BGN 9: Allele tests of seedling lethal mutants on chromosome 2 BARLEY GENETICS NEWSLETTER, VOL. 9, II. RESEARCH NOTES
Ramage and Scoles, pp. 78-79

II. 38. Allele tests of seedling lethal mutants on chromosome 2.

R.T. Ramage and Margaret Patten Scoles, Department of Plant Sciences, University of Arizona, Tucson, Arizona 85721, U.S.A. "R"

A large number of mutants for seedling lethality have been induced on chromosome 2 of barley. These mutants are closely linked in coupling with the male sterile allele, msg2. The mutants are being allele tested to determine the number of loci involved and are being established in balanced tertiary trisomic form (Ramage et al., 1972; Ramage and Jones, 1975, 1976). This communication reports progress made in determining the number of loci involved in the mutant collection.

We have now identified 15 loci with from one to 12 mutants at each locus. The 15 loci are being labeled with the number of the first mutant assigned to that locus and are: 3, 15, 40, 58, 153, 237, 253, 279, 369, 530, 583, 651, 737, 767 and 794. Twelve mutants have been assigned to the 369-locus which is the locus designated alb,,p by Rahman and Eslick (1976). Ten mutants have been assigned to the 15-locus and four to the 360-locus. Four loci, each containing two alleles have been identified: 530 and 758, 767 and 774, 208-a and 308-a and 208-x and 308-x. The number of possible loci involved in the collection has been reduced to thirty-six. The allele tests are being continued and are nearing completion. For example, the 208-a mutant needs one more cross and the 229, 360 and 126 mutants each need two more crosses to complete their allele tests.

As loci have been identified, one allele at each locus has been crossed to tertiary trisomics in order to establish them in balanced tertiary trisomic form. Four mutants have been established (143 at the 15-locus, 253, 279 and 369) and most of the other identified loci are in the process of being established in BTT form. The BTT's have greatly facilitated allele testing because all of the functional pollen produced by them carries the seedling lethal allele.

References:

Rahman, M.M. and R.F. Eslick. 1976. Linkage of spontaneous mutant seedling lethal genes with genetic male sterile genes. Barley Genetics Newsletter 6:53-58.

Ramage, R.T. and J.M. Jones. 1975. Induction of mutations for seedling lethality on chromosome 2. Barley Genetics Newsletter 5:44-45.

Ramage, R.T. and J.M. Jones. 1976. Mutations for seedling lethality on chromosome 2. Barley Genetics Newsletter 6:58-59.

Ramage, R.T., &.A. Wiebe, R.F. Eslick and R.K. Thompson. 1972. Use of mutagenic agents in hybrid barley breeding. Barley Newsletter 15:73-78.

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