382 Handbook of herbs and spices
a form of bulbing multiplying onion, differentiated by their smaller size. Originally,
they were named for a plant found by the Crusaders, but they bear no botanical
relationship to that plant. Most shallots in the market today are not even the same
shallot so beloved by the French. Instead, they are varieties developed by crossing
common onions with Welsh onions or other multipliers – a primary aim of the plant
breeders was to create varieties that could be readily reproduced.
Some authorities differentiate shallots from other multipliers by the colour of their
skins. The Ontario Ministry of Agriculture and Food, for example, identifies shallots
as those with red skins (or scales) and true multipliers as those with yellow or brown
skins. Most shallots do not flower or produce seed, although breeders have developed
some new varieties that can be grown from seed. In practical terms, shallots are
small, layered multipliers with a special taste that falls somewhere between onion
and garlic. They are propagated in the ground the same way as other bulbing multipliers,
and each bulb produces from four to twelve baby bulbs in a bunch, joined at the base
by a membrane. In most varieties, each bulb is split into two large cloves that may or
may not share a common wrapper. Shallots are favoured by chefs for their distinctive
flavour, described as a blend of onion and garlic (Brook Eliot, 2003).
Botany
The term shallot refers to the vegetatively propagated forms of Allium cepa var.
ascalonicum, which were included in aggregatum group of the species. Shallots of
this type appear to have been derived by selection from a naturally occurring variant
within Allium cepa. Several cultivars are actually derived from A. cepa ¥ Allium
fistolosum crosses (e.g. Delta Giant). These should not be confused with the shallots
of the Allium cepa aggregatum group. Allium cepa shallots are distinguished from
natural bulb onion by their habit of multiplying vegetatively by laterals and growth
- a single shallot bulb usually contains several initial shoots. The bulb can be planted
(Currah and Proctor, 1990), and several leafy shoots will grow out from it. Each
shoot then rapidly produces a small bulb, forming a cluster that remains attached to
the original base plate (Vadivelu and Muthukrishnan, 1982). The bulbs can be separated
and the process repeated in the next growing season.
Morphologically, a shallot bulb (synonyms: set, bulblet, bulbil) is very similar to
the bulb of the common onion. A mature bulb consist of a compressed stem axis or
basal plate, storage leaf-bases of the outer leaves, which have lost their blades, and
bladeless ‘true scales’. In the centre of each bulb there are a few leaf buds that under
favourable conditions sprout when dormancy ends. Unlike the modern bulb onion, a
typical shallot bulb contains a number of laterals in the axils of the inner leaves. All
sets formed from a single propagule usually remain attached to the original basal plate,
thus forming a cluster of sets (Currah and Proctor, 1990). The foliage and the inflorescence
of shallots are usually smaller than those of the bulb onion. However, root morphology,
the unifacial, hollow, slightly flattened tubular leaves, the hollow scape, the terminal
inflorescence and the flowers are similar to those of the common onion.
Origin and distribution
In the tropics, shallots are often grown in areas where onion culture is difficult
because the climate is humid and bulb onion is susceptible to leaf diseases that
shallot can withstand. Shallot has a very short growing season of only two to three
months, which allows it to be grown between other crops or during a short-day
season. In the lowland tropics, lack of a distinct cool period can prevent onion from