Cherries, botany, production and uses- Edited by: José Quero-García, Amy Lezonni, Joanna Pulawska and Gregory Lang.
Edited, adapted and commented by Carlos J. Tapia T. Technical director of Avium and content director of SmartCherry 2020.
In a few days, one of the phenological states most eagerly awaited by fruit producers will occur, especially those involved in the production and development of cherry trees in the different climatic zones of the country, where the result of the efforts made during the post-harvest of the last season can be seen graphically. Although, the productive potential of the orchard can be observed with certainty after about 15 to 20 days after full blossom (DDPF) and that is when the fruit can be defined in the great majority of varieties. However, according to the latest studies of Avium in the cvs. Regina and Kordia, this potential could be reflected with greater certainty after 25 to 30 DDPF.
From this point of view, the flower can also be seen in situ for probable frost damage, even before the flower is open, and also some problems with flower malformations that can eventually generate double fruits that must be discarded at harvest.
DOUBLE FRUIT, caused by the formation of a double pistil at the time of floral differentiation, is a problem that can seriously affect the profitability of a production and that has increased in orchards that are located in more temperate areas and increased by global warming.
Traditionally, cherries have been produced in cold areas, but with the commercial goal of harvesting early when the market offers better prices, many cherry growers have moved to warmer regions around the world (Micke et al., 1983; Southwick et al., 1991; Garcia-Montiel et al., 2010; Li et al., 2010; Beppu and Kataoka, 2011; James and Measham, 2011).
However, the new production reality has had repercussions on the formation of a high standard fruit, and has generated the formation of double fruit, malformed flowers containing pistils as appendages instead of anthers (Philp, 1933; Beppu and Kataoka, 1999; Roversi, 2001; Martin, 2008) and fruits with deep sutures, because the margins of the carpel did not fuse with the base and remain open (Southwick, 2008). et al., 1991; Engin et al., 2009).
Formation of double pistil and double fruit.
According to different studies, it is believed that high temperatures in summer during flower bud differentiation may be the cause of double pistil formation, resulting in double fruit the following year (Micke et al., 1983). Double pistil formation is due to abnormal differentiation of pistil primordia (Philp,1933; Tucker, 1934).
Flower bud induction and early stages of bud development may occur before harvest (Tufts and Morrow, 1925; Westwood, 1993), with development continuing throughout the remainder of the season (Guimond, 1993). et alIn cherries, the interval between initial flower formation and final reproductive development can vary from 86 to 112 days, depending on climate and cultivar (Faust, 1989). Flower bud induction occurs via a biochemical signal to switch from a vegetative to a reproductive state (Faust, 1989), as a result of the balance of gibberellins, auxins, cytokinins and ethylene (Westwood, 1993). Under natural conditions, cherry flower initiation begins in July (northern hemisphere) and sepals, petals and pistils differentiate sequentially (Guimond, 1993). et al., 1998; Engin and Ünal, 2007). Temperatures above 30° are critical for double pistil formation (Beppu and Kataoka, 1999). High temperatures cause double pistil more severely in buds with differentiated sepals and petal primordia compared to buds at early stages of flower bud differentiation or buds that already have formed stamen and pistil primordia (Beppu and Kataoka, 2011), suggesting that buds are more sensitive to the induction of an abnormal flower primordium at the transition stage of sepal to petal differentiation. Considerable cultivar variation in percentage of double fruit has been reported between years (Tucker, 1934, 1935; Micke et al., 1983; Beppu, 2000; Engin and Unal, 2008; Roversi et al., 2008; Garcia-Montiel et alCoastal areas exposed to cold breezes tend to have fewer double fruits than regions without a coastal influence (Southwick et al., 1991).
Double pistil Flower malformation caused by high temperatures
Variations in crop duplications
In areas with warm summers, the risk of producing double fruit is high (and consequently a reduction in marketable fruit) and may limit cherry planting. Hand thinning can be used to selectively remove double fruit, but in some crops the cost is considerable (Patten et al., 1989). Various strategies have been used to modify orchard climate to minimize double fruit occurrence in cherries. These findings suggest that susceptibility to cultivars with double fruit formation has a strong genetic influence. Therefore, it may be possible to develop new cultivars with a low occurrence of double fruit.
