In addition, lack of seeds results in longer shelf-life for seedless varieties because seed exudates cause the flesh to break down in ripe, seeded melons. These phenomena have not been exploited, however, due primarily to endemic viral diseases that cause plant decline and do not allow an extended fruiting period. For example, in Florida, some level of viral disease is present in nearly all cucurbit fields. Potyviruses cause continual and, in many cases, major losses in watermelon and muskmelon croppings in the Caribbean area. Field surveys of cucurbits in Florida show two major viral diseases that limit watermelon production.
Infections commonly become so severe as to stop production.
Most control efforts have been directed toward eradication of virus in weed hosts and the control of insect vectors with environmentally-harmful chemicals. However, the genetic engineering of these important crops lags well behind that of other crops. Using genetic engineering technology, a CBAG research project at the University of Florida has now created two transgenic varieties of seedless watermelons that are resistant to virus diseases. This is a conservative estimate that does not take into account the anticipated continuing increase in consumption. With this development, Florida would regain its status as producer of the largest and most valuable watermelon crop in the United States.