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In 1996, more than 72,000 acres of vegetables were produced in Alabama. This number has been steadily increasing since the mid-1980s. Growers and county agents requested information on which vegetable varieties performed well in Alabama. To support a growing vegetable industry, Auburn Univ. committed itself to developing an extensive vegetable variety trial (VVT) program focusing on rapid dissemination of results. Presently, replicated trials are held at nine experiment stations, each representing a unique growing environment. The VVTs are divided into a spring and fall section. The spring trials evaluate spring/summer planted crops such as tomato, peppers, watermelon, sweetpotato, eggplant, southernpea, lettuce, melons, cucumber, summer squash, and others. Fall trials examine cole crops, winter squash, pumpkin, and other late-summer/fall-planted crops. Turn around time from final harvest of the final crop to placing the report in the county agent's or grower's hands is 2 to 3 months. Good support is received from industry through financial contributions and/or materials. More than 3000 copies of the spring and fall VVT reports are distributed annually at field days, statewide and county meetings, and in direct mailings. Other research projects, such as projects on nutritional composition of vegetables, postharvest quality, and consumer acceptance, have been supported by materials from the VVT program. Without overwhelming support and commitment from the State of Alabama, Auburn Univ., grower organizations, and industry, the VVT program would not be the success that it is today providing timely and needed information to strengthen the growing vegetable industry in Alabama.
The effect of various mulch colors (black, yellow, red, blue, white, and aluminum) on growth and development of `Vates' collards was evaluated in Fall 1996 at the E.V. Smith Research Center in Shorter, Ala. Black polyethylene mulch was installed onto raised, fumigated beds, then sprayed with a 1: 2 (v/v) mixture of exterior oil-based enamel paint to paint thinner with one of the five mulch colors listed. Five-week-old plants were transplanted into beds. Beginning two weeks after transplanting and continuing every other week thereafter, heads were harvested to determine head fresh weight and dry weight. Hourly soil temperatures at 10 cm soil depth were recorded and growing degree days (GDDs) with a base temperature of 4.4 °C were calculated. At two weeks after transplanting, average head fresh and dry weight were highest for the aluminum-colored treatment with head fresh (24.7 and 12.3 g, respectively) and dry weights (2.7 and 1.3 g, respectively) twice that of the yellow treatment (P ≤ 0.05). By four weeks after transplanting and up through the final harvest, marketable yield and average head fresh weights did not differ among the treatments (17,900 kg/ha, 1.4 kg per head, respectively). The red and black mulch treatments accumulated more GDDs than the other treatments, but total marketable yields did not differ among any treatments.
While lettuce is one of the most widely consumed vegetables in the United States, production is mainly concentrated in the western states. This research investigated the feasibility of lettuce production in the Southeast (SE), where downy mildew, tip burn, bitterness, bolting, and postharvest handling are potential production problems. Lettuce varieties were evaluated on plastic mulch and drip irrigation under several growing conditions. Cultivar and location significantly (P < 0.01) affected yield and transplant survival rate. Following these tests, 'Salinas 88 Supreme', 'Legacy', 'Bullseye', 'Epic' (crisphead); 'Nancy', 'Nevada', 'Ostinata' (butterhead); 'Parris Islands', 'Augustus' (Romaine); and 'Red Salad Bowl', 'Red Prize', and 'Slobolt' (loose leaf) are considered best-performing lettuce varieties for Alabama. These results, along with bitterness evaluation, support the potential for lettuce production in the SE.
Feeding damage by white-tailed deer to vegetable and ornamental crops are often adverse to plant growth, and result in economic and aesthetic losses. While the efficacy of commercially available deer repellent products is questionable, plant extracts may provide an environmentally sound alternative to traditional chemical treatments. Commercially available plant extracts (Dusty Miller, peppermint, Madagascar periwinkle, wax myrtle, barberry, juniper, geranium, rosemary, lemon balm, and yucca) known to be unpalatable plants were chosen as treatments. Thiram and putrescent egg spray were used as positive controls along with a no-spray treatment. Gomphrena were grown off-site in trade gallon pots and used as test plants. Sixteen deer were confined in two 1-acre study pens at the Auburn Univ. Deer Research Facility. Feeding damage was recorded daily using a 0 to 3 rating scale corresponding to 1/3, 2/3, and complete destruction, respectively. All damage data were converted into percent damage. Barberry and wax myrtle extracts made gomphrena more palatable to the deer as feeding damage exceeded that of the untreated plants. However, lemon balm, rosemary, yucca, and peppermint provide some level of protection against feeding damage to gomphrena. Fifth-day damage ratings for these extracts were 37%, 35%, 13%, and 19%, respectively. Fifth-day damage for untreated plants was 40%. Peppermint and yucca extracts appear to be promising alternatives to thiram and putrescent egg-based products.
