Sweet corn (Zea mays L. var. rugosa Bonaf.) seed carrying the mutant endosperm gene shrunken-2 (sh2) are very susceptible to seed rot and pre- and post-emergence damping off. Experiments were conducted to determine if selected organic solvents were suitable carriers for fungicide infusion of sh2 sweet corn seed for improved germination and stand establishment. Seed of `Florida Staysweet' and `Crisp-n-Sweet 710' were immersed in acetone, cyclohexane, decahydronaphthalene (Decalin), dimethylsulfoxide (DMSO), ethanol, or xylene for 5 seconds, 0.25, 0.50, 1.0, 2.0, 4.0, or 8.0 hours, air-dried, and subjected to a cold-stress test. Total germination and percentage of normal seedlings in both cultivars were significantly decreased after 8 hours of immersion in acetone. Average seedling dry weight, however, did not decrease. DMSO was highly toxic to both cultivars. Ethanol increased seed mortality with increasing immersion times. Cyclohexane, Decalin, and xylene caused erratic responses in all measured variables as immersion time increased. In a second experiment, the effects of immersion time up to 4 hours in acetone on germination and vigor of 11 sh2 cultivars were compared. There was no correlation between cultivar germination or vigor and immersion in acetone. Results indicate acetone could be used to infuse fungicides into the seed of some sh2 cultivars without compromising seed germination or vigor. However, each sh2 cultivar must be screened individually to determine if it is a suitable candidate for organic solvent infusion of fungicides.
Patricia E. Hung, Vincent A. Fritz, and Luther Waters Jr.
Vincent A. Fritz, James B. Hebel, Alicia M. Borowski, and Patricia E. Hung
Ethephon and 2,4-D were foliarly applied to red-skinned `Norland' potatoes (Solarium tuberosum L.) to determine if periderm color could be enhanced at harvest and throughout storage. Base rates of 250 and 185 ml·liter–1 for ethephon and 2,4-D, respectively, were applied at the onset of tuberization (tubers ≥ 2.5 cm in diameter). Base or double-rate foliar applications of either ethephon or 2,4-D resulted in significant U.S. No. 1 yield reductions and did not affect periderm color intensity at harvest or throughout storage sufficiently to warrant their use. Chemical names used: (2-chloroethyl)phosphonic acid (ethephon), (2,4 -dichlorophenoxy) acetic acid (2,4-D).
Patricia E. Hung, Vincent A. Fritz, Thor Kommedahl, Albert H. Markhart III, and Luther Waters Jr.
Experiments were conducted to determine if the fungicide imazalil infused into shrunken-2 sweet corn (Zea mays L. var. rugosa Bonaf.) seed via acetone could protect against soil- and seedborne fungi enough to improve germination and vigor. `Florida Staysweet' and `Crisp-n-Sweet 710' seeds were infused for 0.25 hours with 1% or 2% (w/w) imazalil-acetone (LA) solutions, air-dried, and subjected to a modified laboratory seedling growth cold test using sterile soil or soil inoculated with Fusarium moniliforme Sheldon. Both IA concentrations significantly reduced the incidence of diseased seedlings in soil inoculated with F. moniliforme when compared to nontreated controls. Neither treatment significantly reduced the incidence of seedborne fungi. Chemical name used: 1-[2-(2,4-dichlorophenyl)-2-(2-propenyloxy)ethyl-H-imidazole (imazalil).