Russeting in ‘Apple Mango’: Causes, consequences and management

• Applicant: Professor Dr. Moritz Knoche
• Subject Area: Plant Cultivation, Plant Nutrition, Agricultural Technology
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 448601884

Russet is an important fruit surface disorder in many fruit crops grown worldwide. This includes ‘Apple’ mango, a mango variety that has considerable market potential, but that is currently not exploited due to the frequent occurrence of russet and the poor visual appearance of russeted fruit. The objective of the project is to identify the mechanistic basis of the russet in ‘Apple’ mango in Kenya and to develop appropriate counter strategies. The following hypothesis three will be investigated and tested: (1) Russet in ‘Apple’ mango is preceded by microscopic cracking of the cuticle and formation of a periderm. (2) Formation of microcracks in ‘Apple’ mango is due to growth stress resulting from a mismatch of surface expansion and cuticle deposition. In addition, moisture on the fruit surface aggravates microcracking. The resulting russeted ‘Apple’ mango shrivels postharvest due to increased skin permeance to water vapor (Khanal et al., 2019).(3) Preventing surface moisture by bagging of fruit and strengthening the structural support of the cuticle by underlying cell layers using GA application decreases russet susceptibility of ‘Apple’ mango without compromising fruit quality.The project is expected to provide fundamental insight into russet formation and the effects of russet on pre- and postharvest performance in ‘Apple’ mango and many other fruit crop species. A better understanding of the mechanism of russet is helpful in developing effective management strategies to reduce russet and to improve marketability of ‘Apple’ mango in Kenya.

• DFG Programme: Research Grants
• International Connection: Kenya
• International Co-Applicant: Professor Dr. Willis Owino