Seed harvested from 41 entries in the 1994 southernpea variety trial was grown in a greenhouse for evaluation of seedborne mosaic viruses. When second trifoliate leaves were fully expanded, 100 plants per plot per block (4) were evaluated for blackeye cowpea mosaic virus (B1CMV), cucumber mosaic virus (CMV), cowpea severe mosaic virus (CSMV), and southern bean mosaic virus (SBMV). The average number of plants with virus symptoms ranged from 2% (Pinkeye Pinkpod) to 44% (Bettergreen). Plants with symptoms were assayed using enzyme-linked immunosorbent assay (ELISA). At least one virus was detected with ELISA in all entries, except for `Zipper Cream' in which none were evident. All viruses were detected in seven entries. B1CMV and CMV were present in 13. CMV was present in all but `Zipper Cream', `Mississippi Cream', and `Texas Pinkeye'. Symptomatology was poorly correlated to ELISA results: six entries having all four viruses had symptoms on less than 13% of their plants.
In addition to managing soilborne diseases, grafting with vigorous rootstocks has been shown to improve yield in tomato (Solanum lycopersicum L.) production. However, the influence of different levels of nitrogen (N) and irrigation supplies on grafted tomato plants has not been fully examined in comparison with non-grafted plants, especially under field conditions. The objective of this two-year study was to determine the effects of different irrigation regimes and N rates on yield, irrigation water use efficiency (iWUE), and N use efficiency (NUE) of grafted tomato plants grown with drip irrigation in sandy soils of north Florida. The determinate tomato cultivar Florida 47 was grafted onto two interspecific hybrid rootstocks, ‘Beaufort’ and ‘Multifort’ (S. lycopersicum × S. habrochaites S. Knapp & D.M. Spooner). Non-grafted ‘Florida 47’ was used as a control. Plants were grown in a fumigated field under 12 combinations of two drip irrigation regimes (50% and 100% of commonly used irrigation regime) and six N rates (56, 112, 168, 224, 280, and 336 kg·ha−1). The field experiments were arranged in a split-plot design with four replications. The whole plots consisted of the irrigation regime and N rate combination treatments, whereas the subplots represented the two grafting treatments and the non-grafted plants. Self-grafted ‘Florida 47’ was also included in the 100% irrigation and 224 kg N/ha fertilization treatment as a control. In 2010, the 50% irrigation regime resulted in higher total and marketable yields than the 100% irrigation regime. Tomato yield was significantly influenced by N rates, but similar yields were achieved at 168 kg·ha−1 and above. Plants grafted onto ‘Beaufort’ and ‘Multifort’ showed an average increase of 27% and 30% in total and marketable fruit yields, respectively, relative to non-grafted plants. In 2011, fruit yields were affected by a significant irrigation by N rate interaction. Grafting significantly increased tomato yields, whereas grafted plants showed greater potential for yield improvement with increasing N rates compared with non-grafted plants. Self-grafting did not affect tomato yields. More fruit per plant and higher average fruit weight as a result of grafting were observed in both years. Grafting with the two rootstocks significantly improved the irrigation water and N use efficiency in tomato production. Results from this study suggested the need for developing irrigation and N fertilization recommendations for grafted tomato production in sandy soils.
A renewed interest in sulfur (S) deficiency has occurred because of reductions in atmospheric depositions of S caused by implementation of clean air regulations around the world. In vegetable production systems, other sources of S exist, such as soil S, fertilizers, and irrigation water. While soil testing and fertilizer labels impart information on quantity of S, it is unknown how much S within the irrigation water contributes to the total crop requirement. Two studies were conducted to determine the influence of elemental S fertilization rates and irrigation programs on tomato (Solanum lycopersicum) growth and yield. Irrigation volumes were 3528, 5292, and 7056 gal/acre per day and preplant S rates were 0, 25, 50, 100, 150, and 200 lb/acre. Data showed that neither plant height, leaf greenness, soil pH nor total soil S content was consistently affected by preplant S rates. During both seasons, early marketable fruit weight increased sharply when plots were treated with at least 25 lb/acre of preplant S in comparison with the nontreated control. Early fruit weight of extralarge and all marketable grades increased by 1.5 and 1.7 tons/acre, respectively, with the application of 25 lb/acre of S. There were no early fruit weight differences, regardless of marketable fruit grade, among preplant S rates from 25 to 200 lb/acre. Based upon this result, adding preplant S to the fertilization programs in sandy soils improves tomato yield and fall within the current recommended application range of S (30 lb/acre) for vegetables in Florida. At the same time, irrigation volumes did not consistently influence soil S concentration, soil pH, leaf S concentrations or tomato yield, which suggested that irrigation water with levels of S similar to this location [58 mg·L−1 of sulfate (SO4) or 19 mg·L−1 of S] may not meet tomato S requirement during a short cropping seasons of 12 weeks, possibly because microbes need longer periods of time to oxidize the current S species in the water to the absorbed SO4 form.
