Chromosome composition of some citrus species and cultivars based on the chromomycin A3(CMA) banding patterns

Abstract

Chromosomes which were derived enzymatically from young leaves of the following species and cultivars were sequentially stained with Giemsa, chromomycin A3(CMA), and quinacrine mustard (QM): 'Suisho-Buntan', 'Banpeiyu' and 'Ban- okan' pummelo (Citrus grandis [L.] Osb.), fingered citron (C. medica L. var. sarcodactylis), 'Okitsu- Wase' satsuma mandarin (C. unshiu Marc.), koji (C. leiocarpa hort. ex Tanaka), and 'Duncan' grapefruit (C. paradisi Macf.). The chromosome compositions are: 3A+3C+3D+9E in 'Suisho- Buntan', 2A+1B+3C+3D+9E in 'Ban- okan', 2B+8D+8E in fingered citron, 1A+IC+8D+8E in 'Okitsu- Wase', 1C+8D+9E in koji and 2A+1B+1C+6D+8E in 'Duncan'. In 'Banpeiyu', the composition of the 17 chromosomes was 1A+2B+2C+4D+8E; the remaining chromosome could not be discerned whether it was A or B. In all species and cultivars except fingered citron, some chromosome CMA bands are not paired, indicating that some exist as partial homologue chromosomes. Type- D and type- E chromosomes are predominant types in species or cultivar, such as fingered citron, 'Okitsu- Wase', and koji. They are considered to have differentiated earlier during their phylogeny. Therefore, it is thought that type- D and type- E chromosomes are the basic types in citrus.