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Two short staple variety trials were held in Graham county, one toward the west end of the valley (Eden), and one in the center of the valley (Thatcher), both with 15 varieties. Delta Pine 90 was the highest yielding variety at both locations, with yields of 1,386 pounds of lint per acre at Thatcher and 1,123 pounds at Eden. Two new varieties, Northrup King 111 and BR 110, show some promise in the area, with yields close to that of Delta Pine 90. Lint quality and grade are listed for each variety.

Eleven varieties of short staple cotton, containing four varieties of Acala 1517 (including two new releases from New Mexico State University) were grown near the town of Cochise, which is at an elevation of 4,180 feet and has an average growing season of 232 days. Northrup King's KC 380 (the same as the experimental variety 2019) was the high yielder for the second year in a row, with 954.6 pounds of lint per acre. One of the new Acala' s, 1517-77BR was second in yield, with 936.5 pounds per acre. With the current premium structure, 1517-77BR would produce about $50 more gross farm income per acre than KC 380.

The check variety, Delta Pine 90, produced more than any of the new varieties in this unreplicated strip test. However, three new varieties produced yields within 10 % of the Delta Pine 90 yields; they were BR 110, Northrup King 111 and Germains GC 365.

Four short staple variety trials were harvested in Greenlee county in 1987, covering long season varieties, early maturing varieties, acala varieties and a regional variety trial which was duplicated in Cochise county. Germains GC 510 and Delta Pine 90 yielded equally with acala 1517-75 in the long season trial. Delta Pine 20 out-yielded acala 1517-SR1 in the trial of earlier maturing varieties. An experimental acala, B 510, out-yielded the other acalas in the trial, but required more time to produce the yield. Wider experience with this new acala and others in the trials will be necessary before recommendations can be made. The better yielding varieties produced more than two bales of lint this season.

A feasibility study of short season management in Pima cotton, using short season genotypes, was initiated in 1993. Four short season genotypes, a full season check, and a short season check were evaluated in replicated tests under short season and full season regimes. In this first preliminary year of data, no significant yield loss could be attributed to management regime or to earliness of genotypes. Three of the putative early maturing genotypes exceeded the full season Pima S-7 check in yield. Results were contrary to expectations. The short season test is planned for repeat in 1994. An investigation of a virescent mutant discovered in 1990 (CM-1-90) was conducted in 1991, 1992, and 1993. Crosses of the mutant to Pima S-6 to determine inheritance, and to various virescent mutants to determine allelism produced results which were anamolous to normal, nuclear inheritance. Reciprocal crosses to PS-6 and to various virescent mutants confirmed that the new mutant was cytoplasmicaly inherited.

Pima experimental strains P73, P75, P76, P77, and the cultivars Pima S-6 (PS-6) and Pima S-7 (PS-7) were grown in replicated regional tests at twelve locations across the Pima belt in 1993. Tests were machine harvested for yield determination, plant heights were measured, and lint samples were collected for fiber analysis. Considerable genotype by environment interaction for yield potential occurred across tests in 1993. Across all locations, the strain P76 ranked first in yield followed by the cultivar PS-7 and strain P75. Strains P73 and P76 produced fiber of equal or greater length, strength, and elongation than PS-7. Plant heights were greatest for the entries PS-6 and P75. Entries PS-7 and P73 were intermediate in height, while P76 and P77 were the shortest of the entries tested. Considering yield and fiber properties concurrently, P76 was the superior entry of the 1993 tests.

Twelve Pima varieties and experimental strains were grown in a replicated trial at the Maricopa Agricultural Center. Lint yield, boll size, lint %, gin turnout %, plant population and fiber property data are presented in this report.

Sixteen long staple cotton varieties (including 4 Pima experimental lines) were tested in a replicated small plot trial on the Safford Agricultural Center. Plots were machine harvested twice to determine yield and percent first pick Small hand samples were taken to determine boll size, percent lint turnout and fiber qualities. Pima S-6 was the highest yielding variety with 1110 pounds per acre of lint. Five of the sixteen varieties yielded over 2 bales per acre. A new variety OA 312 looks particularly promising with yield very close to S-6, fiber quality better than S-6 and an earliness that approaches that of S-7.

A short season feasibility study, using early maturing Pinta genotypes was conducted for a second season. Four early maturing genotypes, a short season check (P62) and a full season check variety (PS-7) were evaluated in replicated tests under short season and full season regimes. In both 1993 and 1994, most genotypes reached cutout around August 4, with 2759 accumulated heat units. All genotypes were earlier maturing than PS-7, as indicated by plant growth measurements and by sequential harvests. In 1994, the four early maturing experimental genotypes produced yields equal to or slightly better than the longer season cultivar PS-7. No differences in yield occurred between the short season and standard practice management systems in either year. A fiber improvement project was initiated in 1989 with the primary goals of increasing the fiber length and strength potential of Pima cotton. In 1989 the early maturing, short statured Pima strain P62 was crossed to Giza 45 and Giza 70 to transfer the fiber strength of those varieties into a heat tolerant, earlier maturing, productive Pima background. Likewise, P62 was crossed to the Sea Island cultivar St. Vincent V-135 with the objective of transferring the latter cultivar's long fiber length into an agronomic Pima background. Two resulting lines, one possessing high fiber strength and the other possessing high fiber length are planned for release in 1995-96.