Review on rain induced fruit cracking of sweet cherries (Prunus avium L.), its causes and the possibilities of prevention

Abstract

The rain induced fruit cracking is a big, serious and costly problem for cherry growers. Cracked fruits lose their value and they are not marketable because of the poor fruit quality. Cracked fruits have different storage diseases and shorter storage and shelf life.
 There are many influencing factors of the cherry fruit cracking such as: water uptake; fruit characteristics (fruit size, fruit firmness; anatomy and strength of the fruit skin, stomata in fruit skin, cuticular properties, osmotic concentration, water capacity of the fruit pulp, growth stage of the fruit,); orchard temperature and other environmental conditions;
 The most effective protection technique is the plastic rain cover over the tree rows. The installation of these equipments is too expensive for the cherry growers. That is the reason why researchers tried to find other less expensive and sufficiently effective ways against the Lim induced fruit cracking.
 Several calcium formulas: calcium chloride (CaC1,), calcium hydroxide (Ca (OH)2) and calcium nitrate (Ca(NO3)2 ) can be sprayed in appropriate concentration. Spraying with other mineral salts (aluminium and copper salts, borax) and PBRs (Plant Bioregulators) may be also effective to reduce fruit cracking.

Physiological and genetic factors influencing fruit cracking

“…There are many causes of fruit cracking. Genetic and fruit characteristics such as fruit maturity, fruit size and fruit firmness (Peet 1992;Simon 2006), lack of orchard management such as moisture stress, nutrient deficiency, insect-pest and disease, bagging and early picking (Predieri et al 2003) and environmental factors such as temperature and wind (Simon 2006) are the main causes influencing fruit cracking.…”

“…Also, temperature influences many other agents such as the cell walls' permeability and cells' biochemical processes. It is very important to know the influence of temperature in fruit cracking if we want to find some measure against fruit cracking, because usually the temperature is higher underneath the screen than outside (Simon 2006). Furthermore, the distribution and quality of rainfall during the maturation and ripening stages can affect the susceptibility of sweet cherry to fruit cracking (Christensen 1996;Simon 2006).…”

“…Three types of fruit cracking in sweet cherry are known: 1-semicircular or circular cracks around stem end on the cavity; 2-similar small splits at the fruit apical end; and 3-many often deep splits on the fruit sides and it is known as lateral splitting (Simon 2006;Khadivi-Khub 2009). The small and fine splits at the base and apical end of cherry fruit may occur at very early stages, many days before fruit Fig.…”

“…Cultivars with kidney or heart fruit shape such as 'Rafat' and 'Ghazvin', Iranian cultivars, have deeper stem cavity and therefore the rain drops may remain there for a long time giving possibility for higher water uptake through the fruit skin ). It means that if a cultivar is genetically determined (based on structure and thickness of the cuticle and sugar content) for moderate susceptibility to splitting and it has kidney, blocky or heart shape, maybe it will have stem end type splitting (Simon 2006;Khadivi-Khub 2007).…”

“…Fruit cracking disorder is commonly found in sweet cherry, plum, apricot, apple, litchi, pomegranate, citrus, banana, avocado, grape, persimmon, peach, tomato, pistachio etc. (Opara 1996;Simon 2006;Khadivi-Khub 2009).…”