II. 26 Linkage studies of msg 6 using four translocations involving chromosomes 5 and 6.
L. Lehman and P. Hagberg. Swedish Seed Association, S-268 00 Svalöv, Sweden "R".
The male sterile msg 6 has been described by Eslick et al. (1974) as being located near the centromere of chromosome 6 and possibly in the long arm. The mutant has been extensively studied by Roath and Hockett (1971) and by Ahokas (1975a, 1975b). Ahokas described the mutant msg 6 pollen as being inaperaturate and non-functional.
Four T5-6's which have had their breakpoints proposed by G. Hagberg et al. (1975) were used in this study. The translocations were crossed onto male sterile plants (msg6 msg6) from the BTT 67b msg6 line which had been provided by R.T. Ramage.
The linkage data, based on F3 readings and computed using the maximum likelihood method, are shown in Table 1, as well as the proposed breakpoints of the translocations. The data confirm that the msg 6 gene is located near the centromere of chromosome 6 because linkage was found regardless if the breakpoints were located in the long or short arm. T5-61 showed closer linkage to msg 6 than T5-6m. The latter's breakpoint is in the satellite of chromosome 6. The linkage data (Table 1) also indicate that the breakpoint of T5-6a is located closer to the centromere than T5-6b.
Table 1. F2 linkage data based on F3 plant rows.
References:
Ahokas, H. 1975a. Male sterile mutants of barley. I. Inaperturate pollen
of the msg6 cf mutant. An. Bot. Fennici 12:17-21
Ahokas, H. 1975b. Male sterile mutants of barley. II. Cttochemical of non-mutant and msg6 of microspore and pollen. Hereditas 81:33-45.
Eslick, R.D., R.T. Ramage, and D.R. Clark. 1974. Two genetic male steriles, msg6 and msg,,bk assigned to chromosome 6. BGN 4:11.
Hagberg, G., L. Lehmann, and P. Hagberg. 1975. Segmental interchanges in barley. I. Translocations involving chromosome 5 and 6. Hereditas 80:73-82.
Roath, W.W. and E.A. Hockett. 1971. Genetic male sterility in barley. III. Pollen and anther characteristics. Crop Science 11:200-203.
