II.7 Genetic and linkage studies of the five types of induced 'six-row' mutants.
Fukuyama, T., J. Hayashi and R. Takahashi. The Ohara Institute for Agricultural Biology, Okayama University, Kurashiki, Japan.
This work was commenced in order to answer the following questions; (1) Can all the known induced 'six-row' mutants be attributable to a change from V to v? t2) If not, how many different genetic changes have occurred which are similarly able to bring about the fertile lateral florets?
As reported in BGN 2, we have made an allelism test using a total of 32 induced 'six-row' mutant lines which had kindly been provided by the following workers: Prof. A. Moës (Belgium), Drs. E. Pollhamer (Hungary), F. Scholz (East Germany) and T. Tsuchiya (U.S.A.), to whom we are obliged very much. As the result, these mutants were known to be classified into five distinct types. Thereafter, three additional mutants were received from Mr. Hirai, Kirin Brewery Co. Tokyo. So, they were subjected to a similar allelism test, using 2 or 3 mutant lines taken from each of the five different genotypes stated above. The result has shown that two of them are resulted from the change to v from V, but the remaining one line, 38X-193, has a gene different from anyone of the five known genes. This was hence named v5. In the following table are given the genes involved in each of these six different 'six-row' mutant types and their respective head characters.
Linkage study: In 1973-1974 season we have been successful in locating three 'six-row' genes, v3, v4 and v5, on chromosomes 5, 3, and 4, respectively. The methods used and summarized results are given below.
Detection of linkage of the gene, v3 in Kmut 213, was made by the method of trisomic analysis. The F2 data, shown in Table 1, clearly indicates that the gene v3 is on chromosome 5.
Table 1. Linkage of the gene, v3 in Kmut 213, by the method of trisomic analysis.
The linkage of the gene v4 in Gamma III 3/B, was studied by the use of two crosses of the mutant with LT 16 and Russian 56. As shown in Table 2, F2 segregation of v4 in relation to uz involved in LT. 16 indicates the linkage between these two genes with 27.6% recombination. In the same F2 tests, the data showing independent inheritance of the markers, n, K, B, trd, o, and s on chromosomes 1, 4, 5, 5, 6 and 7, respectively were obtained, though they are not shown here.
Table 2. Linkage of the genes, v4 and v5 in Gamma III3/B and 38X-193, respectively.
For the linkage analysis of v5 in 38X-193, crosses were made with three testers, LT 16, Russian 56 and Nigrinudum. The F2 data indicated that the gene v5 is linked with K on chromosome 4 with 16.2% recombination. The data is given in Table 2. The gene v5 was known to be independent of n, uz, B and trd, o and s, on chromosomes 1, 3, 5, 6 and 7, respectively (the data omitted).
