Stem-end splitting and internal ring-cracking of 'Gala' apples as influenced by orchard management practices

The influences of irrigation (frequent versus none), crop density (high ver sus low), and nitrogen (urea fertilizer versus none) on the incidence of st em-end splitting (SES) and internal ring-cracking (IRC) in 'Gala' apples we re studied. Of the three orchard management factors considered, only irriga tion significantly affected the incidence of stem-end splitting and interna l ring-cracking; while the increase in fruit splitting due to low crop dens ity was marginal. Frequently irrigated trees produced over twice as many sp lit and ring-cracked fruit, respectively, compared with nonirrigated trees. The incidence of both SES and IRC increased with advancing fruit maturity, and percentage splitting in the experimental orchard varied considerably f rom 0.7% to over 28% for single tree replicates. None of the orchard treatm ents affected fruit nitrogen and other major nutrients (Ca, P, K and Mg), b ut fruit with SES or IRC had significantly higher concentrations of Ca, P a nd K than good fruit. The increase in the concentration of these minerals i n split or ring-cracked fruit may be a secondary response which probably oc curred after cortical cells began to break down as a result of stem-end spl itting or internal ring-cracking.