IV.9. Desynaptic genes.
J. M. Hernandez-Soriano and R. T. Ramage. Department of Agronomy and Plant Genetics, University of Arizona, Tucson, Arizona 85721, U.S.A.
Last year (BGN 2:65-68) we reported that 12 desynaptic mutants had been assigned to 8 loci and that an additional 11 desynaptic mutants had been collected but not assigned to loci. Allele tests to assign mutants to loci and the collection of new mutants are being continued. The present status of the desynaptic mutant collection is shown in Table 1.
Since last year, three mutants have been assigned to loci: des,,v is allelic to des 1a and des,,m and des,,o are allelic to des 6i. The unassigned mutants des,,p and des,,q are allelic as are des,,s and des,,w. Two new mutants, of spontaneous origin in the cultivar Ingrid, were added to the collection and assigned the symbols des,,x and des,,y.
Several of the desynaptic mutants exhibit various anomalies. When des 5 is crossed with certain non-allelic desynaptics, the F1 frequently shows a low degree of desynapsis (up to 3 rod bivalents). The mutants des 8k and des 81 are allelic and exhibit similar cytological behavior. They are very different in percent selfed seed set: des 8k sets about 20 to 30% while des 81 is almost completely self sterile. There is little difference in crossed seed set on the two mutants, so the difference in selfed seed set is due to some form of male sterility in des 81. The mutant des,,t exhibits other meiotic abnormalities such as stickiness of chromosomes and fragmentation of prophase I chromosomes.
Descriptions of all of the desynaptic mutants that have been assigned to loci have been prepared for inclusion in this issue of BGN.
Limited amounts of seed of the desynaptic mutants are available upon request from R. T. Ramage, Agronomy and Plant Genetics Department, University of Arizona, Tucson, Arizona 85721, U.S.A.
