Progress 10/01/05 to 09/30/10
Outputs
OUTPUTS: A key part of this project was to evaluate yield and quality of cultigens for key cucurbit crops and sweetpotatoes (SPs) grown in NC. Annual cultivar recommendations are updated each yr in the SE Vegetable Growers Guide which is heavily utilized in 9 SE states (KY, NC, SC, GA, TN, VA, LA, MS, AL). Watermelon (WM), melon, and squash cultigens have been evaluated each yr. WM, melon and squash cultivar information is presented at grower and allied industry meetings (mtgs) in the SE US (i.e., NC WM Association (Assn), GA Fruit and Vegetable Growers Assn, MarDel WM Assn). Each yr an in-house WM and melon publication summarizes the results of the cultivar studies. WM results were presented and published at the SR-ASHS in the National WM Research group session. A specialty crops field day (FD) was held in 2008 to expose the industry and public to the array of opportunities associated with SMs and WMs. Also, an agent training focused on SMs; this has been the focus in several county grower mtgs. State vegetable mtgs have been the venue for presenting current findings. WM, melon and squash trial results are disseminated through in-house annual reports. Pickling cucumber cultivar studies for once over mechanical harvest have been conducted in commercial fields over a 3 yr period. Results have been conveyed at state vegetable meetings, NC Pickle Producers Association mtg, and regional county mtgs. Pumpkin cultivar evaluations have been ongoing for 4 yrs and involved students, county agents, faculty (Univ. TN, GA), seed companies, and the public through a series of FDs at the Research Station in Waynesville, NC. Results have been disseminated at the Western NC Vegetable mtg, TN and GA grower mtgs, through presentation and publication at the Southern Region American Society for Horticultural Science (SR-ASHS) mtg (horticultural professionals and scientists). Sweetpotato (SP) variety evaluations were conducted during one season in 2 locations, one was a grower field, the other on the research station in Clinton, NC. Results from these trials were reported at the NC SP FD, and at the National SP Collaborators mtg which was a part of the ASHS-SR mtg. A hand out, published abstract, and/or report is shared in an annual NC Sweet Potato Commission (NCSPC) publication. Miniwatermelon in-row spacing was evaluated in 4 test locations, FL, Blackville & Charleston, SC, and NC. A second miniwatermelon in-row spacing study which varied the population density was conducted twice in NC. Pollenizer research studies were conducted as part of a graduate student's Master of Science degree program. Results from these studies were reported at the ASHS, SR-ASHS mtgs and published as refereed journal publications, and the Cucurbitaceae 2006 mtg. Research on pickling cucumber and SP nitrogen (N) fertilization was conducted for 2 and 3 seasons, respectively. Results on SP N fertilization were reported at national mtgs (National SP Collaborators mtg), state mtgs (NC Vegetable Grower Assn mtg, NCSPC mtg) and Regional SP mtgs. Results were published in the annual NCSPC annual report and in the horticultural science journal, and disseminated at SP FDs. PARTICIPANTS: The cultivar and specialty crop development, and mini watermelon in-row spacing research of this grant was in partnership with several colleagues. Collaboration on these trials was with faculty from other land grant universities in the southeastern United States; University of Georgia (Terry Kelley), University of Florida (Steve Olson), Clemson University (Richard Hassell, Gilbert Miller), and University of Tennessee (Annette Wszelaki). In addition to collaboration with colleagues outside of NC State University, I have also collaborated with faculty from NC State University; Deanna Osmond, Todd Wehner, Bill Jester, Allan Thornton. Each summer my program hires 2 to 3 individuals to help with the various research trials. This provides the summer help the opportunity to learn and be trained with respect to vegetable research, and give consideration to working in the vegetable production industry. We also work extensively with industry. For the cultivar trials, several seed companies provide supplemental funds so the trials can be conducted. The research stations provide infrastructure and expertise in growing the crop. Most of our cultivar trial work is conducted at the Central Crops Research Station (Clayton, NC) and Cunningham Research Station (Kinston, NC). We have also used trials as a way to provide hands on in service training for county extension agents with horticulture crop responsibilities as well as conduct field days (i.e. Specialty Crops, Sweetpotato) to educate the growers and allied industry. We have also conducted fertilization and planting density studies on-farm. This includes sweetpotatoes in which we have evaluated various fertilizer rate and planting densities for the Covington variety (i.e Warren Farms, Jones Farms), and pickling cucumber cultivar and planting density trials (H&H Farms). A graduate student, Peter Dittmar, did much of the watermelon pollenizer work as part of his MS thesis. He went on to obtain his Ph.D. and is now a faculty member of the Horticultural Sciences department at the University of Florida. Various commodity associations have provided financial assistance to conduct the various trials associated with this project (NC Watermelon Association, NC Vegetable Growers Association, NC Sweet Potato Commission). TARGET AUDIENCES: The key audiences are county extension agents, growers, seed company personnel, processing companies, agricultural sales businesses and other individuals allied with the agricultural industry. Efforts to take this knowledge and disseminate it are through written reports to the industry. Vegetable cultivar recommendations are provided annually in a regional Vegetable Handbook publication in which the following states are targeted (KY, NC, SC, GA, TN, VA, LA, MS, AL). State grower meetings in North Carolina and in other southeastern states are also key mechanisms to provide information to our key audiences. Field days provide timely hands on experience in the new knowledge being discovered that can then put immediately in practice. Finally, professional meetings such as the Southern Region - American Society for Horticultural Science (SR-ASHS) or the national ASHS meeting or the international Cucurbitaceae meeting. