Virgilio Gavicho Uarrota ● Profesor Asistente

[vc_section el_class="container mx-auto align-items-center circle--pattern" css=".vc_custom_1648956589196{padding-top: 3rem !important;}"][vc_row el_class="pb-5"][vc_column][vc_wp_custommenu nav_menu="6"][uoh_breadcrumb_component automatic_breadcrumb="true"][uoh_title_component title_dropdown="big" title_decorator="true"]{{title}}[/uoh_title_component][vc_column_text css=""]Avocado is a very nutritious and tasty fruit, characteristics that have caused a high global demand for this fruit. Increasing evidence of health benefits of the avocado is both driving increased consumption and stimulating research. Over the next few decades, a number of climate-related factors are expected to undergo significant change, leading to increases in CO2 and, depending on the region, temperature, humidity, salinity, flooding, and drought. Chile is expected to experience more frequent and severe flooding in the future due to climate change and sea level rise. By 2050, flooding in Chile could increase by an order of magnitude compared to the previous decade, while by the end of the century, Chile could experience more than 100 days of flooding each year. The frequency and severity of flooding will increase as sea levels rise. Under such predicted conditions, avocado orchards will suffer significant harm from waterlogging, which significantly will affect the growth, physiological performance and a general avocado production. The majority of avocado orchards are currently vulnerable to sporadic waterlogging as a result of climate change, either because of poor soil qualities or occasionally rising water tables. Waterlogging detrimentally affects avocado orchards at various levels. Reduced root and shoot growth due to soil oxygen depletion (plant-soil system), decreased transpiration rate, changes in the soil's oxidation-reduction status, decreased redox potential and ultimately decreased avocado production are the main effects of waterlogging on avocado. Climate change is increasing the frequency and severity of extreme weather events with flooding being the largest concern for Chile. Investigating how climate change factors combine with waterlogging stress, novel genes, and signaling components can provide useful insights into plant responses to waterlogging stress and future agricultural difficulties The species and occasionally the cultivar determine how long a plant may survive in a waterlogged condition. The rootstock (clonal or seedling rootstocks) used in the orchard may have an impact on the sensitivity to waterlogging. In this Project, it was hypothesized that: (1) Hass avocado grafted to different rootstocks (clonal or from seedling) may have a differential performance under waterlogging conditions and that the tolerance is driven by rootstock cultivar, stress severity, balance of oxidative stress and defense system at morpho-physiological, biochemical and molecular level and (2): Clonal o seedling rootstock influence Hass avocado responses to waterlogging by affecting root microbial community, carbon, nitrogen cycling and reduced soil components. Thus, the main objective of this proposal is to evaluate the effects of waterlogging on grafted Hass avocado to 04 different rootstocks (Dusa, Duke 7, Mexicola and Zutano) mainly used in the Central and South-Central region of Chile. A systematic fingerprinting analysis will be used in this project by integrating different tools for deep analysis (Chemo-Metabolomics, transcriptomics and metagenomics) and for monitoring changes in morpho-physiological and gas-exchange parameters, changes in plant-soil system by evaluating the composition and function of microbial communities within the pot soil in each treatment, the antioxidant defense system and reactive oxygen species, for better understanding the regulatory mechanisms of tolerance to waterlogging, identification of the potential genes regulating tolerance to waterlogging in Hass avocado and finally the selection of the rootstock with better agronomic performance. Four (4) different rootstocks will be used in this research (two hybrids from Mexican and Guatemalan races - Zutano and Dusa, two Mexican races - Mexicola and Duke 7) which will be grafted with the scion material collected from Hass avocado cultivar. Mexicola and Zutano Will be propagated by seeds; Duke 7 clonally propagated and clonal Dusa plantlets acquired in the national plant propagation nurseries due to protection of intellectual property. One year grafted Hass avocado on different rootstocks will be subjected