Received for publication 22 Oct. 2001. Accepted for publication 9 Apr. 2002. This research was supported by the Florida Agricultural Experiment Station and a grant from the U.S. Dept. of Agriculture, Tropical/Subtropical Agriculture Research Programs and approved for publication as Journal Series No. R-08431 Cucurbita moschata Duchesne, known as calabaza in Puerto Rico and in Florida by those of Latino descent, is a species of pumpkin that is grown throughout the tropics and subtropics. It is known as pumpkin or calabash in the English-speaking Caribbean islands, auyama in the Dominican Republic, ayote in Central America, and zapallo in South America. Plants are monoecious, and insects, mostly honeybees and bumblebees, are required for pollen transfer. Fruit are produced along trailing vines that may spread up to 15 m from the crown of the plant. Each plant commonly produces two to five fruit that range from 2 to 20 kg each. The variability in fruit weight causes packaging problems because pumpkins are often marketed in 23-kg burlap sacks resulting in as few as two or as many as 10 pumpkins per sack. Fruit shape varies from globe, round, oval, obovate, pear, and oblate in unimproved types. Likewise, rind color varies from green immature fruit to light-orange mature fruit and in rind pattern from piebald to mottled. The rind may be smooth or sutured. The fruit flesh varies in color through several shades of yellow to orange and is from 3 to 5 cm thick. Although widely grown in tropical America, pumpkin plantings are generally small and most do not exceed a few hectares in size. Tropical pumpkin is the most important nonroot vegetable in Puerto Rico, where per capita annual consumption is ≈7 kg compared to <6 kg for tomato, the second most important vegetable (Alamo, 1990). In Jamaica, tropical pumpkin is the principal ingredient of pumpkin soup, a national culinary treasure. Currently, open-pollinated cultivars developed in Florida or Puerto Rico or farmerselected landraces are used by growers. Farmersaved seeds are generally used because commercially produced seed is not readily available. As a result, genetic contamination is exacerbated in this already diverse crop. Growers use cultivars or derived selections from ‘La Primera’, introduced by the Florida Agricultural Experiment Station (Volin, 1979); ‘La Segunda’, developed by Volin but not formally introduced; and ‘Soler’, selected in Puerto Rico but not formally introduced. These cultivars are traditional long-vine types. Our objectives were to develop hybrid tropical pumpkins with a compact plant habit, uniform fruit size, and desirable fruit quality. Hybrid seed provides a profit incentive based on exclusivity that encourages a commercially available seed supply. A compact plant habit permits higher plant populations, easier cultivation, and a more concentrated maturity, which facilitates production.