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The adverse effect of moisture stress at flowering and maturation stages on corn (Zea mays L.) grain yield is well documented. Stress at vegetative stages, on the other hand, affects dry matter more than grain yield but is also reported to condition the corn plant to withstand later stress. The objectives of this study were (1) to determine if moisture stress at vegetative stages could condition the corn crop to minimize the effect of stress at reproductive stages, and (2) to document the effect of this vegetative stress on corn root growth, water use and yield. Secondary root initiation was reduced by moisture stress at the 4 and 7 leaf stages. Moisture stress during vegetative stages reduced water use and stover weight but not grain yield. However, stress at silking reduced grain yield. Stress at vegetative stages did not precondition the corn to endure water deficit later in the season.

A field experiment was conducted to evaluate the effect of planting date on Upland as a short staple (Gossypium hirsutum L.) and Pima cotton as a long staple (Gossypium barbadense L.) cotton. Planting dates were 27 April, 13 May, 27 May, and 9 June, 1988. Cotton varieties consisted of three maturity groups: early maturity Delta and Pine Land 20 (DPL 20) and full season Delta and Pine Land 90 (DPL 90) from G. hirsutum L., and Pima S-6, a variety of the more indeterminate type G. barbadense L. A number of cold periods at Marana in the early spring of 1988 created unfavorable conditions for all cotton varieties on the early planting date. This condition resulted in lower head unit (H.U.) availability during germination, and significantly altered the usual pattern for flowering on planting date (PD) 1. The amount of H.U. accumulation for PD 2, especially during germination, was higher than for PD 1. (Abstract shortened with permission of author.)

A greenhouse experiment was conducted to evaluate the effect of five amendments (H₂SO₄, Al₂(SO₄.18H₂O, FeSO₄.7H₂O, and CaS₅ and CaSO₄.2H₂O) on crust formation, seedling emergence, dry matter yield (DMY) of tomato and soil properties in a sodic soil from the Safford Agricultural Center. When applied in equivalent quantities (600 kg/ha S), sulfuric acid and Al-sulfate proved to be the best anti-crusting agents and gypsum the least. Tomato seedling emergence and DMY increased with addition of H₂SO₄ followed by gypsum. Sulfuric acid was superior in reducing ESP in 0-3 cm depth, while EC was increased with additions of all amendments. In 3-8 cm depth the amendments affected pH, EC and ESP less than at the 0-3 cm depth. DTPA extractable and plants concentrations of Zn, Fe and Mn significantly increased with the addition of various amendments, while Cu was not effected by any amendments.

Crop performance depends on genotype, the environment in which the crop is grown, and interaction between genotype and environment. A measure of these effects is important in determining adaptation and in recommending crop genotypes to growers. In instances where hybrid seed has been introduced into developing countries, which often traditionally save seed for the next planting, determining the adaptation of genotypes and making accurate recomendations may be difficult. This experiment evaluated 15 commercial hybrid grain sorghums (Sorghum bicolor (L.) Moench), along with their segregating F₂ and F₃ generations, for adaptation to variable moisture environments. Grain yield per entry in all tests was the main phenotypic character used to measure adaptation in environments differing in mean moisture stress. Grain yield was also the main characteristic used to observe changes through generations F₁ to F₃.There was an expected decrease in yield with decreased irrigation, and with advanced generations. A close association was observed between mean 3-year grain yield of the selected hybrids and their F₂ and F₃ progenies when grown in the same environment.

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