Ginzberg, I., Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, P.O. Box 6, Bet Dagan, Israel
Stern, R.A., MIGAL, Galilee Technology Center, P.O. Box 831, Kiryat Shmona, Israel, Department of Biotechnology, Faculty of Life Sciences, Tel-Hai College, Upper Galilee, Israel

Russeting and cracking of fruit skin are major disorders that limit fruit quality and marketability. The causes suggested to be environmental condition, orchard management and failure of the skin to resist surface tensions due to fruit expansion. Basically, fruit skin is made of epidermis cells and cuticular matrix. Increased cuticle thickness, higher epidermal cell density and cell morphology that support strong adhesion between neighboring cells are characteristic of fruits tolerant to cracking compared to susceptible genotypes.Apple is being increasingly considered as a model for fruit development studies. Recently, spraying a mixture of gibberellin A4plusA7 (GA4+7) and the cytokinin 6-benzyl adenine (BA) at cell division stage of apple fruit development was shown to result with reduced incidence of skin cracking by maintaining a higher number of epidermal cells compared to untreated fruit.Various treatments with plant growth regulators (PGR) were tested for controlling cracking incidence in other fruits, including tomato, pear, persimmon, apricot, grape, mandarin and kiwi. We hypothesize a common mechanism for BA+GA4+7 effect on fruit skin, and propose to view the skin as a tissue whose characteristics may be manipulated to improve its resistance to environmental and growth strains.The review paper links practical approaches in the orchard to control costly yield losses with (limited) knowledge on fruit skin anatomy and development, and discussed the hypothesis that similar treatments may be applied with various agricultural important fruits. © 2015 Elsevier B.V.