Characterization of Diploid Watermelon Pollenizers and Utilization for Optimal Triploid Watermelon Production and Effects of Halosulfuron Post and Post-directed on Watermelon

Abstract

Characterization experiment.

The objective of this research was to compare several cultigens' vegetative characteristics, staminate and pistillate flower output over time, and exterior and interior fruit characteristics. In experiments conducted during 2005 and 2006, 15 pollenizer cultigens were evaluated. Based on shorter vines and internodes, pollenizers which produced a more compact plant were 'Companion', 'Sidekick', 'TP91', 'TPS92', and 'WC5108-1216'. Those cultigens with a standard vine length (longer vines and internodes) were 'Ace', 'Jenny', 'High Set 11', 'Mickylee', 'Mini Pool', 'Nun6017', 'Pinnacle', 'Summer Flavor 800' ('SF800'), 'Super Pollenizer 1' ('SP1'), and 'WH6818'. The greatest quantity of staminate flowers produced over the 5 week period was obtained with 'Sidekick' and 'SP1'; the lowest number with 'TP91' and 'TPS92'. The number of pistillate flowers produced over time followed a similar pattern according to each cultigen's production of staminate flowers. Based on fruit production and quality, pollenizers with consumption market potential include 'Mickylee', 'SF800', 'Mini Pool', 'Jenny', and 'Pinnacle'. Other pollenizers, such as 'SP1', have a white flesh and thin rind and should be used strictly as a pollenizer. Based on staminate flower production, certain cultigens may potentially be superior pollenizers and increase triploid fruit yields.

Utilization experiment. Studies were conducted to maximize triploid watermelon fruit yields and quality by optimizing the choice and use of pollenizers. Treatments included 'Companion', 'Super Pollenizer 1' ('SP1'), 'Summer Flavor 800' ('SF800'), and 'Mickylee' as the only pollen source (#1-4); and the various combinations of 'Companion', 'SF800', and 'SP1' using two pollenizer cultivars as pollen sources (#5-7). Planting arrangement was compared; 'SF800' in a hill (#8) versus an inter-planted field arrangement. Time of pollenizer establishment was evaluated by establishing 'SP1'three weeks after planting (#9) with the establishment of 'SP1' at time of triploid plant transplanting. A triploid planting with no pollenizer (#10) was included to determine if pollen movement occurred outside of the treatment area. Pollen movement was minimal among plots. For individual pollenizer treatments, 'Companion', 'SP1', and 'Mickylee' produced similar total yields. The lowest yields were obtained with the 'SF800' treatment. 'Companion' produced more large fruit than the individual pollenizer treatments. Combining the pollenizers generally did not enhance triploid yields or quality. Inter-planting of pollenizers resulted in better yields than if hill planted. The late planting of 'SP1' resulted in a high percentage of severe hollow heart. The selection of pollenizer, planting arrangement, and time of pollenizer establishment are all important considerations to optimizing triploid yield and quality.

Halosulfuron study. Studies were conducted to determine the influence of halosulfuron postemergence-direct and postemergence on growth and yield of 'Precious Petite' and 'Tri-X-313' triploid watermelon. Treatments included a nontreated check, 39 g ai/ha halosulfuron applied to 25% distal or proximal region, and over the top. Two additional treatments were applied to 'Precious Petite' only: 50% distal or proximal. Watermelon treated with halosulfuron had chlorosis, shortened internodes and increased stem splitting. Halosulfuron POST over the top of watermelon caused the greatest injury. Halosulfuron directed to 25 or 50% (distal or proximal) of the plant caused less injury than halosulfuron applied over the top. Stem splitting was greatest with proximal application. Internode shortening was greatest with distal applications. However, 'Tri-X-313' in the 25% distal treatment produced similar total and marketable fruit weight as the nontreated check at Clinton. Fruit number did not differ among treatments for either cultivar. In 'Precious Petite', differences were found in the marketable fruit weight at Kinston. Plants in the nontreated check and 25% distal end treatment had greater marketable fruit weight than the 50% proximal and over the top treatments. Limiting halosulfuron to no more than 25% of the watermelon plant will likely improve crop tolerance.