Browsing by Author "Valdes Gomez, Hector"

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    Characterization of Botrytis cinerea and B. prunorum From Healthy Floral Structures and Decayed 'Hayward' Kiwifruit During Post-Harvest Storage
    (AMER PHYTOPATHOLOGICAL SOC, 2021) Riquelme, Danae; Aravena, Zdenka; Valdes Gomez, Hector; Latorre, Bernardo A.; Diaz, Gonzalo A.; Pablo Zoffoli, Juan
    Gray mold is the primary postharvest disease of 'Hayward' kiwifruit (Actinidia deliciosa) in Chile, with a prevalence of 33.1% in 2016 and 7.1% in 2017. Gray mold develops during postharvest storage, which is characterized by a soft, light to brown watery decay that is caused by Botrytis cinerea and B. prunorum. However, there is no information on the role of B. prunorum during the development and storage of kiwifruit in Chile. For this purpose, asymptomatic flowers and receptacles were collected throughout fruit development and harvest from five orchards over two seasons in the Central Valley of Chile. Additionally, diseased kiwifruits were selected after storage for 100 days at 0 degrees C and 2 days at 20 degrees C. Colonies of Botrytis sp. with high and low conidial production were consistently obtained from apparently healthy petals, sepals, receptacles, and styles and diseased kiwifruit. Morphological and phylogenetic analysis of three partial gene sequences encoding glyceraldehyde-3-phosphate dehydrogenase, heat shock protein 60, and DNA-dependent RNA polymerase subunit II were able to identify and separate B. cinerea and B. prunorum species. Consistently, B. cinerea was predominantly isolated from all floral parts and fruit in apparently healthy tissue and diseased kiwifruit. During full bloom, the highest colonization by B. cinerea and B. prunorum was obtained from petals, followed by sepals. In storage, both Botrytis species were isolated from the diseased fruit (n = 644), of which 6.8% (n = 44) were identified as B. prunorum. All Botrytis isolates grew from 0 degrees C to 30 degrees C in vitro and were pathogenic on kiwifruit leaves and fruit. Notably, B. cinerea isolates were always more virulent than B. prunorum isolates. This study confirms the presence of B. cinerea and B. prunorum colonizing apparently healthy flowers and floral parts in fruit and causing gray mold during kiwifruit storage in Chile. Therefore, B. prunorum plays a secondary role in the epidemiology of gray mold developing in kiwifruit during cold storage.
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    Leaf Morpho-Colorimetric Characterization of Different Grapevine Varieties through Changes on Plant Water Status
    (MDPI, 2021) Gutierrez Gamboa, Gaston; Torres Huerta, Nicolas; Araya Alman, Miguel; Verdugo Vasquez, Nicolas; Moreno Simunovic, Yerko; Valdes Gomez, Hector; Acevedo Opazo, Cesar
    (1) Background: Currently, some ampelographic methods are developing in order to identify grapevine varieties. For this purpose, morpho-colorimetric parameters in leaves have been analyzed by digital imagen analysis, but some environmental conditions may affect their determinations. (2) Methods: A research study was conducted to characterize leaf morpho-colorimetric parameters in five grapevine varieties growing under different plant water status and to discriminate them under these conditions. Leaves were collected in vines, and twelve leaf morpho-colorimetric and fractal dimension variables were assessed. (3) Results: Merlot presented the highest values of perimeter and area to perimeter ratio in leaves and higher leaf area than Chardonnay in both plant water conditions. Most of the leaf morpho-colorimetric variables allowed discriminating the grapevine varieties under the contrasted hydric conditions. Under non-water stress, Carmenere was not related to any measured parameters. Merlot was positively related to most of the leaf morphometric parameters, whereas Chardonnay presented the opposite behavior. RGB color system variables allowed discriminating the grapevine varieties under water stress conditions, and Sauvignon Blanc was not related to any measured parameter. Chardonnay and Pinot Noir were positively related to green color and negatively related to most of the leaf morphometric parameters, whereas Merlot showed the opposite behavior. (4) Conclusions: Leaf morpho-colorimetric and fractal dimension parameters were affected by plant water stress and more variables should be incorporated into the new ampelographic methods in order to characterize leaf morpho-colorimetric parameters of the different grapevine varieties more clearly.