Person: Royo Díaz, José Bernardo
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
Royo Díaz
First Name
José Bernardo
person.page.departamento
Agronomía, Biotecnología y Alimentación
ORCID
0000-0003-1146-4989
person.page.upna
32
Name
4 results
Search Results
Now showing 1 - 4 of 4
Publication Open Access Sampling stratification using aerial imagery to estimate fruit load in peach tree orchards(MDPI, 2018) Miranda Jiménez, Carlos; Santesteban García, Gonzaga; Urrestarazu Vidart, Jorge; Loidi Erviti, Maite; Royo Díaz, José Bernardo; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta ElikaduraA quick and accurate sampling method for determining yield in peach orchards could lead to better crop management decisions, more accurate insurance claim adjustment, and reduced expenses for the insurance industry. Given that sample size depends exclusively on the variability of the trees on the orchard, it is necessary to have a quick and objective way of assessing this variability. The aim of this study was to use remote sensing to detect the spatial variability within peach orchards and classify trees into homogeneous zones that constitute sampling strata to decrease sample size. Five mature peach orchards with different degrees of spatial variability were used. A regular grid of trees was established on each orchard, their trunk cross-sectional area (TCSA) was measured, and yield was measured as number of fruits/tree on the central tree of each one of them. Red Vegetation Index (RVI) was calculated from aerial images with 0.25 m pixel -1 resolution, and used, either alone or in combination with TCSA, to delineate sampling strata using cluster fuzzy k-means. Completely randomized (CRS) and stratified samplings were compared through 10,000 iterations, and the Minimum Sample Size required to obtain estimates of actual production for three quality levels of sampling was calculated in each case. The images allowed accurate determination of the number of trees, allowing a proper application of completely randomized sampling designs. Tree size and the canopy density estimated by means of multispectral indices are complementary parameters suitable for orchard stratification, decreasing the sample size required to determine fruit count up to 20–35% compared to completely randomized samples.Publication Open Access Evaluating the influence of the microsatellite marker set on the genetic structure inferred in Pyrus communis L.(Public Library of Science, 2015) Urrestarazu Vidart, Jorge; Royo Díaz, José Bernardo; Santesteban García, Gonzaga; Miranda Jiménez, Carlos; Producción Agraria; Nekazaritza EkoizpenaFingerprinting information can be used to elucidate in a robust manner the genetic structure of germplasm collections, allowing a more rational and fine assessment of genetic resources. Bayesian model-based approaches are nowadays majorly preferred to infer genetic structure, but it is still largely unresolved how marker sets should be built in order to obtain a robust inference. The objective was to evaluate, in Pyrus germplasm collections, the influence of the SSR marker set size on the genetic structure inferred, also evaluating the influence of the criterion used to select those markers. Inferences were performed considering an increasing number of SSR markers that ranged from just two up to 25, incorporated one at a time into the analysis. The influence of the number of SSR markers used was evaluated comparing the number of populations and the strength of the signal detected, and also the similarity of the genotype assignments to populations between analyses. In order to test if those results were influenced by the criterion used to select the SSRs, several choosing scenarios based on the discrimination power or the fixation index values of the SSRs were tested. Our results indicate that population structure could be inferred accurately once a certain SSR number threshold was reached, which depended on the underlying structure within the genotypes, but the method used to select the markers included on each set appeared not to be very relevant. The minimum number of SSRs required to provide robust structure inferences and adequate measurements of the differentiation, even when low differentiation levels exist within populations, was proved similar to that of the complete list of recommended markers for fingerprinting. When a SSR set size similar to the minimum marker sets recommended for fingerprinting it is used, only major divisions or moderate (FST>0.05) differentiation of the germplasm are detected.Publication Open Access Severe trimming and enhanced competition of laterals as a tool to delay ripening in Tempranillo vineyards under semiarid conditions(Université de Bordeaux, 2017) Santesteban García, Gonzaga; Miranda Jiménez, Carlos; Urrestarazu Vidart, Jorge; Loidi Erviti, Maite; Royo Díaz, José Bernardo; Producción Agraria; Nekazaritza Ekoizpena; Gobierno de Navarra / Nafarroako GobernuaAim: An advance in grapevine phenological stages (including ripening) is occurring worldwide due to global warming and, in the hottest seasons, already results in a lack of synchrony between sugar and phenolic ripeness, leading to unbalanced wines. In order to cope with this fact, a general effort is being made by researchers and growers aiming at delaying ripening through cultural practices, particularly under warm growing conditions, where these effects are more deleterious. The aim of this work is to evaluate to which extent severe trimming and enhanced competition of laterals can delay ripening in Tempranillo vineyards under semiarid conditions. Methods and results: The experiment took place during two consecutive seasons in Traibuenas (Navarra, Spain) in a cv. ‘Tempranillo’ vineyard trained to a vertical shoot positioned (VSP) spur-pruned bilateral cordon. Severe mechanical pruning was performed ca. 3 weeks after fruit-set in order to reduce leaf-to-fruit ratio, and in the trimmed plants, three irrigation doses were applied until harvest aiming at enhancing lateral growth, hypothesized to compete with ripening. All measurements were performed in six 10-vine replicates per treatment. Trimming significantly reduced leaf area and yield, resulting in higher water availability in trimmed plants. The whole ripening process was delayed by trimming: mid-veraison was delayed by about 5 days, and the delay in sugar accumulation and acid degradation was longer, differences being more marked in malic than in tartaric acid concentration. The use of increased irrigation levels compensated the losses in yield caused by trimming, enhanced laterals’ growth and implied an additional delay in ripening. Conclusion: trimming and increased irrigation had an additive effect in terms of delaying ripening, and they can be used jointly when that delay is needed. Significance and impact of the study: this study proves the potentiality of the joint use of trimming and increased irrigation to delay ripening, although it is necessary to analyze the implications the obtained delay has on other quality aspects. The lower anthocyanin and phenolic values observed in trimmed vines were not solely due to delayed ripening, as lower values were observed even when data were compared for a given total soluble solid content.Publication Open Access Evaluation of the agronomic performance of 'Syrah' and 'Tempranillo' when grafted on 12 rootstocks(Julius Kühn Institute (JKI), 2019) Marín Ederra, Diana; García, R.; Eraso Zabalegui, Javier; Urrestarazu Vidart, Jorge; Miranda Jiménez, Carlos; Royo Díaz, José Bernardo; Abad Zamora, Francisco Javier; Santesteban García, Gonzaga; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Gobierno de Navarra / Nafarroako Gobernua; Universidad Pública de Navarra / Nafarroako Unibertsitate PublikoaBeyond pest resistance, rootstocks significantly influence the performance of grapevine varieties. However, the effect of the rootstock is strongly affected by its interaction with the environment, and it is therefore necessary to evaluate their influence in a particular terroir. With the aim of evaluating the influence of 12 rootstocks on the agronomic performance of 'Syrah' and 'Tempranillo', a trial was established in 2011 and 2012 in Miranda de Arga (Navarra, Spain), under the typical environmental conditions of the Ebro Valley. Growth and yield, as well as industrial and phenolic maturity parameters were analysed during four consecutive seasons (2015-2018). Most rootstocks showed a similar performance with both varieties, not always following the trends reported in bibliography, which highlights the relevance of studying rootstocks in different conditions. 3309 C was the rootstock conferring the highest vigour, whereas the lowest were provided by 420 A MGt and 'Fercal'. The implications on grape composition were much more diverse, and were partially conditioned by yield. Results were obtained during the four first harvests of the vineyard, and could therefore change to some extent as the vineyard reaches stability.