Purple Passion Fruit, Passiflora edulis Sims f. edulis, Variability for Photosynthetic and Physiological Adaptation in Contrasting Environments

Abstract

Purple passion fruit (Passiflora edulis Sims f. edulis) is a tropical juice source. The goal of this project was to evaluate photosynthetic and physiological variability for the crop with the hypotheses that landraces contain the diversity to adapt to higher elevation nontraditional growing environments and this is dependent on specific parameters of ecological adaptation. A total of 50 genotypes of this crop were chosen from divergent sources for evaluations of their eco-physiological responses in two equatorial locations at different altitudes in the Andes Mountains, a center of diversity for the species. The germplasm included 34 landraces, 8 commercial cultivars, and 8 genebank accessions. The two locations were contrasting in climates, representing mid and high elevations in Colombia. Mid-elevation valleys are typical regions of production for passion fruit while high elevation sites are not traditional. The location effects and variables that differentiated genotypes were determined. Results showed statistically significant differences between locations and importance of physiological parameters related to photosynthesis and water use efficiency. Some landraces exhibited better water status and gas exchange than commercial types. Parameters like maximum photosynthesis, points of light saturation and compensation, darkness respiratory rate, and apparent quantum yield varied between genotype groups. The landraces, commercial types, and genebank entries also differed in content of carotenoids and chlorophylls a and b. Meanwhile, photosynthesis measurements showed that altitudinal difference had an effect on genotype-specific plant growth and adaptation. An important conclusion was that landraces contained the diversity to adapt to the new growing environment at higher altitudes.