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Several outstanding new watermelon (WM) cultigens were identified. Some standard size triploids: Declaration, RWT 8216, RWT 8228, and RWT 8230; several new mini WMs: RWT 8225, Leopard, Pixie and 9145. Excursion, Expedition and Lafayette pickling cucumber (PC) cultivars yielded the most fruit in a once over harvest test conducted on-farm and are now widely grown in the PC industry. For zucchini some excellent cultivars are: Leopard, Wrangler, Spineless Perfection. Pumpkin cultivars have been released with improved characteristics; Camaro (PM tolerance), Harvest Time (high yielding giant size), Field Trip (high yielding, deep orange small size); Magic Wand (high yielding, uniform large size). We documented these improvements in our tests; these cultivars are being tested or being increasingly grown by the commercial industry. The new sweetpotato (SP) variety Evangeline is promising due to its higher sucrose content at harvest when compared with other varieties. Evangeline, however, generally has lower yields (yds) than the predominant variety grown, Covington. It has a tendency to air crack; however, its microwave appeal make is a promising variety. Several promising Galia melons were identified; Kelsey, Courier, Visa, Merak, Estoril. Excellent quality and yielding juan canary melon types include Sugar Nut, HMX 7590, Hibrix, and Sol. Other melons: Venezia and Margitte (Italian), Sancho (piel de sapo), and Honey Max, HSR 4347, Jade Delight, PX 4156, and Summer Dew (honeydew). The diversity of melons provides the opportunity for growers. Commercial specialty melon acreage has increased as improved cultivars are identified. Market size range for mini WM is specific. As the plant population increased from eight plants per plot (21-in in-row spacing) to 12 plants per plot (15-in in-row spacing), total marketable mini WM fruit yds increased. Vanessa and Petite Perfection cultivars in-row spacings were spaced 6, 12 and 18 in and contained 1 or 2 plants per hill. Having 2 plants per hill resulted in more cull fruit that were unmarketable fruit because of small size. Planting density and arrangement should be adjusted to meet size demand depending on cultivar for the mini WM market with only 1 plant per hill. For PC, the 120 lb/ac N rate was best, with the slow release material offering no benefit over a conventional release N product. With Covington SP, the use of 90 lb N/ac for the growing season resulted in the most consistent high yds. Additionally, applying the N into split applications provided benefit in enhancing yds under some stress conditions. These studies assist the commercial industry in maximizing yds of cucumbers and SPs. Pollenizers Sidekick and SP-1 produced the highest numbers of male flowers which likely translates into more available viable pollen. An overabundance of pollen was produced for triploid fruit set even though pollenizer male flower production did not peak at the time of triploid female flower peak production time. Inter- planting versus hill substitution improves triploid fruit yds, while plots with no pollenizer had minimal fruit set and those fruit that were set generally had severe hollow heart.
Publications
- Osmond, D.L., S L. Cahill, J.R. Schultheis, G J. Holmes, and W.R. Jester. 2011. Tillage Practices and Nitrogen Rates on Pickling Cucumber Production. Int. J. Veg. Sci. 17(1):13-25.
- Dittmar, P. J., J.R. Schultheis, and D.W. Monks. 2010. Use of Commercially Available Pollenizers for Optimizing Triploid Watermelon Production. HortScience. 45(4):541-545.
- Schultheis, J.R. and W.B. Thompson. 2010. 2009 Watermelon cultivar evaluations. Horticultural Research Series 191 45 pp. (CD only).
- Schultheis, J.R. and W.B. Thompson. 2010. 2009 North Carolina melon cultivar evaluations. Horticultural Research Series 191. 16 pp. (CD only).
- Schultheis, J.R. and W.B. Thompson. 2010. 2009 Yellow summer and zucchini squash cultivar evaluations. 19 pp. (CD only).
- Kemble, J.M. et al. 2010. Vegetable crop handbook for the southeastern U.S. NC Vegetable Growers Association. (in cooperation w/ Auburn Univ., Clemson Univ., Louisiana State Univ., & Mississippi State Univ., Univ. Florida, Univ. Georgia, Univ. Kentucky, Univ. Tennessee, Virginia Tech) 276 pp.
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: One of the key objectives of this project is to evaluate various cultivars and advanced lines (cultigens) of cucurbit species that are adapted to growing conditions in North Carolina and across the southeastern United States. One of the largest standard size triploid red flesh watermelon cultigens tests (33 entries) in the United States was conducted in 2009 in Clayton, NC. Additionally, a triploid miniwatermelon cultigen test with 8 entries and a seeded cultigen test were also conducted. A mechanical pickling cucumber cultigen evaluation study was conducted on-farm to determine those cultigens with high yield potential and quality for commercial production. Both a yellow summer squash and a zucchini cultigen study were conducted in the fall season of 2009 and cultigens were evaluated for yield potential and quality. A pumpkin cultigen yield and quality study was conducted in western North Carolina in collaboration with a colleague from the University of Tennessee. In-row spacing was evaluated in miniwatermelons in a regional study with Clemson University and the University of Florida. The goals of these studies were to determine how miniwatermelon (Citrullus lanatus) cultivars differed and responded to plant in-row spacing in terms of percentage of marketable fruit and yields, and if plant spacing impacted internal fruit quality. Three genetically diverse triploid miniwatermelon cultivars (Mohican, Petite Perfection, and Xite) were selected. These cultivars were evaluated in field locations at northern Florida (Quincy), central South Carolina (Blackville), coastal South Carolina (Charleston), and eastern North Carolina (Kinston) at five within-row distances. Within-row distance included 9, 12, 15, 18, and 21 inches. Fruit were categorized as marketable if they weighed