Randomly amplified polymorphic DNA-based genetic linkage maps of three apple cultivars

Genetic linkage maps were created for three apple (Malas x domestica Borkh.) cultivars using data from two progenies ('Wijcik McIntosh' x NY75431-67 and 'Wijcik Mcintosh' x NY75441-58). The maps consist primarily of randomly amplified polymorphic DNA (RAPD) markers, but also contain six isozyme loci and four morphological markers (R-f, fruit skin color; V-f, scab resistance; Co, columnar growth habit; Ma, malic acid). Maps were constructed using a double pseudo-testcross mapping format and JoinMap mapping software. An integrated 'Wijcik McIntosh' map was produced by combining marker data from both progenies into a single linkage map. Homologous linkage groups from paternal maps were paired with their counterparts in the 'Wijcik McIntosh' map using locus bridges composed of markers heterozygous in both parents of a progeny. The 'Wijcik McIntosh' map consists of 238 markers arranged in 19 linkage groups spanning 1206 cM. The NY 75441-67 map contains 110 markers in 16 linkage groups and the NY 75441-58 map consists of 183 markers in 18 linkage groups. The average distance between markers in the maps was approximate to 5.0 cM.