ISHS Acta Horticulturae 663: XI Eucarpia Symposium on Fruit Breeding and Genetics
IDENTIFYING GENETIC MARKERS FOR AN APPLE ROOTSTOCK DWARFING GENE |
| Authors: | R.L. Rusholme, S.E. Gardiner, H.C.M. Bassett, D.S. Tustin, S.M. Ward, A. Didier |
| Keywords: | linkage analysis, genetic mapping, single nucleotide polymorphism, QTL, bulked segregant analysis, Malling 9 |
| Abstract:
The mechanism by which a rootstock induces dwarfing in apple (Malus x domestica) is not well understood and little is known of its genetic control. Genetic analysis of a segregating population derived from a cross between Malling 9 and the vigorous non-dwarfing rootstock ‘Robusta 5’ revealed that the ability of the rootstock to dwarf the scion could be divided into four phenotypic classes, suggesting that it may be possible to resolve dwarfing as a qualitative genetic trait controlled by as few as 2 major genes. Bulked segregant analysis yielded a group of four linked loci associated with dwarfing. Using the phenotypic extremes from this population, the putative dwarfing locus was mapped to a 2.5 cM region flanked by a SNP marker and a RAPD marker. Dw1 is the first reported rootstock dwarfing gene to be genetically mapped, and is a key step in unravelling the precise mechanism behind the phenomenon of dwarfing by apple rootstocks. | |
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