Use and effects of diploid pollenizers for triploid watermelon [Citrullus lanatus (Thunberg) Matsumura and Nakai] production

The use of in-row pollenizers has become popular because it allows a greater number of triploid plants to be planted per hectare. Multiple in-row pollenizer cultivars are available but it is unclear if any exhibit superior performance with respect to triploid watermelon yield and if so, what varietal characteristics contribute to a pollenizer's performance.;Field trials were conducted during the Spring and Fall of 2005 and 2006 at various locations in FL. and S.C. to determine the performance of various pollenizers and also what contributed to their success. Of the in-row pollenizers that were tested, 'Sidekick' resulted in the greatest triploid watermelon yields. Yields from plots pollenized by 'Patron', 'SP-1', 'Jenny', and 'Mickylee' were not significantly lower. The use of 'Companion' resulted in significantly lower yields than plots pollenized 'Sidekick', 'Patron', 'SP-1', and 'Jenny'.;Pollen viability can vary between cultivars of a plant species and the pollen viability of four pollenizer cultivars was evaluated. Poor pollen viability from a pollenizer could result in increased fruit abortions and lower yield. No significant differences in pollen viability were detected between pollenizer cultivars tested. The production of staminate flowers is a crucial factor for pollenizers as there must be adequate pollen flow during triploid watermelon fruit set. Flower production for 'Companion', 'Jenny', 'Mickylee', and 'SP-1' was recorded and 'Companion' produced as many flowers as 'Jenny' or 'Mickylee' throughout most of the season. The flowering period of 'Companion' does appear to be shorter than other cultivars. Pollinator preference was examined between 'Companion', 'Mickylee', and 'SP-1' and 'Companion' was found to be the least attractive of the three. The lack of pollinator visitation to 'Companion' appears to be the greatest contributor to its poor performance.;'Mickylee' is an attractive option to use as a pollenizer because of its lower seed costs. However, 'Mickylee' has a growth habit that is more vigorous than most other pollenizers. Studies comparing 'SP-1' and 'Mickylee' showed that the 'Mickylee' competed more with associated triploid plants and reduced yield. Factors affecting pollenizer performance the most appear to be pollinator preference, staminate flower production, and competitive effect on associated triploids.