No Chill Stone Fruit for Hawaii

Growers on small family farms in Hawaii are always looking for varieties of niche market crops that differ from crops that their neighbors might offer for sale and for greater diversification. Chefs express an increasing interest in fruit grown locally, which may include fruits that do not normally grow in a tropical environment. The purpose of this project was to research and investigate options for peaches and plums of the Prunus species that may produce at lower elevations (300’) in Hawaii. A number of plum (Prunus mume) plants were obtained and distributed to project cooperators. The project coordinator also obtained a number of “low-chill” peaches for grafting onto plums, which had previously been shown to produce at low Hawaiian elevations. The peach varieties sold at the nurseries in Hawaii had little or no success to produce in Hawaii except for locations higher than 3000’ elevations. The standard commercial Prunus rootstock used for the peach varieties requires an average of 1,400 hours of chill time, which does not take place at farm locations in Hawaii. The project coordinator speculated that some of the chill time requirements must transmutate from the stock to the low-chill peach variety. Grafting of the varieties to the Prunus mume rootstock showed that some of the peach varieties would produce at 500-foot elevations. The Prunus mume would also produce acceptable plums which chefs have asked for in much greater quantities than currently in production. This project has opened up many new diversification possibilities for growers in the Kona district.

The project was able to meet the objectives stated in the original proposal by propagating and purchasing trees for project cooperators. The project coordinator was able to research additional varieties of low-chill plums and peaches that might be able to produce in Hawaii. Some of these will remain under test until they can be propagated and shared with grower-cooperators. Plums were given to American Culinary Association chefs, who developed recipes and communicated with other chef members. One chef was given a few peaches, which the project found was much slower to develop than plums, to test. Growers will continue to develop and work with these Prunus species to build the waiting market. The project was also successful in grafting the low-chill peaches to the no-chill plum rootstock. A few peaches have developed from these grafts, but more time will be needed to determine yield and other data. Cooperators will continue to work with these fruits.