MOLECULAR GENETIC ANALYSIS OF THE Sd1 APHID RESISTANCE LOCUS IN MALUS

To facilitate a map-based cloning approach of the gene(s) responsible for the resistance to biotypes 1 and 2 of the rosy leaf curling aphid (Dysaphis devecta Wlk), saturated mapping has been initiated of the Sd1 region of linkage group 7 in the resistant apple variety ‘Fiesta’. This involves the identification of new markers using AFLP bulked segregant analysis, and establishment of detailed collinearity between the Sd1 region and corresponding region(s) of Arabidopsis. Fine ordering of the markers in the Sd1 region has been carried out by identification of additional key recombinants from the pool of over 2000 trees available from mapping and breeding populations resulting from crosses involving the varieties ‘Fiesta’, ‘Cox’ or other resistant derivatives.
Following pre-screening with linked markers, a number of genotypes have been identified and grafted.
Assessment of pest interactions of these plants has been carried out to provide the accurate trait data required for physical mapping.
Large-insert BAC clones of Malus genomic DNA have also been identified using markers within 1 cM of Sd1. This work will enable development of BAC contigs spanning the Sd1 region.

Eucarpia symposium on Fruit Breeding and Genetics

V. Cevik, G.J. King

Dysaphis devecta, apple, insect resistance, molecular markers, fine mapping, collinearity

https://doi.org/10.17660/ActaHortic.2000.538.97