Derivation: river Ucayali.
Location: R. Ucayali, Peru.

Notes:  Arevalo et al, 1996 [ARE96A] The U [PER] (Ucayali) clones originated from abandoned fields in the Ucayali (U 1 [PER] to U 52 [PER]) and the Urubamba (U 53 [PER] to U 70 [PER]) river valleys which were under high disease pressure from Witches' Broom. Between the 28th November and 4th December 1987 the clones U 1 [PER] to U 11 [PER] from along the valley of the Ucayali and its tributaries: Contamana, San Carlos, Pampa Hermosa, Ucayali, Cushabatay and Lago Chiatipiishca. Clones U 12 [PER] to U 33 [PER] were collected from Contamana, Pampa Hermosa, Orellana, Juancito, Nueva Berlin, Tamanco, Pueblo Libre, Requena, Ucayali, Tapicho and Inahuaya. In June 1988 clones U 34 [PER] to U 52 [PER] were collected from Pucallpa, Contamana, Pampa Hermosa, Roaboya, Masisea, Puerto Inca, Puerto Sol, Ucayali, Pisque, Pachitea and Cushabetay. At the same time another group of clones (U 53 [PER] to U 70 [PER]) were collected from the Urubamba valley: Maranura, Quillabamba, Echarate, Suhuayacu, San Agustin, Quellouno, Chanchamayo, Limoniyoc, Ciriaco, Liteni, Korebeni, Santoato. On another expedition to the Urubamba - Sahayacu in January 1989 the clones U 71 [PER] to U 99 [PER] were collected for high productivity.