2019 ASHS Annual Conference

There is growing interest in using native and edible plants in home landscapes. Vaccinium ovatum, evergreen huckleberry, is a native plant in the Pacific Northwest which has evergreen leaves and tart fruit. The native and evergreen qualities make this plant an ideal candidate for breeding for home landscapes. However, its poor form and small, tart fruit detracts from its aesthetics and use in gardens and of these traits, we are focusing on fruit qualities first. Little is known about the development of huckleberry fruit over the course of a season. Therefore, the purpose of this project was to investigate fruit size and sugar concentration over nine weeks to compare plants with different ploidy levels. Specifically, our objectives were to 1) assess the impact of ploidy level on fruit size and brix and 2) determine optimum harvest time. Tetraploids (2n = 4x = 48) and mixoploids (2x+4x) were developed in 2013 and ploidy was confirmed in 2018. This project assessed overall fruit size using a digital caliper, sugar concentration (Brix) using a digital refractometer, and seed germination percentage in 2017 and 2018. In 2017, there was only one harvest date where it was found that Brix was highest for mixoploids and lowest for diploids. Ploidy level had a positive relationship with fruit size in 2017. In 2018, fruit characteristics were measured over a nine-week period to determine optimal harvest time. Berry volume gradually increased finally plateauing after seven weeks, while Brix started decreasing immediately after sampling began. To allow fruit size to reach its maximum but maintain Brix at peak levels, our data suggests collecting at approximately 2723 Growing Degree Days (GDD). GDD were calculated by summation of all days with mean daily temperature above the base temperature of 10°C.Germination percentages increased following 3 weeks of cold stratification, suggesting this species has physiological dormancy.