between 3.1 and 9.0 lb per fruit. Within this range further categories were divided as follows: 3.0 lb (cull), 3.1 to 5.0 lb (small), 5.1 to 7.0 lb (average), 7.1 to 9.0 lb (large), and 9.1 lb (cull). Another miniwatermelon population study was conducted in 2010 to determine the effects of two plants versus one plant per hill, as well as in-row spacing of 6, 12 and 18 inches. These results need to be analyzed before they can be reported. In-row spacing and nitrogen fertilization were conducted on a new sweetpotato variety release, Hatteras in comparison with Covington to optimize production practices but results will not be reported due to limitation in space. PARTICIPANTS: Much of cultigen work was supported by gift funds from seed companies; Syngenta, Harris Moran Seed Company, Sakata, Hollar Seed, DP Seeds LLC, Seedway, Abbott & Cobb Inc., Zeraim Gedera, Willhite Seed Inc., and Nunhems. The pickling cucumber mechanical harvest cultigen evaluation study was supported by the North Carolina Vegetable Growers Association. The pumpkin cultigen study was a collaborative effort between the University of Tennessee and North Carolina State University with Annette Wszelaki being the cooperator from Tennessee. The work conducted on in-row spacing effects on miniwatermelon production was a collaborative effort between the Clemson University, and the University of Florida, with Gilbert Miller and Richard Hassell being the cooperators for Clemson, and Steve Olson the cooperator for Florida. We have partnered with the North Carolina Sweet Potato Commission in conducting research on in-row spacing and nitrogen fertilization of new sweetpotato varieties. I have attended several professional development meetings, National Sweetpotato Collaborators, and the National Research and Development Group. TARGET AUDIENCES: Much of this information has been shared at grower meetings; Regional Sweetpotato meetings in NC, Southeast Vegetable and Fruit EXPO (Myrtle Beach, SC), the Southeast Regional Fruit and Vegetable Conference (Savannah, GA), and the North Watermelon Association. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
There were several outstanding new triploid watermelon cultigens that show good commercial promise. NUN 6032 (Declaration) was the 3rd overall yielder (of 33 total entries) at 672 cwt/acre. Additionally, the fruit produced were of uniform size desired by commercial shipping markets and the preferred rind pattern. Several Syngenta cultigens had outstanding interior quality; RWT 8216, RWT 8228, and RWT 8230. All of these lines had excellent interior color and a good contrast between the rind and flesh. All lines yielded in the top half of the entries included in the 2009 test. RWT 8228 and 8230 had rind patterns that resembled a Fiesta fruit type, while RWT 8216 had a solid dark green rind. In the miniwatermelon test, the Syngenta cultivars generally produced fruit uniform in size that meets marketing sizing demand. They included Petite Perfection, Precious Petite, RWT 8225, and Little Deuce Coupe cultigens. Cultigen 9145 from Zeraim Gedera had the firmest flesh and may hold better when shipped; however, it tended to be less sweet than most of the other cultigens evaluated in the study. Lastly, in the seeded watermelon test evaluation, a new line from Sakata Seed Company, SWD 4046, had excellent yields, shape, and size. Excursion, Expedition and Lafayette pickling cucumber cultivars yielded the most marketable fruit of the 6 cultigens evaluated in an on-farm mechanical harvest study. The cultigen that had fruit with the darkest green color was Sassy, while the cultigen with the lightest green color was Treasure. Four Abbott & Cobb yellow summer squash lines were included in our fall study. The ACX 7001 cultigen had superior fruit type with good yield that make it a prime candidate for commercial production. There were 21 zucchini entries;Wrangler (Zeraim Gedera), one of newly released cultivars, had excellent yields and fruit quality for a medium green fruit. An unusual specialty type was Butta, which is a butter yellow zucchini that could be used to diversity ones market. Some of the standard cultivars currently produced commercially in NC which produced high quality fruit were Payroll, Paycheck, and Spineless Beauty. A pumpkin evaluation study in western NC contained approximately 25 replicated cultigens. Field Trip and Fall Splender were extremely high fruit yielders with exceptional bright orange color exhibited by the former cultivar. Fruit size of these cultivars generally ranged between 3 to 6 pounds. The standard for North Carolina, Magic Lantern, produced consistent shaped fruit that were generally 15 to 20 pounds and yielded well. In the miniwatermelon spacing trial, Petite Perfection was among the highest yielding and produced the highest percentage marketable fruit at all locations except Quincy,FL where it was the lowest yielding cultivar. Within-row plant distances and populations affected total marketable yield, both for fruit weight and number per plant, regardless of cultivar and location. As the plant population increased from eight plants per plot (21-in. in-row spacing) to 12 plants per plot (15-inch in-row spacing), total marketable miniwatermelon fruit yields increased in total fruit number as well as total weight.
Publications
- Hassell, R.L., Schultheis, J.R., Jester, W.R., Olson, S.M., and Miller, G.A. 2009. In-row distance in triploid watermelon cultivars affects yield and quality in diverse environments in the southeastern United States. HortTechnology 19:538-545.
- Holmes, G.J. and Kemble, J.M. et al. 2008. Vegetable crop handbook for the southeastern U.S. NC Vegetable Growers Association. (in cooperation with Auburn Univ., Clemson Univ., Univ. Georgia, Univ. TN, Louisiana State Univ., & MI State Univ.)
- Schultheis, J.R. and Thompson, W.B. 2008. 2007 Watermelon cultivar evaluations. Horticultural Research Series. 69 pp (on CD only).
- Schultheis, J.R., Thompson, W.B., Ducharme, D., Kelley, T., and Wszelaki, A. 2008. 2007 Squash and pumpkin cultivar evaluations. Horticultural Research Series. 29 pp (on CD only).
- Schultheis, J.R., Thompson, W.B., Jester, W.R., and Taylor, B. 2008. 2007 Melon cultivar evaluations. Horticultural Research Series. 23 pp (on CD only).
