Three overlapping genomic clones covering 29.0 kilobases of cotton DNA were found to encompass a cluster of two presumptive osmotin genes (OSMI and OSMII) and two osmotin pseudogenes (OSMIII and OSMIV). A segment of 16,007 basepairs of genomic DNA was sequenced from the overlapping genomic clones (GenBank Accessions AY303690 and AF304007). The two cotton osmotin genes were found to have open reading frames of 729 basepairs without any introns, and would encode presumptive osmotin preproteins of 242 amino acids. The open reading frames of the genes are identical in sequence to two corresponding cDNA clones (GenBank Accessions AF192271 and AY301283). The two cDNA inserts are almost full-length, since one lacks codons for the four N-terminal amino acids, and the other cDNA insert lacks the coding region for the 34 N-terminal amino acids. The cotton osmotin preproteins can be identified as PR5 proteins from their similarities to the deduced amino acid sequences of other plant osmotin PR5 preproteins. The preproteins would have N-terminal signal sequences of 24 amino acids, and the mature 24 kilodalton isoforms would likely be targeted for extracellular secretion. Prospective promoter elements, including two ethylene response elements, implicated as being positive regulatory elements in the expression of a number of PR-proteins, occur in the 5'-flanking regions. The mature osmotin proteins accumulate in cotton plants treated with the inducers ethephon and hydrogen peroxide. Thus, the two cotton osmotin genes encode osmotin proteins. The coding regions of the two genes have been expressed and isolated as fusion polypeptides in a bacterial expression system. Binary constructs containing the open reading frames of the two osmotin genes under the control of the 35S CaMV promoter have been generated for eventual production of transgenic Arabidopsis and cotton plants for potential constitutive expression of the osmotin proteins for increased resistance against fungal pathogens.

Nuclear DNA content of the amphidiploid, G. hirsutum, and two closely related diploid species, G. herbaceum var. africanum and G. raimondii, was ascertained by the reassociation kinetics of 250 nucleotide DNA fragments. Between diploid species the difference in chromosome size is attributed largely to variation in repetitive sequences, where there has been a change in both frequency and complexity. The evolution of single-copy DNA sequences by cross hybridizations among species reveals: (1) a high degree of sequence conservation between diploid species, showing 78% duplex formation under standard criterion and 6% sequence mismatch upon thermal denaturation; and (2) greater than 95% duplex formation between the diploid species and the amphidiploid with less than 1% single-copy sequence mismatch. The latter findings are consistent with an early Pleistocene origin for the tetraploid cottons.

Seventeen pima cotton varieties were grown at the Marana Agricultural Center as part of the national cotton variety testing program. Lint yield, boll size, lint percent and fiber properites are presented in this report.

Seventeen Pima varieties were grown in a replicated trial at the Maricopa Agricultural Center as part of the national cotton variety testing program. Lint yield, boll size, lint percent, plant populations, plant heights and fiber properties are presented in this report.

Sixteen long staple varieties 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 OA 340 with a yield of 1021 pounds of lint per acre. It was followed by two other Olvey varieties yielding over 900 pounds per acre, including OA 322 and OA 361 (White Pima). In the adjacent regional short staple cotton trial were three interspecific hybrids from Hazera, an Israeli Seed Company. These hybrids grew like short staple cotton, but the fiber was more like the barbadense parent. These hybrids yielded from 1146 to 1091 pounds per acre. Their data is included at the bottom of the tables for comparison with the other long staple variety values. Yield and other agronomic data as well as fiber quality data are contained in this paper.

Thirty long staple varieties 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 Hazera 83-208 with a yield of 1272 pounds of lint per acre. This interspecific hybrid from Israel yielded nearly 300 pounds per acre more lint than the next closest variety. The average yield in the trial was lower than in the previous year’s study. Yield and other agronomic data as well as fiber quality data are contained in this paper.

Twenty long staple varieties 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 HAZ 195 with a yield of 1408 pounds of lint per acre. This interspecific hybrid possessing a “fuzzy” seed and was tested with the Acala varieties in 2000, but was included in the Pima study this year because of it’s fiber characteristics. OA 345 was the highest yielding nonhybrid variety in the study, it yielded nearly 800 pounds of lint per acre. Yield and other agronomic data as well as fiber quality data are contained in this paper along with estimated values of the lint.

The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.

The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.

The 1985 and 1986 Cotton Reports have the same publication and P-Series numbers.