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An experiment was carried out to determine when to initiate training potted rooted cuttings of olive (Olea europaea L.), so that tall and well developed nursery trees could be produced in an 8-month growing season. Initiating training to single shoot when average height of tallest shoots was 38 cm (15.0 inches) produced 1-m (3.28-ft) tall nursery trees in 7.5 months, with training restricted to the last 2.5 months. Taller plants [1.17 m (3.84 ft)] and some lateral shoots growing above 1 m were produced following another 0.5 month of growth. Five training months were needed to produce 1.43-m (4.69-ft) trees if training was initiated when main shoots were only 16 cm (6.3 inches). Initiating training at the beginning of the growing season did not produce significantly taller trees. Untrained plants only reached a height of 69 cm (27.2 inches) at the end of the test period.
Several experiments showed that whole, unmilled olives (Olea europaea L.) could be dehydrated in 42 hours in a forced-air oven at 105 °C (221 °F), so that they could be used in determining their oil content in a nuclear magnetic resonance (NMR) analyzer. After confirming that the NMR and the official Soxhlet methods estimate the same oil percentages in milled olives, linear regression analysis also showed that NMR provides the same oil percentage results with milled and unmilled fruit. This new method avoids sample manipulation before dehydrating the fruit, making it possible to work with olive samples weighing as little as 70 g (2.47 oz). It allows for processing a large number of samples in a short period of time and may be also used with unmilled fruit flesh. The method is also very useful for screening genotypes, either from germplasm banks or progenies from olive breeding programs, and for evaluating cultivars in comparative trials.
The resistance of 26 olive (Olea europaea L.) cultivars to the defoliating pathotype of Verticillium dahliae Kleb. was evaluated in experiments under controlled conditions by stem puncture inoculation. The area under disease progress curve with reference to the maximum value potentially reached over the assessment period (AUDPCP), calculated from the symptom severity values (0–4 rating scale), was the main parameter for assessing resistance, and the percentage of dead plants (PDP), the final mean symptom severity (FMS), and the disease recovery were used as additional parameters. Five cultivars were catalogued as extremely susceptible showing values of AUDPCP, PDP, and FMS higher than 70%, 50%, and 3.0, respectively. Six other cultivars exhibited AUDPCP values ranging from 50% to 70% and FMS higher than 3.0 and were classified as susceptible. A group of 11 cultivars, including ‘Koroneiki’, was moderately susceptible with AUDPCP ranging from 31% to 50%. Finally, ‘Frantoio’, ‘Grosal de Albocafer’, ‘Kato Drys’, and ‘Manzanilla Picúa’ showed maximum AUDPCP values of 22%, no dead plants, and slight symptom severity, being classified as resistant. Stem puncture inoculation was an effective tool for identifying resistance in olive cultivars, but a reduction or a delay in the disease symptom expression of plants was observed regarding the symptom progress observed in plants root dip-inoculated in previous works of resistance assessment. These differences were more pronounced in susceptible than in resistant cultivars.