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Several cultivar and advanced line evaluations were conducted during the 2008 growing season. One hundred eight specialty melons, 16 muskmelons, and 16 honeydew melons were evaluated for yields and quality. Additional cultivar evaluations were conducted on mechanical harvest pickling cucumber, yellow squash, zucchini, and pumpkins. In addition to cultivar testing, we evaluated nitrogen and potassium rates and method of application to sweetpotatoes. As in 2007, two watermelon grafting experiments were conducted to evaluate the effect of plant populations on yield and quality, and to evaluate the effect of root stocks on yield and quality. Several sweetpotato herbicide trials were conducted to evaluate the control of weeds and effects on sweetpotato growth and roots. Use of Prep at various rates to three sweetpotato varieties were evaluated for its effects on the internal quality of sweetpotato, and the use of Prep or mowing one week and two weeks prior to harvest were evaluated as to whether sweetpotato skinning resistance was enhanced in the sweetpotato variety Beauregard. PARTICIPANTS: Much of the work on specialty melon and honeydew melons, and pumpkins was done in partnership with the Specialty Crops program administrated by Bill Jester. We conducted a cucurbit in-service training for agents. We continue to partner with industry (seed industry) to evaluate new vegetable cultivars. We also conducted several fertilization studies on sweetpotatoes as there is much interest in reducing fertilizer costs. We have partnered with fertilizer companies and the NC Sweet Potato Commission. TARGET AUDIENCES: Target audiences are the grower and allied industry. Use of best cultivars and production practices improves efficiencies and profits. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Several galia melons that are promising were 'Kelsey', 'Courier', 'Visa', 'Merak', 'Estoril' and 'Visa Premium'. Excellent juan canary cultivars or advanced lines included, 'Sugar Nut', 'HMX 7590', 'Hibrix', and 'Sol'. Other melon picks included 'Margritte' and 'Venezia' (Italian melons), and 'Sancho', a piel de sapo cultivar, and 'NC-Star' and 'NC-Stella', oriental-crisp flesh melons. 'Snow Leopard' offers the roadside stand sellers the opportunity to market an eye catching unique, good tasting honeydew specialty type. 'Seranade' has extremely high sugar content and offers a unique flavor. This melon may be more suited for local rather than shipping markets. 'Pixie', and 'Red Queen' are two unclassified specialty melon types that both hold promise. There were many outstanding honeydew cultivars. Some that stood out with respect to quality and yield were Honey Max, HSR 4347, Jade Delight, PX 4156 and Summer Dew. 1056-CN was a much earlier developing cultivar than the rest and was ready 7 to 10 days before the other entries evaluated in the 2008 study. Some of the outstanding muskmelon cultivars or advanced lines included 4099, 7055, ACX 1085, and Victoria. All yielded more fruit per acre than 'Athena', which is the main cultivar grown in the eastern United States. The results from the pumpkin trial conducted in 2007 revealed that certain cultivars were high yielders and produced quality fruits. The best yielding giant orange pumpkin cultivar was PrizeWinner, the best giant white pumpkin was New Moon. Very large (25 lbs+) jack-o-lantern cultivars that yielded well with quality fruit included Aladdin, Dependable, Harvest Time, Gold Medal and Super Herc. Large (15 to 25 lbs) jack-o-lanterns that yielded well with good quality fruit included HMX 6685, HSR 4700, Howden, Magic Lantern, Magician, Progold 510, and 20 Karat Gold. 'Bumpkin' was a prolific yielding small pumpkin that averaged 1.0 lb fruit size. In 2007 trials, some of the highest yielding zucchini cultivars were Cashflow, Declaration II, Leopard, and Tigress, while the best yielding yellow squash out of 6 entries was Lioness. We also evaluated rates and split applications of nitrogen in an attempt to optimize these for the soon to be release variety 'Hatteras' sweetpotato. No yield response to nitrogen was measured for 'Hatteras' in response to application rates up to 120 lb/acre nitrogen or when one versus two applications were made. No response in yield to in-row spacing was found when varied from 6 to 15 inches. Finally, rates of potash were varied from 0 to 150 lbs per acre, two carriers (potassium sulfate and potassium chloride), and meothod of application (band versus broadcast) were compared. No yield response was found when rate, compound or method of application were varied. Growers may be able to use lower rates of potash based on this one study; however, follow up studies need to be conducted to verify this. Testing of organic sweetpotato organic production systems as well as some weed management work by former graduate students resulted in refereed journal publications as well as a publication regarding the new release of 'Covington' sweetpotato (see publications).
Publications
- Yencho, G.C., Pecota, K.V., Schultheis, J.R., VanEsbroeck, Z., Holmes, G.J., Little, B.E., Thornton, A.C., and Truong, V. 2008. 'Covington' sweetpotato. HortScience. 43(6):1911-1914.
- Treadwell, D.D., Creamer, N.G., Hoyt, G.D., and Schultheisk, J.R. 2008. Nutrient management with cover crops and compost affects development and yield in organically managed sweetpotato systems. HortScience. 43: 1321-1627.
- Dittmar, P.J., Jennings, K.M., Schultheis, J.R., and Monks, D.M. 2008. Effects of postemergence and postemergence-directed halosulfuron on triploid watermelon (Citrullus lanatus). Weed Tech. 22(3):467-471.
- Schultheis, J.R., Thompson, W.B., Ducharme, D.T., Kelly, T., and Wszelaki, A. 2008. 2007 Squash and pumpkin cultivar evaluations. North Carolina State University, Dept. Horticultural Science. 29 pp.
- Schultheis, J.R. and Thompson, W.R. 2008. 2007 Watermelon cultivar trials. North Carolina State University, Dept. Horticultural Science, 73 pp.
- Schultheis, J.R., Jester, W.R., Thompson, W.B., and Taylor, B. 2008. 2007 Melon cultivar evaluations. North Carolina State University, Dept. Horticultural Science, 23 pp.
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: A series of experiments were conducted during the 2007 growing season. These included pumpkin, squash, muskmelon, specialty melon, once-over harvest of pickling cucumbers, seedless watermelon, seeded watermelon and mini watermelon cultigen tests. Additionally, N fertilization rate and application tests were conducted on the recently released sweetpotato variety Covington. Two watermelon grafting experiments were conducted to evaluate the effect of plant populations on yield and quality, and to evaluate the effect of root stocks on yield and quality. Several sweetpotato herbicide trials were conducted to evaluate the control of weeds and effects on sweetpotato growth and roots. Use of Prep at various rates and mowing one week and two weeks prior to harvest were evaluated for its effects on the internal quality of sweetpotato and whether sweetpotato skinning resistance was enhanced.
