Since the last reports in Barley Genetics Newsletter (BGN) not many allelic tests have been performed or reported.

The eceriferum gene cer-u is part of a complex locus cer-cqu which controls epicuticular wax layer formation on the surface of the spike, leaf sheath and stem. The deposition of ß-diketone lipids is reduced or eliminated by mutants in the cer-cqu gene. Specifically the cer-u gene has impaired hydroxyl group insertion (von Wettstein-Knowles, 1972, 1992). The surface wax coating on the spike, leaf sheath and stem appears to be reduced, with a wax code + + ++ (+=reduced, ++=normal). 160 mutation events belong to this locus (Lundqvist and von Wettstein, 1962; Lundqvist and Lundqvist, 1988).

The mutant gs8 was induced in the Japanese variety Akashinriki (stock number OUM 24 and OUM 31 from Okayama, Japan) with ethyl methanesulfonate (Konishi, 1973). The surface wax coating of this mutant on the spike, the leaf sheath and stem appears to be absent or reduced with a wax code -/+ -/+ ++ (-=absent, +=reduced). Rasmusson and Lambert (1965) localized gs8 in chromosome 2 not far from e (wide glume), and they suggested that gs5, also located in chromosome 2, might be the same as gs 8. Takahashi et al., (1966) reported location in chromosome 2, but were suspicous if they are the same genes. The same authors verified this localization in 1971, but after several linkage studies they concluded that gs5 and gs8 are two different genes in chromosome 2 .

In Sweden, the gene gs8 was tested against the Swedish eceriferum loci with the phenotypes of reduced wax coating and absent wax coating on the spike, leaf sheath and stem. In the F/1/ generation in 1994, all plants of two alleles at the eceriferum locus cer-u in combination with gs8 were glossy sheath or waxless, while the F/1/ plants of crosses to representatives of all the other loci, cer-c and cer-q, inclusively, with the same glossy sheath/spike phenotype had normal wax layer. It should be observed that the Swedish alleles of the cer-u locus are in two-row barley and the gene gs8 is in six-row barley. The F/1/ plants were of six-row heterozygous character. Thus, it can be settled that the Swedish eceriferum locus cer-u is allelic to gs8. This is even very likely, as the loci cer-c, cer-q and cer-u are closely linked and located in the very end of the short arm in chromosome 2 (von Wettstein-Knowles, 1992; Franckowiak, 1995).

The F/2/ generation will be grown and tested during the summer of 1995.

The Swedish eceriferum collection, as reported in BGN 24:174, is maintained at the Nordic Gene Bank and is available for every research worker and plantbreeder. Seed requests of the mutant stocks can be sent to the coordinator for eceriferum genes.

References:

Franckowiak, J.D. 1995. Coordinator's report: Chromosome 2. BGN 24:

Konishi, T. 1973. Genetic analyses of EMS-induced mutants in barley. BGN 3:28-31.

Lundqvist, U., and Lundqvist, A. 1988. Mutagen specificity in barley for 1580 eceriferum mutants localized to 79 loci. Hereditas 108:1-12.

Lundqvist, U., and Wettstein. D. von. 1962. Induction of eceriferum mutants in barley by ionizing radiations and chemical mutagens. Hereditas 48:342-362.

Rasmusson, D.C. and Lambert, J.W. 1965. Inheritance of the Glossy Sheath character in barley, Hordeum vulgare L. Crop Science 5:251-253.

Takahashi, R., Hayashi, J., Moriya, Y. and Hirao, Ch. 1966. Linkage studies. Barley Newsletter 9:68-69.

Takahashi, R., Hayashi, J. and Moriya, I. 1971. Linkage studies in barley. BGN 1:51-58.

Wettstein-Knowles, P. von. 1972. Genetic control of ß-diketone and hydro-ß-diketone synthesis in epicuticular waxes of barley. Planta 106:113-130.

Wettstein-Knowles, P. von. 1992. Molecular genetics of the lipid synthesis in barley. Barley Genetics VI, Vol. II. Proc. Sixth Int. Barley Genet. Symp. Helsingborg 1991 (Eds. L. Munck, K. Kirkegaard and B. Jensen), Munksgaard International Publishers Ltd., Copenhagen K, Denmark. p. 753-771.