Agriculture Reference
In-Depth Information
Table
.
Effects of rootstock on incidence of bitter pit and senescent breakdown, for
'Cox's Orange Pippin',
Treatments in
Rootstock
Hand
Light
Heavy
means % of
pollinated
Control
thinning
thinning
total
Rootstock
b.p.
s.b.
b.p.
s.b.
b.p.
s.b.
b.p.
s.b.
b.p.
s.b.
'M.'
. . . . . . . .
.
.
'M. '
. . . . . . . . . .
'M.'
-
-
. . . . . . ..
'MM. '
. .. . . . . . . .
b.p., % number of fruits showing bitter pit; s.b., % number of fruits showing senescent
breakdown.
From Blasco ( ). Reproduced with permission.
a higher soluble solids content in fruits of 'Red King Delicious' and 'Fuji' on
'M.
' than on 'M.
a' or 'M.
'. Autio et al. (
), in trials of 'Starkspur
Supreme Delicious' on
rootstocks at four sites, found significant negative
correlations between rootstock vigour, expressed as scion trunk cross-sectional
area, and soluble solids in the fruit at three of the sites. The effects were large:
at the Californian site the soluble solids content ranged from
.
% on the
most dwarfing rootstock ('P.
') to
.
% on the most invigorating ones ('M.
'
and 'P.
'). Sansavini et al. (
) did not find any effect of rootstock on acidity.
Effects on fruit maturity and storage
It has been known for a long time that fruits of trees on 'M.
' ripen on the
tree earlier and require earlier picking (MAFF,
). Autio et al. (
) found
that the time of ripening of 'Starkspur Supreme Delicious' on
rootstocks, as
measured by the date of the C H climacteric and the fruit starch index(see
Chapter
),wasanegativefunctionofrootstockvigour.Thismayindicatethat
the rootstock effect on fruit maturity is a consequence of its effect on tree size
and shade or on vigour-related hormonal factors. Early findings on the effects
of rootstock on fruit storage potential were probably confounded with effects
on fruit maturity. Harvested at the correct (earlier) time, fruits from trees on
dwarfing rootstocks store well.
Rootstocks can also influence storage through their effects on fruit calcium
content. Blasco (
) showed that fruits of 'Cox's Orange Pippin' on 'M.
'
rootstock had less calcium per unit fruit weight than when on 'M.
', 'M.
'
or 'MM.
', both on average and when only fruits of the same size were
considered. This was accompanied by a significant and large increase in stor-
age losses from bitter pit and senescent breakdown in fruits grown on 'M.
'
compared with the other rootstocks (Table
.
).
 
Search WWH ::




Custom Search