Kasha, pp. 90-92

IV. 7. Coordinator's Report: Chromosome 6.

K. J. Kasha, Crop Science Department, University of Guelph, Guelph, Ontario, Canada N1G 2W1. "R"

Linkage Map - Chromosome 6 Gene Order

The above gene order for chromosome 6 is the probable order based upon reported (and some of our unreported) linkage data. The gene order and direction near the centromere (location not precisely known) is msg6 o - g4 - sexl. Therefore, the data of Falk et al. (BGN 10:13-16) would place alb,,t in the short arm, probably distal to nec while alb,,q would be distal to fll in the long arm. The chlorophyll mutant fll is located between gs4 and mt,,f.

Associated Genes
In addition to cu3 (curly) and ert-3 (erectoides) listed in previous reports, a large number of new genes have been reported to be assigned to chromosome 6. Islam and Shepherd (1981) indicated that the isozymes GOT-1 (glutamate oxaloacetate transaminase) and AMP-1 (aminopeptidase) are on chromosome 6. Fischbeck and Hauser (BGN 6) reported a necrotic leaf spot mutant (non-allelic to the mutant 1339/62) was associated with chromosome 6. This mutant as well as the one placed on the linkage map have not been allele tested against the three necrotic leaf spot mutants reported by Jensen (1971) to be associated with chromosome 6. A second shrunken endosperm high lysine mutant Riso 527 is also on chromosome 6 and non-allelic to sexl (Jensen, 1979; Fastnaught, Eslik and Ullrich, BGN 11). Other such mutants; Riso 13, Riso 29, and Riso 86, are allelic to sexl.

Ramage, Clark and Crandall (1981) have assigned 31 new mutants to chromosome 6. These include 7 albino, 5 white stripe, 4 dwarf, 2 light green, 2 xantha, 2 male sterile, 2 defective endosperm xenia, 1 yellow stripe, l shrunken endosperm xenia, 1 light green stripe, 1 virescent, 1 prostrate growth habit, 1 desynaptic and 1 erectoid. These are now being allele tested among themselves and known genes on chromosome 6.

Ukai and Yamashita (1981) reported the production of two early mutations concerned with photoperiod response which are allelic to ea7.

New Stocks
Fujigaki and Tsuchiya (BGN 11) have obtained a new metacentric trisomic for chromosome 6.

Falk et al. (1981) and Falk and Kasha (1980, BGN 10; 1982) have produced and registered as GP59 a multiple marker gene stock of value for the presowing selection of seeds giving rise to male sterile plants. The stock contains msg6 - o - sexl closely linked in coupling and uc2 in repulsion. Plants heterozygous for the stock will produce shrunken and plump seeds and the shrunken seeds will produce male sterile plants about 98% of the time. Aspects of seed separation and crossing results are reported elsewhere in BGN 12.

We have found close linkage 2.7 + 3.0% between ribbon grass (unlocated gene rb) and a grandpa (gp,,?) mutation at Guelph (GBC445)

Seed stocks are available for various multiple marker genes for chromosome 6 including GP59.

References: (Other than BGN refs)

Falk, D. E. and K. J. Kasha. 1982. Registration of a shrunken endosperm, male sterile germplasm to facilitate hybridization in barley. Crop Sci. 22 (In press).

Falk, D. E., K. J. Kasha and E. Reinbergs. 1981. Presowing selection of genetic male sterile plants to facilitate hybridization in barley. Barley Genetics IV (In press).

Islam, A.K.M.R. and K. W. Shepherd. 1981. Wheat-barley addition lines: their use in genetic and evolutionary studies in barley. Barley Genetics IV (In press).

Jensen, J. 1971. Mapping of 10 mutant genes for necrotic spotting in barley by means of translocations. Barley Genetics II:213-219.

Jensen, J. 1979. Chromosomal location of one dominant and four recessive high-lysine genes in barley mutants. pp 89-96 In: Seed Protein Improvement in Cereals and Grain Legumes. Vol. 1 IAEA, Vienna.

Ramage, R. T., D. R. Clark and C. L. Crandall. 1981. Induction of mutations on chromosome 6 in barley. Barley Genetics IV (In press).

Ukui, Y. and A. Yamashita. 1981. Early mutants of barley induced by ionizing radiations and chemicals. Barley Genetics IV (In press).

BGN 12 toc
BGN Main Index