Phenolic variability in fruit from the ‘Arbequina’ olive cultivar under Mediterranean and Subtropical climatic conditions

In the present work, we compared the phenol content and composition of fruit from the ‘Arbequina’ cultivar in four Mediterranean (in Andalucía, Southern Iberian Peninsula) and two Sub-Tropical (Canary Islands) locations throughout the harvest period. Two Mediterranean and two Sub-Tropical locations were maintained with drip irrigation, while the remaining two Mediterranean locations were in dry farming. Water availability and harvest date seemed to play more important roles than air temperature on the phenolic content and most of the studied components. The variability associated with location was a result of the high values observed in the two Mediterranean locations in dry farming, with respect to the other four maintained with drip irrigation. Few differences were found among the four drip-irrigated locations, despite the fact that two were Mediterranean and the other two Sub-Tropical. In addition, a sharp decrease was observed during the harvest period for phenolic content and most of the phenolic compounds.

Compatibility between “Arbequina” and “Souri” Olive Cultivars May Increase Souri Fruit Set

The “Souri” olive cultivar, which is autochthonous to the eastern Mediterranean region, has been the major olive variety cultivated traditionally under rain-fed conditions in northern Israel. The aim of this study was to determine the optimal pollen donor for the olive cultivar Souri in order to maximize Souri fruit set. Artificial cross pollination of Souri flowers with several local varieties has identified the “Nabali” as the most efficient pollinizer of the Souri. However, further experiments using artificial cross pollination conducted with cultivars not common to this region have revealed the “Arbequina” as a more efficient pollinizer of the Souri cultivar than the Nabali. Based on a preliminary paternity analysis, the Nabali was identified as the dominant pollinizer of Souri trees in traditional olive orchards in the north of Israel. However, in a multi-variety orchard, molecular paternity analysis has shown Arbequina to be the most frequent pollinizer. We then tested, during two consecutive years, whether the presence of a pollen-producing Arbequina tree adjoining Souri trees in the field will increase their fruit set. We found that Souri fruit set was 8.36% when pollinized by an Arbequina tree in close proximity to them, significantly higher than the fruit set of 5.6% for Souri trees without the nearby Arbequina cultivar. On the basis of these trials, we expect that the yield of Souri orchards will improve if Arbequina trees are planted.

Fresh and Aromatic Virgin Olive Oil Obtained from Arbequina, Koroneiki, and Arbosana Cultivars

Three factors for the extraction of extra virgin olive oil (EVOO) were evaluated: diameter of the grid holes of the hammer-crusher, malaxation temperature, and malaxation time. A Box–Behnken design was used to obtain a total of 289 olive oil samples. Twelve responses were analyzed and 204 mathematical models were obtained. Olives from super-intensive rainfed or irrigated crops of the Arbequina, Koroneiki, and Arbosana cultivars at different stages of ripening were used. Malaxation temperature was found to be the factor with the most influence on the total content of lipoxygenase pathway volatile compounds; as the temperature increased, the content of volatile compounds decreased. On the contrary, pigments increased when the malaxation temperature was increased. EVOO from irrigated crops and from the Arbequina cultivar had the highest content of volatile compounds. Olive samples with a lower ripening degree, from the Koroneiki cultivar and from rainfed crops, had the highest content of pigments.

Rooting of semihardwood cuttings of olive: indolbutyric acid, calcium and Azospirillum brasilense

Nowadays the semihardwood cuttings of olive is the most used method to produce seedlings of this specie; however, it is necessary to improve the efficiency of this method to enable the intensive exploitation of this fruit crop and reduce the seedling production costs. Thus, two experiments were conducted concurrently in sand bed, under a canvased shelter of the State University of Western Paraná (Brazil) to evaluate the number and average length of roots per cuttings, the percentage of rooted cuttings, cuttings with callus and dead cuttings. In the first experiment cuttings of olive cultivars Arbequina, Maria da Fé and clone 2 were treated with IBA (3.0 g L-1) associated with calcium concentration at 0.0; 0.25; 0.50 and 1.0 mmol L-1, implanted in a completely randomized design in a split plot design, with four replications containing ten cutting each, under intermittent mist. For this experiment the Arbequina cultivar presented the highest average number of roots per cutting and the highest percentage of rooted cuttings, but Maria da Fé cultivar promoted the highest average of cuttings with callus. In the second experiment Clone 2 cuttings were submitted to calcium (0.5 mmol L-1) and IBA (3.0 g L-1), and substrate inoculation with Azospirillum brasilense bacterium, implanted in a completely randomized design containing three replications of ten cuttings each. In this experiment, the highest percentage of rooted cuttings was obtained for IBA (3.0 g L-1) + A. brasilense.

GROWING OLIVES IN TEXAS; REGULATION OF FLOWERING IN `ARBEQUINA'

Olives have not been commercially grown in Texas because earlier investigators considered Texas climate inappropriate for olive cultivation. No experimental investigations were conducted in Texas. Olives, however, grow in very diverse climatic conditions throughout the world, and >2000 cultivars of olives have been reported worldwide. To study temperature regulation of flowering in olives, relatively inexpensive growth chambers were developed. These walk-in type growth chambers can be made with about $7K where as costs of similar size commercial chambers could reach to $100K. Using these chambers we have discovered that flowering and fruiting in `Arbequina' cultivar of olives could be achieved under mild conditions with almost no typical chilling (<7 °C) hours. We postulated that it is the high daytime temperature that prevent flowering in olives in southern Texas rather than lack of chilling hours. Further experiments demonstrated that subjecting trees to 24 °C for 4 hours everyday during winter could significantly reduce flowering in Arbequina. It appeared that several sites near coastal Texas, particularly Galveston, may not experience high daytime temperatures and hence could be suitable for olive cultivation. Trees have now been planted in these sites, but serendipitously several olive trees, >25 years old, were found in Galveston that had been flowering and fruiting for years. Olive accessions have also shown adaptability to local climates at various other sites in Southern Texas. Our initial surveys of olives groves established during the last 4–6 years have revealed the existence of at least two trees with remarkable adaptability to Texas conditions. One of these trees had flowered and fruited in the Rio Grand Valley where earlier workers had predicted that flowering in olives will not occur. Thus, there appears some genetic diversity and clonal variations among limited number of existing olive trees in Texas that there is a hope for viable cultivations of olives in Texas. Clones from these trees have now been produced which will be planted at various locations within the Texas Valley to evaluate their performance in the next few years.