KARYOTYPE STUDIES ON SIX TAXA OF CAMELLIA IN CHINA
Li Guangtao and Liang Tao (Institute of Tea,Yunnan Academy of Agricultural Sciences, Xishuangbanna )
The present paper deals with the karyotypes of 4 species and 2 varieties of Camellia in China by wall degradation hypotonic treatment and flame-drying method. According to the classification systems given by Levan et al. the karyotype formula of C. taliensis with 2n=20m+2m ( SAT )+8sm; C. manglaensis with 2n=20m+2m ( SAT ) +6sm+2sm ( SAT ); C. dehungensis with 2n= 20m+8sm+2sm ( SAT ) ; C. assamica var. kucha with 2n=20m+9sm+1sm ( SAT ); C. sinensis with 2n=16m+2m ( SAT ) +12sm; C. sinensis var. pubilimba with 2n=18m + 2m ( SAT ) +9sm+1sm (SAT). All of these species were diploid (2n=2X=30), no polyploid wal found. Two B-chromosomes were found in the karyotype of C. manglaensis. The karyotype asymmetry demonstrates that all of these species belong to 2A type of Stebbins karyotype symmetry. The variation in number and position of SAT-chromosome; the longest chromosome/the shortest chromosome; proportion of chromosome with arm ratio 2:1 (%) ; centromeric ter-minalization value; the chromosome length " among these species are obvious. The variation in karyotype demonstrates that the chromosomal evolution in these species are C. taliensis-→C. manglaensis-→C. dehungensis-→C. assamica-→ C. sinensis var. pubilimba-→C. assamica var. kucha-→C. sinensis. The results basically tallied with viewpoint in "A Taxonomy of the Genus Camellia" of Chang Hunta. The heterozygosity and polymorphism of karyotype on Camellia plants are also discussed in this paper. The chromosome number and karyotype of C. manglaensis, C. dehungensis, C. assamica, var. kucha and C. taliensis are reported here for the first time.