Verdial De Research Articles

Machine learning unveils the action of different endogenous phenolic compounds present or formed along the rooting development in olive stem cuttings

Changes in the endogenous phenolic content of plant rooting could be influenced by genotype, hormones, or the interaction of both factors, thus modifying the plant rooting capacity/ability along the rooting development. In this study, the combined effects of IBA treatment and cultivar capacity on the rooting development of olive cuttings were modeled by the temporary assessment of simple and total phenolic content (TPC). Rooting ability and phenolic profile were monitored. Results indicated the lowest cumulative rooting in `Lechin-de-Sevilla´, and the highest rooting speed during the first days of the trial in high-rooting cultivars (‘Verdial-de-Huévar’ and ‘Arbequina’). A total of 14 phenolic compounds comprising phenolic acids and aldehyde (8), flavonoids (5), and a glycosylated seco-iridoid were quantified in rooted olive cuttings. Most of the phenolics presented a significant higher concentration in the ‘Lechin-de-Sevilla’ cultivar, except for the ferulic acid and luteolin, as well the TPC that varied as did the rooting parameter. At the end of the rooting trial (60 days), luteolin in `Verdial de Huévar’ and `Gordal sevillana’ cultivars and ferulic acid in `Lechin de Sevilla’ were the phenolics exclusively found in the highest concentrations. Time did not affect vanillin and oleuropein, although in the case of high-rooting cultivars, values for these compounds were almost constant, while in low- or medium-rooting cultivars, by general, increased or decreased, respectively. The Random Forest algorithm allowed to predict from a complex number of variables, which affected the rooting ability of olive cuttings independently of the cultivar and auxin treatment, finding that luteolin was the best indicator over time.

Variability in Susceptibility to Anthracnose in the World Collection of Olive Cultivars of Cordoba (Spain).

Anthracnose of olive (Olea europaea ssp. europaea L.), caused by Colletotrichum species, is a serious disease causing fruit rot and branch dieback, whose epidemics are highly dependent on cultivar susceptibility and environmental conditions. Over a period of 10 years, there have been three severe epidemics in Andalusia (southern Spain) that allowed us to complete the assessment of the World Olive Germplasm Bank of Córdoba, one of the most important cultivar collections worldwide.A total of 308 cultivars from 21 countries were evaluated, mainly Spain (174 cvs.), Syria (29 cvs.), Italy (20 cvs.), Turkey (15 cvs.), and Greece (16 cvs.). Disease assessments were performed using a 0–10 rating scale, specifically developed to estimate the incidence of symptomatic fruit in the tree canopy. Also, the susceptibility of five reference cultivars was confirmed by artificial inoculation. Because of the direct relationship between the maturity of the fruit and their susceptibility to the pathogen, evaluations were performed at the end of fruit ripening, which forced coupling assessments according to the maturity state of the trees. By applying the cluster analysis to the 308 cultivars, these were classified as follows: 66 cvs. highly susceptible (21.4%), 83 cvs. susceptible (26.9%), 66 cvs. moderately susceptible (21.4%), 61 cvs. resistant (19.8%), and 32 cvs. highly resistant (10.4%). Representative cultivars of these five categories are “Ocal,” “Lechín de Sevilla,” “Arbequina,” “Picual,” and “Frantoio,” respectively. With some exceptions, such as cvs. Arbosana, Empeltre and Picual, most of the Spanish cultivars, such as “Arbequina,” “Cornicabra,” “Hojiblanca,” “Manzanilla de Sevilla,” “Morisca,” “Picudo,” “Farga,” and “Verdial de Huévar” are included in the categories of moderately susceptible, susceptible or highly susceptible. The phenotypic evaluation of anthracnose reaction is a limiting factor for the selection of olive cultivars by farmers, technicians, and breeders.

Identification of some spanish olive cultivars using image processing techniques

The aim of this research was to identify some Spanish olive cultivars using image processing techniques. For this purpose, Lechin De Granada, Arbequina, Picual, Verdial De V-M, Picudo, Hojiblanca and Empeltre Olive cultivars were identified utilizing the image processing and analysis techniques. Therefore, images of olives taken as 300 dpi with the 2896×1944 pixels, were captured using a DSLR camera, and evaluations of pixels were used for considering the pixel distribution and dimension measurements. LabVIEW Vision Assistant v2013 (NI) and Image j (NIH) software were used for image analysis procedures. Artificial Neural Network analysis were used to assess information of the length, width and color data results obtained from the fruits and stones (olive stones). All cultivars were identified. In addition, different classification techniques were applied to the olive stone and fruit data with the help of SPSS v22. Clementine v12 was used as a data mining software package from SPSS. The cultivars were identified 90% from dimensions with Artificial Neural Networks.

Assessing the Susceptibility of Olive Cultivars to Anthracnose Caused by Colletotrichum acutatum.

Selected olive (Olea europaea) cultivars were tested in the field and laboratory for their relative susceptibility to anthracnose caused by Colletotrichum acutatum. A rating scale to assess fruit-rot incidence in naturally infected trees was validated by comparing ratings with direct counts of affected fruit. Fruit-rot incidence varied greatly among 20 cultivars and was correlated with the severity of branch dieback symptoms that developed after fruit-rot epidemics. For determining whether artificial inoculation can be used to predict anthracnose susceptibility in the orchard, detached fruit of 12 cultivars were inoculated with C. acutatum and fruit-rot severity was assessed periodically. Progress of disease severity over time fit the logistic function for all cultivars. The best correlation between fruit-rot incidence in the field and disease severity on inoculated fruit was obtained using a disease susceptibility index that integrated the maximum disease progress rate and the estimated time to reach 50% disease severity. Based on field observations and laboratory data on susceptibility to anthracnose, 21 cultivars were classified into three groups: highly susceptible (Cornicabra, Hojiblanca, Lechín de Sevilla, Manzanilla de Sevilla, Morona, Ocal, Picudo, and Verdial de Huévar); moderately susceptible (Arbequina, Arbosana, Morrut, Pajarero, and Villalonga); and resistant (Blanqueta, Empeltre, Frantoio, Koroneiki, Leccino, Morona-D, Picual, and Razzola). The assessment method may be useful to screen olive cultivars for anthracnose resistance.