• Cotton Variety Observation, Safford Agricultural Center 1988

      Clark, L. J.; Carpenter, E. W.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Twenty-four short staple cotton varieties were compared in a strip trial on the Safford Agricultural Center, 15 of which were seen for the first time, 7 of which were acala varieties from New Mexico. Three varieties, BR 110, Delta Pine Experimental 7124-293, and Northrup King KNX111 (now KC 311) exceeded the yield of the standard variety DP 90 by 12.6 %, 8.1 %, and 4 %, respectively. Other new cultivars that performed well but didn't exceed the yield of the standard, were HYP 1211, HYP 274, and Acala 2745. The first 2 are hybrids supplied by Dr. Warner Fisher, the latter is an experimental acala from New Mexico State University. Per acre values were affected by lint value as well as lint yield per acre. Using a value of $0.65/lb for New Mexico acala and $0.56/lb for Delta Pine acala, Acala 2745 produced $975/ac compared with DP 90's $916/ac and BR 110's $1031/ac.
    • Short Staple Variety Trial, Cochise County, 1988

      Clark, L. J.; Schwennesen, E.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Nine acala varieties were grown in the Cochise area of Cochise county. An experimental New Mexico variety B510 was the top yielder in the test, producing 1,287 pounds of lint per acre. The top variety in 1987, 1517-77BR, was next to the bottom in the 1988 test, probably due to low plant population. Variety characteristics such as plant height, wilt susceptibility, relative maturity and lint turnout are quantified in the study along with final plant populations and lint quality. Information on cotton variety strip trials implemented in the county is also given.
    • Short Staple Variety Demonstration, Graham County, 1988

      Clark, L. J.; Cluff, R. E.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Cotton lint yields in the variety trials in Graham county were higher than the 1987 yields by close to 200 pounds per acre. Two varieties, BR 110 and NK KNX 111 (now KC 311) yielded more than DP 90 at the Thatcher site, the highest yield being 1,569 pounds of lint per acre. In Eden, DP 90 was the highest yielding variety with 1,237 pounds of lint per acre. The New Mexico acalas didn't yield as much lint per acre as the top yielding varieties, but with 1988's premium, produced substantial income per acre. In Thatcher the highest yielding acala produced $861 per acre compared with BR 110's $910, whereas in Eden the highest yielding acala produced $736 per acre against DP 90's $717.
    • Short Staple Variety Demonstrations, Pinal County

      Malcuit, J.; Stedman, S.; Silvertooth, J.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
    • Variety and Date-of-Planting Test

      Pegelow, E. J. Jr.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Three upland cotton varielies--Stoneville 506, Deltapine 20, and Deltapine 77--were planted on 4 dates in 1988 at the Maricopa Agricultural Center and observed for flowering boll opening and lint yield. Results from the 1988 studies and those from similar tests in 1985-1987 are being used to determine the relationship of accumulated heat units to the timing of key stages in crop development.
    • Regional Variety Test

      Pegelow, E. J. Jr.; McAlister, A. C.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
    • Growth Regulator Test on Upland Cotton at the Marana Agricultural Center, 1988

      Briggs, R. E.; Nelson, J. M.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      A field study was conducted at the Marana Agricultural Center to evaluate the effectiveness of growth regulators on Deltapine 90 cotton. The Pix treatment yielded significantly higher than the check and any of the other treatments.
    • Evaluation of PIX Multiple Application Treatments on Upland and Pima Cotton in Arizona, 1988

      Silvertooth, J. C.; Howell, D. R.; Farr, C. R.; Malcuit, J. E.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Four field experiments were conducted in Arizona in 1988 to evaluate the effects of various multiple application treatment combinations of PIX on the growth and development, as well as the lint yields of both upland and pima cotton. Plant height was significantly reduced (P ≤ 0.05) in some FIX treatments in comparison to the checks for short periods of time after the treatment applications. Those effects did not persist, nor did they translate into any significant positive differences among treatments in terms of lint yields for either of the upland or pima experiments.
    • Hormonal Changes in Relation to Cutout

      Guinn, G.; Brummett, D. L.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Experiments were conducted in 1987 and 1988 to determine whether hormonal changes may be involved in the decreases in growth and boll retention commonly referred to as cutout. Nitrogen deficiency decreased the auxin content and growth of fruiting branches. The auxin contents of fruiting branches, squares, and bolls decreased during the season as the plants entered cutout. ABA in bolls increased slightly, but the ABA content of squares and fruiting branches showed no consistent changes. The results indicate that decreases in auxin (IAA) may be involved in cutout.
    • Comparison of Irrigation Termination Dates on the Yield of Upland and Pima Cotton

      Silvertooth, J. C.; Terry, L. I.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Field experiments were conducted in 1988 to begin an assessment of both the agronomic and entomological implications from differences in irrigation termination dates imposed on both upland and pima cotton. Nine study sites were established with non-replicated treatment arrangements. Two replicated experiments were established at Marana, AZ on both upland and pima comparing early and late irrigation terminations. The upland (DPL 20) field was planted 26 April 1988 and irrigation terminations of 18 August (early) and 5 September (late) were imposed. The pima S-6 field was also planted 26 April and irrigation was terminated on 13 August (early) and 1 September (late). Yield measurements showed no significant differences (P ≤ 0.05) between early or late termination with the DPL 20, but quite substantial and significant differences were observed between treatments in the pima experiment.
    • Progress of Upland Cotton Harvesting