PARTICIPANTS: The following individuals worked as seasonal workers on the various field experiments reported under the outputs section; Dennis Adams. Additionally, Brad Thompson, technician, was integral in the execution of all the experiments and their protocol. Collaboration on the watermelon grafting project was regional with faculty at other land grant institutions. They included; Steve Olson (University of Florida), Terry Kelley (University of Georgia), Richard Hassell (Clemson University), and Gilbert Miller (Clemson University). Others key collaborators were Allan Thornton, Billy Little, Todd Wehner and Rakesh (NC State University). In the pumpkin cultigen study, both Terry Kelly (Univeristy of Georgia) and Annette Wszelaki University of Tennessee were key collaborators. Allan Thornton, was also a key collaborator on the N rate study sweetpotato study, while Bill Jester collaborated on the melon cultigen study. Diane Ducharme, Area Specialized Agent, collaborated and conducted
a Squash cultivar study in Fletcher, NC. I attended a grafting workshop in Naples, Florida which was sponsored by Syngenta. I also attended the National Sweetpotato Collaborators meeting, National Watermelon Association meeting, and Southern region ASHS meeting in Mobile, Alabama. I was also involved with several national grower meetings; USA Sweetpotato Council, San Fransisco, CA and National Watermelon Association meeting, Asheville, NC.
TARGET AUDIENCES: As mentioned earlier, a sweetpotato field day and pumpkin field tour were offered to these vegetable industries. Additionally, the NC Vegetable meeting will be held in Myrtle Beach, SC. Information will be shared regarding the once-over pickling cucumber cultigen trial. Several on-farm field tests were conducted in collaboration with agents, Billy Little (once-over pickling cucumber trial, sweetpotato N fertilization trial) and Diane Ducharme (squash cultigen trial). This is one-on-one agent training.
Impacts
Many of the studies conducted in 2007 have not been analyzed but are in process as our research and extension team only completed its field work in November. We did have a sweetpotato field day in which the effects of N fertilization on sweetpotato yield and quality were discussed. An informal field tour also was conducted for the public to discuss and show the newest pumpkin cultigens. A pumpkin media interview was done on WMYA news television and currently can be found at the following website (http://www.wlos.com/players/news/absolute_le/video.shtml). Similar sweetpotato N fertilization tests from the previous year illustrated that a 90 pound per acre seasonal rate of N was superior (highest yeilds) to the other rates tested. In addition, it was beneficial to split the applications rather than to apply the entire amount of N one time. By using a split application, sweetpotato yields were enhanced and root sizing promoted. This information was shared at the NC
Sweetpotato Commission meeting, the annual State sweetpotato meeting. The results of the 2007 cultigen tests will be shared at grower meetings and information will be published so growers can make informed decisions regarding cultigen selection. The NC Pickle Producers Association will meet in December 2007 and a report and presentation will be be made regarding the once-over pickling ucumber cultigen test. Testing of organic sweetpotato organic production systems from a previous graduate student resulted in a refereed journal publication (see publications).
Publications
- Schultheis, J.R., Jester, W.R., Thompson, W.B., Taylor, B., and Ducharme, D. 2007. 2006 Cucurbit cultivar evaluations. North Carolina State University, Dept. Horticultural Science, Horticulture Research Series No. 165. 69 pp.
- Hassell, R.L., Schultheis, J.R., Jester, W.R., Olson, S.M., Maynard, D.N. and Miller, G.A. 2007. Yield and quality of triploid miniwatermelon cultivars and experimental hybrids in diverse environments in the southeastern United States. HortTechnology 17: 411-617.
- Treadwell, D.D., Creamer, N.G., Schultheis, J.R., and Hoyt, G.D. 2007. Cover crop management affects weeds and yield in organically managed sweetpotato systems. Weed Tech. 21:xxx-xxx(10pp). In press.
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Progress 10/01/05 to 09/30/06
Outputs
The relatively new sweetpotato clone 'Covington', was again evaluated for its yield response to nitrogen (N) rate. The clone was evaluated in three locations in NC in 2006; Kinston, Hugo, and Newton Grove. As expected, the greatest response to N was obtained in the light, sandy soils in Newton Grove. Yields were improved when the application of N was split versus applying it all at once. Splitting the application resulted in roots sizing faster. In addition, the higher rates of 90 and 120 lbs of N/acre led to the highest yields. In soils that were less sandy, response with respect to application and timing was not as dramatic, and one location (Hugo), little of no response was obtained to N treatment. It is likely that the Hugo location had ample amounts of carry over N as the treatment in which no N was applied was every bit as good as any of the other treatments. In the Kinston location, there was a response to N treatment. Generally, yields were increased as N rate
was increased. It is likely that some residual N and the better nutrient holding capacity of the soil at the Kinston site resulted in the muted response to N than what was obtained at the Newton Grove location. A similar set of N tests is proposed for a final year in 2007. Melon evaluations have continued on various types, with emphasis on honeydew. Several honeydew advanced lines and cultivars continue to show good yield potential and have very high quality. In addition to honeydew melons, several muskmelon new lines from Sakata showed good potential for southeastern commercial production. Several head lettuce cultigens, both iceberg and romaine were evaluated in both eastern and western NC. Several cultigens of both head lettuce types were adapted to eastern NC growing conditions and had extremely high quality. Mini seedless watermelons were evaluated for their adaptation when grown in NC. Their yield potential and quality were again evaluated. Most of the best yielding mini
seedless watermelons were propietary and are only available to growers on a contract basis. A significant body of work was conducted on watermelon pollenizers. With respect to triploid yield, the use of a single pollenizer was as good or better than using a combination of pollenizers as long as a superior individual pollenizer was selected. The use of inter-planted pollenizers typcially resulted in more triploid yields without a reduction in fruit size compared with a hill planted pollenizer. Delaying the planting of a pollenizer until 3 weeks after planting reduced yields and led to more fruits with hollow heart compared to when pollenizers were set at the time of triploid plant establishment. Selection, placement and the time of establishemnt of the pollenizer are all critical considerations in optimizing triploid watermelon production.
Impacts
The ability to determine what rate of N fertilizer to use when growing 'Covington' sweetpotato should help to acheive the highest yields yet avoid over fertilization of the crop. The selection of adapted cultivar, whether is be melons, watermelons or lettuce; should provide growers a better opportunity to successful produce these crops. The choice and placement of a pollenizer for triploid watermelon production should enable growers to produce the highest yielding and best quality fruit.
Publications
- Dittmar, P.J., D.W. Monks, J.R. Schultheis, and K.M. Jennings. 2006. Effects of postapplication halosulfuron-methyl at various percents of vine coverage on watermelon yields. HortScience. 41(3):518 (abstr.).
