Bearing pecan [Carya illinoinensis (Wangenh.) K. Koch] trees overly stressed by crop load and premature autumn defoliation either died or were severely damaged by -3°C in mid-November. Orchard damage was associated with death of tree roots during the dormant season. Exposure of stressed trees to -5°C in mid-March produced an atypical, but distinct, bottom-to-top-of-canopy gradient in bud death and reduced growth of shoots and foliage that was consistent with the pattern of reduced carbohydrate reserves of associated support shoots. Additionally, the foliage of damaged trees contained higher concentrations of N, P, K, Ca, Mg, Mn, Fe, and B. Trees did not exhibit traditional symptoms of cold damage, thus these findings extend cold injury diagnostic criteria to include both root and tree death during the dormant season and also a distinct gradient in shoot death during early spring. Damage by cold appears to be preventable by avoiding excessive tree stress due to overcropping and premature defoliation.
Bruce W. Wood and Charles C. Reilly
Dana F. Faubion, Mary Lu Arpaia, F. Gordon Mitchell, and Gene Mayer
Optimum controlled atmosphere (CA) storage conditions were evaluated over a two year period for California-grown `Hass' avocado (Persea americana). Fruit harvests corresponded to early, middle and late season commercial harvests. Various temperatures and CA conditions were tested. The results indicate that the storage life of `Hass' can be extended from 3 to 4 weeks in 5C air, to 9 weeks in 5C CA if they are held in 2% oxygen and 2 to 5% carbon dioxide. Loss of quality as determined by chilling injury expression and flesh softening was greatly reduced in these conditions. Fruit maturity influenced the response to CA storage. Late season fruit had greater loss of quality in storage than earlier fruit. In 2% oxygen and 2.5% carbon dioxide, continuous exposure to ethylene levels as low as 0.1 ppm significantly increased quality loss. Delays in cooling and CA atmosphere establishment of up to three days after harvest did not effect quality.
Dan E. Parfitt, Craig E. Kallsen, and Joe Maranto
`Randy' is an early flowering male pistachio that will be used as a pollenizer for `West Hills' and `Lost Hills'. It has excellent flowering synchrony with `West Hills' and `Lost Hills' and can be used to cover the earlier part of the `Kerman' flowering period during seasons in which `Kerman' flowering is extended. This generally occurs during seasons of low chill, which are expected to become more frequent in the future due to continued global warming. `Peters', the standard male used to pollenize `Kerman', often flowers too late to cover the earlier part of the `Kerman' bloom period under these conditions or to serve as an effective pollenizer for the new female cultivars. `Randy' was selected for high pollen viability, pollen durability, and a high level of pollen production (based on visual evaluation). `Randy' flowers 1–3 weeks earlier than `Peters', the standard pollenizer for `Kerman'.
William Terry Kelley
Carrots (Daucus carota L.) have become an economically important vegetable crop for Georgia. Currently the harvest season extends from December through May. One possibility for extending the harvest season would be to produce carrots in the cooler mountain area of Georgia during the summer months. This study was undertaken to examine the potential for fresh-market carrot production on Georgia mountain soils and to evaluate which varieties of carrots might be most suitable for this area. Ten commercially available carrot varieties were direct seeded into a Transylvania clay loam soil on 28 May 1999 in Blairsville, Ga. Plots consisted of three twin rows of carrots each 20 feet in length. The twin rows were each three inches apart and there were 20 inches between each set of twin rows. Each plot was replicated four times. Base fertilizer of 20 pounds of nitrogen, potassium, and phosphorous were incorporated into the plots prior to seeding. Sidedress applications of 15 pounds each of N, P, and K were applied at 3-week intervals throughout the season. Recommended pest control practices were applied. A three-foot section of the center twin row was harvested on 23 Sept. 1999. The varieties `Pacific Gold' and `Topnotch' produced the highest marketable yield; however, all yields were below acceptable levels. Percent marketability was <60% for all varieties. Percent stand was extremely variable due to variability in seed size. All carrots had severe nematode damage although a nematicide was used preplant. The length of season for spring-planted carrots was too long for the life of the nematicide at the rate and method applied. Late summer–planted carrots would likely be a more viable option for this area.
Cultivated blueberries (Vaccinium section Cyanococcus species, including lowbush, highbush, and rabbiteye) normally produce flower buds at the end of the growing season; these remain dormant during the winter and give rise to flowers the following spring. However, rabbiteye and low-chill highbush cultivars that are maintained in a state of vigorous growth throughout the winter in an unheated greenhouse in Gainesville in north Florida flower and produce fruit continuously on new growth throughout December, January, and February. The regimen of cool (but not freezing) nights and short, warm days permits the plants to continue growth throughout the winter and results in rapid conversion of newly-formed axillary buds into flower buds. These do not become dormant, but sprout to produce flowers and fruit almost as quickly as they are formed. Extending the photoperiod or raising night temperatures inhibits primocane flowering by allowing the axillary buds to remain vegetative. Primocane flowering, which occurs naturally in highbush blueberry production fields south of lat. 28°N in Florida and at lat. 30°S in eastern Australia, can contribute to an extended harvest season (4 to 8 months per year) from a single cultivar.
