Agriculture Reference
In-Depth Information
'Judeline', an apple grown for juice production in France. Other sources of
resistance genes are
M.
×
micromalus
(
Vm
),
M. pumila
R
-
A(
Vr
),
M. baccata
jackii (
Vbj
),
Hansens baccata
H
(
Va
). Dessert
apples with scab resistance include 'Freedom', 'Liberty', 'Saturn', 'Enterprise',
'Goldrush', 'Topaz', 'Santana' and 'Florina'. Some of these may become im-
portant in the future if there is greater consumer demand for 'organically
produced' apples.
It is also possible that with the spread of fire blight, caused by the bacterium
Erwinia amylovora
, the degree of resistance to this disease shown by 'Delicious'
could increase its importance.
(
Vb
) and 'Antonovka' PI
Apple cultivar requirements
re
length of
growing season
The length of time which elapses between flowering and fruit maturation is
a very important cultivar characteristic. It cannot be modified to any great
extent by cultural practice, although it is influenced by rootstock and some
plant growth regulators. It is one of the most important factors in determining
where the world's major cultivars can be grown.
The actual length of the period from flowering to fruit maturation varies
with temperature. Luton and Hamer (
) showed that, over the years from
to
, the length of season for 'Cox's Orange Pippin' in England varied
from
days. Much of this variation was associated with variations in
temperature, the harvest date being later by
to
◦
C decrease in
days for each
mean temperature between
September. The necessary length of
growing season therefore varies from place to place (compare requirements in
South Africa, Table
May and
, and with those
mentioned for other areas in the text) but the rankings of different cultivars
in terms of earliness are fairly consistent. 'Golden Delicious' can be grown
over a particularly wide range of climates. 'McIntosh' fruits require
.
, with those in northern Italy, Table
.
weeks
less to mature than 'Golden Delicious' and it is still a leading cultivar in the
colder, more northerly, apple producing regions such as Canada, the northern
USA and Poland. 'Gala', 'Cox' and 'Elstar' mature in about three weeks less
than 'Golden Delicious' and can be grown to high quality in England and the
Netherlands. The 'Delicious' group can ripen earlier or later than 'Golden
Delicious', but their tendency to small fruit size in cool summers limits their
production in cool areas. In contrast, 'Jonagold', although harvested as late as
or later than 'Delicious', is a large-fruited cultivar which is widely grown in
northern Europe especially Belgium and Germany. The long-season group of
cultivars, 'Braeburn', 'Fuji' and 'Granny Smith', cannot generally be grown
successfully in northern apple areas and this applies even more strongly to
ultra-late cultivars. such as 'Pink Lady' and 'Sundowner'. There are, however,
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