TY - BOOK

T1 - Peel russeting in ‘apple’ mango (Mangifera indica L.)

T2 - characterization, mechanisms and management

AU - Athoo, Thomas Ochieng

PY - 2023

Y1 - 2023

N2 - The aesthetic value and marketability of table fruits are greatly reduced by russeting, a disorder that severely affects the ‘Apple’ mango (Mangifera indica L.) cultivar in Kenya. Despite its prevalence, the underlying mechanisms and prevention strategies for russeting in mangoes are unknown. To address this gap in knowledge, this project aimed to: (1) review existing literature on russeting, (2) characterize the disorder in ‘Apple’ mango, (3) identify its mechanistic basis in comparison to a non-russet susceptible cultivar, (4) investigate the role of moisture and (5) lenticels on russeting, and (6) develop strategies to prevent the disorder. To achieve these objectives, russeting was quantified in ‘Apple’ mango within fruit and in different geographic locations in Kenya. Fruit skins and cuticles from russet susceptible ‘Apple’ and russet tolerant ‘Tommy Atkins’ mangoes were examined during fruit development, and cuticular strain was partitioned into its reversible and irreversible components. Mechanical properties of isolated cuticles from both cultivars were tested. The role of moisture in microcrack development and russeting was studied by partially wetting the fruit surface. Lenticels were characterized microscopically across cultivars and locations. Field studies were also conducted to establish the effect of pre-harvest bagging on russeting and postharvest performance. The results showed that russeting in ‘Apple’ mango increased with fruit development particularly in the stem end region. Russeting was triggered by rainfall and low temperature. The skin’s permeance to water vapor was larger in russeted than in non-russeted skin. The cuticle of ‘Apple’ mango was thinner than that of ‘Tommy Atkins’. Strains released on excision and isolation and wax extraction were higher in ‘Apple’ than in ‘Tommy Atkins’. Stiffness, fracture force, and strain at fracture were consistently lower in ‘Apple’ than in ‘Tommy Atkins’. Surface wetness induced microcracking and increased the skin's water vapor permeance, and moisture-treated fruit skins later developed russet symptoms in ‘Apple’ mango. Russeting began at lenticels and then spread across the surface, ultimately forming a network of rough, brown patches over the skin. Cross-sections of russeted areas revealed stacks of phellem cells. Pre-harvest bagging of mangoes effectively prevented russeting and lowered the rates of transpiration postharvest.

AB - The aesthetic value and marketability of table fruits are greatly reduced by russeting, a disorder that severely affects the ‘Apple’ mango (Mangifera indica L.) cultivar in Kenya. Despite its prevalence, the underlying mechanisms and prevention strategies for russeting in mangoes are unknown. To address this gap in knowledge, this project aimed to: (1) review existing literature on russeting, (2) characterize the disorder in ‘Apple’ mango, (3) identify its mechanistic basis in comparison to a non-russet susceptible cultivar, (4) investigate the role of moisture and (5) lenticels on russeting, and (6) develop strategies to prevent the disorder. To achieve these objectives, russeting was quantified in ‘Apple’ mango within fruit and in different geographic locations in Kenya. Fruit skins and cuticles from russet susceptible ‘Apple’ and russet tolerant ‘Tommy Atkins’ mangoes were examined during fruit development, and cuticular strain was partitioned into its reversible and irreversible components. Mechanical properties of isolated cuticles from both cultivars were tested. The role of moisture in microcrack development and russeting was studied by partially wetting the fruit surface. Lenticels were characterized microscopically across cultivars and locations. Field studies were also conducted to establish the effect of pre-harvest bagging on russeting and postharvest performance. The results showed that russeting in ‘Apple’ mango increased with fruit development particularly in the stem end region. Russeting was triggered by rainfall and low temperature. The skin’s permeance to water vapor was larger in russeted than in non-russeted skin. The cuticle of ‘Apple’ mango was thinner than that of ‘Tommy Atkins’. Strains released on excision and isolation and wax extraction were higher in ‘Apple’ than in ‘Tommy Atkins’. Stiffness, fracture force, and strain at fracture were consistently lower in ‘Apple’ than in ‘Tommy Atkins’. Surface wetness induced microcracking and increased the skin's water vapor permeance, and moisture-treated fruit skins later developed russet symptoms in ‘Apple’ mango. Russeting began at lenticels and then spread across the surface, ultimately forming a network of rough, brown patches over the skin. Cross-sections of russeted areas revealed stacks of phellem cells. Pre-harvest bagging of mangoes effectively prevented russeting and lowered the rates of transpiration postharvest.

U2 - 10.15488/15095

DO - 10.15488/15095

M3 - Doctoral thesis

CY - Hannover

ER -