NATIVE APPLE ROOTSTOCKS FOR THE MARITIME NORTHWEST AN ON- FARM TRIAL ERIC LEE- MÄDER, NORTHWEST MEADOWSCAPES LLC, WHIDBEY ISLAND, WA, [email protected] OVERVIEW RESULTS RECOMMENDATIONS AND FUTURE Grafting apple trees onto specific rootstocks has Evaluating over a two- year timeframe: QUESTIONS been practiced for hundreds of years, providing options for managing tree size, precocity, pest and Approximately 1/3 of the rootstocks failed, likely Based upon our initial findings, the use of disease resistance, and more. Yet, the diversity of due to poor root structure and excessive root Pacific crab has the potential to: commercial rootstocks today remains limited. pruning (due to variable bare root quality of nursery stock), and due to a poor tolerance on • Provide a viable apple rootstock for wet and Malling, Geneva, Budagovsky, and other rootstocks the part of the Pacific crab for root disturbance poorly drained locations in the Maritime provide various good options, but all have been and drying. Northwest, including eliminating the need to selected for optimal traits in climates that differ drain wet farm fields for crop production; significant from the Maritime Pacific Northwest. In Overall, Pacific crab produced successful grafts particular, none offer exceptional performance in with 86% of the scion varieties. • Provide a fully fire blight- resistant rootstock poorly drained soils which can be typical in our – Malus fusca has documented polygenic wet climate. Varieties with a greater than 70% grafting resistance to fire blight; success rate included: Bulmer’s Norman, To address this challenge, in 2017 we launched an Domaines, Frequin Rouge, Vilibrie, Dabinette, • Foster a more ‘native’ and ecologically on- farm research project to evaluate the Blanquina, Bedan des Parts, Brown Snout, appropriate crop system, potentially suitability of the native Pacific crabapple (Malus Ashmead’s Kernal, Normannischen Ciderbirne, supporting native soil biodiversity. fusca) as a rootstock for domesticated cider apple Sangre de Toro, Nehou, Brown Thorn, and Amere varieties. While a number of individual orchardists de Berthencourt. Despite these potential benefits, additional have dabbled with the Pacific crab as a rootstock, questions remain for future evaluation, no previous replicated trials have been conducted Varieties with a greater than 50 to 70% including the longevity of grafting to assess how widely compatible this wild native grafting success rate included: De la Riega, compatibility, dwarfing potential, bearing age of tree is with various domesticated apple varieties Butt Pear, Muscat de Bernay, Zabereau Reinette, grafted trees, and consistency of these traits Barland Pear, Reine des Pommes, Thorn Pear, among a wild plant population. METHODS Cimitere, Raxao, Kerry Pippin, Pepa, Rieneta do Six Malus species are native to North America. In Caravia, and Collaos. Based on our findings we make the following the West, the Pacific crab is abundant in maritime initial recommendations on the use of Pacific climates extending from Alaska to Northern Varieties with a less than 50% grafting crab as a rootstock plant: California. Unique among apple species, it exhibits success rate included: Wickson Crab, Repinaldo a wide- range of adaptability, thriving in hydric and do Liebana, Calville Blanc, Te o r i c a , Perico, Court • Due to potential root drying and disturbance wetland soils including saltwater estuaries, as well Pendu Rose, Medaille D’Or, Peil de Sapa, Hendre sensitivity (as a wetland plant), container- as in heavy clay soils, and poorly drained upland Huffcap Pear, Michelin, Coloradano, Manchurian grown nursery stock should be used over sites. It is common in both coastal rainforests, and Crab, Barnet Pear, Vedialona, Yellow Huffcap Pear, bare- root plants where available. in areas of the Olympic rain- shadow where annual Peau de Vache, Blanc Mollet, Muscadet de Dieppe, precipitation averages less than 20- inches. Xuanina, De Bouteville, Mettais, and Jouveaux. • Grafting should be conducted in the orchard (as opposed to bench grafting), after the To evaluate the Pacific crab’s rootstock Varieties with no grafting success rate rootstock plant has been successfully compatibility with various cider apple varieties, we included: Irish Peach, Binet Rouge, Maria Elena, established. performed whip and tongue grafting with 50 apple Solarina, Dolgo Crab, Red Pear, Old Field Pear, varieties (primarily cider varieties), and an and Taynt on Squash Pear. additional 7 pear varieties. With 10 to 12 replicates of most varieties (although limited scion Based upon our observations, Pacific crab is wood availability in some cases resulted in fewer compatible with most apple and pear varieties. replicates). Limited success with some varieties is likely due to low quality rootstock material, rather than actual incompatibility. Support and Acknowledgements This project was made possible through funding from Western SARE, and the generous assistance of technical advisor, Dr. Carol Miles of Washington State University Department of Horticulture. .