BGN 2: Tight linkage of the awnless gene in Engleawnless with the Vv locus BARLEY GENETICS NEWSLETTER, VOL. 2, II. RESEARCH NOTES
Wiebe, p. 108

II.43. Tight linkage of the awnless gene in Engleawnless with the Vv locus.

G. A. Wiebe. Collaborator, USDA, ARS, PSRD, Cereal Crops Research Branch, Beltsville, Maryland 20705, U.S.A.

Englelawnless CI 3119 is an awnless 2-rowed barley from Iraq. It was crossed with Manchuria CI 2330, a 6-rowed fully awned variety. The F1 is awnless or nearly so with considerable seed set in the lateral flowers. The F2 gave only three types; 2-row awnless, the F1 type, and 6-row awned in a 1:2:1 ratio. Additional F2 populations gave similar results. Since the heterozygote F1 type is easily identified, a large number of such plants were saved. A large F2 population of approximately 200,000 plants were grown over a 3-year period. Not a single 2-rowed awned or a 6-rowed awnless plant was recovered. It is concluded these two genes are very tightly linked.

It would seem very unusual if the Vv locus controlled both row type and awning, or conversely for the awning locus. The existence of a short inversion covering the Vv and awning loci is suggested as an explanation for these results. Crossing over as measured by recombinants is drastically reduced within the inversion loop because of the formation of duplications and deficiencies. Barley workers have long observed many associated differences between 6-rowed and 2-rowed genotypes in their breeding and research programs, and I found a similar pattern in my 20 pairs of 6-rowed vs 2-rowed isogenic lines. These observations support the notion of an inversion at the Vv locus.

BGN 2 toc
BGN Main Index