The Cytogenetic Map of the Poncirus trifoliata (L.) Raf.—A Nomenclature System for Chromosomes of All Citric Species

摘要

A cytogenetic map was established for the trifoliate orange, Poncirus trifoliata. Chromosome size, centromere position and CMA+ heterochromatin content were determined for each chromosome pair, together with the position of BAC clones previously described as chromosome-specific markers. Although P. trifoliata is a true biological species, heteromorphisms for the size of the heterochromatic bands in two chromosome pairs were observed. A minimum set of four BACs was proposed for chromosome identification in P. trifoliata, as well as a chromosome nomenclature that can be applied to all citrus species. The Ctv locus was assigned to chromosome 9 and the remaining linkage groups can now be integrated to this physical map. This standard nomenclature for trifoliate orange will be valuable for genome-sequencing projects in all citrus species.