Extension postharvest quality maintenance programs in North Carolina were significantly enhanced by engineering inputs and Exxon violation escrow funds. Equipment and storage designs and recommendations have provided tangible results for North Carolina horticultural crops producers and shippers, including “Cool and Ship,” a portable, pallet-size forced-air cooling system, thermal storage immersion hydrocooling systems, and the horizontal air flow sweetpotato curing and storage system. Impacts include: 30% to 50% blueberry and strawberry loss reductions using forced-air cooling; and 20% to 30% sweetpotato packout rate increases when cured and stored with the new system. Useful materials include a video on cooling options, a computer decision aid for precooling, a storage poster, and more than two dozen publications on Maintaining the Quality of North Carolina Fresh Produce.
L.G. Wilson, M.D. Boyette, and E.A. Estes
D.P.M. Wilson, J.A. Sullivan, A.A. Marsolais, and M.J. Tsujita
The origin and development of somatic embryos from petiole sections of Regal geranium (Pelargonium ×domesticum Bailey `Madame Layal') were studied using time-series sections at days 0, 4, 8, 14, and 24. Somatic embryos originated as early as day 4 of culture. The proembryo stage resembled that of a zygotic embryo and the somatic embryos developed through the globular, heart-torpedo, and cotyledonous stages characteristic of in vivo zygotic embryogenesis. A suspensor-like structure was observed with some somatic embryos but this was not consistent. Strong evidence is presented to suggest that somatic embryos arose from single subepidermal parenchyma cells.
C. Stevens, V. A. Khan, A. Y. Tang, C. K. Bonsi, and M. A. Wilson
A three year study involving solar heating of soil (soil solarization) with clear polyethylene mulch demonstrated for two years, control of root-knot nematodes (Meloidogyne incognita). The population of M. incognita was reduced >90% in the 0-30cm depth of solarized soil. The number of eggs per gram root recovered and the root gall index from `Georgia-Jet' sweetpotatoes were reduced (92-98%) by soil solarization. Growth and yield were enhanced in solarized soil. The beneficial effects of solarization was observed in the second year following two additional cropping cycles of collard greens and sweetpotatoes.
C. Stevens, V. A. Khan, J. Y. Lu, M. A. Wilson, Z. Haung, and J. E. Brown
In 1988 and 1989 a muscadine vineyard at Tuskegeee, Alabama was treated by post plant soil solarization (PSS) (covering of moist soil around 'Carlos' muscadine plants (Vitis rotundifolia Michx.) with clear polyethylene plastic mulch to achieve high soil temperature for 30 and 75 days, respectively during PSS. Grape plants grown in solarized soils showed increases in growth response such as increased yield. Foliage of grape plants was evaluated for reaction to black rot incited by Guignardia bidwellii. A significant reduction of the foliage disease black rot was observed. The number of lesions per leaf, lesion size and percent leaves with lesions were significantly reduced by as much as 56% up to three years after solarization.
C. Stevens, L. P. Pusey, V.A. Khan, J.Y. Lu, C.L. Wilson, M.A. Wilson, M.K. Kabwe, J. Liu, E. Chaultz, and S. Droby
Flavorcrest, Camden. C. L. Wilson, Loring, Elberta, Summergold and Harken peach varieties were inoculated and naturally infected with Monilinia fructicolo after ultraviolet light irradiation (W-C 254nm) showed increased resistance to brown rot disease. Although dosages ranged from 0 to 20 KJ/m2. 7.5 KJ/m2 was considered the most effective for the peach varieties tested. Pretreatment of peaches by field spraying or dipping into a benomyl fungicide showed no significant differences between non-treated and UV-C treated peaches. However. a combination of a low dose of benomyl (.15g/L) 3 days following UV-C treatment showed a synergistic effect on brown rot reduction when compared to Peaches treated with UV-C alone and a greater reduction of brow rot than benomyl control.
