II.8 Positioning sex l on chromosome 6.
R.F. Eslick and M.N. Ries. Department of Plant & Soil Science, Montana State University, Bozeman, MT. 59715, U.S.A.
Jarvi and Eslick (1975) assigned the shrunken endosperm gene, sex 1, to chromosome 6 with translocations. Recombinations of sex 1 with several translocations were reported.
Ramage and Paluska (1975) reported on recombination of a series of translocations with the male sterile gene, msg,,bk. Using combined recombination values for a number of translocations known to be broken in the long arm of chromosome 6 they determined msg,,bk to be carried on the short arm of chromosome 6, .07+ .011 recombination units from the centromere.
Eslick et al. (1974) reported a combined recombination value of .063 + .006 between orange lemma, o and msg,,bk.
On the basis of data presented by Ramage, et al. (1961) we have assumed for some time that o is located very near the centromere of chromosome 6.
Three point linkage data for msg,,bk - o - sex 1 are presented in table 1. The genes will most satisfactorily map in that order, figure 1.
This mapping would place sex 1 on the long arm of chromosome 6 but very near o and is not inconsistent with previously reported data.
Table 1. F3 segregation from the msg,,bk o Sex 1 / Msg,,bk O Sex 1 genotype.
Literature cited:
Eslick, R.F., R.T. Ramage, and D.R. Clark. 1974. Two genetic male steriles, msg 6 and msg,,bk assigned to chromosome 6. BGN 4:11-15.
Jarvi, A.F., and R.F. Eslick. 1975. Shrunken endosperm mutants in barley. Crop Sci. 15:363-366.
Ramage, R.T , C.R. Burnham, and A. Hagberg. 1961. A summary of translocation studies in barley. Crop Sci. 1:277-279.
Ramage, R.T. and M. Paluska. 1975. Mapping chromosome 6. BGN 5:49-51.
