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Vaccinium ovatum (evergreen huckleberry) is an evergreen shrub native to the Pacific Northwest. Evergreen huckleberry is diploid (2n = 2x = 24), but unreduced gametes have been reported that facilitated in interspecific tetraploids. To our knowledge, tetraploid forms of evergreen huckleberry have not previously been evaluated. There is interest in this species as a native, edible, evergreen landscape shrub, but it requires improvement of the fruit and plant qualities for an eventual cultivar release. To obtain variation in plant qualities, we induced polyploidy in a collection of plants in 2013. The purpose of this study was to assess the impacts of polyploidy on the fruit and plant qualities of V. ovatum. This fruit and plant quality study provides a contribution to the scientific knowledge base that is currently lacking for evergreen huckleberries. Plant qualities were determined by measuring plant height and width, obtained in Fall 2017. The fruit volume (mm³) and for soluble solids content (SSC, °Brix) were measured using a digital caliper and a digital refractometer, respectively. Measurements were taken on diploid, mixoploid, and tetraploid (2x, 2x + 4x, 4x) cytotypes, once in 2017, five times over 9 weeks in 2018, and three times over 9 weeks in 2019. Tetraploids had larger fruit than diploids in 2017 (P < 0.0001), suggesting there was a gigas effect from polyploidy in evergreen huckleberries. However, during 2018 and 2019, tetraploid fruit was smaller than that of diploid and mixoploid genotypes. Differences were observed in diploid fruit volume among all years (P < 0.0001) such that 2019 was largest and 2017 was smallest. It is unclear what led to this variation. In tetraploids, SSC was statistically significant among years (P = 0.0002) such that 2017 was highest and 2019 was lowest. Although our preliminary data suggested that induced polyploidy may result in larger fruit, this was not observed in subsequent years, and it does not appear that tetraploids necessarily will have larger or sweeter fruit. However, these tetraploids may facilitate crossing with other species at the tetraploid level as a means for improvement of various traits.

The genus Cotoneaster is composed of ≈400 species with a wide variety of growth habits and forms. These hardy landscape shrubs used to be commonplace because of their low maintenance and landscape functionality. However, the interest in and sales of cotoneaster have decreased for a variety of reasons, with the greatest being its susceptibility to a bacterial disease fire blight caused by Erwinia amylovora. The resistances of 15 different genotypes of Cotoneaster to a wild-type strain of Erwinia amylovora (Ea153) and a strain LA635 that has a natural mutation in avrRpt2 that encodes for a type III secretion effector were tested separately by inoculating leaves. Fire blight resistance was assessed by calculating the percent shoot necrosis (PSN) [PSN = 100 × (lesion length ÷ total branch length)] at 6 to 8 weeks after inoculation. Across all experiments, Cotoneaster genotypes H2011-01-002 and C. ×suecicus ‘Emerald Sprite’ consistently had the lowest PSN values when inoculated with either strain. Cotoneaster ×suecicus ‘Emerald Beauty’ was significantly more resistant to Ea153 than to LA635, whereas C. splendens was significantly more susceptible to Ea153 than to LA635.