Triploid (seedless) watermelons have increased in popularity and compose three fourths of the watermelon production in the United States ( U.S. Department of Agriculture, Economic Research Service, 2005 ). Triploid watermelons produce nonviable
Peter J. Dittmar, David W. Monks, and Jonathan R. Schultheis
Joshua I. Adkins, Joshua H. Freeman, and Stephen M. Olson
Triploid (seedless) watermelons accounted for ≈89% of the watermelons grown in the United States in 2010 ( U.S. Department of Agriculture, 2011 ). Special production considerations must be taken into account when growing triploid watermelons
S. Alan Walters
Although mini triploid watermelons are a relatively new specialty vegetable, they have captured a segment of the watermelon market due to their convenience ( Maynard and Perkins-Veazie, 2004 ). These types of watermelons garner a premium retail
Joshua H. Freeman, G.A. Miller, S.M. Olson, and W.M. Stall
Over the last decade, the popularity of triploid watermelons has increased. However, unlike diploid or seeded watermelons, triploid watermelon plants have an uneven number of chromosomes and consequently are not able to produce viable pollen
Joshua H. Freeman, Stephen M. Olson, and William M. Stall
Over the last decade, the popularity of triploid watermelons has increased. In 2006, triploid watermelons accounted for 78% of the watermelons sold in the United States and averaged 4.5 to 11 cents more per kilogram than seeded watermelons ( USDA
Maria Victoria Huitrón, Manuel Diaz, Fernando Diánez, Francisco Camacho, and Antonio Valverde
In recent years, the cultivation of triploid watermelon in Almeria has increased significantly. The annual increase in surface area expanded to this crop has been maintained ( Fig. 1 ). The efficacy of grafting to control soil-borne diseases
S. Alan Walters
Honey bees (Apis mellifera L.) are important pollinators of triploid watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai]. Pistillate (or female) watermelon flowers require multiple honey bee or other wild bee visitations after visiting staminate (or male) flowers for fruit set, and pollination is even more of a concern in triploid watermelon production since staminate flowers contain mostly nonviable pollen. Six honey bee visitation treatments—1) no visitation control, 2) two visits, 3) four visits, 4) eight visits, 5) 16 visits, and 6) open-pollinated control—were evaluated to determine the effectiveness of honey bee pollination on `Millionaire' triploid watermelon fruit set, yield, and quality utilizing `Crimson Sweet' at a 33% pollenizer frequency. `Millionaire' quality characters (hollow heart disorder or percent soluble solids) did not differ (P > 0.05) between honey bee pollination treatments. The open-pollinated control provided the highest fruit set rate (80%) and the greatest triploid watermelon numbers and weights per plot compared to all other honey bee visitation treatments. Fruit set, and fruit numbers and weights per plot increased linearly as number of honey bee visits to pistillate flowers increased from 0 (no visit control) to the open-pollinated control (about 24 visits). This study indicated that between 16 and 24 honey bee visits are required to achieve maximum triploid watermelon fruit set and yields at a 33% pollenizer frequency, which is twice the number of honey bee visits required by seeded watermelons to achieve similar results. This is probably due to many honey bees visiting staminate triploid watermelon flowers (that are in close proximity) before visiting pistillate flowers thus providing mostly nonviable pollen that is useless for fruit set and development. Therefore, more honey bee visits to pistillate triploid watermelon flowers would be required to achieve maximum fruit set and subsequent development compared to seeded watermelons.
Kuan Qin and Daniel I. Leskovar
arranging each irrigation line). Plant and soil measurements. Triploid watermelons were harvested three times (indicated by arrows in Fig. 1 ) and marketable yield was sorted by fruit size at each harvest time. WUE at the crop level was then calculated by
The successful germination of triploid watermelon seeds depends largely upon three factors; moisture control, planting depth, and temperature control. The planting medium must be moistened until it is humid, but not wet enough for free water to be squeezed from a handful. This level of humidity must be maintained until germination is complete. The planting depth should be 1.25 to 2.5 cm. This reduces the number of seeds that “push” themselves from the medium and also facilitates correct moisture maintenance. Seeded trays should be placed in a germination room and held 48–72 hours at a temperature of 30 to 32 °C and a relative humidity of 90% to 95% until germination begins. When germination is complete, the plants can be watered normally.
Marietta Loehrlein and Dennis T. Ray
Triploid watermelon seed does not germinate in cold, wet soils as well as diploids; germination is slower due to reduced embryo size and thicker seed coat; fissures on the seed coat provide safe harbour for fungal spores; and triploid fruit set is later than most diploid cultivars. Because of these problems producers often transplant rather than direct-seed seedless watermelons. Seed priming has been shown to improve germination in other crops and would be an attractive method allowing for direct seeding of seedless watermelons. Seed from open-pollinated 4n × 2n crosses were primed in solutions of H2O, polyethylene glycol 8000, KNO3, or left untreated. Treatment times were 1, 3, or 6 days, and treated seed were subsequently dried for either 1 or 7 d. Seed were scored for germination in the laboratory and emergence under field conditions. Germination was better using H2O than KNO3 and PEG but not always better than the untreated control. Treatment time of 1 day was superior to 3 or 6 days, but length of drying time was insignificant. In the field trial, treatments did not differ in emergence.