• Changes in Free and Bound Auxin with Development of Squares and Bolls in Relation to Shedding

      Guinn, Gene; Brummett, Donald L. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Hormone analyses were conducted to determine why large squares seldom shed while young bolls do. Large squares contained five times as much free auxin as flowers, and they contained 16 times as much bound auxin. The high auxin content of large squares is probably a major reason that they almost never shed unless injured (for example, by insects). Free and bound auxin both decreased to very low levels at flowering and remained low for four days thereafter. This low concentration of auxin at, and just after, flowering is probably a major reason that bolls are likely to shed during the week after flowering. Both free and bound auxin increased rapidly between 7 and 9 days after flowering, possibly accounting for the decrease in boll shedding rate at this stage of development. Amide-linked IAA was the major form of auxin in squares, whereas ester IAA (presumably bound to sugars) was the major form of auxin in bolls.
    • Response of Texas Root Rot to a Soil Sterilant in Marana in 1987

      Thacker, Gary; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Methyl bromidelchloropicrin, a soil sterilant, was deep-injected into cotton beds ten days before planting. Within the kill areas of the Texas Root Rot, the soil sterilant had some significant effects on the mortality and yield of the cotton.
    • Controlling Purple Nutsedge in Fallow Soil with EPTC and Butylate

      Heathman, E. S.; Chernicky, J. P.; Barstow, B.; Farr, C.; Tickes, B.; Howell, D. R. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
    • Irrigation Termination of Cotton with Boll Weevil Infestations

      Farr, Charles (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Two irrigation termination trials at Buckeye and two at Laveen determined that irrigation the last four days of August produced as much lint as irrigation seven to ten days later. Pima S-6 and a late planting of DP 90 after oats responded to water in the same way as the early April plantings of Deltapine 77.
    • Effect of Ethphon (PREP™) on Short Staple Cotton in Marana, 1987

      Thacker, Gary; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Ethephon was applied to Deltapine 55 cotton with 35% of the bolls open. Ethephon significantly increased the percent first pick yield of the cotton. There was no significant difference in the total yield.
    • Natural Resistance of Cotton to Cotton Leaf Crumple Virus

      Wilson, F. Douglas; Brown, Judith K.; Butler, G. D. Jr. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Cultivars and germplasm lines of cotton, Gossvpium hirsutum L., differed in response to infection by the cotton leaf crumple virus (CLCV). The most widely grown cultivars in Arizona and southern California, 'Deltapine 90' and 'Deltapine 61', are susceptible, while ' Cedix', developed in El Salvador, and 'Coral', developed in Nicaragua, are highly resistant or immune. Nineteen other lines from a resistance breeding project in Nicaragua showed highly variable responses.
    • Lint Yield of Several Cotton Varieties Planted on Five Dates at Three Locations in Arizona in 1987

      Kittock, D. L.; Silvertooth, Jeff; Hofmann, C.; Malcuit, J.; Else, P. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Wide variations existed in the performance of cotton varieties over the five planting dates among three locations over three years. However, on the average, DP 77 performed best when planted between 27 March and 22 April at Maricopa and Marana. DP 90 was best for April and early May plantings at Safford. Stoneville 506 and DP 50 were among the best for May plantings. DP 20 Stoneville 112, and DP 50 averaged best for early June plantings, except Germain 510 was superior at Safford.
    • Pest Control Advisors' Recommendations for Cotton Insecticides: A Historical Review

      Baker, Paul B.; Brew, Tasha M. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      A survey of agricultural pest control professionals showed that certain compounds have consistently been recommended to control cotton pests for more than 40 years. Over that same period, the number of preferred materials available for recommendation has greatly increased. Other trends are toward greater use of compounds using lower application rates and biological insecticides.
    • Decline in Water Uptake by Irrigated Cotton During Boll Filling, and its Amelioration by Daily Drip Irrigation

      Radin, John W.; Mouney, Jack R.; Kerridge, Peter C. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      In 1984,1985, and 1986, leaf water potentials of irrigated cotton declined markedly as the crop approached cutout. Midday transpiration rates also declined, indicating a water-stressed condition. The water stress occurred despite the fact that measurements were made only when the soil was fully charged with water. In 1986, plant hydraulic conductances were estimated. The conductance was high early in the season, declined to a low value during cutout, and increased during regrowth to the high value of the early season. It is suggested that root length and efficiency of water uptake, or both, decrease during boll filling as most assimilates are partitioned into the bolls. Daily drip irrigation prevented this susceptibility to stress during boll filling. In 1984 and 1986, drip irrigation decreased the length and severity of cutout, resulting in an increased boll load at the end of the season.
    • Defoliation of Pima Cotton

