Mejora de olivo para resistencia a la verticilosis: evaluación de progenies y material silvestre

La Verticilosis del olivo (Olea europaea L.) causada por el hongo de suelo Verticillium dahliae Kleb., representa en la actualidad el mayor problema fitosanitario del olivar en muchas zonas de cultivo a nivel global. Para el control de la Verticilosis del olivo se recomienda un manejo integral de medidas preventivas y/o paliativas, de entre ellas, la más recomendada es el uso de variedades resistentes a la enfermedad. Sin embargo, un número muy reducido de variedades han exhibido cierto nivel de resistencia al desarrollo de síntomas ante la colonización de v.dahliae. Por este motivo, una nueva línea de trabajo se incorporó en el programa de mejora de olivo con el objetivo de obtener nuevas variedades que combinen buenas características agronómicas y altos niveles de resistencia al desarrollo de síntomas de la enfermedad. El primer objetivo de este trabajo fue obtener información sobre la heredabilidad de algunos caracteres agronómicos de interés en olivo con el fin de alcanzar una estrategia combinada de selección a la enfermedad. De este modo, 26 caracteres morfológicos y agronómicos fueron evaluados en progenies de polinización libre de olivo procedentes de 17 variedades españolas conservadas en la Colección Mundial de Variedades de Olivo del Centro IFAPA de Córdoba, España (Junta de Andalucía, CAP; Universidad de Córdoba, UCO; Instituto Andaluz de Formación Agraria y Pesquera, IFAPA), así como de los cultivares parentales. Diferencias significativas entre progenies fueron observadas en todos los caracteres evaluados y diferente nivel de heredabilidad fue obtenido para diferentes caracteres. La evaluación de la resistencia a la Verticilosis realizada en esta Tesis constituye, por tanto, una etapa avanzada dentro del programa de mejora de olivo del citado centro. Así, la evaluación inicial comentada antes permitió seleccionar 52 genotipos en base a sus características agronómicas interesantes. Las evaluaciones de la resistencia a la Verticilosis se realizaron además en 38 genotipos procedentes de tres cruzamientos de variedades conocidas de olivo: 'Changlot Real' x 'Dolce Agogia', 'Frantoio' x 'Arbosana' y 'Koroneiki' x 'Empeltre', presentando todas ellas al menos un parental categorizado en trabajos previos como resistente a la Verticilosis. Dichos genotipos se seleccionaron igualmente a partir de la evaluación agronómica de las progenies iniciales. Con el objetivo de diversificar el origen del material evaluado, se han incluído 64 genotipos con diferente origen genético: olivos silvestres o acebuches (Olea europaea subsp. europaea var. sylvestris) , nuevos genotipos procedentes de subspecies afines de Olea (Olea europaea subsp. guanchica) y genotipos procedentes de cruzamientos entre la variedad 'Picual' y dos acebuches seleccionados. Las plantas se inocularon por inmersión de las raíces con un aislado altamente virulento del pato tipo Defoliante de V. dahliae y después crecieron en condiciones controladas para evaluar la resistencia de los genotipos. Las variedades 'Picual' y 'Frantoio' se incluyeron como controles de enfermedad susceptible y resistente respectivamente, en los experimentos realizados. La reacción a la enfermedad también se evaluó en todos los parentales conocidos de los genotipos evaluados. Se ha desarrollado un Índice de Susceptibilidad Relativa (ISR o RSI en inglés) que aúna diferentes parámetros de enfermedad comúnmente utilizados. La colonización de la planta por el hongo se estimó mediante aislamientos de tejido aéreo y radicular. Entre todos los genotipos evaluados, ocho procedentes de polinización libre, diez genotipos procedentes de los cruzamientos dirigidos de olivo cultivado y trece de los procedentes de genotipos silvestre y subsp. guanchica, mostraron un nivel de resistencia al desarrollo de sÍnromas similar que 'Frantoio' (cultivar control resistente). El nivel de colonización de los genotipos por el hongo sugiere la implicación de posibles mecanismos de tolerancia ya que se han encontrado genotipos categorizados como resistentes similarmente colonizados que genotipos susceptibles. La asociación entre resistencia al desarrollo de síntomas y elevada colonización vascular no se halló entre los genotipos silvestres y se reprodujo sólo para una parte de los genotipos resistentes provenientes de cruzamientos dirigidos y polinización libre. El material evaluado en este trabajo se encuentra en crecimiento en fincas experimentales aunando diferentes objetivos: posibles futuras propagaciones de los genotipos de interés, continuar las evaluaciones paralelas del programa de mejora, usar esros genotipos como posibles genitores y/o patrones y aplicar metodologías moleculares si se corrobora su resistencia. Evaluar el nivel de resistencia a la enfermedad en campo naturalmente infestado por V dahliae permitirá en el futuro continuar los trabajos en el programa de mejora de olivo hasta el posible registro de nuevas variedades resistentes a la enfermedad

