Chromosomal variation in the K2T genome complex of polyploid Trilliums

Abstract

Chromosomal variation in the tetraploid species Trillium tschonoskii (4x= 20, K2K2TT) from a population in Hokkaido and three populations in Kyushu was analyzed by the patterns of H-segments which were revealed by cold treatment of the chromosomes. Chromosomal variation in the K2T genome complex in the interspecific hybrid, T.×miyabeanum (4x=20, K2TSU), was also analyzed. A total of 21 different chromosome types were distinguished in the K2T complex, i.e., A1-A2 in chromosome A, B1-B4 in B, C1-C6 in C, D1-D4 in D, and E1-E5 in E. All were assortable into two series of homologous chromosomes, K2^* and T^*. K2^* is either the genome K2 or T in each of the chromosomes A to E. The same holds true for T^* also. Since K2^* and T^* were both polymorphic in all chromosomes, A to E, it is valid that both the genomes K2 and T are chromosomally polymorphic. Consequently, it is certain that both extinct diploid progenitors, K2K2 and TT, are chromosomally polymorphic.