Jonathan R. Schultheis, Professor and Vegetable Extension Specialist and Keith D. Starke, Research Associate, Department of Horticultural Science, NC State University, Raleigh, NC 27695-7609
Acknowledgments: We gratefully acknowledge the assistance of Cathy Herring (Superintendent) and Charles Barrow (Horticulture Crops Supervisor), Central Crops Research Station, Clayton, NC, as well as, the personnel at the research station for their help to establish, maintain, and harvest the cultigen evaluation trials. We want to also acknowledge the following summer research assistants for their help with the study: Maxton Collins, Benjamin Indermaur, Ryan Jarrett, Kimberly McAllister, Tanner Seay and Emma Westbrook.
The cooperation and support of the following seed companies and university is also greatly appreciated: HM Clause; Rjik Zwaan; Sakata Seed USA; Seminis; Syngenta Seeds, Inc,; Texas A&M University; United Genetics and VoloAgri/US Agriseeds.
General Cultural Practices
This melon study was grown using recommended practices for commercial melon production in North Carolina. All plots in the study used black plastic mulch and were fertigated with drip irrigation. Furthermore, pesticides used on all plots were chemicals labeled for use on that crop.
Disclaimer
This publication presents data from the cultigen evaluation study conducted during 2019. Information in this report is believed to be reliable but should not be relied upon as a sole source of information. Limited accompanying detail is included but excludes some pertinent information, which may aid interpretation.
Introduction
The acreage for melon production in North Carolina has not been published in recent years, however, it is estimated that 3,000 to 4,000 acres are produced in the state. In 2017 a survey of US growers estimated orange flesh melon production was 58,000 acres (USDA, National Agriculture Statistics Service). Since 2013, the US orange flesh melon crop has seen significant decreases in acreage (2013, 74,000 acres valued at 319 million) to 2017 when US acreage was reported to be 58,000 with a total crop value of 267 million. Further reporting showed domestic orange flesh melon prices have steadily declined from their peak of 0.25/lb in 1980 to a season-average of 0.15/lb in 2018 (USDA, National Agriculture Statistics Service). The majority of melons grown in North Carolina are eastern type with ‘Athena’ being the principle cultivar produced for more than two decades. In addition to the eastern shipper type orange flesh melon, other orange flesh melons being grown on much smaller acreage include Extended Shelf Life (ESL); Long Shelf Life (LSL) melons, often termed Harper melons; and a third type termed Italian (Tuscan) melons. The ESL or LSL melons, as the name suggests, will hold for a longer period than the eastern type melons. Flesh firmness and sweetness tend to be higher in the ESL or LSL type melons than in eastern type melons. Greater flesh firmness allows the fruit to hold up better over time. This trait increases the shipability, a term often referred to as giving the fruit ‘better legs’. It can be more difficult to determine readiness on LSL melons and this has delayed willingness from growers in part to move into larger scale production of these melons. More recently, the release of new cultigens with ESL traits have performed well for growers and have received favorable support from consumers. Two such examples would be ‘Accolade’ and ‘Astound’ that were released by Syngenta in 2016. It is reported that these new cultivars comprise as much as 30% of the market, taking some market share from ‘Athena’. The Italian (Tuscan) type melons tend to split easier than the ESL/LSL or Eastern types and more intense management of the crop harvest may be necessary in order to minimize fruit loss due to splitting. In spite of these challenges with ESL/LSL and Italian (Tuscan) type melons, North Carolina growers have had some success in producing and marketing these newer melon types. In 2019 several new cultigens were evaluated in our melon field study that included 18 advanced lines or cultivar entries (cultigens) from 8 seed companies and 1 University. All entries were evaluated for yields, earliness, and various other qualities.
Materials and Methods
In February and March commercial seed companies were contacted to obtain seed for the orange flesh melon cultigen evaluation study.Seed were sown into 72 cell Poly trays to grow transplants (Hummert Int.; Earth City, MO) on 29 March 2019. The planting medium used was a Fine Germinating Mix, a commercial soilless mix (SunGro, Agawam, MA). In October 2018 the field study area (0.28 acre) was fumigated with Telone C-17 at 10 gal/acre and a cover crop was established. Based on soil test results lime was applied at 500 lbs/acre to adjust soil pH on 20 March 2019.
A complete fertilizer (12-6-24 @ 400 lbs/ac) was broadcast applied and black polyethylene plastic mulch(0.70 mil thick high density plastic film, 48 inches wide; B.B. Hobbs, Clinton, NC) was laid in the field on 24 April. Herbicide products, Prefar (5 qt/ac), Sonolan (4 pt/ac) and Honcho Plus (1 pt/ac)were applied to row middles for pre-emergent weed control on 30 April. Orange flesh melon transplants were approximately 3 weeks old when placed in a “hardening” greenhouse for 7 days prior to being established in the field on 2 May.
Plot size was one row with 10 plants per plot (20 ft) with in-row spacing of 2 feet and between-row spacing of 5 feet. Field arrangement for the orange flesh melon cultigen study was a Randomized Complete Block Design (RCBD) with four replications.Plots that were missing plants were replanted approximately 7 days after transplanting to achieve 100% stand, in most cases.Drip irrigation was utilized(NETAFIM, 12 inch spacing, 0.24 gal/hr; NETAFIM, Tel Aviv, Israel) throughout the growing season. Fertigation with 4-0-8 liquid fertilizer was initiated 6 days after planting and applied weekly, thereafter. The first application of liquid fertilizer (3 gal) was applied through the drip tube on 8 May and the last application (2 gal) was applied 17 July. Fertilizer was applied either preplant or through fertigation in this study. Total amount of fertilizer applied through fertigation for the season was 79 lbs/ac of N and 158 lbs/ac of K2O. The total amount of fertilizer applied for the entire growing season was 127 lbs/ac of N, 24 lbs/ac of P2O5 and 254 lbs/ac of K2O.
