Agriculture Reference
In-Depth Information
China has increased garlic production at a rapid rate in
recent years and this has had a suppressing effect on
production in other countries which are failing to compete
on price. Countries such as Argentina are upgrading quality
so as to retain traditional markets in Europe. Spain and
France are traditional producers which are feeling the
effects of competition. Trade sanctions are being used by
some countries to restrict Chinese garlic imports in order to
protect local garlic producers. However, with greater
openness in world trade, this will probably only work in
the short term. The demand for garlic continues to rise as
new health findings make it more attractive to consumers
and new uses are found, such as for the control of diseases
(for example, white rot of onions; Crowe
et al
. 2000) or to
deter pests. However, temporary bulges in supply, as for all
perishable commodities for which demand is relatively
inelastic, can lead to price collapse and this can be
disastrous for local producers.
widely genetically different onions by Stow (1975a).
Abdalla and Mann (1963) made the first detailed records of
what happened to two contrasting onion cultivars when the
freshly harvested bulbs were placed on damp peat and
allowed to sprout; these authors wrote a classic paper
which set a high standard for subsequent work on onion
dormancy and dormancy breaking.
Once onions started to be transported for long distances
in the twentieth century, defects which had occurred before
or during transport were noticed at city markets. Ceponis
and Butterfield (1981) listed onion defects found in New
York supermarkets and by consumers in bulbs from various
production regions in the United States. Losses of 6-9%
from multiple causes were found. From extensive surveys
by Ceponis
et al
. (1986) of wholesale market information,
the higher occurrence of neck rot (
Botrytis allii
and other
Botrytis
species) in Spanish-type storage onions from the
western United States and of black mould (
Aspergillus
niger
) on Grano/Granex-type onions from warmer regions
was clear. Much work in storage pathology has concentrated
on these damaging species.
Jones and Mann (1963) included a chapter on onion
post-harvest in their book
Onions and Their Allies
: they
described examples of several methods of storage in use in
different countries. Fairly crude field storage in clamps or
heaps was common in Europe and the United States for
long-storing onions at that period. However, methods
changed greatly during the next two decades, as scientists
and growers experimented with better ways to control
environmental conditions during drying, curing and long-
term storage (Maude
et al
. 1984). At the same time, the
biology and epidemiology of many storage diseases were
also elucidated, and treatments developed led to marked
improvements in onion storage life. Extension literature
produced in the 1970s and 1980s (e.g. Maude
et al
. 1984)
established a framework for the 'direct harvest' methods
which are still being refined today in temperate countries
where large-scale storage is practised (O'Connor 2002).
Problems of onion storage in the tropics were reviewed
several times from the 1970s to the 1990s by scientists
from the Natural Resources Institute in the United Kingdom,
in response to many requests for advice (Thompson
et al
.
1972; Thompson 1982; Currah & Proctor 1990; Brice
et al
.
1997). Experimental studies were made on the reactions in
storage of a range of cultivars to different levels of tempe-
rature and humidity (Stow 1975a, 1975b). Later, the
biology and control of black mould (
A. niger
) and other
onion storage fungi were investigated on onions in the
Sudan and in the United Kingdom (Hayden
et al
. 1994a,b;
Hayden & Maude 1997). Since only short-day (SD) onions
HISTORICAL REVIEWS AND KEY FINDINGS
A compendium of information on vegetables by Messrs
Vilmorin-Andrieux of the famous French seed company,
in the mid-nineteenth century, mentions the keeping quali-
ties of about 30 European and US cultivars of that time.
In William Robinson's English translation of this topic
(1885), the Brown Spanish, or Oporto onion, or Oignon
Jaune des Vertus (the French name of a similar onion), is
stated to be the main storage onion supplying Paris and a
great part of Europe in the winter. Vilmorin noted that very
early varieties (i.e. overwintered onions) in general did not
keep well. Some of the varieties trialled in the United
States in the 1930s can be traced back to lines mentioned
in Vilmorin's topic. Robinson (1885) mentioned that very
large onions were sent to British markets during the winter
from Spain, Italy and Africa.
Some of the earliest detailed accounts of onion post-
harvest performance came from experiments made on US
onion cultivars during the 1930s (e.g. Wright
et al
. 1935).
Varieties current at the time were grown in several different
parts of the United States (Magruder
et al
. 1941a) and their
post-harvest performance was studied at seven different
locations, under ambient and cold storage (Magruder
et al
.
1941b). Results agreed well across the country and the
cultivars were reliably classed into storage categories as
poor to very good. Many of the forebears of today's onion
varieties were described at that time. In the same era, a
study made in India allowed the main effects of
temperature on local red onions from near-freezing up to
40°C to be identified (Karmarkar & Joshi 1941), effects
which were later found to hold true across a range of