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Progress 10/01/04 to 09/30/05
Outputs
The new sweetpotato clone NC 98-608, now named 'Covington', was evaluated for its yield response to nitrogen rate. The clone was evaluated in three locations in NC in 2005; Kinston, Autryville, and Richlands. In two of the three locations, more yield was obtained when 90 pounds per acre nitrogen rates were used compared with lower rates. This indicates that 'Covington' may require more nitrogen to optimize yields compared with the Beauregard variety. In one location, however, little response was measured in response to nitrogen rate. The difference in response to nitrogen rates in the one location versus the two locations may have been caused by the limited rainfall throughout most of the growing season. In addition, in-row sweetpotato plant spacing trials were conducted in two locations in 2004 with 'Covington'. Generally, 15 inches would be the recommended spacing. However, if the plants are set by early June, 12 inch in-row spacing may result in better yields than
more distant in-row spacing. Melon evaulations have continued on various types, with emphasis on honeydew. Several honeydew advanced lines and cultivars show good yield potential and have very high quality. They include a line from Seminis, a few lines from Nunhems, and a line from Harris Moran. In addition, the cultivar Rocio has grown and produced well in North Carolina. Mini seedless watermelons were evaluated for their adaptation when grown in NC. Their yield potential and quality were evaluated. Some of the best yielding mini seedless watermelons were propietary and are only available to growers on a contract basis. Some mini seedless watermelon cultivars that produced good yields and quality and that were not proprietary were Mielhart, HA 5130, Mohican, Solitaire, Extazy and Vanessa.
Impacts
The optimization of sweetpotato cultural practices with the new Covington variety provides the opportunity for commercial growers to more efficiently grow the Covington variety for increased yields. Determination of adapted honeydew cultivars or lines provides NC growers the chance to successful produce a high yielding, high quality honeydew melon produced closer to shipping points in the eastern United States. Mini seedless watermelons might offer NC growers additional marketing opportunities as some cultivars were identified to be superior to others.
Publications
- No publications reported this period
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Progress 10/01/03 to 09/30/04
Outputs
The sweetpotato clone, NC 98-608, has many attributes that are attractive for production in NC. Because it has many promising attributes, several production practices for NC 98-608 were evaluated in order that they might be optimized. The goal of this research was to determine the effects of in-row spacing and planting time on yield and root grade of NC 98-608 over time. In addition, various nitrogen rates were evaluated in order to optimize yields. A late May planting time resulted in roots reaching the highest percentage grade of U.S. number one roots as early as 100 days after planting, while a late planting in June resulted in roots never reaching their full potential number one yields. For an early harvest after planting (90 days after planting), 15 inch in-row spacing produced the most marketable number one yields compared with a 9, 12 and 18 inch in-row spacings. For a later harvest time after planting (105 days or later), it appeared as though the 12 inch
in-row spacing was the most economical spacing to use. Roots from the earlier plantings (late May) and finer textured soils appeared to have shorter roots than roots from later plantings (after June 15) or coarser textured soil. Shape was more uniform with NC 98-608 than with the Beauregard clone. Nitrogen rates had little influence on yields in the two studies conducted in 2004. In one location, the use of as little as 30 pounds nitrogen per acre resulted in significant yield increases compared with plots which had no nitrogen applied. No additional yield benefit was gained when up to 120 pounds per acre was applied during the sweetpotato growing season. A total of 27 diploid watermelon cultivars and advanced breeding lines (hereafter referred to as cultigens) were evaluated for staminate flower and pollen grain production to assess their potential to serve as pollenizers (pollen source plants) in triploid watermelon production systems. Male reproductive output (staminate flower and
pollen production) was quantified during the peak flowering and fruit setting phase of the cultigens under field conditions. The number of staminate flowers produced per plant per day, number of pollen grains produced per flower, and total number of pollen grains produced per plant per day (staminate flowers per plant x pollen grains produced per flower) differed greatly among cultigens (for all tests, P < 0.01). Staminate flower production by cultigens differed by year (P < 0.0029) and days-within-years (P = 0.0225), but pollen production between years by cultigens was stable (P = 0.4841). Total male reproductive output ranged from 134,206 pollen grains per plant per day for Jamboree to 321,905 pollen grains per plant per day for Summer Flavor 500. These studies demonstrate the genotypic variability in watermelon male reproductive output potential, and may assist growers in choosing a good diploid pollenizer for triploid watermelon production. Several honeydew cultigens were
evaluated for adaptation and commercial production in NC. Several cultigens were very promising as they produced high yields and quality. They included Rocio, PS 3911298, Honey Star, HDM-02-02, and Fantasma.
Impacts
Sweetpotato growers want to produce their crop with a new, improved clone. NC 98-608 offers this opportunity to growers since it produces roots that are more uniform in shape and size, and is more disease tolerant is some cases than Beauregard. Optimizing in-row spacing to 15 inches for early harvests and 12 inches for later harvests will result in more profits for NC sweetpotato growers and provide best management practices for the successful adoption of the clone to be released in 2005. Growers can choose watermelon seeded cultivars which produce more pollen and potentially result in increased yields and profits growing triploid watermelons. Honeydew cultivars have been identified that are resistant to splitting, have good to excellent yields, and produce higher quality fruit than those grown in the southwestern United States or Central America. The identification of these cultivars provides new marketing opportunities for NC growers by diversifying the crops they
grow resulting in more potential profits.
Publications
- Gusmini, G., Schultheis, J.R. and Wehner, T.C. 2004. Rind use of watermelon cultivars for use in pickle production. 14(4):540-545.
- Schultheis, J.R., Thompson, W.B., Adams, D.E., Jester, W.R. and Taylor, B. 2004. 2003 Cucurbit cultivar evaluations: Research and extension report. Horticultural Research Series No. 161. 77 pp.
