Browsing by Author "Tuncay, Ö."
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Item Advances in the purple-fruited pitanga (Eugenia uniflora) long-term breeding program in Hawai’I, USA(International Society for Horticulture Science, 2018) Griffis Jr., J. L.; McDonald, T. G.; Manners, Malcom M.; Tuncay, Ö.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.Item Unexpected variations in flowering and fruiting occur in clonally propagated, purple-fruited pitanga (Eugenia uniflora ‘Zill Dark’) grown in Kona, Hawai’i USA(International Society for Horticultural Science, 2018) Griffis Jr., J. L.; McDonald, T. G.; Tuncay, Ö.; Manners, Malcom M.Many tropical fruits such as the Brazilian purple-fruited pitanga (Eugenia uniflora) are not well known or widely produced outside of their countries of origin. The reasons many of these minor fruit crops do not become more widely available are complex. However, many of the reasons revolve around a lack of research into appropriate horticultural practices such as propagation, nutrition, pest and disease management, and proper harvesting, handling and processing. Another major missing component is cultivar improvement. The purple-fruited pitanga has several named selections available in Brazil, Israel and the USA, but difficulties with clonal propagation have severely limited their availability. Breeding trials using the purple-fruited pitanga ‘Zill Dark’ were initiated in Florida and seedling fields were planted out for further evaluation in both Florida and Hawai’i where the crop is already known. Additionally, twenty veneer-grafted ‘Zill Dark’ pitanga were also planted in the Hawaiian field to provide production data and to serve as comparisons to the seedlings. Scionwood was all obtained from the same ‘Zill Dark’ plant and seedling rootstocks were all grown from seed produced by the same plant that provided the scionwood, as there are no clonal rootstocks available for pitanga. In 2013, five years after the planting of the veneer-grafted ‘Zill Dark’ pitanga, collection of flowering and fruit production data from both the grafted trees of ‘Zill Dark’ and the seedlings was initiated. As a rule, clonally propagated fruit trees of the same cultivar that are the same age, planted in the same field and fertilized, irrigated and pruned in the same manner are expected to produce similar fruiting and flowering results. However, in the Hawaiian field there were statistically significant differences in both times of flowering and ripening of fruit among the ‘Zill Dark’ clones. Why these clonally propagated fruit trees do not have well-synchronized production schedules is unclear; possible causes for this dissimilarity are examined.