Agriculture Reference
In-Depth Information
is gradually being introduced into breeding programmes around the world, from
which the benefits will become apparent in cultivars released in the coming decades.
It is likely that future cultivars will have a wider range of adaptation, enabling cul-
tivation for longer seasons of production in many areas and improved tolerance to
stresses such as drought and extreme temperatures, both hot and cold.
The most notable achievement from over 200 years of breeding has been to
transform the strawberry from a plant with a short season of production and a mod-
est yield of small, soft berries to a highly productive plant capable of cropping over
a long period with large firm berries suitable for shipping over long distances. The
breeding programme at the University of California has been successful in develop-
ing cultivars that are grown in many countries around the world, including the Medi-
terranean region, Central and South America, Australia and China. A comparison of
the cultivars released in 1945-1966 with those released 1993-2004 showed yield,
fruit size and firmness increased by factors of 2.4, 1.7 and 1.9 respectively (Shaw
and Larson
2008
).
F
x
ananassa
is a complex allo-octoploid which is highly heterozygous. This
makes it a difficult subject for genetic investigations but in recent years there has
been significant progress in
Fragaria
molecular genetics. The first linkage map of
the cultivated strawberry was published by Lerceteau et al. (
2003
) and was based on
AFLP markers, which are largely non-transferable. Sargent et al. (
2006
) produced a
linkage map of an interspecific diploid progeny (
F. vesca
x
F. bucharica
) which was
adopted as the international reference map for diploid
Fragaria,
and the progeny
was distributed to research teams in different countries. This linkage map is based
mainly on transferable SSR markers, many of which were used to develop a
F.
x
ananassa
map of the progeny Redgauntlet x Hapil (Sargent et al.
2012
), which is
currently the most densely saturated published map for the cultivated strawberry.
In 2011 an international collaboration resulted in publication of the genome se-
quence for the diploid
F. vesca
(Shulaev et al.
2011
), which is considered to be
closely related to one of the diploid ancestors of the octoploid species. The genome
sequence has been anchored to the diploid reference map in seven pseudochromo-
somes and represents a very valuable resource for strawberry geneticists. It has
been demonstrated that there is a high level of colinearity between the diploid and
octoploid strawberry species (Sargent et al.
2012
).
Commercial Production
Main Global Areas
The world's largest producer is USA, with 1.27 million tonnes
but production in China has been increasing rapidly in recent years and is likely to
overtake this figure soon, although no official statistics are published for China.
Within the USA, California produces 88 % of the strawberries and Florida 9 %. Other
major world producers include Turkey (299,940 tonnes), Spain (275,300 tonnes),
Egypt (238,432 tonnes) and Republic of Korea (281,803 tonnes) (FAO statistics).
The leading producing nations all have climates offering long growing seasons
which lend themselves to high levels of production.
