• Double-Crop Grain Sorghum Variety Trial, Graham County, 1986

      Clark, Lee; Cluff, Ronald, E.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      Nine medium to medium -late maturing grain sorghum hybrids were compared for yield, percent moisture at harvest, bushel weight, plant height, percent bird damage and standability. The highest yielding entry in the trial was a new hybrid from Northrup King (NK 2656). Its yield of 6185 pounds per acre was 11% higher than the most, commonly grown hybrid in the area.
    • Dryland Catchment Test Planted to Hybrid Sorghum and Pearl Millet in Avra Valley Near Three Points, 1986

      Thacker, Gary; Voigt, Robert; Schmalzel, Carl; Ottman, Mike; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
    • Grain Sorghum Variety Trial in Greenlee County, 1986

      Clark, Lee; DeRose, Edith; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      Eleven full season hybrid grain sorghums, representing seven commercial sources, were grown on a silty clay soil south of Duncan. The test plots were managed the same as the rest of the field planted to DeKalb 69. Grain yields ranging from 6911 to 4546 pounds per acre were obtained, with DeKalb 69 the top yielder.
    • Stomatal Response to Water Stress in Two Pearl Millet Genotypes

      Osman, Mohamoud; Dobrenz, Albert; Tewolde, Haile; Voigt, Robert; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      A study was conducted in the field to test whether stomatal sensitivity to water stress can be used as a selection criterion for drought tolerance in two pearl millet genotypes. In both cultivars, stomatal aperture was significantly reduced by the water stress. However, the proportion of reduction per 20 mm decrease in applied water was much higher for the hybrid than for the female parent. This is clearly an indication of a higher stomatal sensitivity in the hybrid, which probably explains the superior performance under water stress that was previously observed in this genotype.
    • Summary of Commercial Hybrid Grain Sorghum Yield Tests at Marana, 1983-85

      Ottman, Mike; Voigt, Robert; Schmalzel, Carl; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
    • Water Stress Indices for Research and Irrigation Scheduling in Pearl Millet

      Teowolde, Haile; Voigt, Robert L.; Osman, Mahamoud; Dobrenz, Albert K.; Ottman, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1987-09)
      The capability to measure the magnitude of water stress in plants is useful for precision irrigation scheduling and other purposes. This paper reports an evaluation of leaf (TL) and canopy (Tc) temperatures, leaf minus air (TL -Ta) and canopy minus air (Tc -Ta) temperatures, and leaf water stress index (LWSI) and crop water stress index (CWSI) in detecting stress in pearl millet (Pennisetum americanum (L.) Leeke) over two growing seasons. Baselines which were used to compute LWSI and CWSI were obtained. The upper and lower baselines for the Tc data, respectively, were Tc -Ta = 4.10 C and Tc -Ta = 3.87- .2001VPD where VPD is vapor pressure deficit in mbars. For the TL data, the upper and lower baselines, respectively, were TL -Ta = 1.97oC and TL -Ta = 1.308- .03006VPD. Tests against photosynthesis, transpiration, and grain yield showed that LWSI and CWSI are better indices of stress than TL -Ta, Tc -Ta, TL, Tc, or Ta. Average seasonal LWSI and CWSI ranged from approximately 0.03 for non- stressed to 0.80 for stressed plants. The reliability of LWSI and CWSI to detect stress and their relation with grain yield suggested the possibility of using these indices for irrigation scheduling decisions.