FIFTEEN YEARS AND 120 GENOTYPES LATER WHAT HAVE WE LEARNED ABOUT TRIALING BLUEBERRY CULTIVARS IN THE PACIFIC NORTHWEST?

Abstract

The U.S. Department of Agriculture Agricultural Research Service (USDAARS), in cooperation with Oregon State University (OSU) and the Oregon Blueberry Trial Support Group, has been running an extensive selection and cultivar evaluation trial at the OSU North Willamette Research and Extension Center (NWREC) in Aurora Oregon. Since the initial planting in 1990, over 120 genotypes have been evaluated. Over the years, the evaluation approach has been streamlined and improved based on experience and data analyses. The very practical things that have been learned include: 1) netting is essential for evaluating genotypes ripening in June and July; 2) a randomized complete block design, while not as ideal as a completely randomized design for detecting genotypic differences, is better from a practical standpoint when managing the best way to add new genotypes to the planting; 3) three replications were sufficient to detect differences that were meaningful to growers, about 2.69 t/ha vs. 1.80 t/ha with five replications; and 4) good harvests in years 4, 5 and 6 after planting was highly correlated with performance of total yield over years 3–9. As far as blueberry type was concerned, northern highbush blueberries were well adapted to the NWES site but most southern highbush were not. The southern highbush, with the notable exception of ‘Legacy’ and ‘Ozarkblue’, grew well but tended to be very low yielding due in part to mid-winter flowering. Rabbiteye blueberries grew well although their fruit quality was generally poorer than highbush blueberries. Rabbiteye cultivars that overlap with the highbush ripening season are not of much interest, whereas cultivars like ‘Powderblue’, which has good quality and ‘Ochlockonee’ that is very late ripening have excellent potential for late-season markets. INTRODUCTION New and potentially better blueberry cultivars are being developed around the world. In past decades, potential new cultivars were planted at many locations over several years before they were released to growers as cultivars for commercial planting. Now, with public research programs, primarily at land-grant universities, struggling with funding and the incredible growth of the blueberry industry new cultivars are more likely to be tested on commercial farms without extensive testing at research stations. The Oregon blueberry industry through the Oregon Blueberry Commission and an industry driven and funded Blueberry Trial Support Group made a strong commitment to selection and cultivar testing. The first replicated trial of over 40 selections and cultivars was planted in 1990 at the OSU-NWREC. Approximately every 2–3 years a new trial has been established since then although typically with fewer genotypes. The tremendous cost associated with establishing, maintaining and harvesting this trial has forced us to try to figure out ways to reduce costs as much as possible while still collecting data we have confidence in. This discussion has two objectives 1) to give insight into the development of the USDA-ARS/OSU testing strategy and 2) to give some insight into what has been learned a Chad.Finn@ARS.USDA.GOV Proc. IX IS on Vaccinium Eds.: K.E. Hummer et al. Acta Hort. 810, ISHS 2009 72 about the types of blueberries and genotypes that do well in the Pacific Northwest.