Author
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RUFATO, LEO - University Of Santa Catarina |
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SILVA, PRICILA - University Of Santa Catarina |
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KRETZSCHMAR, AIKE - University Of Santa Catarina |
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BOGO, AMAURI - University Of Santa Catarina |
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MACEDO, TIAGO - University Of Santa Catarina |
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WELTER, JULIANA - University Of Santa Catarina |
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Fazio, Gennaro |
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PETRY, DAIANA - University Of Santa Catarina |
Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 8/10/2021 Publication Date: 8/30/2021 Citation: Rufato, L., Silva, P., Kretzschmar, A., Bogo, A., Macedo, T., Welter, J., Fazio, G., Petry, D. 2021. Geneva series rootstocks for apple trees under extreme replanting conditions in southern Brazil. Frontiers in Plant Science. https://doi.org/10.3389/fpls.2021.712162. DOI: https://doi.org/10.3389/fpls.2021.712162 Interpretive Summary: Replant disease complex occurs when older apple orchards are removed and replaced with new trees. This disease causes newly planted apple trees to be stunted and show low productivity. Geneva® rootstocks have displayed tolerance to replant disease in several experimental and commercial sites in the USA. These rootstocks were tested in several apple growing areas in Brazil under severe replant situations. The tolerance of Geneva® rootstocks to replant disease complex was observed in all plantings but featured different levels of productivity depending on individual rootstock, grafted variety (Gala or Fuji) and site. These experiments show the potential of Geneva® rootstocks to be applied in apple replant disease areas in other places in the world where fumigation with methyl bromide or similar fumigants cannot be used. Technical Abstract: The Geneva® rootstocks in Brazil are efficient in controlling vigor, are precocious and resistant to diseases. The objective of this study was to evaluate the performance of apple tree cultivars grafted on the Geneva® rootstocks in severe replant disease areas, by planting 60 days after the eradication of former orchards aged 15 years, in unfumigated soil. The experiments were implemented in 2017, in São Joaquim and Vacaria. The cultivars Gala Select and Fuji Suprema grafted onto rootstocks G.202, G.814, G.210 and G.213 in the Tall Spindle training system. In 2018/2019 total thinning was carried out to promote plant growth. In the São Joaquim area, partial thinning was carried out in the 2019/2020 harvest of the Gala, aiming to standardize production to approximately seven t.ha-1. In the Vacaria area, maximum plant production was prioritized, with no thinning in 2019/2020 for any of the cultivars. For both areas and cultivars, rootstocks were divided into two groups as to vigor, G.202 and G.213 were 40% less vigorous than G.210 and G.814. For Gala, the extreme non-fallow condition mainly affected the vigor and productivity of G.213 in both areas. At the end of two harvests the G.213 was 17% less productive than G.210, contrary to what is observed in areas where the fallow period is respected. However, G.213 confirmed its condition of greater productive efficiency, 27% higher than G.210. This suggests a perspective of forecasting production for the third crop higher for G.213 than for G.210. For Fuji , G.210 rootstock was the most productive in both areas. In São Joaquim, G.202 matched G.210 in productivity and efficiency as it sprouts better in colder regions. As the fruit quality, G.213 anticipated the maturation with fruits of larger size and higher SST in both areas and cultivars, making possible to anticipate the harvest. It was concluded that the non-fallow condition does not alter the relative differences in vigor and fruit quality between the rootstocks. However, notwithstanding the overall replant tolerance of these rootstocks it does reduce productivity by mainly affecting less vigorous rootstocks that need about three crops to overcome the allelopathic effect of the soil and start growing normally. |