Pitahaya or Dragon Fruit (Hylocereus spp.) Varieties: Evaluation, Morphological Description, and Genetic Characterization

Hylocereus (Berger) Britton and Rose and Selenicereus (Berger) Britton and Rose are two genera of a vining cactus commonly named pitahaya (in America and Europe) and/or Dragon Fruit (in Asia). The plant, native to tropical America, adapts very well to various climatic conditions in its native habitat, where it grows at nearly sea level in the arid coastal plains of the Pacific Coast and in more humid, cloud forests conditions at higher elevations. Pitahaya produces an edible fruit that has gained popularity as an exotic fruit in many countries in Asia, America and Europe, and this popularity has increased consumer demand for the fruit. The plant has tolerance to drought and adapts well to dry, hot environments where sub-tropical fruit cannot be grown and this has generated enormous interest among backyard growers and commercial producers in Southern California. There is uncertainty among named varieties and significant taxonomic confusion about the species within these genera, which limits the growth and expansion of this industry.

Twenty varieties of pitahaya were planted in a randomized complete block design at the University of California South Coast Research and Extension Center (SCREC) in Irvine, California to assess their adaptation and performance in field grown conditions. A selected set of these varieties were planted at UC Hansen Agricultural Center (HAREC) in Santa Paula and at the University of California, Riverside Coachella Valley Research Station (CVRS) to expand the geographic scope of the research and further screen these varieties in different, harsher environments. In addition, a germplasm collection was curated at the SCREC and 54 accessions were grown for observation.

Results from our project show that pitahaya or dragon adapts well to local microclimates and is a viable crop alternative for small-scale agricultural producers California. In addition to performance data, our study also helped develop detailed morphological description of all pitahaya cultivars planted. Finally, amplified fragment length polymorphism (AFLP) were used to genotype 230 accessions of pitahaya to determine redundancy among commonly named varieties and to assess the diversity of the collection. Some differently named varieties were identical based on our analysis, but there was also genotypic diversity within putatively named varieties. The results of this study will help growers and researchers to choose genetically distinct or genetically similar accessions from the germplasm collection or from nursery operations in order to investigate how different varieties and/or accessions perform in their growing regions.