Agriculture Reference
In-Depth Information
●
the
Pekinense
group of China, which are derived from the
longicuspis
group
but are smaller and produce a few large top-sets.
●
the
Subtropical
group from India, Vietnam and Myanmar, which have
small bulbs and are selected for eating as fresh leaves.
A number of authors have proposed alternative classifications based on
comparisons of morphology, growth pattern and, in several cases, isozymes or
other molecular markers (Etoh and Simon, 2002). Most schemes are broadly
compatible with the above groupings but include more detailed subgroups
within some of them. Several authors report that the greatest polymorphism in
genetic markers is found within the central Asian
Longicuspis
types, and fertile
flowers and seed production have been found within this group only (Etoh and
Simon, 2002). Within the last 20 years a number of these fertile garlic accessions
have been collected in central Asia. Following pollination and removal of top-sets
seeds have been produced, of which 12% have germinated (Etoh and Simon,
2002). This has opened up the possibility for improvement of garlic worldwide,
using seed reproduction and selection to introduce useful traits from the central
Asian centre of origin of the crop.
Garlic clones exist that are adapted to many ecological zones through their
responses of growth and bulbing to temperature and photoperiod, their cold-
hardiness and duration of bulb dormancy (Takagi, 1990). Diversity also exists
in the size of cloves, their number, bulb weight, colour and number of outer
skins and size and vigour of the foliage, and the extent to which inflorescences
occur. On the basis of a comparison of a wide range of clones growing in a
standard environment, Jones and Mann (1963) concluded that there was no
justification for using some of the subspecies names previously ascribed to
some variants of garlic. They suggested that the name 'Rocambole' might be
applied to variants with coiled scapes, but should not be applied to the wild
species
A. scorodoprasum
. This has occasionally been so named and it has been
used for food but it is not cultivated. Messiaen
et al.
(1993) compared the garlic
varieties grown in all parts of the world, except Asia, in comparative trials in
France and classified them into six groups characterized by the presence or
absence of flower stalks, the size and number of the cloves and their degree of
dormancy, and the earliness of bulbing in the trials.
Leek, kurrat, great-headed garlic and pearl onions,
Allium
ampeloprasum
L.
This species includes several distinct crop types (see below), but where they
have been crossed they have proved interfertile and are therefore variants of
the one species. Wild
A. ampeloprasum
is found from Portugal in the west
through the Mediterranean countries to western Iran in the east (van der Meer
and Hanelt, 1990; Kik, 2002). It grows wild in open, often man-made,