Irrigation Detection using Sentinel‐1 and Sentinel‐2 Time Series on Fruit Fields

En países caracterizados por climas áridos y semiáridos, el riego juega un papel importante porque reduce la pérdida de rendimiento afectada por el estrés hídrico. Sin embargo, la sobreexplotación del agua por parte del sector agrícola puede conducir a la escasez de recursos hídricos. Es por esto que la extensión de los campos de regadío ha requerido la implementación de diversas estrategias y políticas de riego para el ahorro de agua. La gestión eficaz del agua regional o de mayor escala depende de la demanda de riego estimada a partir de mapas de áreas irrigables o de estadísticas nacionales y regionales de áreas irrigadas, que a menudo son inexactas. Estos datos estadísticos no siempre son de calidad confiable porque: (i) generalmente no reflejan en el tiempo la distribución espacial de las áreas irrigadas y de secano, (ii) también cuando los agricultores no reportan el riego. En consecuencia, una distribución espacial más actualizada del área de riego es importante para garantizar la aplicación de políticas regionales de agua. Por lo tanto, el mapeo preciso de las áreas irrigadas es esencial. En este contexto, la teledetección proporciona métodos fiables para recuperar información agrícola útil a partir de sus registros derivados. El uso combinado de datos de observación de la tierra ópticos y de radar aumenta la probabilidad de detectar eventos de riego que pueden mejorar la precisión del mapa de riego. Es por ello que nos propusimos explotar Sentinel‐1 (VV y VH) y Sentinel‐2 (NDVI) de las Misiones Sentinel para clasificar los frutales de regadío de los de secano sobre un área de estudio situada en la región de Castilla La‐Mancha donde se encuentran árboles frutales como la vid, el almendro y el pistacho que están aumentando sus superficies alcanzando cerca del 31% de la superficie total de regadío en 2021. Esta expansión es consecuencia del aumento de los precios de la almendra y los bajos precios de los cereales en el mercado internacional lo que ha provocado la aparición de prácticas ilegales de riego que deben ser detectadas para garantizar una adecuada gestión de los recursos hídricos. Para obtener las series temporales de los índices derivados de las misiones espaciales Sentinel‐1 y Sentinel‐2, que constituyen los datos de entrada de los algoritmos empleados en la posterior clasificación que detecta las parcelas con los cultivos de interés, se ha desarrollado una herramienta que automatiza el uso de Sentinel‐Hub para calcular en el propio servicio y descargar únicamente los productos organizados por tiles para la región de interés y para toda la serie temporal, garantizando la repetibilidad espacial de cada píxel en todos los productos y fechas. La clasificación de parcelas de riego se realizó seleccionando el algoritmo de aprendizaje automático con mejor rendimiento entre todos los disponibles en la aplicación ʺClassification Learnerʺ de Matlab®. Nuestra metodología utilizada mostró resultados prometedores con una precisión general del 88,4% y, de hecho, la herramienta pudo detectar cuatro parcelas irrigadas que fueron clasificadas erróneamente como no irrigadas en la base de datos SIGPAC. Para evaluar estos resultados, aplicamos el método de detección de cambio del coeficiente de retrodispersión a escala de parcela

