Breeding, research and development of purple-fruited pitanga (Eugenia uniflora L.) as a commercial crop in Hawai'i, USA - 2007 to 2017
In 2003, purple-fruited pitanga was one of only 12 tropical fruit crops selected from more than 200 prospective crops for development in Hawaii by tropical fruit growers, processors and chefs. The most desirable seedlings were selected for further research, plants of these were propagated by grafting and one established, named cultivar, Zill Dark, was selected as the parent for a breeding project to look for variation within the crop. A planting of 137 seedlings from a self-cross of Zill Dark was installed in a field at the Kona Experiment Station in Holualoa, Hawaii in February 2007. While evaluating the seedling plants for various traits, they were also used in a trial to evaluate the effects of fertilizer rates on growth and development of the crop. In summer 2008, 20 grafted plants of Zill Dark were added to the field for comparison with the seedlings. Seedling plants may begin to produce fruits only two years after planting in the field, but full production takes several years of growth and maintenance. Grafted plants often produce some fruit within a year of grafting. The fertilizer trial continued for several years and fruits were harvested and evaluated for traits such as color, size and taste. Fruits were successfully marketed at local farmers markets and to local chefs. After six years in the field, fruit production data was collected for all of the purple-fruited seedlings and the Zill Dark grafted plants from 2013 to 2015. Surprisingly, plants were not all synchronized to produce fruits at the same time, so the potential to find new varieties from among the seedlings that could alter the growing season for producers in Hawaii was noted. Substantial variations in fruit yield and length of fruiting period were also discovered. In 2017, during further evaluation of fruits in the field, three seedlings in the plot were discovered bearing large numbers of ripe, seedless fruits, something not previously reported for this crop. These plants have been propagated by veneer graft for further evaluation. Experiments to measure brix in relation to exact fruit color of ripening fruits (measured with a Nix Pro Color Sensor) have also been initiated to determine if fruits might be harvested and marketable sooner in the crop cycle so that fewer fruits are lost when very soft, fully ripe fruits abscise and drop from the plants.
Griffis, J.L., Manners, M.M. and McDonald, T.G. (2020). Breeding, research and development of purple-fruited pitanga (Eugenia uniflora L.) as a commercial crop in Hawai'i, USA - 2007 to 2017. Acta Hortic. 1299, 221-228
pitangueira, Myrtaceae, Surinam cherry, Hawaiian cherry