Browsing by Author "Pablo Zoffoli, Juan"

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    Biological indicators to estimate the prevalence of gray mold and hairline cracks on table grapes cv. Thompson Seedless after cold storage
    (ELSEVIER SCIENCE BV, 2009) Pablo Zoffoli, Juan; Latorre, Bernardo A.; Rodriguez, Jessica; Aguilera, Jose M.
    Gray mold caused by Botrytis cinerea and hairline cracks are the major cold storage deterioration problems of table grapes (Vitis vinifera). Currently. table grapes are treated with sulfur dioxide (SO2), but this treatment does not sufficiently and consistently control B. cinerea. This is probably associated with latent infections that are poorly controlled with SO2, and to the increased berry propensity to develop hairline cracks following SO2 treatment. Therefore, the objective of this work was to obtain an early biological indicator to segregate grape lots at harvest to later develop according to the potential gray mold and hairline cracks. In this study, it was possible to distinguish gray mold infections at the stylar end, cheek, and base of the berries. However, on commercial SO2-treated lots of 'Thompson Seedless' table grapes, the occurrence of gray mold after cold storage was best predicted (Y= 0.45X, R-2 = 0.84, P < 0.001) by the number of gray mold infections that developed at the base of the berry of surface-disinfected (100 mu L L-1 SO2 for 1 h) grapes that were incubated at harvest in humid chambers (100% relative humidity) for 2 d at 0 degrees C then 5 d at 20 degrees C. Similarly, the occurrence of hairline cracks after cold storage was best predicted (Y= 1.48 + 0.51X, R-2 = 0.66, P= 0.0002) by the number of hairline cracks induced at harvest by dipping berries in 0.1 mol L-1 citric acid, pH 2, for 3 h at 20 degrees C, and stained with 0.1 mol L-1 methylene blue for 30 s at 20 degrees C. At harvest, cuticle content and porosity also predicted the occurrence of hairline cracks after cold storage. However, the cuticle content at harvest did not significantly predict gray mold occurrence at the berry base after cold storage. The occurrence of gray mold in commercial SO2-treated lots after cold storage was predicted by the prevalence of gray mold at the berry base at harvest. Similarly, the occurrence of hairline cracks after cold storage was predicted by the ability to induce hairline cracks at harvest by acidic pH. Further refinement in this research is needed before using these biological indicators to segregate table grape lots commercially. (C) 2008 Elsevier B.V. All rights reserved.
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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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    Eco-physiological response, water productivity and fruit quality of sweet cherry trees under high tunnels
    (ELSEVIER, 2021) Blanco, Victor; Pablo Zoffoli, Juan; Ayala, Marlene
    It is known that high tunnels modify sweet cherry physiological and agronomical response; however, horticultural practices such as irrigation have usually not been adapted to this cultivation system because there is no information about the effects of sweet cherry growing under this controlled environment on fruit tree water relations, water productivity and the possibility of saving water. The present work aims to assess the positive and negative impacts of irrigation regime and protective cultivation on tree water status, agronomical and physiological responses of the sweet cherry tree combination 'Santina'/'Colt' in Mediterranean dry weather conditions of Central Valley of Chile. Two treatments were imposed, plastic covered trees under multi-bay high tunnels and uncovered trees under open field conditions. Within each environment, two irrigation treatments were assayed, a conventional treatment, which followed growers' normal irrigation practices in the region, and a reduced irrigation treatment, which was irrigated the 75 % of the conventional treatment. High tunnel increased maximum air temperature, relative humidity and altered light radiation in relation to the environmental conditions in the open. Overall, trees under high tunnel showed higher values of soil matric potential, midday stem water potential (-0.8 MPa) and stomatal conductance (250 mmol m(-2) s(-1)). In the open, trees under reduced irrigation showed soil matric potential values below -150 kPa. Thus, soil water deficit affected tree water status, decreased vegetative growth and fruit size. Covered trees blossomed 7 d earlier than those in the open and were harvested 10 d earlier. Total tree yield did not show significant differences among treatments (11.9 kg tree(-1)); however, when the tree was divided into bottom and top canopy layers, it was found that the top layer of covered trees resulted in significantly lower yield. The cherries from the covered trees were significantly larger (10.4 g) and less firm (75 Durofel units) than those from uncovered trees (8.4 g and 82 Durofel units). The reduced irrigation strategy did not negatively affect tree yield or fruit quality of covered trees and increased water productivity compared with those irrigated with the conventional irrigation. The results obtained highlighted the possibility of decreasing the irrigated water applied to sweet cherry trees under high tunnels by 25 % compared to conventional irrigation.
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    Pruning effects on vegetative growth and fruit quality of 'Bing'/'Gisela (R) 5' and 'Bing'/'Gisela (R) 6' sweet cherry trees (Prunus avium)
    (PONTIFICIA UNIV CATOLICA CHILE, FAC AGRONOMIA INGENIERIA FORESTAL, 2012) Villasante, Macarena; Godoy, Soledad; Pablo Zoffoli, Juan; Ayala, Marlene
    M. Villasante, S. Godoy, J.P. Zoffoli, and M. Ayala. 2012. Pruning effects on growth and fruit quality of 'Bing'/'Gisela (R) 5' and 'ffingTGisela@6' sweet cherry trees (Prunus ovum:). Cien. Inv. Agr. 39(1): 117-126. Annual pruning is one of the most efficient ways to regulate crop load and renew fruiting wood in highly productive sweet cherry (Prunus (whim L.) combinations. Although Chilean growers did not previously prune cherry trees of more vigorous combinations, in recent years, the adoption of more dwarfing rootstocks and self-fertile cultivars has led to the inclusion of annual pruning as a practice in modem orchards. At first, this alteration in orchard management practices was not considered by growers, and thus, many of the initially established cherry orchards were not pruned as intensively as they should have been. As a consequence, many trees showed a reduction in fruit quality after 4 or 5 years of being planted, as they became overcropped and, consequently, registered reductions in their vegetative growth. There are only a few studies related to the effect of corrective pruning on dwarfing combinations that display an imbalance between reproductive and vegetative growth due to a reduction in the leaf area to fruit ratio of the tree. For this reason, the objective of this research was to study the effect of pruning in an orchard consisting of the dwarfing combinations 'Bing'/'Gisela (R) 5' ('Bing'/'GI (R) 5') and 'Bing'/'Gisela (R) 6' ('Bing'/'GI (R) 6'), which shown a reduction in vigor, fruit quality and yield. Trees of both combinations were treated with a medium intensity pruning in late winter (early September). Several vegetative (shoot length, leaf area of spurs and shoots, trunk cross sectional area) and reproductive (total yield per tree, fruit growth and quality) parameters were evaluated after pruning. One of the most important effects of pruning for both combinations was an increase in the total current season shoot (CSS) growth, which was 112.5 and 125.6% for 'Bing'/'GI (R) 5' and 'Bing'/'GI (R) 6', respectively. Additionally, the average shoot length increased by 820.0 and 325.4% for 'Bing'/'GI (R) 5' and 'Bing'/GI (R) 6', respectively. Furthermore. CSSs developed a higher leaf number in the pruned trees. There was no change in leaf number for reproductive spurs, but these had bigger leaves in the pruned trees, demonstrating increased total leaf area per spur. Additionally, pruning allowed crop load regulation and increased fruit size by 8.5 and 6.1% for 'Bing'/'GI (R) 5' and 'Bing'/'GI (R) 6', respectively. However, fruits from pruned trees showed a higher susceptibility to mechanical damage compared with unpruned trees of both combinations.