Articles
EFFECT OF M.27 AND M.9 USED AS ROOTSTOCK AND AS INTERSTEM ON APPLE-TREE BEHAVIOUR IN TWO DIFFERENT GROWING CONDITIONS.
Three tree distances within the row ranging from 0.75 to 1.5 m were involved with a common between row distance of 3.5 m.
M.9 proved more vigorous than M.27, especially as a rootstock but also as an interstem.
The M.27 interstem induced more growth than the M.27 rootock, but with M.9 both were about equally vigorous.
Vigour increased with increasing tree distance with M.9 trees, but not with M.27 ones.
At PS vegetative development was much stronger than at WD.
In tree yield M.27 remained behind the other 3 treatments, which were similar.
With increasing tree distance production per tree increased, but more so at PS than at WD. Tree yield at PS was much lower than at WD in spite of the larger trees at the former site.
Per ha the production of the treatments followed the same trends as the tree yield on the understanding that ha production increased with decreasing tree distance.
Trees with M.27 interstem planted at 0.75 m in the row gave the highest yields, but significantly so only at WD.
The production efficiency of M.27 was higher than that of M.9, especially as a rootstock.
In general the M.27 rootstock was more efficient than the M.27 interstem; with M.9 both were more alike.
Tree distance hardly affected efficiency at PS, but at WD efficiency increased with decreasing tree distance.
At PS efficiency was much lower than at WD.
Fruits of M.27 trees tended to be smaller than those of trees with a M.9 component, but significantly so only in a few cases.
Apples from M.27-interstem trees tended to be slightly larger than those from M.27-rootstock trees.
With M.9 this was not the case.
Fruit weights at PS were lower than at WD.
Trees on M.27 rootstock were considered too small.
At PS trees on M.27 interstem are considered worthy of further attention, because the M.9 rootstock often induces too much growth.
At WD trees on M.9 rootstock are preferred.
The differences between the treatments and the sites are discussed.