A.M. Armitage and J.M. Laushman
We would like to thank Rosemary Scully-Key, Anita Harris, and Henaege Tseng for assistance with this work. Special thanks are also extended to Van Waveren and Sons, Mt. Airy, N. C., for donation of the bulbs and Yoder Bros. Barberton, Ohio
S.J. Locascio, A.G. Smajstsrla, D.H. Hensel, and D.P. Weigartner
Growth and production uniformity of potato (Solanum tuberosum L.) as influenced by conventional seepage irrigation and by subsurface drip irrigation was evaluated in field studies during two seasons in plots 16 rows (18.3 m) wide and 183 m long. Seepage irrigation water was supplied through ditches located on each side of each plot. Drip irrigation water was distributed through buried tubes placed under the beds 6.1 m apart extending the length of the rows. Water application throughout the plots was accomplished more rapidly with the subsurface drip system and water use during the two seasons was 33% less than with the conventional seepage system. Tuber yield during the first season was similar with the two irrigation systems. During the second season, plant growth, tuber development, and tuber yield were sampled on alternate rows beginning on each outside bed, at each end of each plot, and in the middle of the plots. Irrigation method and bed location among the 16 beds had little influence of potato growth and development. With water flow from north to south, plant growth, and tuber yield were significantly higher from potatoes growing at the north end, lowest in the plot center, and intermediate from potatoes growing at the south end. These data indicate that potato production with the two irrigation systems was similar.
Rebecca Grube Sideman
tunnels compared with open field conditions ( Fitzgerald and Hutton, 2012 ). This may be because tunnels lengthen the potential harvest season for green bell peppers and also facilitate production of ripe colored fruit, which is difficult in field
Robert J. Dufault, Ahmet Korkmaz, Brian K. Ward, and Richard L. Hassell
Extending the production season of melons (Cucumis melo L.) by using very early and late planting dates outside the range that is commercially recommended will increase the likelihood of developing a stronger melon industry in South Carolina. The objective of this study was to determine if early (February) transplanted melons or later (June through July) planting dates are effective in extending the production season of acceptable yields with good internal quality of the melon cultivars: Athena, Eclipse, and Sugar Bowl and Tesoro Dulce (a honeydew melon). Melons were transplanted in Charleston, S.C., in 1998, 1999, and 2000 on 12 and 26 Feb., 12 and 26 Mar., 9 and 23 Apr., 7 and 21 May, 4 and 18 June, and 2 July and required 130, 113, 105, 88, 79, 70, 64, 60, 60, 59, and 56 days from field transplanting to reach mean melon harvest date, respectively. Stands were reduced 67%, 41%, and 22% in the 12 and 26 Feb. and 12 Mar. planting dates, respectively, in contrast to the 26 Mar. planting date but ≤15% in all other planting dates. Planting in February had no earliness advantage because the 12 and 26 Feb. and 12 and 26 Mar. planting dates, all reached mean melon harvest from 19 to 23 June. Comparing the marketable number of melons produced per plot (averaged over cultivar) of the standard planting dates of 12 and 26 Mar. indicated decreases of 21%, 32%, 36%, 36%, 57%, 57%, and 54%, respectively with the planting dates of 9 and 23 Apr., 7 and 21 May, 4 and 18 June, and 2 July. The most productive cultivar of all was `Eclipse', which yielded significantly more melons per plot in all 11 planting dates followed by `Athena' (in 8 of 11 planting dates), `Tesoro Dulce' (7 of 11 planting dates), and `Sugar Bowl' (2 of 11 planting dates). In our study, any planting date with melon quality less than the USDA standard of “good internal quality” or better (Brix ≥9.0) was considered unacceptable because of potential market rejection. Therefore, the earliest recommended planting date with acceptable yield and “good internal quality” was 12 Mar. for all cultivars; the latest planting dates for `Athena', `Eclipse', `Tesoro Dulce', and `Sugar Bowl' were 4 June, 18 June, 7 May, and 9 Apr., respectively. With these recommendations, the harvest season of melons lasted 40 days from 24 June to 3 Aug. for these four cultivars, which extended the production season an additional 2 weeks longer than the harvest date of last recommended 21 May planting date.
Karen L. Panter
management to soil management to the various crops being grown with this season-extending technology. The colloquium objectives were two-fold. The first was to impart applied information on the commercial practices used to produce horticultural crops