Genotype, environment and their interaction on olive

Resumen del trabajo presentado en la 6th International Conference on the Olive Tree and Olive Products, celebrada en Sevilla (España) del 15 al 19 de octubre de 2018.The wide olive genetic patrimony has revealed high variability for most of the agronomic and oil quality traits of interest in olive growing. Few studies, however, have addressed the interaction of this variability with the environment, a subject of particular interest considering the natural high instability of the Mediterranean climate and the challenge of the predicted climate change. The current work presents results on the interaction between genotype and environment from multi-environment trials of olive cultivars and breeding selections, planted in different edaphoclimatic conditions of Andalusia, Southern Peninsular Spain and Canary Islands. For most of the agronomic and oil quality characters evaluated (flowering phenology, flower quality, pattern of oil accumulation, fatty acid composition and phenol content and composition), significant genotype and environment effects have been observed. For example, olive cultivars grown in Tenerife under much milder winter temperatures than in the Iberian Peninsula showed substantially earlierflowering and oil accumulation. Only in the case of flowering phenology was no significant genotype effect found. Furthermore, a strong genotype x environment effect was highly consistent in all characters considered. Regarding resistance to disease, such as Verticillium wilt, the variability of results from both natural and artificial inoculations also tends to indicate a considerable environmental effect and the need for careful testing of disease evolution. All this information strongly suggests the necessity of comparative trials of olive cultivars for both adequate choice of cultivar and final selection in breeding programs

Design and evaluation of a mobile-based intervention for Maya adults during the COVID-19 pandemic

Introduction: The COVID-19 pandemic has had a direct impact on mental health. International organisations have emphasised the vulnerability of indigenous people. Digital Mental Health approaches deliver online therapy as an evidence-based, effective, and accessible treatment option for common mental health problems. However, the evidence regarding these approaches is limited in indigenous populations. The objective of this study is to describe the design, development, and evaluation of the efficacy of a self-applied online intervention regarding the psychological symptoms of depression, anxiety, and fear of COVID-19 in a sample of the Maya population. Method: A prospective longitudinal quantitative study was designed, where a single group was measured before and after receiving the online intervention. This study took place from April to September 2021 and consisted of six sessions delivered via WhatsApp in Spanish and Mayan. Results: The initial assessment was implemented with 82 participants who were evaluated using the Patient Health Questionnaire, Scale for Generalised Anxiety Disorder and the Fear of COVID-19 Scale; 18 participants remained in the intervention for the post-as-sessment. Statistical differences were observed in PRE and POST measures of depression and anxiety, but not in fear of COVID-19. Conclusions: This study produced positive results for the first online mental health intervention implemented in the Latin American indigenous population. Future studies might consider developing similar interventions for other indigenous communities in Latin America.</p

Anti-Spike antibodies 3 months after SARS-CoV-2 mRNA vaccine booster dose in patients on hemodialysis: the prospective SENCOVAC study

Background: Patients on hemodialysis are at high-risk for complications derived from coronavirus disease 2019 (COVID-19). The present analysis evaluated the impact of a booster vaccine dose and breakthrough severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections on humoral immunity 3 months after the booster dose. Methods: This is a multicentric and prospective study assessing immunoglobulin G anti-Spike antibodies 6 and 9 months after initial SARS-CoV-2 vaccination in patients on hemodialysis that had also received a booster dose before the 6-month assessment (early booster) or between the 6- and 9-month assessments (late booster). The impact of breakthrough infections, type of vaccine, time from the booster and clinical variables were assessed. Results: A total of 711 patients [67% male, median age (range) 67 (20-89) years] were included. Of these, 545 (77%) received an early booster and the rest a late booster. At 6 months, 64 (9%) patients had negative anti-Spike antibody titers (3% of early booster and 29% of late booster patients, P =. 001). At 9 months, 91% of patients with 6-month negative response had seroconverted and there were no differences in residual prevalence of negative humoral response between early and late booster patients (0.9% vs 0.6%, P =. 693). During follow-up, 35 patients (5%) developed breakthrough SARS-CoV-2 infection. Antibody titers at 9 months were independently associated with mRNA-1273 booster (P =. 001), lower time from booster (P =. 043) and past breakthrough SARS-CoV-2 infection (P <. 001). Conclusions: In hemodialysis patients, higher titers of anti-Spike antibodies at 9 months were associated with mRNA-1273 booster, lower time from booster and past breakthrough SARS-CoV-2 infectionThe present project has been supported by Fresenius Medical Care, Diaverum, Vifor Pharma, Vircell, Fundación Renal Iñigo Álvarez de Toledo and ISCIII FEDER funds RICORS2040 (RD21/0005

