Articles
Effect of foliar calcium application on senescent breakdown in ‘Summerred’ apple fruit
Article number
1458_33
Pages
251 – 258
Language
English
Abstract
The mid-early-ripening cultivar ‘Summerred’ is popular among consumers and widely grown in Norway.
However, ‘Summerred’ fruit is prone to rapid softening and development of senescence-related disorders, especially senescent breakdown.
Calcium can have a significant role in maintaining firmness and delaying senescence of fruits.
In a two-year study, foliar application of calcium chloride (CaCl2) was conducted six times, with varying weather conditions between the growing seasons.
Fruit was harvested at optimal commercial maturity and stored at 4°C for either 6 or 9 weeks, followed by simulated shelf-life conditions at 20°C. Ethylene levels were monitored during storage to detect ripening discrepancies.
At harvest, CaCl2-treated fruit exhibited significantly lower ethylene production compared to untreated fruit, although no differences were observed at the end of the storage period.
Senescent breakdown showed significant variability between the two seasons, with an incidence of up to 15% in the first season and nearly no incidence in the second.
Senescent breakdown increased with storage duration but was unaffected by foliar CaCl2 application.
Real-time PCR analysis of fruit flesh samples revealed increased expression of polygalacturonase and
-galactosidases genes after storage, indicating their involvement in apple softening.
Notably, there were no differences in gene expression between CaCl2-treated and untreated fruit after storage.
Expression patterns of genes involved in ethylene biosynthesis at harvest were different between the two seasons.
Higher expression was observed in the year with greater disorder development, indicating greater maturity at harvest.
There were no significant differences in the Streif index between the two years.
However, ‘Summerred’ fruit is prone to rapid softening and development of senescence-related disorders, especially senescent breakdown.
Calcium can have a significant role in maintaining firmness and delaying senescence of fruits.
In a two-year study, foliar application of calcium chloride (CaCl2) was conducted six times, with varying weather conditions between the growing seasons.
Fruit was harvested at optimal commercial maturity and stored at 4°C for either 6 or 9 weeks, followed by simulated shelf-life conditions at 20°C. Ethylene levels were monitored during storage to detect ripening discrepancies.
At harvest, CaCl2-treated fruit exhibited significantly lower ethylene production compared to untreated fruit, although no differences were observed at the end of the storage period.
Senescent breakdown showed significant variability between the two seasons, with an incidence of up to 15% in the first season and nearly no incidence in the second.
Senescent breakdown increased with storage duration but was unaffected by foliar CaCl2 application.
Real-time PCR analysis of fruit flesh samples revealed increased expression of polygalacturonase and
-galactosidases genes after storage, indicating their involvement in apple softening.Notably, there were no differences in gene expression between CaCl2-treated and untreated fruit after storage.
Expression patterns of genes involved in ethylene biosynthesis at harvest were different between the two seasons.
Higher expression was observed in the year with greater disorder development, indicating greater maturity at harvest.
There were no significant differences in the Streif index between the two years.
Authors
T. Weigl, J. Børve, E. Follett, I. Øvsthus, C.G. Fossdal, H. Larsen, S.F. Remberg
Keywords
calcium chloride, ethylene, fruit quality, gene expression, physiological disorders, storage length
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