2017 ASHS Annual Conference

The American persimmon (Diospyros virginiana) is a slow-growing, moderately sized tree native to the forests of Kentucky. The golden orange fruit are sweet when fully ripened and astringency is reduced. This fruit has great processing potential. Persimmons are normally dioecious; that is, separate trees produce the male and female flowers. These self-infertile trees require cross-pollination with another variety to produce fruit. There are two races of persimmon. The tetraploid (60 chromosome) race is centered in the southern Appalachian region and adjacent areas while the hexaploid (90 chromosome) race generally occupies a range north and west of the tetraploid range although the ranges overlap in Kentucky. Most cultivated varieties are thought to be the northern, 90-chromosome race. Since the ranges overlap, cross-pollination may cause sexual incompatibility, resulting in pollination without fertilization. This could result in the production of seedless fruits. The objective of this study was to confirm the existence of both the 60 and 90 chromosome races of persimmon in native Kentucky populations and to compare them to established cultivars using flow cytometry. Leaf samples were collected from 20 native trees located in the Bernheim Arboretum and Research Forest, in Bullitt County, Kentucky, five native trees in Franklin County, Kentucky, and persimmon varieties ‘Prairie Sun,’ ‘Prairie Star,’ ‘Mohler,’ ‘Early Golden,’ ‘Garretson,’ ‘Meader,’ ‘100-46,’ and a male persimmon tree located at the Kentucky State University Harold R. Benson Research and Demonstration Farm, in Franklin County, Kentucky. Flow cytometer analysis of the leaf samples showed that all varieties located at the KSU Research Farm were from the 90 chromosome race. All native trees sampled from Franklin County were from the 60 chromosome race. For the trees sampled in Bullitt County, six trees were from the 60 chromosome race and 14 trees were from the 90 chromosome race. Since pollen from native trees could result in seedless fruit formation in Kentucky, native seedlings should be examined for use as pollenizers in commercial production of American persimmon.