to a waterlogging greenhouse experiment by submerging them in a plastic water tank with water level 5 cm above the soil Surface (140% field capacity) for 3, 6, 9, and 15 days against the control treatment (no waterlogging stress). Morphological, physio-biochemical and gas-exchange parameters, soil nutrient dinamics, function and composition of microbial community within the pot soil and sampling for transcriptomic analysis will then be performed. The results of this study are expected not only to provide more foundation into the agronomic, biochemical and molecular aspects associated to waterlogging of ‘Hass’ avocados grafted on different rootstocks but also provide potential biomarkers and genes involved in stress tolerance and select the best suited rootstocks for the current and the upcoming extreme climate change events, which may help to implement new Hass avocado production protocols that will reduce this predicted climate change problem in practice. This project will generate scientific and academic publications, extension and training of young researchers and will strengthen the network with national and international key partners. The findings will be also valuable for agronomists, plant physiologists, microbiologists and plant breeders to develop new avocado production protocols useful for waterlogging conditions that are predicted in Chile.[/vc_column_text][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649209804184{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5"][vc_row el_class="container mx-auto align-items-center p-md-0 pt-5"][vc_column el_class="p-0"][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649210787516{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5 pb-md-5"][vc_row el_class="container mx-auto align-items-center"][vc_column][/vc_column][/vc_row][/vc_section]

[vc_section el_class="container mx-auto align-items-center circle--pattern" css=".vc_custom_1648956589196{padding-top: 3rem !important;}"][vc_row el_class="pb-5"][vc_column][vc_wp_custommenu nav_menu="6"][uoh_breadcrumb_component automatic_breadcrumb="true"][uoh_title_component title_dropdown="big" title_decorator="true"]{{title}}[/uoh_title_component][vc_column_text css=""]Chile is one of the world’s largest producers of avocados contributing to its economy growth. Increased production and international competition, in addition to changes in production conditions, require Chilean producers to focus on developing competitive advantages. Recently, a new problem for Chilean Hass exported avocado has appeared and it is known as “black spot”, which caused rejections of up to 20%. The causes of this disorder are still unknown and sometimes associated to physiological or pathological disorders. The symptoms visible after storage are variable and the causes of the black spot symptoms are not known in the literature and there is no scientific consensus regarding the causesof black spot disorder in avocado. Preliminary work of our group at PUCV has analyzed fruit from orchards from different agro-ecological regions during the season 2017/2018 and recorded different incidence of black spot associated to climatological conditions and to the defense mechanisms of the fruit. A deep study for better understanding the causal factors of black spot is needed. In this project we hypothesized that black spot development in Hass avocado epidermis is driven by an imbalance of oxidative stress markers and antioxidant defense system. Thus, the main objectives of this proposal are to evaluate the balance/imbalance between oxidative stress markers and antioxidant defense systems of Hass avocado epidermis at different levels (enzymatic, transcriptomic and metabolomic) and its correlation to “black spot” development under different scenarios. We will use a metabolomics approach (GC-MS, HPLC and transcriptomics) to monitor changes in antioxidant defense system, reactive oxygen species and fruit quality parameters of stored Hass avocado combined with chemometrics for data integration. Fruits from 2 different orchards (high and no incidence of black spot based on historical data) during two subsequent harvests and two different seasons (early and late season) will be collected and stored in two different storage conditions for subsequent laboratory analyses. The results of this study are expected not only to provide more foundation into the biochemical processes associated to black spot of ‘Hass’ avocados but also provide potential ‘biomarkers’ involved in this disorder, which may help to implement postharvest protocols to reduce this problem in practice. Important variables or biomarkers found will be also used in model building to predict black spot development during storage. This project will generate scientific and academic publications, extension and training of young researchers and will strengthen the network with our national and international key partners. The findings of this project will help growers, agronomists, and packing houses achieve significant cost savings during postharvest handling and storage of avocados.