Jonathon spot – Three factors related to incidence, fruit size, breakdown, and seed numbers

Abstract

Observations are reported which show that: (1) There is an interaction between the disorders Jonathan spot and breakdown. There is a negative correlation between them, but the same fruits tend to be susceptible to both disorders. (2) In the absence of other disorders there is a positive intercorrelation between percentage Jonathan spot, mean fruit size, and mean seed number both within and between trees. (3) In the one fruit size group on a tree, fruits with Jonathan spot have a higher mean seed number per fruit than sound fruit, and the seeds have a greater tendency to germinate. (4) Within trees, a thinning treatment which produces fruit of differing sizes but with the same seed number does not alter the percentage Jonathan spot. Between trees, a thinning treatment which produces fruit of the same size but a differing seed number results in differing levels of Jonathan spot.

Spur Fruit Set Is Negatively Related with Current-year Spur Leaf Area in Almond

“…In apple, flower thinning has been reported to cause increases in relative fruit set (Martin et al, 1961;Quinlan and Preston, 1968). Similar results have been reported in almond (Socias I Company et al, 2004).…”

The influence of harvest maturity, calcium concentration and storage conditions on the keeping quality of Spartan apples grown in England

“…Jonathan Spot (Wilkinson & Fidler, 19736) was only observed in fruit from the 1976/77 trial and its incidence may have been the result of the abnormally hot, dry summer of 1976, followed in September by rain and rapid fruit expansion. Susceptibility to the disorder increased as picking was delayed but there was no relationship between fruit size and the incidence of Jonathan Spot for particular harvest dates as suggested by Martin, Lewis & Cerny (1961).…”