II. ll. Allele tests and BTT establishment of seedling lethal mutants on chromosome 2.
R. T. Ramage and M. P. Scoles. Department of Plant Sciences, University of Arizona, Tucson, Arizona 85721, U.S.A. "R"
A number of mutants for seedling lethality that are closely linked in coupling with the male sterile allele, msg2, have been induced on chromosome 2 (2,5). These mutants may be useful in producing female parents of hybrid barleys by the balanced tertiary trisomic method. This communication reports progress in determining the number of loci involved in the collection and in establishing the mutants in BTT form.
Seventeen loci have been identified (2,3,4) and we have labeled them 3, 15, 40, 58, 153, 208-a, 237, 253, 279, 360, 369, 530, 583, 651, 737, 767 and 794. Twelve mutants have been assigned to the 369 locus which has been designated alb,,p (1). Ten mutants have been assigned to the 15 locus and four to the 360 locus. Four loci, each having two alleles or mutational events, have been identified: 530 and 758, 767 and 774, 208-a and 308-a and 208-x and 308-x. Allele tests are nearing completion and the number of possible loci involved in the collection has been reduced to 36.
As previously reported (3,4), four of the mutants, 143 at the 15 locus, 253, 279 and 369, have been established in BTT form. These BTT's are also balanced for the male sterile allele, msg2. We have now established five more of the mutants in BTT form, 58, 116-x, 530, 415-x and 737. Crosses are being made to confirm that these new BTT's are balanced for both the seedling lethal mutants and the male sterile allele, msg2. The use of BTT's greatly facilitates allele testing as all of the functional pollen produced by them carries the mutant allele. We plan to establish BTT's balanced for both the male sterile allele msg2 and for a seedling lethal allele for each locus represented in the collection.
References:
1. Rahman, M. M. and R. F. Eslick. 1976. Linkage of spontaneous mutant seedling lethal genes with genetic male sterile genes. BGN 6: 53-58.
2. Ramage, R. T. and J. M. Jones. 1975. Induction of mutations for seedling lethality on chromosome 2. BGN 5: 44-45.
3. Ramage, R. T. and J. M. Jones. 1976. Mutations for seedling lethality on chromosome 2. BGN 6: 58-59.
4. Ramage, R. T. and M. P. Scoles. 1979. Allele tests of seedling lethal mutants on chromosome 2. BGN 9: 78-79.
5. Ramage, R. T., G. A. Wiebe, R. F. Eslick and R. K. Thompson. 1972. Use of mutagenic agents in hybrid barley breeding. Barley Newsletter 15: 73-78.