Yields ranged from 829 to 1428 lbs. lint acre⁻¹ for STY 110 and STV 1324 respectively. Results from the statistical analysis showed significant differences among varieties. Those varieties that were medium to short - season maturity types yielded higher than long, full season maturity types. This difference in yield was most probably due to the hot and humid weather conditions experienced in the 1990 growing season and the varietal differences associated with heat tolerance.

Short staple variety trials were grown in two locations in Graham county in 1990, Thatcher in the central part of the valley and Eden on the west end Acala Prema from the San Joaquin Valley in California had the top seed cotton yield in both locations with yield of 3789 and 3162 pounds per acre, at the two locations, respectively. The average lint yield in the Thatcher site was down more than 200 pounds per acre from 1989, whereas the average at the Eden site was about the same as in 1989. 1990 is characterized by its record setting heat spell in the end of June, even though fewer heat units were received in 1990 than in 1989. HS 46, a variety first seen in Graham county in 1989, performed well in both sites and in fact, topped both trials with lint yield Data on yields, percent first pick, plant height and plant populations are presented for each variety in each location.