9500 WMZ Siegers. Materials and Methods Location Field 12 at the University of Delaware Research and Education Center Farm, Georgetown, DE.

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1 2010 University of Delaware In-Row Watermelon Demo Gordon Johnson & Emmalea Ernest University of Delaware Elbert N. & Ann V. Carvel Research and Education Center County Seat Highway Georgetown, DE (302) Introduction Fourteen special pollenizer varieties and the standard diploid variety Stargazer were interplanted with the seedless variety Crunchy Red in a demonstration plot at the Carvel Research and Education Center in Georgetown, Delaware. A plot with no pollenizers was planted as a control. Treatments Company Pol-3949 Pol Pol Pol Sp-5 Syngenta Polimax Nunhems ACE Sakata Sidekick Harris Moran Accomplice Harris Moran Patron Companion Jenny 9500 WMZ SSC 2221 Shamrock No Control Stargazer Control Materials and Methods Location Field 12 at the University of Delaware Research and Education Center Farm, Georgetown, DE. Cultural Practices Field was fertilized according to soil test results. On May 7, 2010, 60 lbs/a of nitrogen (30% UAN) was applied before the beds were shaped and black plastic mulch and trickle irrigation were laid on 7 centers. Plants were seeded in the greenhouse on April 16, 2010 and transplanted to the field on May 17, Field plots were one row (7 ft) wide and 30 ft. long. In-row spacing of the seedless melons ( Crunchy Red ) was 3 or 10 plants per plot. A total of three plants of the in-row pollenizer variety was planted in each plot: between the second and third plants, the fifth and 1

2 sixth plants, and the eighth and ninth plants. The border rows next to the drive rows were planted in the diploid variety Stargazer. An application of Gramoxone 2 pt/a +Sandea 0.6 oz/a +Prefar 5 qt/a was made to the row middles on June 1 with a hooded sprayer. Gramoxone 2pt/A +Crop Oil Concentrate 0.16 qt/a was applied with a hooded sprayer on June 18, Vines were turned before this application as they had just started to run off of the plastic. Select 10 oz/a was applied on July 15, Applications for disease and insect control were as follows: Bravo at 3 pt/a on 6-12, 6-19, 6-26, 7-10, 7-16, 7-24, 8-1, and 8-13; Previcur Flex at 8.5 oz/a on 7-10; Ranman at 2.75 oz/a on 7-16 and 8-1;Oberon at 8 oz/a on 7-16; and Lamda Star at 4 oz/a on The trial was fertigated with UAN on June 22 (50 lb/mulched A), July 12 (25 lb/mulched A), and July 26 (25 lb/mulched A). Data Collection The seedless melons from the demo were harvested four times: August 10/11 (85/86 DAT), August 25 (100 DAT), September 9 (115 DAT), and October 1 (137 DAT). The weight of each watermelon harvested was recorded individually. All melons from the plot were cut to check for hollow heart. plant habit, male flower number and fruit set data were collected on five days: 42, 51, 66, 73 and 79 days after transplanting. For one pollenizer plant from each plot the following data was collected: number of male flowers open that day, number of male flowers open the previous day, length of pollenizer stem. For one seedless plant from each plot the following data was collected: number of seedless melons set, number of the first node at which a melon was set, number of aborted female flowers. Results The maximum stem length measured for each pollenizer variety is reported in Table 1. Maximum stem lengths ranged from 127 to 83 inches. Total male flower counts are reported in Table 2. This represents the total number of male flowers counted on the five pre-harvest survey dates. At each survey the number of male flowers open that day and the previous day was counted. On the first survey date the number of male flowers open before 41 DAT was also recorded, consequently the totals reported in Table 2 represent approximately 11 days of male flower counts. The number of male flowers counted on each survey date is shown in Chart 1. Some pollenizer varieties produced male flowers earlier than others and some varieties produced male flowers for a longer portion of the season. Table 3 shows the total number of seedless melons harvested from each plot. The plot with no pollenizer had the lowest yield. The plots with the highest yield were Jenny, ACE, 9500 WMZ and Stargazer. However these four plots also happened to be next to the border rows of Stargazer and may have benefited from additional pollen from the border plants. The Polimax and Pol-3949 plots were also next to border rows. There is not much correlation between the number of melons counted in pre-harvest survey and the final yield. It is notable that the plot with no pollenizer set more melons per plant (3.2) than it carried to harvest (2.2). 2

3 As shown in Chart 2, the bulk of the watermelons were harvested at the first harvest date 85 and 86 days after transplant. Only one of the harvested melons had hollow heart. Acknowledgements The authors gratefully acknowledge: seasonal Extension Vegetable Program employees Peggy McDaniel, Brooke Drury, Chelsea Aydelotte and Heather Baker for their assistance throughout the season. Brian Hearn and the REC Farm Crew for assistance with field operations and irrigation. Seedway, LLC, for donation of seed for the border rows. Harris Moran for donation of seed of Crunchy Red. 3

4 Plant Data Table 1: Maximum Stem Length (in) Measured During the Season Variety Maximum Stem Length (in) ACE 127 Pol Jenny 124 SSC Pol Patron WMZ 112 Sp Pol Pol Sidekick 104 Polimax 102 Stargazer 99 Companion 86 Accomplice 83 Table 2: Total Male Flowers for 11 Days During the Season Variety Total Number of Male Flowers SSC WMZ 28 Pol ACE 22 Accomplice 22 Jenny 21 Pol Sp-5 20 Stargazer 20 Polimax 18 Pol Patron 15 Sidekick 11 Pol Companion 5 Chart 1. Number of Male Flowers Open Previous to 41 DAT and Two-Day Totals from Counts Taken 42, 51, 66, 73 and 79 DAT 40 Number of Male Flowers prev

5 Seedless Fruit Set and Yield Data Table 3. Yield in Number of Seedless Melons per Plot and the Average Number of Melons Set Per Plant Counted in Pre-Harvest Surveys Treatment Total Melons Harvested from Plot (10 plants) Average # Set Melons per Plant Counted in Pre- Harvest Surveys Jenny ACE WMZ Stargazer Accomplice Pol Sp Companion Pol Patron Pol Sidekick Polimax SSC Pol No Chart 2. Number of Seedless Melons Harvested Per Plot on Each Harvest Date No Pol SSC 2221 Polimax Sidekick Pol Patron Pol-3949 Companion Sp-5 Pol Accomplice Stargazer 9500 WMZ ACE Jenny 85/ Number of Seedless Melons Harvested 5