Olive breeding for Verticillium wilt resistance: evaluation of progenies and wild materials

The Verticillium wilt of olive (Olea europaea L.), caused by the soilborne fungus Verticillium dahliae Kleb., constitutes currently the major cultivation constraint in many olive growing areas. An integrated disease management strategy is recommended for Verticillium wilt of olive with preventive and/or palliative control including the use of resistant cultivars as one of the most efficient control measures. However, only a few traditional cultivars have showed high levels of disease resistance. For this reason, a new area of work in the olive breeding program was initiated aiming at obtaining new cultivars combining high levels of resistance to the development of disease symptoms and good agronomic characteristics. The first target in this work was to obtain information about the inheritance of the main agronomic traits in olive in order to make a subsequent combined strategy for selection to the disease. For that, 26 morphological descriptors and agronomic traits were evaluated in progenies coming from open-pollination of 17 Spanish cultivars of the World Olive Germplasm Bank (WOGP) of Andalusian Institute of Agricultural Research and Training (IFAPA) of C&oacute;rdoba (Spain) (Andalusian Regional Government, CAP; University of C&oacute;rdoba, UCO; Andalusian Institute of Agricultural Research and Training, IFAPA) and in their corresponding parents. Significant differences among progenies were observed for all the evaluated traits and different level of heritability estimated for different characters.Resistance of olive genotypes to Verticillium wilt was, therefore, evaluated in this work at an advanced phase into the olive breeding program. Thus, the above mentioned evaluation allowed to select 52 genotypes coming from open-pollination on the basis of their favorable agronomic performance. In addition, resistance to Verticillium wilt was also evaluated in 38 genotypes from three crosses: &lsquo;Changlot Real&rsquo; x &lsquo;Dolce Agogia&rsquo;, &lsquo;Frantoio&rsquo; x &lsquo;Arbosana&rsquo; and &lsquo;Koroneiki&rsquo; x &lsquo;Empeltre&rsquo;, including all of them as parent at least one cultivar previously categorized as resistant to the disease. These genotypes were also previously selected from the agronomic evaluation of the initial progenies.The potential of wild olives tree could represent new sources of resistance to Verticillium wilt in olive. We evaluated 64 genotypes from different genetic origin: wild olive trees (Olea europaea subsp. europaea var. sylvestris), genotypes belonging to related subspecie (Olea europaea subsp. guanchica) and genotypes coming from crosses between &lsquo;Picual&rsquo; and two selected wild olive trees.Plants were inoculated by dipping roots in a highly virulent defoliating pathotype isolate of V. dahliae and then screened under controlled conditions to test the resistance of the genotypes. &lsquo;Picual&rsquo; and &lsquo;Frantoio&rsquo; cultivars were included as susceptible and resistant controls respectively in the experiments. The reaction to the disease of known parent cultivars was also evaluated. A Relative Susceptibility Index (RSI), which summarized several usual disease parameters, was developed. Plant colonization by the fungus was also assessed in root and stem by isolates.Among all olive evaluated genotypes, eight from open-pollination, ten genotypes from the three selected crosses of cultivated olive and thirteen genotypes from wild or related subspecie, showed a resistance level to external development of symptoms similar than &lsquo;Frantoio&rsquo; (the control resistant cultivar).Genotypes colonization by the fungus led to suggest the possible involvement of tolerance mechanisms because some genotypes categorized as susceptible and resistant to development symptoms were colonized similarly. The association between resistance to development of symptoms and high vascular colonization was not found among the wild genotypes. This association was observed in some of the resistant genotypes from directed crosses and open-pollination.Plant materials evaluated in this work are currently growing in experimental field trials with differents aims: possible future propagations of the interesting genotypes, to complete agronomic evaluations of the breeding program, to use these genotypes as potential genitors in future breeding cycles and/or rootstock, and application of molecular methods if their resistance would be confirmed. Assess the disease&acute;s level in field naturally infested by V. dahliae would allow in the future to continue the works on the olive breeding program up to the possible registration new cultivars resistant to the disease.La Verticilosis del olivo (Olea europaea L.) causada por el hongo de suelo Verticillium dahliae Kleb., representa en la actualidad el mayor problema fitosanitario del olivar en muchas zonas de cultivo a nivel global. Para el control de la Verticilosis del olivo se recomienda un manejo integral de medidas preventivas y/o paliativas, de entre ellas, la m&aacute;s recomendada es el uso de variedades resistentes a la enfermedad. Sin embargo, un n&uacute;mero muy reducido de variedades han exhibido cierto nivel de resistencia