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Progress 10/01/02 to 09/30/03
Outputs
To determine the effects of Sweet potato feathery mottle virus (SPFMV), and possibly other newly described potyviruses, on sweetpotato yield and storage root appearance, virus-indexed Beauregard and Hernandez mericlones testing free of known viruses were compared with virus-infected mericlones in two separate experiments over two years. SPFMV was the only virus detected in the study, using available testing methodologies. Field monitoring indicated that almost 100% of the VI- plants were reinfected with SPFMV by 9 weeks after planting. The presence of virus before planting reduced yields of No. 1 roots by 26% and decreased overall appearance ratings for the three Beauregard mericlones. In addition, VI+ planting materials resulted in increased storage root width of both cultivars leading to increased storage root length/diameter ratios, further detracting from overall appearance. A total of 27 large-fruited and 15 miniature-fruited pumpkin (Cucurbita pepo) cultivars
were evaluated for adaptation to eastern North Carolina growing conditions. Some test categories were yield (fruit number and weight), preharvest and postharvest fruit decay, and viruses. Yields of large pumpkins ranged from over 3,200 fruit per acre for SVT 4613367, Autumn Gold, and Gold Standard to less than 1,000 fruit/acre for Gold Rush and Progold 200. For miniature pumpkins, over 33,000 fruit /acre were produced by Touch of Autumn, Lil Pumpkemon, and HMX 5682, whereas Mystic and Progold 100 produced less than 7,000 fruit/acre. Preharvest fruit decay ranged from 0% for Howden and EXT 4612297 to over 20% for Lil Goblin, Jumping Jack, Peek-A-Boo, and Tom Fox. Aspen and Magic Lantern (large) and Baby Pam, Lil Goblin, and Spooktacular (miniature) were the most susceptible to postharvest fruit decay. Virus incidence and/or severity on foliage and fruit were not related. Fifty cultivars of various melon types were screened during the 2003 production season. A candidate for
commercialization must have three things. It must look good, taste good and have shelf life capabilities. One ananas melon type, HSR 4011, offered firmness and quality not found in other ananas cultivars tested in previous years. Other melons with good market potential in the test included galia types Elba, Makdimon and Melon 6004. The last two are 5 days earlier than the standard galia melon, Galia. Juan canary melons included Golden Beauty, Bartlett Hybrid and SXM 7056. Bartlett Hybrid has a pear-like taste. Sugar Nut was outstanding. It is a small canary colored melon which has a brix over 14% and has some shelf life. Lettuce cultivar studies were initiated in the fall of 2001, spring and fall of 2002 and continued in 2003. In 2003, over 28 varieties of crisp head lettuce were trialed. Crisp head varieties that stood out in the trials included Mighty Joe, Javelina, Raider, Gator and G 612. The varieties averaged over 1.5 lbs /head. Thirteen varieties of Romaine were trialed in 2003
the best being Siskiyou. All the varieties but Siskiyou bolted in the fall.
Impacts
Sweetpotato growers know that viruses can reduce sweetpotato quality and yields, regardless of variety. Our research reemphasizes this point. Growers will incorporate high quality seed stock into their sweetpotato production program, while those who already are using high quality planting stock materials will continue to do so. Pumpkin growers in NC can choose cultivars that are most adapted to the growing conditions in the state. The HSR 4011 cultigen, an ananas type, and ZG-463, a charentais cultivar which had high eating quality yet did not consistently split in the field may provide NC growers with the potential to grow and market these melon types. Melons in other categories with good market potential in the test included galia types Elba, Makdimon and Melon 6004; and juan canary melons which included Golden Beauty, Bartlett Hybrid and SXM 7056. All these melons provide either improved quality and/or increased production and marketing potential for the NC
industry. Processed lettuce accounts for over 50 % of the all the head lettuce in the market place. Interest in sourcing head lettuce and Romaine out of North Carolina is increasing. Questions on the economic viability of growing lettuce in Eastern NC are being addressed as a result of this research. Identification of the proper cultivar provides the opportunity for NC growers to supply an alternative crop which can be grown in NC which could return additional income to the NC grower.
Publications
- Bryan, A.D., Pesic-VanEsbroeck, Z., Schultheis, J.R., Pecota, K.V., Swallow, W.H., and Yencho, G.C. 2003. Cultivar decline in sweetpotato: I. Impact of micropropagation on yield, storage root quality, and virus incidence in 'Beauregard'. J. Amer. Soc. Hort. Sci. 128:846-855.
- Bryan, A.D., Schultheis, J.R., Pesic-VanEsbroeck, Z., and Yencho, G.C. 2003. Cultivar decline in sweetpotato: II. Impact of virus infection on yield and storage root quality in 'Beauregard' and 'Hernandez'. J. Amer. Soc. Hort. Sci. 128:856-863.
- Stanghellini, M.S., Schultheis, J.R., and Holmes, G.J. 2003. Adaptation and market potential of jack o'lantern and miniature pumpkin cultivars in eastern North Carolina. HortTech. 13:532-539.
- Schultheis, J.R., Jester, B., Thompson, B., and Taylor, B. 2003. Potential opportunities with specialty melons and watermelons. In. Proceedings, 2003 pacific northwest vegetable association. Nov. 19-20, Pasco, WA. pp. 115-129.
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Progress 10/01/01 to 09/30/02
Outputs
Over 40 cultivars of various melon types were screened during the 2002 production season. The goal is to help NC growers diversify their product line and become more competitive in the market place. Several of the ananas melon types, such as 'Duke', had improved keeping quality compared with cultivars tested in previous years. Shelf life is an important characteristic for any produce item, but is much more critical for ananas melons compared with most melon types. Charentais melon types were rated high in taste tests but in order to obtain maximum sweetness and flavor, the fruit often split while on the vine in the field prior to harvest. No charentais cultivars or numbered hybrids were found in 2002 or previous growing seasons which had high eating quality yet did not consistently split in the field. Other melons with good market potential are the striped, oblong, crisp flesh oriental melons, juan canary melons, and the Japanese melons. Few Japanese melons have been
evaluated over the past two years and one goal of the melon evaluation program is to target more of these melons for inclusion in melon screening trials in future years. Honey dews also offer potential for NC growers if they can be harvested nearer to peak quality than those produced in TX, AZ, and CA. Several cultivars are promising such as 'Santa Fe'and 'Millenium'. Galia type melons also provide the grower the opportunity to diversify. Like ananas melons, an important deterrent preventing US industry acceptance is limited shelf life. Specialty watermelons also provide growers the opportunity to diversify. Seedless yellow and orange flesh watermelons fit niche markets. 'Buttercup' provides excellent sweetness, flesh texture and shipping characteristics compared with most other yellow flesh watermelons. This cultivar has been successful grown and sold by NC growers during the past two seasons. Suitable orange flesh cultivars have not been developed as they are prone to hollow heart..
