ISHS Acta Horticulturae 903: IX International Symposium on Integrating Canopy, Rootstock and Environmental Physiology in Orchard Systems
THE RESULTS OF THE ESTONIAN APPLE ROOTSTOCK BREEDING PROGRAM |
| Authors: | T. Univer, N. Univer, K. Tiirmaa |
| Keywords: | Malus × domestica, growth vigour, yield, parentage, propagation, winter hardiness |
| DOI: | 10.17660/ActaHortic.2011.903.14 |
| Abstract:
The Estonian apple rootstock breeding program was initiated in 1954, with the goal of obtaining rootstocks best suited for local soil and climatic conditions. The following parents were used: M.2, M.4, M.11, winter-hardy cultivars ‘Anoka’, ‘Chulanovka’, a seedling of ‘Ranetka Purpurovaya’ and local forms of Malus prunifolia. The program resulted in the release of 10 semi-vigorous and vigorous clones, marked with the letter E (for Estonia). A semi-vigorous rootstock E20 and vigorous rootstocks E53 and E56 were selected for production in nurseries. In more recent breeding activity (starting from 1970), E-series rootstocks and MM.106 have been used as parents. Two hundred sixty-seven clones were selected from the resulting seedlings, from which 43 promising clones were taken into orchard trials. Two semi-dwarfing clones (comparable to M.26) and three dwarfing clones (comparable to B.9) were selected in the orchard trials. E-series rootstocks are easy to propagate in stoolbeds and their roots tolerate temperatures down to -14 to -16°C. The rootstocks E53 and E75 are good parents for breeding winter hardy and productive mother plants. In propagation by layers in stoolbeds, the rooting capacity of apple rootstocks may decrease in older plants. Potential parents for breeding dwarfing and semi-dwarfing rootstocks in Estonia are the F3 generation from M8 (B.396, Pure 1, P59). | |
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