Effect of Rootstock and Soil Amendment on Three Highbush Blueberry Cultivars

A grafted blueberry research plot was established at the North Willamette Research and Extension Center in Aurora with a split-split plot design with soil treatments and root types as sub plots respectively. There were two root types (own roots vs. grafted) and three highbush varieties ('Draper', 'Liberty', and 'Aurora') growing in two soil treatments (sawdust amended soil vs. no amendment). Leaf tissue analysis found that grafted plants had higher tissue N, P, K, and Mn, but lower Ca, and Mg than own-root plants, indicating rootstock affected key nutrients uptake. Sawdust amendment reduced foliar Fe concentration. Foliar P concentration in ‘Aurora’ was higher than that in both ‘Liberty’ and ‘Draper’, while ‘Liberty’ has a lower foliar K concentration than both ‘Draper’ and ‘Aurora’.  Fruit firmness was not affected by grafting and sawdust amendment and differed as expected among three highbush blueberry varieties.  Yield and other growth parameters among cultivars, root types, and soil amendment will be determined in future years.