Red sweet corn and new augmented shrunken -2 sweet corn tyes were grown and evaluated through surveys at a roadside stand and farmers' market in Raleigh. Both sweet corn types received very positive reviews with the white augumented type receiving over a 90% favorable review. Bag lettuce accounts for over 50 % of the all the head lettuce in the market place. Interest in sourcing head lettuce out of North Carolina is increasing. Cultivar, spacing and fertility studies were initiated in the fall of 2001, 2002 and will continue in 2003. Questions on the economic viability of growing lettuce in Eastern NC are being addressed as a result of this research. In the lettuce phosphorus trial, the average head weight in the first transplanting was significantly higher where 68 lbs of P2O5 per acre was applied through the drip system within a week after transplanting as compared to a zero check. In the cultivar trials started in spring 2002, it was apparent that Maverick, the standard spring
cultivar in New Jersey, is not the cultivar of choice for NC. The studies will continue through 2003.
Impacts
As a result of the melon screening program, increased planting of specialty melon acreage is expected in 2003. 'Sprite', a sweet, oriental, crisp flesh melon, is expected to jump in production from less than 100 acres in 2000 and 2001 to about 1000 acres in 2003. Over $1 million dollars was realized by NC growers in 2001 and 2002. Much greater returns are expected in 2003. Other specialty melons are being grown; however, financial returns are fairly minimal compared to those obtained with the 'Sprite' melon. Improving shelf life of certain melon type such as the ananas, galia, and muskmelon would provide NC with an array of quality melon products with longer shelf life than its competitors. If additional funding is obtained, various products which extend the shelf life of products such as melons will be evaluated in the 2003 season. The plan for the coming growing season is for a major national suppier to market red sweet corn. Growers are also planning to grow some
of the augmented shrunken-2 sweet corn in the coming growing season In 2003, small (3-6 pound) personalized red flesh watermelons will be evaluated for their adaptation in NC and their market potential. This is a new market being exploited through exclusive contracts with seed companies at the present time. The opportunity for head lettuce production in NC will continue to be explored. If NC can produce a quality product consistently for certain market windows, this will provide some growers the opportunity to realize additional revenues growing alternative crops.
Publications
- Schultheis, J.R., Jester, W.R. and Augostini, N.J. 2002. Screening melons for adaptability in North Carolina. In: Trends and New Crops and New Uses. Eds. J. Janick and A. Whipkey. Proc. of the Fifth National Symposium, New Crops and New Uses Strength and Diversity. ASHS Press, Alexandria, VA. pp. 439-444.
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Progress 10/01/00 to 09/30/01
Outputs
The evaluation of specialty melons continues to be a key focus of this program. Several melons have been identified with good commercial potential due to their uniqueness and/or some exceptional quality. The fruit development of the oriental, crisp flesh melon, 'Sprite', was carefully monitored in 2001. We determined that high quality fruits (high sugars and attractive exterior) are obtained when horizontal cracking is initiated at the distal end of the fruit. In addition, 'Sprite' was grown on nearly 70 acres in NC on about 10 commercial farms. Yields were very good with approximately 20,000 fruit per acre expected. Other types or cultivars that show promise are the juane canary melon, 'Golden Beauty', and the Galia melon, 'Sunny Gal'. Sweetpotato stand establishment was evaluated in a series of studies. Use of containerized transplants resulted in the production of deformed sweetpotato roots, while cut plants produced normal shaped roots. Propagation method also
influenced yield and plant stand. Growing sweetpotatoes for cut transplants in the float system resulted in stand reduction and yield compared to when sweetpotatoes were grown in containerized trays, greenhouse beds or hanging baskets. No difference in plant stands or yields were measured when plants were grown in plant beds in greenhouses versus in the field. Sweetpotato growth regulators were evaluated as a preharvest treatment 10 days before harvest to reduce skinning in sweetpotatoes at and after harvest. Some of the more promising compounds included Ethrel and Aim. As in previous studies, mechanical removal of the vines also reduced skinning.
Impacts
Diversification is key to maintaining profitability of farmers. Identifying and marketing alternative crops is one method a grower has to diversify their farming enterprise. Various specialty melons are one type of crop that is well adapted to NC growing conditions. 'Sprite' melon has been identified specifically as an alternative crop. Growers realized approximately $1 million in additional income from this crop in 2001. The future looks bright as even greater returns may be realized in subsequent years. Sweetpotato is an extremely important vegetable crop in NC. The crop contributes to the livelhood of many growers in eastern NC. The information obtained from the stand establishment studies allows growers to adopt those practices which result in the best quality and highest yielding crop and to avoid those practices which might hinder them. Growth regulators might also provide growers the opportunity to improve sweetpotato appearance or quality by a reduction in the
skinning of roots.
Publications
- No publications reported this period
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Progress 10/01/00 to 12/31/00
Outputs
Several tests were conducted and field evaluations were completed in October to determine the effects of saving sweetpotato seed on yield and quality over several generations. Generally, sweetpotato yield and quality were reduced as seed became more removed (increasing number of years/generations) from virus indexed planting stock. Continued work on the long term effects of sweetpotato generations on root yield and quality will be conducted in subsequent years. In addition, the economics of how long growers should save seed needs to be determined. With this new project, some of the other tests in the coming years will evaluate new crops for potential commercial significance, various considerations of stand establishment of sweetpotato and other crops, and the potential for no tillage of spring cucumbers.
Impacts
It is critical that growers use virus indexed, hill selected and field tested sweetpotato seed for improved sweetpotato yield and quality.
Publications
- No publications reported this period
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