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.

Seven New Mexico acala varieties and one non-acala short staple variety were evaluated for yield and other agronomic variables. 1517-88 produced the most seed cotton but HS 46, the non-acala produced slightly more lint. Both varieties yielded slightly less than three bales of lint per acre. Yields of most of the varieties in the trial were 100 to 200 pounds less than in the previous year. It is felt that the yield reductions were probably more due to lack of heat units during the growing season than the heat spell in June.

Fourteen short staple varieties were evaluated in Greenlee county in 1990 in two separate trials. Average yields were higher in 1990 than in 1989 in both locations. The highest yielding variety in the acala trial was a new variety from California, C-37, with a yield of 1271 pounds of lint per acre. The highest yielding delta variety in the trials was DP 20 with a yield of 1116 pounds of lint per acre.

Forty four 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, ChemBred and from Delta Pines were included. Seventeen varieties produced more than 4000 pounds of seed cotton per acre with the top variety, BR 110, yielding 4921 pounds per acre. The second variety, HS Sal 10, is a new variety developed by Bill Salmons. 1990 contained some record breaking high temperatures in the month of June which were detrimental to yields in other parts of the state. In this area, this heat spell was not as devastating and in some respects this year was a better cotton year than even 1989.

High Volume Instrument (HVI) classing of eighteen cotton varieties grown at several elevations in southeastern Arizona are compared by location in this paper. Data presented herein would indicate that elevation does not affect fiber length nor strength, these factors are more a function of variety and management. Micronaire values were seen to be lower at the higher elevations and this was felt to be a function of lower maturity level because of reduced growing season coupled with production of fine fibered New Mexico acalas. This report also contains HVI values on lint from 47 varieties of short staple cotton grown on the Safford Agricultural Center during the 1989 season.