K. YAMASHITA
Division of Cytogenetics, Biological Laboratory, Kyoto University, Kyoto, Japan
The main principles of the reciprocal translocation method or RT-method are ex- cerpted from Yamashita (1951) as follows : (1) If a normal plant having a certain gene is crossed with a certain RT-type with known chromosome rearrangement, the hybrids have (4) in F1 generation and segregate 7II normal : (4) : 7II RT-homozygote in a ratio, of 1 : 2 : 1 in F2 generation. (2) If the transmission of the gene is linked with the RT chromosome complex, for instance a-b, the gene must be located on either a- or b- chromosome, and if it is free from b-c, then it must be located on a-chromosome. (3) If the transmission of the gene is linked with both a-b and b-c, it must be located on a common chromosome b.
By this method a considerable number of gene locations have been established. The following table shows the tentative results obtained in the 1956 season.