C. Stevens, V. A. Khan, J. Y. Lu, M. K. Kabwe, Z. Haung, M. A. Wilson, and J. E. Brown
In 1988 and 1989 a muscadine vineyard at Tuskegee, Alabama was treated by post soil solarization (PSS) (covering of moist soil around muscadine plants with clear polyethylene plastic mulch to achieve high soil temperature) for 30 and 75 days, respectively. The average soil temperature in 1989 of 50 and 35 C at 5cm depth for solarized and bare soil, respectively during PSS. The results showed no visible detrimental effect on `Carlos' muscadine (Vitis rotundifolia) from the increased heating of the soil. And the grape plants grown in solarized soils showed increases in growth response e.g. increased yield, revitalization of new softwood vines, vine weight/plant, etc. Uneven ripening of muscadine grapes was reduced on plants grown in PSS over bare soil as indicated by the increases in the percent soluble solids content of grape berries.
A. Mendoza-Wilson, J. Siller, E. Bringas, J. Ojeda, J. M. Báez, and R. Báez-Sanudo
Ripening mutant gene rin (ripening inhibitor) in tomato inhibits, or greatly slows down, a wide range of processes related to ripening of the fruit, leading to a markedly extended shelf life. Although the use of films or coatings has been shown to retard ripening, the natural film that covers the fruit and delimits interchange with the environment, the cuticle, has not been well-characterized and related to ripening. The objective of this work was to characterize cuticle changes and establish their relationship with respiratory behavior. Turning tomato fruits with the gene rin, selection S-164 and normal tomato fruits were stored under marketing conditions (20C; 65% to 70% RH) to determine cuticular and physiological changes. Parameters evaluated were: cuticular weight changes (CW), permeability, soluble cuticular lipids (SCL), and epicuticular waxes (EW). In addition CO2 production was monitored every other day. Normal fruit increased in CW from 1.17 to 1.30 mg·/cm–2 and its EW from 11.49 to 24.49 μg·cm–2. On the other hand, rin tomatoes declined in CW and EW during storage. Both kind of fruits decreased their SCL content. Normal tomatoes exhibited the characteristic climacteric peak and showed an increase of cuticle permeability, while in rin tomatoes, these changes were not expressed.
C. Stevens, V.A. Khan, M.A. Wilson, D. Ploper, P. Backman, J.E. Brown, and R. Rodriguez Kabana
The application of plastic mulches, row cover or a combination of the two were evaluated from 1987 to 1991 for reducing early blight of tomatoes and Alternaria leaf spot of okra. Early blight on early season tomatoes (TU-80-130, New Yorker and Floradade) was significantly reduced by the application of black plastic mulch (BM) or BM plus spunbonded polyester row cover (RC) compared to bare soil. Early blight evaluation of late season tomato (Better Boy) showed that BM significantly reduced the incidence and number of lesions per leaf on the fruit clusters compared to bare soil, but the spunbonded polyester RC treatment didn't improve disease reduction of the BM. Alternaria 14 spot of Clemson Spineless okra in 1989 was severe on plant grown in bare soil compared to those grown on BM, BM plus VisPore row cover, clear plastic mulch (CM) and CM plus VisPore RC treatments. These soldier indicted that the application of agriplastic techniques could be used as a new crop management option in an IPM program to reduce the application of foliar fungicides or application of biological control agents.
L.H. Rolston, D.R. La Bonte, W.A. Mulkey, C.A. Clark, J.M. Cannons, and P.W. Wilson
C. Stevens, V. A. Khan, M.A. Wilson, D. J. Collins, J. E. Brown, and J. Y. Lu
Agriplastic black mulch (BM), row cover (spunbonded) plus black mulch (RBM) and solarized soil treatments plus black mulch (SBM). row cover plus black mulch on solarized soil (RSBM) and row cover plus solar&d soil (RSBS) increased Floradade tomato yield from 56 to 285%. number of tomatoes and plant height compared to the non-solarized bare soil (BS). When comparing increased growth response (IGR) of the plants grown in the solarized soil with no row cover agriplastic treatments, there was no significant differences among them. When comparing the IGR parameters of tomato plants grown under SBS, BM, and RBS there were no significant differences among them. Spunbonded row cover treatments increased IGR of tomatoes over all treatments without row cover. A significant increase in plant growth promoting rhizobacteria (PGPR) was observed in the rhizosphere soil of Floradade tomatoes grown in solarized soil alone and in those other agriplastic treatments compared to bare soil. There appear to be no differences in PGPR population among SBS and all agriplastic treatments.