|Authors: ||M. Skrivele, E. Rubauskis, L. Ikase|
|Keywords: ||Malus × domestica, apple production, compatibility, yield efficiency|
In the first half of the previous century only East Malling clonal rootstocks were know to exist and for Latvia they did not have sufficient winter hardiness.
More extensive research of rootstocks began in the second half of the 20th century, when winter-hardy rootstocks were introduced from Michurinsk, Russia.
The first commercial orchards on clonal rootstocks were planted only a decade ago.
The variety of cultivars and rootstock combinations that can be found in orchards is large.
About 20% of the orchards have been planted on vigorous seedling rootstocks and are approximately 40 to 50 years old.
Of newer orchards, 53% are on medium vigor rootstocks, mostly MM.106 and M.26, at 666 or 1250 trees/ha.
Apple-trees on dwarfing rootstocks, mostly B.9 and B.396, are usually planted at 1250 trees/ha.
Only a small fraction of orchards on dwarfing rootstocks has been planted at 1660 trees/ha.
The early winter-winter cultivar ‘Auksis’, which is the most widely planted and most used in trials, on average gives 29-39 tons/ha from 7-10 year old trees on B.9, B.396, M.26 rootstocks at 1250 trees/ha.
Similar yield has been obtained on Mark and G.30 with 1250 trees/ha, and MM.106 with 666 trees/ha.
The yield efficiency was higher on B.396 and G.30 rootstocks.
Other widely planted cultivars ‘Antei’, ‘Kovalenkovskoe’, ‘Saltanat’, ‘Sinap Orlovskii’, ‘Zarya Alatau’ have good tree health and yield on these rootstocks.
The rootstocks Pure 1 (Latvian origin) and P 60, have shown promise in trials, but have not been broadly adopted.
Of the other tested rootstocks, clones of M.9, P 2, P 22, B.146, B.257, B.476, B.490 and B.491 are not suitable in Latvian conditions, for different reasons.
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