plants Review Review of the Impact of Apple Fruit Ripening, Texture and Chemical Contents on Genetically Determined Susceptibility to Storage Rots Hilde Nybom 1,* , Masoud Ahmadi-Afzadi 2 , Kimmo Rumpunen 1 and Ibrahim Tahir 3 1 Department of Plant Breeding–Balsgård, Swedish University of Agricultural Sciences, Fjälkestadsvägen 459, 29194 Kristianstad, Sweden;
[email protected] 2 Department of Biotechnology, Institute of Science, High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman 7631818356, Iran;
[email protected] 3 Department of Plant Breeding, Swedish University of Agricultural Sciences, Box 101, 23053 Alnarp, Sweden;
[email protected] * Correspondence:
[email protected] Received: 27 April 2020; Accepted: 29 June 2020; Published: 2 July 2020 Abstract: Fungal storage rots like blue mould, grey mould, bull’s eye rot, bitter rot and brown rot destroy large amounts of the harvested apple crop around the world. Application of fungicides is nowadays severely restricted in many countries and production systems, and these problems are therefore likely to increase. Considerable variation among apple cultivars in resistance/susceptibility has been reported, suggesting that efficient defence mechanisms can be selected for and used in plant breeding. These are, however, likely to vary between pathogens, since some fungi are mainly wound-mediated while others attack through lenticels or by infecting blossoms. Since mature fruits are considerably more susceptible than immature fruits, mechanisms involving fruit-ripening processes are likely to play an important role. Significant associations have been detected between the susceptibility to rots in harvested fruit and various fruit maturation-related traits like ripening time, fruit firmness at harvest and rate of fruit softening during storage, as well as fruit biochemical contents like acidity, sugars and polyphenols.