given location, season, and soil type”.[37] That advice was published 50 years ago, and despite consider-
able research, not much has really changed since then. In the search for a reliable criterion (or combina-
tion of criteria) as a guide to optimum picking date for apples, research workers have investigated days
from full bloom, ground color, pull test (ease of separation), pressure test (with various modifications of
the original 1925 Magness-Taylor pressure tester [61]), soluble solids, iodine-starch pattern, seed color,
and corking of lenticels. No criterion has proved consistent across varieties, growing districts, cultural
methods, and seasonal variations in climate. This is in sharp contrast to maturity standards for noncli-
macteric fruits such as grapes and citrus. Such variability makes legal maturity standards for climacteric
fruits difficult to enforce legally, e.g. [62]. Rootstocks can have a significant effect on maturity criteria
[63], as can use of spur-type scion selections. But it is nice to note that organic cultural methods are re-
ported as not significantly affecting maturity criteria [64]. Harvesting criteria for each particular apple va-
riety in each district still have be based largely on local experience and judgment. A user-friendly com-
puter program has been developed to help growers and packers select optimum harvest dates [65].
A further complication is that “stop-drop sprays” have been used for many years to extend the pos-
sible harvesting season for apples [66]. Such prolonging of the harvesting period can be expected to re-
duce potential storage life. This is particularly true for the highly colored strains that usually have been
selected from chance sports regardless of other fruit quality criteria. (This writer has grown weary of at-
tending meetings at which nursery owners and produce merchandisers proclaim that their aim is to “Give
the lady what she wants,” a policy that all too often sacrifices eating quality for appearance.) Now it ap-
pears that the selection of the culturally profitable spur-type strains may also sometimes be at the expense
of keeping quality [67].
- Pears (Pyrus communis)
The situation for pear harvesting is no more promising. Over 50 years ago, this writer was a graduate stu-
dent participating in a massive 5-year project involving five pear orchards throughout Canada’s Niagara
Peninsula. A major objective was to establish a reliable maturity standard for harvesting Bartlett pears,
particularly for research in a then very new and experimental controlled atmosphere storage. (This
method was then called “gas storage,” later renamed “controlled atmosphere” by Bob Smock of Cornell
University.) As well as pressure test, starch-iodine pattern, and so on, this program included measuring
respiration immediately after picking. Although variation among seasons and orchards excluded all other
criteria, one remained consistent. The best quality and longest storage life were always from the picking
at the nadir of fruit respiration on the tree [68]. Because that can only be determined retroactively, it can-
not be used as an indication of when to pick for maximum quality. Developments such as growing pears
with apple interstocks and on clonal apple roots [70] further complicate the prospect of finding generally
applicable criteria to determine optimum picking time for pears. Localized growing areas, particularly in
irrigated districts, may use some standard (pressure test is most common), but it seems unlikely that
statewide legal maturity standards will ever be established such as have long been enforced for citrus
fruits [43,44].
VI. SOME ECONOMIC CONSIDERATIONS
A few fruits, such as Tung Nut (Aleurites fordii), are grown for industrial use. Most, however, are grown
for food or drink. When fruits are to be processed into food products or beverages, external appearance is
of no consequence. But for fresh market sale “eye appeal” can be critical to profitability. Unfortunately,
most customers “taste with their eyes” and usually will not purchase unattractive looking fruit. [Kiwi fruit
(Actinidia deliciosa) is a conspicuous exception.]
A. Color
The public preference for highly colored fruits has led to considerable varietal selection for high color,
regardless of internal quality. (The Delicious apple is a conspicuous example.) However, for the discern-
ing buyer, background color can be a useful indicator of maturity of many fruits such as the Bartlett
(Williams, Bon Chretien) pear. The change in background color from dark green to pale green or yellow
indicates incipient ripening to edible quality.
156 GRIERSON