`Thompson' pink grapefruit (Citrus paradisi Macf.), waxed or film-wrapped, treated with thiabendazole (TBZ) or untreated, were used to determine the effect of high-temperature conditioning at 31C for 3 days on fruit during subsequent storage for 4 weeks at 1 or 10C. Chilling injury (CI) developed in all conditioned fruit stored at 1C, but was drastically reduced in film-wrapped compared to waxed fruit. Thiabendazole slightly reduced CI, and fruit held at 10C had fewer CI symptoms than those held at 1C for 4 weeks. Conditioning Florida grapefruit at 31C for 3 days did not allow subsequent storage at 1C without rind discoloration. Chemical name used: 2-(4'-thiazolyl)-benzimidazole (thiabendazol, TBZ).
The lack of dwarfing rootstocks for peach has led to cultural and genetic approaches that reduce tree size and vegetative growth to establish high-density plantings. The objectives of the study were to evaluate the interactions of pruning strategies, groundcover management, tree densities, and peach (Prunus persica) architecture combined in eight peach production systems on components of yield and economic value. The use of sod management reduced pruning time and costs, but the reduction of crop load reduced net return. High-density plantings in large vegetation-free areas (VFAs) had greater economic return than low-density plantings.
The effects of water stress on internal water potential components and specific physiological processes were investigated in field grown potatoes (Solanum tuberosum L. cv. Viking). Leaf water potential (ψleaf) as estimated by the pressure chamber, was not directly related to soil water potential (ψsoil) until a specific minimum ψsoil was attained. Subsequently ψleaf did not increase in response to increases in ψsoil. Water stress affected physiological processes such as stomatal resistance, photosynthesis and enzyme activity. A decline in ψleaf was apparently responsible for increased stomatal resistance and decreases in photosynthetic rates. The activities of ribulose diphosphate carboxylase and phosphoenolpyruvate carboxylase decreased as ψleaf declined. The relationship between water stress and physiological processes and the inability of ψleaf to respond to increases in ψsoil after a maximum stress may partially explain the extreme sensitivity of potatoes to even mild water stress.
Light has long been known to stimulate anthocyanin accumulation in apple peel, but changes in apple flavor as a result of fruit shading is poorly understood. Some growers maintain that the redder the strain, the less flavorful the fruit. An experiment was conducted to help characterize the role of light in biosynthesis of color versus flavor molecules in apple peel. Bags fashioned from 3 meshes of shade cloth were fastened around fruitlets of red delicious strains `Starkrimson' and `Topred' on M26, MM106, and MM111 by 21 DAFB to produce average light ranges of 100%. 41-68%, 12-30%, and < 1% of full sun incident upon the fruit. Observations from the 1993 harvest indicate that anthocyanin content of peel increased with fruit maturity and level of sunlight. Concentrations of flavor molecules were higher with low and moderate shade than with full sun, and also increased with fruit maturity. From this harvest data, it appears that apple flavor can be enhanced by lightly shading fruit without substantially reducing fruit color.
Thirty-seven species within Cucurbitaceae representing the genera Citrullus, Cucumis, Cucurbita, Lagenaria, and Luffa were evaluated for disease reaction to an Acremonium cucurbitacearum A. Alfaro-Garcia, W. Gams, and Garcia-Jimenez, isolate (TX 941022) from the Lower Rio Grande Valley of Texas. After 28 days in the greenhouse, seedling disease ratings were made on the hypocotyl, stem-root junction, primary root, and secondary roots. An additional disease measure was derived by averaging the four root disease ratings to establish a disease severity index (DSI). Vine and root dry weight were poor measures of plant damage caused by A. cucurbitacearum. According to the DSI, all species within Cucurbita, Lagenaria, Luffa, and three Cucumis sativus L. cultigens were rated as highly resistant to A. cucurbitacearum. Cucumis melo L. and Citrullus lanatus (Thunb.) Matsum. & Nakai cultigens were the only cucurbits receiving DSI ratings of moderately resistant to susceptible.
The mungbean [Vigna radiata (L.) Wilczek] is an important short-duration annual grain legume. Mungbean is grown principally for its edible dry seeds, which are high in protein, easily digested, and prepared in numerous forms for human consumption; e.g., as a green vegetable and for sprouts. Other attributes of the crop include drought tolerance, high lysine content as compared to cereal grains, low production of flatulence, and wide adaptability. Commercial production occurs throughout Asia, Australia, the West Indies, South America, and tropical and subtropical Africa. In North America, production is centered in northern Texas and Oklahoma. Annual world mungbean production is estimated at 1.4 million t harvested from ≈3.4 million ha (1). In the United States >50 million kg of bean sprouts are produced annually from 8.3 million kg of mungbean seeds (4).