Insecticides were applied as needed throughout the growing season beginning 10 May and followed by subsequent applications on 29 May; 6, 12, 19 and 26 June 2019. The following insecticide products were alternated throughout the season to avoid potential resistance development in insect species; Asana, Assail and FanFare. Similarly, the following fungicide products were applied; Previcur Flex Pristine, Procure, Proline, Ranman, Switch and Zampro; and applied on the following dates; 29 May; 6, 12, 19, and 26 June; 10 and 17 July 2019.
There were 14 total harvests of the orange flesh melon cultigens. The first harvest was 24 June 2019 and the fourteenth harvest was 26 July 2019. Harvests occurred three times per week on Monday, Wednesday and Friday. Evaluations of each melon entry included; yield, fruit size, production earliness, soluble solids (using a digital refractometer, Atago, Vernon Hills, IL), fruit shape and size and interior flesh firmness. Flesh firmness was measured (recorded in pounds) by using a Penetrometer FT 011 with a 5/16” plunger tip, (QA Supplies LLC, Norfolk, VA). Melon samples were obtained by cutting through the ground spot of the fruit, lengthwise, from the fruit’s stem end to blossom end. Flesh firmness (measured in pressure) measurements were taken between the interior fruit cavity and the rind (near fruit bottom or ground spot and one from the top of the fruit) on one-half of the cut fruit.The reported measures on flesh firmness are an average of the two sample areas from five fruit per plot (10 total fruit firmness measures were obtained per plot).The majority of quality measurements were taken when the melonsbecame ripe between the first and fourth harvests for a given cultigen.
The field and growing conditions throughout the harvest period were considered typical for eastern North Carolina. Rainfall for the season was above average rainfall throughout the season. Optimal ambient temperatures allowed for good plant growth and fruit set within all the cultigen plots. This study was established in the field nearly 3 weeks earlier than in 2018. Eleven entries included in the study were submitted from Texas A&M. Those cultigens were Davinci, F39, HD 150, HD 252, Infinite Gold, OC 164, TH2, TH3, TH4, TH5 and TH6. Fruits from these cultigens were shipped to Texas and Arizona to be evaluated as part of a food safety and soil borne pathogen evaluation study. HD 150 and HD 252 are honeydew melons, SFR3079 and SFR3083 are specialty melons, OC 164 is an orange casaba melon, while the other thirteen entries were orange flesh melons.
Results
In the early harvests (1-4), entries that yielded over 100 cwt per acre were Athena, HMX 4606, SFR 3079, and SFR 3083 (Table 1). The highest yielding entries based on fruit numbers that exceeded 2,000 fruit per acre for early harvests (1-4) were Athena, F39, HMX 4606, SFR 3079 and SFR 3083 (Table 2). With the exception of TH2, TH3 and OC 164, the accepted market size category of 3.1 to 7 lbs. had the highest percentage of fruit produced from the early yielding entries. A high percentage (69% and 100%, respectively) of fruit produced by TH2 and TH3 weighed less than 3 lbs. in the early harvest 1-4. Fruit produced by OC 164 all weighed greater than 7.1 lbs and may be acceptable in commercial specialty melon markets.
The highest yielding entries for fruit weight, in the mid-season harvests (5-9), that yielded greater than or equal to 400 cwt per acre were Caribbean Jackpot, HD 150, HD 252, TH3, TH6, USAM 14836 and USAM 16203 (Table 5). The entries that yielded the highest (> 8,000 fruit number) in the mid-season (harvests 5-9) were Caribbean Jackpot, Davinci, Infinite Gold, F39, HD 150, HD 252, TH2, TH3, TH5, TH6, USAM 14836, and USAM 16203 (Table 6). Most fruits produced from these entries were between 3.1 to 7 lbs., with the exception of SFR3079, which produced fruits ≤, 3 lbs. (Tables 7 & 8). Orange fleshfruits that weigh ≤ 3 lbs. would ordinarily be culled in eastern US markets, however, other markets in the US sell smaller sized fruits. Smaller sized white flesh specialty melons may be acceptable in these alternative markets.
Some of the latest yielding (harvests 10-14) melon entries that exceeded 75 cwt per acre were SFR 3083 and TH2. (Table 9). These were likely fruit that reset after the initial earlier harvests. Average fruit size for these entries were 3.4 and 3.5 lbs., respectively. (Table 9).Davinci, F39, and SFR 3079 produced fruits that weighed mostly ≤ 3 lbs. andOC164 yielded fruits that weighed mostly above 7.1 lbs. (Table 11).
The highest yielding entries across all harvests, in terms of tonnage (≥ 475 cwt/acre) were Athena, Caribbean Jackpot, HD 252, SFR 3079, TH2, TH3, USAM 14836, and USAM 16203 (Table 13). The melon entries that produced the greatest number of fruit per acre (> 12,000) across all harvests were Davinci, F39, SFR3079, SFR3083, TH2, TH3, and TH6 (Table 14).
Other Support
In addition to the seed companies, this program has been supported by the College of Agriculture & Life Sciences, the North Carolina Agriculture Research Service, and the North Carolina Cooperative Extension Service.
Orange flesh and specialty melon cultigen study Clayton, NC, 2019.