Russeting in ‘Apple Mango’: Causes, consequences and management
Final Report Abstract
The results obtained may be summarized as follows: Russeting is an important surface disorder in the mango cultivar ‘Apple’. The fruit surface area affected by russeting increased during development. Cross-sections revealed stacks of phellem cells, typical of a periderm. Russet differed markedly across sites of different climate. Russet was positively correlated with altitude, the number of rainy days and the number of cold nights, but negatively correlated with minimum, maximum and mean daily temperatures, dew point temperature and heat sum. Compared with non-russet susceptible ‘Tommy Atkins’, fruit of russet susceptible ‘Apple’ had a lower mass, a smaller surface area and a lower growth rate. Lenticel density decreased during development, being lower in ‘Apple’ than in ‘Tommy Atkins’. The mean lenticel area increased during development but was consistently greater in ‘Apple’ than in ‘Tommy Atkins’. The lower rate of cuticular deposition, the higher strain releases on excision, isolation and wax extraction and a mechanically weaker cuticle accounted for the high russet susceptibility of ‘Apple’ mango. Exposure to surface moisture triggers cuticular microcracking in ‘Apple’. When moisture exposure was terminated, microcracking and water vapor permeance decreased again, suggesting a repair process that restores the barrier properties of the fruit skin. Moisture induced microcracking also accounts for the positive correlation between the number of rainy days and the degree of russeting. The frequency of lenticels per unit surface area decreased during development. The number of lenticels per fruit was constant. Stomata became covered over with wax deposits at 33 days after full bloom (DAFB). By 78 DAFB, a periderm had formed beneath the lenticel. At 110 and 161 DAFB, cracks had developed and the periderm had extended tangentially and radially. The presence of lenticels increased the strain released upon excision of an epidermal segment. Further strain releases occurred upon isolation of the cuticle and on wax extraction. Moisture exposure resulted in enlarged lenticels and more microcracking of the cuticle. Russeting in ‘Apple’ mango is initiated at lenticels and is exacerbated if lenticels are exposed to moisture. Bagging fruit in brown paper bags reduced russeting. Bagged fruit had smaller lenticels and fewer microcracks than un-bagged control fruit. Bagged fruit were also greener and showed less blush. There was little difference in skin carotenoid content between bagged and un-bagged control fruit, but skin anthocyanin content was lower in bagged fruit. Bagging decreased russeting and increased postharvest performance of fruit of mango cv. ‘Apple’.
Publications
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Russeting in ‘Apple’ Mango: Triggers and Mechanisms. Plants, 9(7), 898.
Athoo, Thomas O.; Winkler, Andreas & Knoche, Moritz
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Low cuticle deposition rate in ‘Apple’ mango increases elastic strain, weakens the cuticle and increases russet. PLOS ONE, 16(10), e0258521.
Athoo, Thomas O.; Khanal, Bishnu P. & Knoche, Moritz
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Russeting of Fruits: Etiology and Management. Horticulturae, 8(3), 231.
Winkler, Andreas; Athoo, Thomas & Knoche, Moritz
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Surface Moisture Induces Microcracks and Increases Water Vapor Permeance of Fruit Skins of Mango cv. Apple. Horticulturae, 8(6), 545.
Athoo, Thomas O.; Winkler, Andreas; Owino, Willis O. & Knoche, Moritz
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Lenticels are sites of initiation of microcracking and russeting in ‘Apple’ mango. PLOS ONE, 18(9), e0291129.
Athoo, Thomas O.; Winkler, Andreas; Owino, Willis O. & Knoche, Moritz
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Bagging prevents russeting and decreases postharvest water loss of mango fruit cv. ‘Apple’. Postharvest Biology and Technology, 211, 112804.
Athoo, Thomas O.; Yegon, Dennis; Owino, Willis O. & Knoche, Moritz