al desarrollo de s&iacute;ntomas ante la colonizaci&oacute;n de V.dahliae. Por este motivo, una nueva l&iacute;nea de trabajo se incorpor&oacute; en el programa de mejora de olivo con el objetivo de obtener nuevas variedades que combinen buenas caracter&iacute;sticas agron&oacute;micas y altos niveles de resistencia al desarrollo de s&iacute;ntomas de la enfermedad.El primer objetivo de este trabajo fue obtener informaci&oacute;n sobre la heredabilidad de algunos caracteres agron&oacute;micos de inter&eacute;s en olivo con el fin de alcanzar una estrategia combinada de selecci&oacute;n a la enfermedad. De este modo, 26 caracteres morfol&oacute;gicos y agron&oacute;micos fueron evaluados en progenies de polinizaci&oacute;n libre de olivo procedentes de 17 variedades espa&ntilde;olas conservadas en la Colecci&oacute;n Mundial de Variedades de Olivo del Centro IFAPA de C&oacute;rdoba, Espa&ntilde;a (Junta de Andaluc&iacute;a, CAP; Universidad de C&oacute;rdoba, UCO; Instituto Andaluz de Formaci&oacute;n Agraria y Pesquera, IFAPA), as&iacute; como de los cultivares parentales. Diferencias significativas entre progenies fueron observadas en todos los caracteres evaluados y diferente nivel de heredabilidad fue obtenido para diferentes caracteres.La evaluaci&oacute;n de la resistencia a la Verticilosis realizada en esta Tesis constituye, por tanto, una etapa avanzada dentro del programa de mejora de olivo del citado centro. As&iacute;, la evaluaci&oacute;n inicial comentada antes permiti&oacute; seleccionar 52 genotipos en base a sus caracter&iacute;sticas agron&oacute;micas interesantes. Las evaluaciones de la resistencia a la Verticilosis se realizaron adem&aacute;s en 38 genotipos procedentes de tres cruzamientos de variedades conocidas de olivo: &lsquo;Changlot Real&rsquo; x &lsquo;Dolce Agogia&rsquo;, &lsquo;Frantoio&rsquo; x &lsquo;Arbosana&rsquo; y &lsquo;Koroneiki&rsquo; x &lsquo;Empeltre&rsquo;, presentando todas ellas al menos un parental categorizado en trabajos previos como resistente a la Verticilosis. Dichos genotipos se seleccionaron igualmente a partir de la evaluaci&oacute;n agron&oacute;mica de las progenies iniciales. Con el objetivo de diversificar el origen del material evaluado, se han inclu&iacute;do 64 genotipos con diferente origen gen&eacute;tico: olivos silvestres o acebuches (Olea europaea subsp. europaea var. sylvestris), nuevos genotipos procedentes de subspecies afines de Olea (Olea europaea subsp. guanchica) y genotipos procedentes de cruzamientos entre la variedad &lsquo;Picual&rsquo; y dos acebuches seleccionados.Las plantas se inocularon por inmersi&oacute;n de las ra&iacute;ces con un aislado altamente virulento del patotipo Defoliante de V. dahliae y despu&eacute;s crecieron en condiciones controladas para evaluar la resistencia de los genotipos. Las variedades &lsquo;Picual&rsquo; y &lsquo;Frantoio&rsquo; se incluyeron como controles de enfermedad susceptible y resistente respectivamente, en los experimentos realizados. La reacci&oacute;n a la enfermedad tambi&eacute;n se evalu&oacute; en todos los parentales conocidos de los genotipos evaluados. Se ha desarrollado un &Iacute;ndice de Susceptibilidad Relativa (ISR o RSI en ingl&eacute;s) que a&uacute;na diferentes par&aacute;metros de enfermedad com&uacute;nmente utilizados. La colonizaci&oacute;n de la planta por el hongo se estim&oacute; mediante aislamientos de tejido a&eacute;reo y radicular. Entre todos los genotipos evaluados, ocho procedentes de polinizaci&oacute;n libre, diez genotipos procedentes de los cruzamientos dirigidos de olivo cultivado y trece de los procedentes de genotipos silvestre y subsp. guanchica, mostraron un nivel de resistencia al desarrollo de s&iacute;ntomas similar que &lsquo;Frantoio&rsquo; (cultivar control resistente). El nivel de colonizaci&oacute;n de los genotipos por el hongo sugiere la implicaci&oacute;n de posibles mecanismos de tolerancia ya que se han encontrado genotipos categorizados como resistentes similarmente colonizados que genotipos susceptibles. La asociaci&oacute;n entre resistencia al desarrollo de s&iacute;ntomas y elevada colonizaci&oacute;n vascular no se hall&oacute; entre los genotipos silvestres y se reprodujo s&oacute;lo para una parte de los genotipos resistentes provenientes de cruzamientos dirigidos y polinizaci&oacute;n libre.El material evaluado en este trabajo se encuentra en crecimiento en fincas experimentales aunando diferentes objetivos: posibles futuras propagaciones de los genotipos de inter&eacute;s, continuar las evaluaciones paralelas del programa de mejora, usar estos genotipos como posibles genitores y/o patrones y aplicar metodolog&iacute;as moleculares si se corrobora su resistencia. Evaluar el nivel de resistencia a la enfermedad en campo naturalmente infestado por V. dahliae permitir&aacute; en el futuro continuar los trabajos en el programa de mejora de olivo hasta el posible registro de nuevas variedades resistentes a la enfermedad.Universidad de Córdoba. Programa de doctorado: Biociencias y Ciencias Agroalimentarias. Dirección: Lorenzo León Moreno (Investigador Titular IFAPA) y codirección: Dolores Rodríguez Jurado (Investigadora Titular IFAPA) Fecha de Lectura: 24/06/2015. Calificación: Sobresaliente (Cum laude). Mención Internacional

