CONTRIBUTIONS TO THE BIOLOGY OF ECONOMIC PLANTS .7. ON THE VIVIPARITYAND TUBER FORMATION OF THE CHAYOTE [SECHIUM-EDULE (JACQ) SW]

Sechium edule, the Chayote, domesticated and cultivated in Meso-Americ a, is a monoecious tropical-subtropical bush climbing with tendrills. It produces by its up to 15 m long sprouts besides racemose infloresce nces of male flowers singly born female flowers, which per plant durin g the vegetation period yield 300-500 berry-fruits of the shape and si ze of large pears. The prickly or smooth fruits contain only one seed, which viviparously germinates within the fruit still being on the mot her plant. The viviparity is described and its ecological meaning stat ed. Fruits, intended for human consumption as vegetable, are harvested 28-36 days after fertilization but before viviparous germination is s tarting. Furthermore Sechium forms edible starchy tubers which are dis tributed irregularly in the soil. They serve after the dry season, dur ing which the above ground organs of the plant for the most part die a way, as nutritive material if the plant sprouts again in the beginning of the following rainy season. Thereafter the tubers remain as organs emptied out. The root system consisting of shoot-born roots, the shap e and the harvesting of the tubers as well as the many possibilities o f use of all parts of the economic plant are discussed.