Agriculture Reference
In-Depth Information
Stooled layer production of
rootstocks at Summerland, British Columbia
Table
.
Rootstock
Number of rooted shoots m
−
'M.
'
'B.
'
'M.
'
'M.
'
'M.'
'M.'
'J.'
'P. '
'P.'
'B.'
'P.'
'P.'
'O.'
From Quamme and Brownlee (). Repro-
duced with permission.
Nursery productivity
Although the orchard performance of trees grafted on to the different root-
stocks determines the demand for them, differences in the ease with which
they can be propagated determines the supply. Some very desirable root-
stocks are very difficult to multiply by conventional nursery techniques
(Table
). Those which produce the fewest rooted shoots suitable for being
grafted or budded with scions may instead be used as interstocks. Micro-
propagation methods may help overcome the difficulties in producing rooted
propagules.
.
Major apple rootstocks
'Malling
'
) is the most widely used dwarfing rootstock. It is the basis of
the western European apple industry and is rapidly gaining in use in north
America. Trees on 'M.
'
(
'M.
' are relatively easy to maintain at a height of between
metres, depending on cultivar, soil and climate, although they can
be taller if required. The spacings between trees on 'M.
and
' range from about
m
×
m or closer in single rows to
.
m
×
.
m in 'full-field' systems
(Wertheim
et al.
,
' give larger fruits than those on most
other rootstocks. Yield per unit of tree size is outstandingly high and the trees
start to crop within a year or so of planting; indeed, in many areas the early
fruiting has to be reduced to prevent an excessive check to growth. 'M.
). Trees on 'M.
'is