Validation of a fluorometer sensor for characterization of olive varieties and evaluation of fruit ripeness index with non-destructive measurement: preliminary results

Traditionally, the criteria for deciding the optimum time to harvest olives are related to the change in color of the fruit. Olive ripeness is caused by the degradation of chlorophyll together with the synthesis of other pigments such as anthocyanins. The oil content components have also been another indicator for taking the decision to harvest olives. The objective of this work is to obtain a decision support system based on a preliminary validation of the MULTIPLEX RESEARCH™, which is a hand-held multi-parameter optical sensor based on non-destructive leaf and fruit autofluorescence measurements. The MULTIPLEX RESEARCH™ sensor provides accurate and complete information on the physiological state of the plant. The equipment generates several indices related to the quantity of flavonoids, anthocyanins, chlorophyll and other fluorescence indices, among them those related to nitrogen nutrition (NBI®) and fruit quality (FERARI®). This instrument uses the fluorescence of plants to measure the polyphenols and chlorophyll compounds in vivo. In this preliminary study, it was possible to define significant differences between the profiles defined by the set of more than 30 indices generated in the analysis of fruits of 12 olive varieties, considering two ripening stages in each.Peer Reviewe

Validation of a fluorometer sensor for characterization of olive varieties and evaluation of fruit ripeness index with non-destructive measurement: preliminary results

