2018 ASHS Annual Conference

Olive production and acreage in Oregon are limited but growing, as part of a new innovative industry in the state. Some factors limiting growth include a lack of knowledge of cultivar tolerance to winter damage and propagation techniques to produce planting stock for this region. The objective of this study was to determine the rooting response of potential cold-hardy cultivars (Frantoio, easy-to-root; Maurino, moderate-rooting; and Grignan, unknown rooting capacity) to growing media during fall propagation in Oregon. Two substrates were evaluated; 100% fine grade propagation perlite and 1:1 ratio of horticultural peat moss and fine grade propagation perlite by volume. On August 22, 2017, 64 three-inch cuttings of each cultivar were taken from an established orchard in Dallas, OR. On the same date, 32 cuttings of each cultivar were dipped in 3000 ppm IBA rooting hormone and planted in 38-cell, 6.67 cm trays containing the two media. The cuttings were then arranged in a heated greenhouse on benches with bottom heat and automated mist irrigation in a completely randomized design. Data was collected on February 6, 2018 by counting the number of roots per cutting and measuring total cutting root length. Frantoio had the greatest average root number (3), followed by Grignan (2), and then Maurino (1). Average root length was greater in Frantoio (25.1 cm), than in Maurino (10.0 cm), and Grignan (4.4 cm). Cuttings grown in the peat-perlite mix had a greater average number of roots for all cultivars (Frantoio 5, Grignan 4, and Maurino 2) compared to 100% perlite (Maurino and Frantoio 1, and none in Grignan). All cultivars also saw a higher rooting percentage in the peat-perlite mix. Grignan and Maurino both increased from 6.25% to 90.63% and 59.38% respectively, while Frantoio increased from 25.00% to 84.38%. As expected, initial results suggest that Frantoio is an easy-to-root cultivar, while Maurino is moderate-rooting; the results also suggest that the rooting capacity of Grignan is between Frantoio and Maurino. This study will be continued with three different timings (spring, summer, fall) beginning in spring of 2018 in order to determine seasonal variability of rooting.