ISHS Acta Horticulturae 732: VIII International Symposium on Canopy, Rootstocks and Environmental Physiology in Orchard Systems
VALUE OF STANDARD AND NEW SELECTED ROOTSTOCKS FOR APPLES IN POLAND |
| Authors: | A. Czynczyk, T. Jakubowski |
| Keywords: | apple, rootstocks, subclones, interstem, dwarf, semi-dwarf, cropping efficiency coefficient, in vitro propagation, stoolbeds, rooting ability |
| Abstract:
Low winter hardiness of English rootstocks prompted the Research Institute of Pomology in Skierniewice, Poland, to start a breeding program to obtain dwarfing rootstocks suitable for the Polish climate. Rootstocks M.9, M.4 and M.11 were pollinated with the pollen of Antonovka and Longfield cvs. As a result of those crosses, many clones were selected from several thousand hybrids. At present, they are known as the P series: P1, P2, P14, P16, P18, P22. Based on the results obtained from many experiments, apple trees grafted on M.9, M.26, P2, P22, P14, M.7 and MM.106 were found to be the most suitable for Polish climatic conditions. The apple rootstock breeding program was continued using the rootstocks A2, B9, M.9, M.26, P16 and M. robusta 5 for crosses. As a result of that work, a number of new rootstocks have been developed. Among them, the most promising are the semi-dwarfing P60 and very dwarfing P59. In 1973, the program on mutation breeding with rootstocks M.26 and A2 was initiated. Size of tree on rootstock mutants PM 2 (M.26-29) and PM 3 (A2-3) were similar to trees grown on M.26, but yield from these trees were higher. The percentage of rootstocks used in apple tree production in Poland in recent years (about 5.5 million trees) is as follows: M.26 has a 40% share, M.9 and its subclones -27%, M.7 and MM.106 -9%. In recent years, the number of trees produced on M.9 and its subclones, such as M.9 T 337, M.9 RN 29, M.9 EMLA and M.9 ISK, has been increasing. Trees grafted on the Polish dwarfing rootstocks P2, P14, P16, P22, P59 and P60 have a total share of 18%. At present, the most used are the semi-dwarfing rootstocks P14 (8%) and P60 (7%). Under Polish climatic conditions, the P14 and P60 rootstocks will gradually replace M.26, M.7 and MM.106. All virus-free rootstocks for establishing nuclear stock stoolbeds are propagated by in vitro cultures. The apple rootstock breeding program was continued in the years 1975-79. The rootstocks P1, P2, P16, P22, M.9, M.26, M.7, MM.106, M. robusta 5, B9 and B146 were used for crossing to obtain hybrids resistant to collar rot diseases. Finally, 50 clones were selected for testing in the orchard experiment with two cvs. The most interesting dwarfing clones are P61, P62, P63, P64, P66 and P67. They were entered in the Polish Register of Cultivated Plants. Promising are also clones No 577, No 570, No 629 and No 649. In 2002, a new program was initiated which aimed at breeding dwarfing rootstocks tolerant to fireblight. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
