BGS474
Stock number: BGS474
Locus name: Laxatum-a
Locus symbol: lax-a
Previous nomenclature and gene symbolization:
Laxatum 01 = lax 01 (2, 5, 9).
Laxatum-a = lax-a^01^ (10).
Inheritance:
Monofactorial recessive (6, 10).
Located in chromosome 7L (6, 8), about 2.4 cM proximal from the ari-e
(breviaristatum-e) (4, 12), and about 3.1 cM from the ert-g
(erectoides-g) locus (4, 11, 12).
Description:
Florets have five anthers with two developing from transformed lodicules (2, 14).
The grain is thin and angular with the caryopsis exposed between the
lemma and palea. The awn has a very wide base, without a distinct notch in the
lemma attachment region. Rachis internodes are 13% longer than normal.
Tillers arise at oblique angles giving isolated plants an appearance of a tufty
growth habit (5). Treatment of leaves after tillering with GA`3` increased rachis
internode length (13).
Origin of mutant:
A gamma-ray induced mutant in Bonus (PI 189763) (1, 5, 7).
Mutational events:
lax-a.01, -a.4, -a.8, -a.20, -a.37, -a.39, -a.54 in Bonus (5, 7);
lax-a.92 in Bonus (7); lax-a.208, -a.218, -a.222, -a.229, -a.249,
-a.256, -a.278, -a.286 in Foma (CI 11333) (5, 7); a lax-a mutant
(Mut 2100/61) in Proctor (PI 280420) (3).
Mutant used for description and seed stocks:
lax-a.8 in Bonus (T??); lax-a.8 in Bowman*7 (BGS5611).
References:
1. Ehrenberg, E., Å. Gustafsson, and U. Lundqvist. 1961. Viable mutants
induced in barley by ionizing radiations and chemical mutagens. Hereditas
47:257-278.
2. Gustafsson, Å., A. Hagberg, U. Lundqvist, and G. Persson. 1969. A
proposed system of symbols for the collection of barley mutants at Svalöv.
Hereditas 62:409-414.
3. Häuser, H., and G. Fischbeck. 1972. Translocations and genetic analysis
of other mutants. BGN 2:28-29.
4. Jensen, J. 1981. Construction of a barley chromosome 7 linkage map. p.
927-939. In M.J.C. Ascher, R.P. Ellis, A.M. Hayter, and R.N.H.
Whitehouse. (eds.) Barley Genetics. IV. Proc. Fourth Int. Barley Genet. Symp.
Edinburgh, Edinburgh University Press.
5. Larsson, H.E.B. 1985. Morphological analysis of laxatum barley
mutants. Hereditas 103:239-253.
6. Larsson, H.E.B. 1985. Linkage studies with genetic markers and some
laxatum barley mutants. Hereditas 103:269-279.
7. Lundqvist, U. (unpublished).
8. Persson, G. 1969. An attempt to find suitable genetic markers for the dense
ear loci in barley II. Hereditas 63:1-28.
9. Persson, G., and A. Hagberg. 1965. Localization of nine induced mutations in
the barley chromosomes. Barley Newsl. 8:52-54.
10. Persson, G., and A. Hagberg. 1969. Induced variation in a quantitative
character in barley. Morphology and cytogenetics of erectoides mutants.
Hereditas 61:115-178.
11. Søgaard, B. 1974. Three-point
tests on chromosome 1 and 7. BGN 4:70-73.
12. Søgaard, B. 1977. The localization of eceriferum loci in barley. IV.
Three point tests of genes on chromosome 7 in barley. Carlsberg Res. Commun.
42:35-43.
13. Stoy, V., and A. Hagberg. 1967. Effects of growth regulators on ear density
mutants in barley. Hereditas 58:359-384.
14. Wettstein, D. von, Å. Gustafsson, and L.Ehrenberg. 1959.
Mutationforschung und Züchtung. p. 7-50. In Arbeitsgemeinschaft
für Forschung des Landes Nordrhein-Westfalan, Heft 73. Westdeutscher
Verlag Köln und Opladen.
Prepared:
H.E.B. Larsson and U. Lundqvist. 1986. BGN 16:57.
Revised:
U. Lundqvist and J.D. Franckowiak. 1996. BGN 26: