Genetic linkage map of pecan (Carya illinoinensis) cultivars, using RAPD and AFLP markers.
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We report here the first genetic linkage maps of pecan, using random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphisms (AFLP) markers. Maps were constructed for the cultivars Pawnee and Elliot using double-pseudotestcross mapping strategy and using 120 F1 seedlings. A total of 477 markers, including 217(45.5%) RAPD and 258 (54.0%) AFLP markers and 2 (0.5%) morphological markers were used in linkage analysis. The ‘Pawnee’ linkage map has 218 markers, comprising 176 testcross and 42 intercross markers mapped on to 16 major linkage groups and 13 minor linkage groups. The ‘Pawnee’ map covered a total distance of 2,227 cM, with an average map distance of 12.7 cM between adjacent markers. The ‘Elliot’ linkage map has 174 markers, comprising 152 testcross and 22 intercross markers, mapped to 17 major and 9 minor linkage groups. The ‘Elliot’ map covered a total distance of 1,698 cM, with an average map distance of 11.2 cM between adjacent markers. Dichogamy type and stigma color genes were tightly linked and mapped to ‘Elliot’ linkage group 16. These linkage maps are an important first step towards the detection of genes controlling complex traits such as nut size, nut phenology, kernel quality, and disease resistance. Markers linked to these traits could serve the breeding program by allowing marker-assisted selection of seedling trees for adult characteristics.