A genetic map of citrus based on the segregation of isozymes and RFLPs in an intergeneric cross.

Isozymes and restriction fragment length polymorphisms were used as markers in the construction of a genetic map of the citrus nuclear genome. The map was based on the segregation of 8 isozyme, 1 protein, and 37 RFLP loci in 60 progeny of a cross of two intergeneric hybrids, 'Sacaton' citrumelo (Citrus paradisi Macf. x Poncirus trifoliata (L.) Raf.) and 'Troyer' citrange (C. sinensis (L.) Osbeck x P. trifoliata), often used as rootstocks. The map contains 38 of 46 studied loci distributed on ten linkage groups. A genome size of 1,700 cM was estimated from partial linkage data. Approximately 35% of the genome should be within 10 cM and 58% within 20 cM of the mapped markers. Eight loci in three linkage groups and 1 unlinked locus deviated significantly from Mendelian segregation.