elevating carbon dioxide concentration in the storage environment. Al-
though these technologies are not new, continual improvements in re-
frigeration and controlled atmosphere (CA) technology have resulted in
increased quality of fruits and vegetables and further extension of stor-
age life (Hardenburg et al., 1986). Other technologies, such as ethylene
removal, offer the prospect of even greater retention of quality in store
(Knee et al., 1985). Improvements in postharvest storage is a “target”
for the genetic manipulation of apple and other crops. Particular atten-
tion has been paid to slowing the rate of ripening of climacteric fruits
through control of ethylene synthesis (Tucker, 1994).
With the high investment costs associated with modern storage tech-
niques, it is imperative that maximum revenues are realized on fruit from
store. This requires freedom from physiological disorders up to the point
of consumption and an eating quality of all consignments that is above
the minimum required by consumers. Products such as apples are in-
trinsically variable in quality and storage potential at harvest. It is par-
ticularly important therefore that storage conditions and duration of
storage are compatible with achievement of the required quality in all
consignments. Substandard quality in the market place during the nor-
mal period of availability for a given cultivar can have adverse effects
on subsequent sendings. This could result ultimately in total rejection of
any further consignments, regardless of their quality.
The outturn quality of individual consignments of apples and pears,
and presumably also other types of fruit, is dependent on their intrinsic
potential to store and on their response to the imposed postharvest en-
vironment. It is important therefore that research is carried out that rec-
ognizes the continuum between pre- and postharvest physiology. It may
then be possible to assess the storage potential of consignments at, or in
advance of, harvest and to decide on the most appropriate conditions
and duration of storage. Such research may also suggest ways of im-
proving the quality of fruit stored in a particular regime.
CULTIVAR DIFFERENCES IN APPLE QUALITY
There are innate differences in the quality of apples of different cul-
tivars that characterize their eating quality and their potential for long-
term storage. Cultivars also differ in their propensity to commence
autocatalytic ethylene production, for example, Gloster69 is particularly
reluctant. This heritable trait can be used in conventional breeding to
produce cultivars with improved storage quality (Stow et al., 1993).
Fruit measurements taken at commercial harvest for long-term storage