J. PACD - 1997 29 Ethnobotany, Productivity, and Ecophysiology of Pitaya (Stenocereus queretaroensis) Eulogio Pimienta-Barrios 1 , Park S. Nobel 2 , Celia Robles-Murguía 1 Lucila Mendez-Moran 1 , Enrique Pimienta-Barrios 3 , Enrico Yepez-Gonzalez 1 1 Departamento de Ecologia Division de Cencias Biológicas y Ambientales, CUCBA Universidad de Guadalajara Department of Biology and UCLA-DOE Labortatory 2 University of California Los Angeles, CA 90024-1606 Departamento de Produccion Agricola 3 Division de Ciencias Agronomicas, CUCBA Universidad de Guadalajara ABSTRACT Pitaya (Stenocereus queretaroensis) is a columnar cactus that produces attractively colored edible fruits in both wild and cultivated populations in the subtropical semiarid lands of Mexico. Pitaya is a relatively recently domesticated fruit, which during the last 10 years has emerged as a fruit crop whose cultivation is feasible using relatively low inputs of anthropogenic energy or water and whose fruits ripen during the spring season, before summer when the local markets are flooded with other fresh summer fruits. These agronomic traits have increased the economic viability of small farms in semiarid subtropical lands of Mexico. This article summarizes the work on agroecological and biological aspects of Stenocereus queretaroensis conducted during the last seven years in the subtropical semiarid lands of the Sayula Basin, Jalisco, Mexico. Our work is oriented to the development of basic knowledge of the plant and its environment, which allowed us to define opportunities and needs for basic and applied research, oriented to the domestication of pitaya under the modern precepts of sustainable development. Keywords: Cacti, Stenocereus, aridity, ethnobotany, ecophysiology. INTRODUCTION Pitaya are columnar cacti native to subtropical regions of Mexico that produce attractively colored edible fruit (Bravo, 1978). Pitaya belong to the tribe Pachycereae of the Cactoideae subfamily (Sanchez-Mejorada, 1984). Economically, the most important subtribe is Stenocereae, which includes the genus Stenocereus, with 24 species distributed from the southwestern United States to Venezuela and Peru (Bravo, 1978). Stenocereus have provided valuable additions to the diets of Indian tribes inhabiting tropical semiarid lands in coastal plains along the Gulf of Mexico and the Pacific Ocean as well as subtropical semiarid inland regions of Mexico.