Traditionally, the criteria for deciding the optimum time to harvest olives are related to the change in color of the fruit. Olive ripeness is caused by the degradation of chlorophyll together with the synthesis of other pigments such as anthocyanins. The oil content components have also been another indicator for taking the decision to harvest olives. The objective of this work is to obtain a decision support system based on a preliminary validation of the MULTIPLEX RESEARCH™, which is a hand-held multi-parameter optical sensor based on non-destructive leaf and fruit autofluorescence measurements. The MULTIPLEX RESEARCH™ sensor provides accurate and complete information on the physiological state of the plant. The equipment generates several indices related to the quantity of flavonoids, anthocyanins, chlorophyll and other fluorescence indices, among them those related to nitrogen nutrition (NBI®) and fruit quality (FERARI®). This instrument uses the fluorescence of plants to measure the polyphenols and chlorophyll compounds in vivo. In this preliminary study, it was possible to define significant differences between the profiles defined by the set of more than 30 indices generated in the analysis of fruits of 12 olive varieties, considering two ripening stages in each.Peer ReviewedPostprint (published version

The contribution of fruit and leaves to the dynamic response of secondary branches of orange trees

The current commercial technologies for mass harvesting fruit are based on the application of forced vibration to the tree, which is transmitted to the fruits causing their detachment. The dynamic behaviour of the plant under forced vibration is of special interest to improve the design and use of the machinery. The objective of this work is to determine the effect of fruit and leaves on the dynamic response of the citrus branch. In this study, 22 secondary branches of 'Valencia' sweet orange trees were tested by applying forced vibration and measuring the response of the branches with triaxial accelerometers. The branches were tested in three stages: in-fruit branch, out-of-fruit branch and out-of-leaf branch. Three natural frequency values were identified in the branches, and were established as 2, 7 and 11 Hz. Acceleration transmissibility along the branch decreased as vibration frequency increased. The acceleration transmission values were highest for the first natural frequency, were up to 1.3-fold in the out-of-fruit branch and up to 4.6-fold in the out-of-leaf branch. The presence of fruits on the branch did not modify the branch natural frequency values but did slightly reduce the values of acceleration transmissibility. However, the presence of leaves on the branches had a double effect, reducing the first natural frequency and drastically damping acceleration transmissibilit

Optimal spatial and temporal replications for reducing environmental variation for oil content components and fruit morphology traits in olive breeding

UMR AGAP - équipe AFEF - Architecture et fonctionnement des espèces fruitièresThe need for new improved cultivars adapted to modern cultivation techniques and changing climatic environment requires genetic studies able to provide a better understanding of the phenotypic variance decomposition into genetic and environmental variances. In perennial crops, this decomposition requires evaluations carried out among years, trees within a genotype, samples within a tree and their interactions. The aim of this study was to perform such a detailed variance analysis of oil content components (fruit fresh weight-FFW, fruit moisture-FM, oil content on both fresh-OCFFW and dry-OCFDW basis) and fruit morphology traits (fruit maximum diameter-FMD and fruit circularity-FC) in an olive progeny issued from the cross ‘Oliviere’ × ‘Arbequina’. A total of 106 genotypes from this progeny, together with the parents cultivars, were evaluated over two consecutive years in two trees/genotype, and three samples/tree for oil content components and 30 samples/tree for fruit morphology traits. Two dataset were considered during analysis. The first one, including a limited number of genotypes without any missing data, was fully balanced and ANOVA was applied for variance components estimation from expected mean squares. The second dataset contained the full unbalanced information of the 106 genotypes and mixed linear models were built following to the same statistical model. Both analyses showed that variance among genotypes (σ G 2 ) was the main contributor to total variance for FFW, OCFFW and OCFDW and variance among years (σ Y 2 ) for FM. Residual error effect (σ ε 2 ) was the main contributor for morphology traits, whereas variance associated with the genotype × year interaction (σ GY 2 ) and tree × year interaction (σ TY 2 ) represented also important variance components for most traits, and variance among trees within a genotype (σ T 2 ) was negligible. Consistently, the mean broad sense heritabilities (H²) showed the lowest values for FM (0.40) and the highest values for OCFFW (0.94). An estimation of heritability and environmental variation under varying numbers of years and tree replications revealed that including more yearly replications could be more effective than adding trees replications. Finally, this study provides a global view of adequate spatial and temporal replications required to accurately develop criteria for both conventional and marker-assisted selection on fruit traits from olive crossing progenies, and more generally in fruit trees