[/vc_column_text][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649209804184{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5"][vc_row el_class="container mx-auto align-items-center p-md-0 pt-5"][vc_column el_class="p-0"][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649210787516{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5 pb-md-5"][vc_row el_class="container mx-auto align-items-center"][vc_column][/vc_column][/vc_row][/vc_section]

[vc_section el_class="container mx-auto align-items-center circle--pattern" css=".vc_custom_1648956589196{padding-top: 3rem !important;}"][vc_row el_class="pb-5"][vc_column][vc_wp_custommenu nav_menu="6"][uoh_breadcrumb_component automatic_breadcrumb="true"][uoh_title_component title_dropdown="big" title_decorator="true"]{{title}}[/uoh_title_component][vc_column_text css=""]Chile es uno de los líderes mundiales en exportación de fruta de palta, con aumentos de exportaciones cada vez mayores para mercados internacionales durante los últimos años. A pesar de los crecientes aumentos en las exportaciones de frutos, uno de los problemas en palta es conocido como mancha negra “Black spot”. La mancha negra se evidencia solo después del almacenamiento postcosecha prolongado, con la aparición de manchas oscuras circulares sobre el exocarpo del fruto y es detectado sólo tardíamente en los mercados de exportación provocando así el rechazo de la fruta. El presente proyecto tiene como objetivo entender las causas que originan la aparición de Black spot en frutos de palta var. Hass usando un enfoque integral de metabolómica y evaluaciones de calidad poscosecha. Hasta el momento, fueron cosechados frutos de 8 huertos (Ensenada, Pililén, Los Angeles, Resguardo, Inversiones, El Rancho, Quilhuica y Los Lilenes) correspondiente a cosecha temprana y 4 huertos (Resguardo, Pililén, Quilhuica y Los angeles) para cosecha tardía. Los frutos fueron evaluados a cosecha, a la salida de cámara de frio y en madurez de consumo. Los atributos evaluados correspondieron a: peso, color, presencia de daño lenticular, daño de pulpa, daño vascular, firmeza y materia seca. También se hicieron muestreos de epidermis de 5 frutos a la cosecha y cada 10 días de almacenamiento (0, 10, 20, 30 y 40 d) para analizar el sistema enzimático y no-enzimático de defensa y un análisis metabólico integral. Los resultados obtenidos hasta la fecha muestran que hay una disminución de firmeza y peso de frutos almacenados, con disminución más rápida a la salida de cámara hasta madurez de consumo. De todos huertos estudiados hasta la fecha no fue observado presencia de Black spot en los diferentes huertos. Muchos frutos estudiados presentaron presencia de lenticelosis, russet en la piel, picoteo y algunos con antracnosis. Frutos de Ensenada, Resguardo y Quilhuica almacenados por 25 días en aire regular presentaron alto porcentaje de lenticelosis. Frutos almacenados por 40 días presentaron un patrón similar, con alto porcentaje de lenticelosis para frutos provenientes del Resguardo, Ensenada y Los Angeles, y presencia de frutos con russet para Resguardo y Pililén. Frutos almacenados por 25 días de Ensenada maduraron en promedio en 8 días, Los Angeles entre 8 y 10 días, Pililén en 10 días, Quilhuica y Resguardo en 6 días. Cuando los frutos fueron almacenados por 40 días, frutos de Ensenada y Pililén maduraron en 5 días y aquellos de Los Angeles, Quilhuica y Resguardo maduraron en 3 días. La materia seca de los frutos de Ensenada (cosecha temprana) y Quilhuica (cosecha tardía) estuvo por debajo del mínimo de 23% y 27% respectivamente.[/vc_column_text][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649209804184{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5"][vc_row el_class="container mx-auto align-items-center p-md-0 pt-5"][vc_column el_class="p-0"][/vc_column][/vc_row][/vc_section][vc_section css=".vc_custom_1649210787516{background-color: #f6faff !important;}" el_class="p-md-0 pt-md-5 pb-md-5"][vc_row el_class="container mx-auto align-items-center"][vc_column][/vc_column][/vc_row][/vc_section]