Browsing by Author "Blanco, Victor"

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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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    Study of Mineral Composition and Quality of Fruit Using Vascular Restrictions in Branches of Sweet Cherry
    (MDPI, 2023) Quiroz, Maria Paz; Blanco, Victor; Zoffoli Guerra, Juan Pablo; Ayala, Marlene
    Calcium (Ca) and carbohydrate (CHO) supply in sweet cherry have been associated with fruit quality at harvest and during storage. There is little published information integrating CHO and Ca availability and distribution in sweet cherry and their effects on fruit quality. Accordingly, in the 2019-20 season, vascular restrictions were imposed on the phloem (girdling, G, stopping phloem flow) and xylem (transverse incision, S, cutting 50% of xylem cross-section area) of individual vertical branches of the sweet cherry combination 'Lapins'/Colt trained as Kym Green Bush system to modify mineral and CHO composition in fruit and associate such changes with quality at harvest and storage. The girdling to the phloem was used to induce changes in CHO distribution. The transverse incision to the xylem was a tool to modify Ca distribution. Five treatments (TR) were implemented: TR1-CTL = Control (without vascular restriction), TR2-G, at its base, TR3-G + G: at its base, and G further up at the change of year between the second and the third years of growth TR4--S and TR5-S + G. The vegetative (i.e., shoot and leaf growth), reproductive (i.e., fruit set and yield) development and stomatal conductance were monitored. Each branch was divided into the upper (1-and 2-year-old wood) and the lower (3-and 4-year-old wood) segments of the restriction applied. The quality and mineral composition (Ca, Mg, K, and N) of fruit borne on each segment were measured at harvest. The upper segment of TR3-G + G branches were harvested 10 d before the lower segment. The fruit from the upper segment of TR3-G + G was the largest, the sweetest, and had the higher titratable acidity concentration. However, fruits of this segment were the softest, had the lowest Ca concentrations, and had the highest ratios of N:Ca and K:Ca, compared with the other TRs. TR3-G + G branches developed the highest number of lateral current season shoots including shoots below the second girdling in the lower segment of the branch. This vegetative flow of growth would explain the mineral unbalance produced in the fruit from the upper segment of the branch. TR2-G did not register changes in fruit quality and mineral concentration compared with TR1-CTL. Surprisingly, the fruit from the branches with xylem restriction did not show changes in Ca concentration, suggesting that the xylem stream was enough to supply the fruit in branches without lateral shoot development. Fruit firmness was positively related to fruit Ca concentration and negatively related to the ratios of K:Ca and N:Ca.