What is stem-end splitting in apples?
Opara, L. U.;
Good Fruit Grower Year: 1996 Vol: 47 Issue: 16 Pages: 57-59 Ref: 4 ref.
1996
บทคัดย่อ
Physical attributes of fruits affected by stem-end splitting (SES, a type of splitting which originates in the stem cavity region near the fruit-stem joint and extends in a straight line towards the crown) and the chronological development of splitting during the growing season were studied. Fuji and Gala, and strains of Gala such as Royal Gala, Imperial Gala and Regal Gala, are affected. Up to 4 splits can occur in fruits and the severity of splitting can be high, such that affected fruits are almost separated into 2 halves. Examination of the surface of cut fruit sections revealed the presence of internal ring-crack (IRC) in the stem cavity of all fruits with SES. Stem-splitting is thought to occur by 2 distinct fracture mechanisms, firstly by flesh fracture in the vertical plane which results in IRC, and secondly by splitting of the skin and underlying flesh in the horizontal plane which results in SES. The incidence of splitting is believed to be associated with fruit maturity, especially wh
en fruits are allowed to remain longer on the tree for good colour development. In the 1991-92 season, Gala apple fruits were sampled at weekly or fortnightly intervals starting 45 days after full bloom (DAFB). SES and IRC were first detected in fruits harvested 115 days DAFB (3 weeks before commercial maturity). The incidence of IRC increased rapidly with fruit maturity while SES increased slowly initially and rapidly afterwards, reaching up to 8% during the first harvest. SES incidence was highest during the third commercial harvest. At each harvest date, IRC and SES occurred in mature and immature fruits and the incidence of both was higher in large fruits than in small fruits. Studies aiming to induce IRS and SES in detached fruits indicated that IRC and SES are growth cracks rather than superficial skin cracks and that incidence may be reduced by avoiding management practices which induce severe growth stresses on the crop such as sudden or over irrigation.