Advances in the purple-fruited pitanga (Eugenia uniflora) long-term breeding program in Hawai'I, USA

Pitanga is not a newly discovered fruit, although its commercial potential has not been widely developed. European explorers discovered the pitanga in South America several centuries ago and spread red-fruited seedlings throughout the tropics worldwide. However, only in Brazil has this crop seen significant commercialization of the fruits. In Hawai'i, fruits have long been popular in farmers' markets and they are in demand by processors and chefs. Interest in the crop has expanded rather recently because of the availability of purple-fruited, high-antioxidant, better-tasting fruits. Several purple-fruited selections were introduced to growers in Brazil in 2011. In Florida, the tasty 'Zill Dark' purple-fruited cultivar has been available for many years and one plant is the parent plant of the large seedling field of pitanga planted at the Kona Experiment Station in December 2006. Factors that have limited further development of pitanga include considerable variation among seedlings and their fruits, difficulty in clonal propagation, difficulty in harvesting the fruits and lack of recognizably superior cultivars. The planting at Kona, 137 seedlings from a 'Zill Dark' self-pollination and 20 grafted plants of 'Zill Dark' was utilized initially to develop fertilizer recommendations for interested local growers who might replace coffee with another crop. As the planting matured, it was evaluated for pest and disease problems and fruits from individual plants were evaluated for antioxidant content, flavor and postharvest quality. From September 2013 to September 2015, all individual plants were evaluated weekly for presence of flowers and/or fruits in various stages of development. Unlike Florida or Brazil, where both flowering and fruiting in pitanga are highly synchronized, the Kona field has fruits almost continuously year-round (although individual plants do go in and out of production). Analysis of the flower and fruit data collected has allowed comparison of the seedlings with the 'Zill Dark' grafted plants such that selections of early- and late-bearing seedling plants that extend the crop season substantially can be made. Some preliminary fruit yield data will allow us to select seedlings that may have higher yields than the 'Zill Dark' grafted plants. Fruit characteristics of promising seedlings will be evaluated for other important characteristics such as antioxidant content, fruit size and taste.