ABSTRACT:In Pinus , Subgenus Pinus 16 species were investigated on their somatic chromosomes by a fluorescent banding technique using chromomycin A 3 (CMA) and 4',6-diamidino-2-phenylindole (DAPI). The chromosome number of 2n=24 was commonly counted in all the species studied. Their karyotypes were composed of many long metacentric chromosomes and a few short submetacentric chromosomes, and two karyotypes were recognized in respect to number of short chromosomes in the subgenus. CMA-bands appeared at an interstitial and/or proximal region of chromosomes and DAPI-band did at a proximal region. Thin DAPI-bands appeared at interstitial regions and DAPI-dots appeared at a centromeric region in most chromosomes. In a chromosome complement each homologous chromosome was identified on the base of its shape and fluorescent banding pattern. The typical banding patterns were compared among the species studied. Many interstitial CMA-bands at the secondary constrictions appeared on many metacentric chromosomes. Proximal fluorescent bands varied in fluorescent nature and number and divided into several groups. Section Pinus short three chromosome pairs were two or three patterns of fluorescent banding. The section Trifolae species had many proximal DAPI-bands and less proximal CMA-bands than section Pinus. The shortest chromosome had proximal bands indicating two groups on the kinds of fluorescent band.

Somatic chromosomes of seven taxa of Asian haploxylon pines, Pinus armandii var. amamiana, P. armandii var. armandii, P. parviflora, P. pumila, P. x hakkodensis, P. koraiensis and P. bungeana, and a American species of P. edulis were observed by a fluorescent banding method using chromomycin A 3 (CMA) and 4',6-diamidino-2-phenylindole (DAPI). The chromosome number of all taxa was 2n=24 and their karyotypes were composed of 22 long metacentric chromosomes and two short heterobrachial chromosomes as previous reports. CMA-bands appeared at the interstitial region and not at the proximal region of metacentric chromosomes. Interstitial CMA-bands were observed on 16-18 long metacentric chromosomes in chromosome complement of most species excepting for P. bungeana having six interstitial CMA-bands. The short chromosomes of most species have an interstitial CMA-band on their long arms and that of P. edulis had a proximal CMA-band. Clear proximal CMA-or DAPI-bands appeared in most species of subgenus Pinus were not observed in species of subgenus Strobus examined. DAPI-dots appeared at centromeric regions of all chromosomes and many thin DAPI-bands did at interstitial regions as appeared in the species of subgenus Pinus. The karyotype analysis combined with CMA-and DABI-bandings was useful for identification of each homologous chromosome and for chromosomal relationship among species in haploxylon pines.