      Silvertooth, Jeff; Howell, Don R. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Afield study was conducted in Yuma County to evaluate the relative effects of a plant growth regulator application and several defoliation treatments on Pima cotton. There were no statistically significant effects recorded with regard to the plant growth regulator application. There was a significant difference among defoliation treatments by analysis of percent leaf drop estimates. Promising results were recorded for DROPP as a defoliant material for Pima cotton under the given test conditions.
    • An Evaluation of an Alternative Commercial Fertilization Program for Cotton

      Hofmann, W. C.; Else, P. T. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Plant growth products manufactured by BioHumaNetics, Inc. (BHN) were evaluated at the Maricopa Agricultural Center for the third consecutive year in the same field. Treatments included: 1) no fertilizers added; 2) standard fertilization used on cotton at the farm; and 3) a treatment schedule prescribed by BHN. Yields in 1987 were significantly different; the BHN treatment produced the highest yield, and the unfertilized treatment produced the lowest yield. Yields from all three treatments were substantially lower than corresponding 1986 yields.
    • Preplant Zinc Applications to Short Staple Cotton in Marana, 1987

      Thacker, Gary; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      A preplant application of zinc was made to a short staple cotton field where the soil analysis had shown a zinc concentration of 0.64 ppm. No significant yield response was measured.
    • Progress of Cotton Harvesting in 1987

      Farr, Charles (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Cotton growers began cotton harvest earlier in 1987 than during the previous three years, but they fell behind the other years by December first. Rainfall in late October, particularly November 2, slowed harvest and reduced quality of cotton dramatically in some operations.
    • Short Staple Variety Trial, Cochise County, 1987

      Clark, Lee J.; Schwennesen, Eric (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      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.
    • Pima Cotton Improvement

      Turcotte, E. L.; Percy, R. G. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Five experimental strains and Pima S-6 were grown in nine Regional Tests across the Pima belt in 1987. Experimental strain P70 averaged highest in yield both below and above 2,500 foot elevation. The difference in yield between Pima S-6 and P70 across all locations was 48 pounds of lint per acre. Sequential harvests at Phoenix and Safford, AZ, indicated that P70 was the earliest and Pima S-6 the latest entry in the 1987 Regional Test.
    • Nematocide Use for Control of Rootknot Nematodes

      Farr, Charles (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Injection of Telone II in sandy loams containing more than 60 percent sand increased Pima S-6 yield 493 pounds of lint but failed to give economic response with DP 77 in second year cotton. Treatment with Vapam at two rates at the same locations did not increase yield significantly in 1987.
    • Pima Cotton Genetics

      Percy, R. G.; Turcotte, E. L. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Maintenance and evaluation of a collection of primitive Gossypium barbadense L. cottons progressed in 1987. Conversion of the non flowering tropical cottons to a flowering, day- neutral habit progressed. So did efforts to incorporate potentially useful biological and environmental stress tolerant traits into agronomic Pima backgrounds. Six cottons of the primitive cotton collection were found to potentially possess bacterial blight resistance. Genetic populations were developed to investigate the inheritance and distribution of two mutant marker traits in cotton. Interspecific Fl hybrid populations were developed for evaluation in 1988.
    • Purple Nutsedge Control in Fallow Soil, Woodhouse Farm - Roll

      Heathman, Stanley; Chernicky, Jon; Howell, Don; Tickes, Barry (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
    • Irrigated Cotton, Safford Agricultural Center, 1986

      Biggs, E. Niel; Clark, Lee J. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Cotton was grown using a computer model to schedule irrigation; yields of 2.5 bales per acre were produced. Even though some discrepancies were seen between calculated and measured soil moistures, the model was considered successful. No yield differences were seen between cotton grown with small, frequent irrigations and large, infrequent irrigations. The plant heights, however, were significantly altered.
    • Growth and Development of the Beet Armyworm, Spodoptera exigua, on Carbon Dioxide Enriched Cotton

      Akey, David H. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Growth and development was studied in the beet armyworm (BAW), Spodoptera exigua, reared on cotton seedlings at high (650 ppm) or ambient (325 ppm) carbon dioxide (CO₂) levels and at 2 fertilizer levels. Under high fertilization, female BAW reared on CO₂-enriched seedlings weighed significantly less (873 mg) than controls (101.0 mg) and had a significantly longer developmental time (14.2 vs. 12.4 days for controls). Male BAW followed the same pattern but the data were not statistically significant. Combined (male & female) survival rates for BAW reared on CO₂-enriched cotton seedlings on a high fertilizer level were 19.1 compared to 41.6 % for controls; more females survived than males by a significant ratio of 2:1.