Watermelon is a preferred fruit in the Caribbean and all over the world and is the second most consumed cucurbit by harvest weight in the Virgin Islands after cucumber. While quality of water of watermelon is commonly judged by sweetness, the ratios of types of sugars are hardly considered. Watermelon is classified as one of the fruits with very high glycemic index, GI – the measure by which a dietary intake increases the blood sugar compared to pure glucose whose GI is 100. Watermelon is normally promoted as a highly nutritious as it is one of the best sources of potassium, but can be both a blessing and curse, especially for consumers with high blood sugar-related ailments. Here we report on preliminary efforts we are making to produce watermelons that have reduced GI. We are using hybridization as well as exploiting genotype-by-environment interactions to influence sugar composition in fleshy fruit tissues. We have obtained three hybrids that have at least 22% reduced glucose and at per brix compared to the parents. We are also testing a series of shadehouse systems, two of which show the potential to lower glucose ratio in the fruits. We hope to refine these methods and evaluate the watermelon lines for yield and sugar trait stability before recommending plant materials and production systems to interested farmers. Key words: Hybrids, sugar, glycemic index, genotype by environment, production system, sucrose, watermelon.