Vitamin C (VC) levels (mg/l00 g FW) were determined in 10 varieties of colored bell pepper grown under different field conditions. VC was determined by the microfluorometric method. `Orobelle' (169 mg), `King Arthur' (143 mg), `Valencia' (141 mg), and `Chocolate Bell' (134 mg) had significantly higher VC levels than `Dove' (109 mg), `Ivory' (106 mg), `Blue Jay' (93 mg), `Canary' (90 mg), and `Black Bird' (65 mg). The largest variability (53 mg) in VC levels were observed for varieties that had the highest VC content. Mean VC levels were 143a, 143a, 141a, 136a, 108ab, 93bc, and 63c for the yellow, red, orange, brown, white, purple, and black colors, respectively. Since the Recommended Daily Allowance (RDA) for VC is 60 mg per day, these results suggested that a 100-g serving of fresh bell pepper or less would supply 100% RDA of VC. Therefore, after selecting a color, growers still have the freedom to grow a variety that performs well in their area to produce peppers of high VC contents.
Strawberries are a high value commodity with a short shelf life. Florida is the largest producer of winter strawberries in the United States with 2,790 hectares of production, 90% are located in Hillsborough County. Many Florida growers apply additional calcium (Ca) as a foliar spray despite the lack of conclusive evidence of an increase in fruit quality or yield. It is believed that additional Ca will improve cell wall integrity through Ca linkages with pectins with in the cell wall and increase fruit firmness. Preharvest applications of calcium chloride have shown to delay the ripening of strawberry fruit and mold development. The objectives of this two year study were to determine the effects of Ca on yield, growth, and postharvest quality of strawberry when applied to the soil or as a foliar spray. `Sweet Charlie' strawberry plants were grown on a Seffner fine sand in Dover, Fla. The experimental design was a split-block replicated four times with soil and foliar Ca applications. Main plots consisted of a broadcast preplant incorporation of gypsum (calcium sulfate) 0 kg·ha-1, 36.7 kg·ha-1, and 73.4 kg·ha-1. Sub-plots consisted of foliar applications of 400 mg·L-1 Ca from calcium sulfate, 400 and 800 mg·L-1 Ca from calcium chloride and a water control applied weekly throughout the 2002-03 and 2003-04 growing season. Yield data was collected twice weekly through out the growing season. Fruits were graded for quality based upon size, visual appearance of pathogens degradation, frost/water damage, and misshapen form. Calcium content was determined for leaves, fruit, and calyxes in January and March. Postharvest quality evaluations of pH, titratable acidy, soluble solids, and firmness (Instron 4411) were determined in January and March.
Vegetable variety trials are of interest to the entire vegetable industry from breeders, seed companies, growers, consultants, researchers, to Extension personnel. The Auburn Univ. vegetable variety trial results have been made more accessible and user-friendly by becoming available online at http://www.ag.auburn.edu/dept/hf/faculty/esimonne. Users can point and click through a completely searchable database by selecting one of the following categories: 1) explanation of rating system and database, 2) list of vegetable crops, 3) description of variety types of crops, 4) contacting seed companies and web sites, 5) vegetable variety trial team members. For additional information about vegetable variety production, a link to horticulture extension publications has been included. The database gives each vegetable crop tested by Auburn Univ. a rating and allows a search for varieties. For each crop, the five options available to search the database are “rating,” “variety name,” “variety type,” “seed company,” and “type.” The Web page is primarily intended to be a quick, practical reference guide to growers and horticulture professionals in Alabama. Variety performances presented are based on small-scale research plots and test results may vary by location. It is always recommended to perform an on-farm trial of several varieties before making a large planting of a single variety.