      Farr, C.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      In 1984 Maricopa County produced more acres of upland cotton with lower yields than it had in 1987 but also started harvest later. Weather and insects reduced yield and early maturity of the crop; rainfall delayed harvest in the October-November period less than it had in 1987.
    • Current Use of Module Makers

      Farr, C.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Moduling of cotton has increased strongly since its introduction in 1973. The usage is different from gin to gin due to a variety of conditions. However, the addition of moduling has reduced the pressure on ginning capacity so that some growers can continue using trailers without slowing the speed of the harvest.
    • The Probability of Temperature Thresholds for Defoliation

      Farr, C.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      The probability of favorable temperatures for some cotton defoliants decreases importantly in the month of October. More effective and earlier defoliation is crucial to advancing the cotton harvest to reduce rainfall damage and diapausing boll weevil numbers. Probabilities indicate more defoliation should be carried out earlier.
    • Final Irrigation Timing of Upland and Pima Cotton

      Farr, C.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Irrigation termination trials were continued in 1988 to evaluate a newer, popular upland variety and pima S-6. Irrigation in the first week of September increased the yield of a May planting of DP 77, but not of two trials in 1988 with early April planting dates. A March planting of pima S-6 failed to respond to a 10 September irrigation on Coolidge sandy loam.
    • Earlier Timing Can Reduce Rainfall Losses

      Farr, C.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      The analysis of grades of upland cotton picked before and after a 29 October rainfall at Waddell in 1987 reveals significant financial losses for growers. Early harvesters in the area harvested over two thirds of the crop in October; over 98.0% of grades 21 and 31 were harvested before the rainfall. A Buckeye operation also accounted for a difference of $98.60 per acre between an early and a late harvested pima field the same season. The survey indicates that important losses can be reduced by a harvest begun 10 to 15 days earlier than mid- October.
    • Defoliation of Pima Cotton, 1988

      Silvertooth, J. C.; Howell, D. R.; Stedman, S. W.; Thacker, G.; Winans, S. S.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Four field experiments were carried out in several areas of Arizona to evaluate the effects of a plant growth regulator and an array of conventional cotton defoliant treatments on pima cotton. Variable conditions were encountered across locations at the time of defoliant- treatment applications. However, there was a consistent trend observed in terms of treatment effectiveness, and a few distinct treatments appeared to have considerable promise for 1-time applications for satisfactory defoliation of pima cotton.
    • Defoliation Research on Pima Cotton at the Maricopa Agricultural Center in 1988

      Nelson, J. M.; Briggs, R. E.; Hart, G.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      A field study was conducted at the Maricopa Agricultural Center to evaluate the effectiveness of selected defoliation treatments on pima cotton. Defoliants were applied in October under relatively warm conditions. Treatments containing Dropp generally resulted in the highest leaf drop percentages (over 90 %). Def 6 treatments were ineffective in defoliating pima cotton.
    • Effects of Date of Planting on the Lint Yield of Several Cotton Varieties Planted at Four Locations in Arizona, 1988

      Silvertooth, J. C.; Malcuit, J. E.; Howell, D. R.; Else, P.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      Field experiments were carried out at 4 locations in Arizona to evaluate the effects of planting date on the lint yield of several varieties of cotton. One pima and eleven upland varieties were planted on 5 dates at 2 locations and 1 pima and nine upland varieties were planted on 5 dates at a third location. At a fourth location, 1 pima and 3 upland varieties were planted on 4 dates. General trends in lint yields indicate an advantage in yield potential from full- season type varieties, particularly when they are planted early. Full-season varieties, however, diminish rather quickly with regard to yield potential, when planting is delayed in comparison to varieties that are considered mid-or shorter-season varieties.
    • Effect of Plant Nitrogen Status and Growth Regulators on Earliness, Effectiveness of Defoliants, and Yield of Upland Cotton

      Nelson, J. M.; Briggs, R. E.; Hart, G.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      A field study was conducted at the Maricopa Agricultural Center to determine the effect of nitrogen fertility level and growth regulators on earliness, yield of cotton, and effectiveness of defoliants. Nitrogen application rates of 80, 120 and 160 lbs N/A did not influence lint yields or the response of cotton to growth regulators. The growth regulator Piz tended to promote earliness but did not affect final yield. The defoliants tested achieved good leaf drop results independent of the plant nitrogen status. Petiole nitrate-N content at the time of defoliation (4 October) did not correlate well with the response of cotton to defoliation treatments.
    • Effect of Irrigation Termination Date on Defoliation and Yield of Upland Cotton

      Nelson, J. M.; Briggs, R. E.; Hart, G.; Silvertooth, Jeff; Isbell, Joan (College of Agriculture, University of Arizona (Tucson, AZ), 1989-03)
      A field study was conducted at the Maricopa Agricultural Center to determine the influence of plant water stress on the effectiveness of defoliants and yield of cotton. Irrigation termination dates of 12 August, 24 August, and 8 September were used to achieve different levels of plant water stress at the time defoliants were applied (22 September). The defoliants tested performed well on cotton, which had termination irrigations in August. Def 6 was not as effective as other defoliants in defoliating plants with an 8 September termination irrigation, unless used in combination with Prep. Cotton with an 8 September termination irrigation produced lint yields 9% higher than cotton with August irrigation termination dates.