of fruit to specific disorders with the concentration of mineral elements
in the fruit at particular stages during development. In many cases, it
has been possible to produce standards for mineral composition of fruit
that allow fruit growers to rank orchards in terms of their storage po-
tential and to decide on the most appropriate storage conditions and du-
ration of storage for each consignment (Johnson, 1989).
While mineral composition is important in relation to certain physi-
ological disorders, for others, e.g., superficial scald, correlations with
the concentration of mineral elements in the fruit are poor (Johnson and
Ridout, 1993). For this disorder, climatic conditions during fruit devel-
opment provide a good indication of the susceptibility of different con-
signments of apple and it has been possible to develop prediction models
based on the behavior of fruit from many orchards monitored over sev-
eral years. Similarly, it has been possible to develop a regression model
based on climatic variables to predict LTB in Bramley apples (Johnson
et al., 1989). It is a challenge for future research to understand the ef-
fects of climatic changes on fruit physiology and biochemistry. Recent
research on scald provides a good example of this approach, for which
changes in antioxidant activity and extent of alpha-farnesene oxidation
in the peel of apples are used to determine the effects of preharvest fac-
tors (Barden and Bramlage, 1994). This approach will provide opportu-
nities for more accurate prediction methods based on analyses of fruit,
and for the modification of the development of the fruit to confer resis-
tance to disorders and to improve quality in store. The development of
models to predict storage quality based on fruit composition and climatic
variables represents a major step towards achieving consistent quality
from store (Johnson and Ridout, 1998), but further integration of the fac-
tors that influence quality, and its loss in store, is needed before all as-
pects of fruit quality are predictable.
RESEARCH TO MINIMIZE OCCURRENCE
OF BITTER PIT IN COX APPLES
It is useful to provide an example of how this approach has mini-
mized the problem of bitter pit in stored Cox apples. Storage experi-
ments with fruit from different orchards over several years established
that CA conditions affected the potential of fruit to develop bitter pit
(Johnson, 1989). Extensive survey experiments provided the data to de-
velop relationships between the incidence of bitter pit and the mineral
composition of fruit and to establish fruit analysis standards appropriate
Research to Minimize Occurrence of Bitter Pit in Cox Apples 79