IX. 1 Correction of barley genetics literature
Zali, A.A. and R.W. Allard. 1976. The effect of level of heterozygosity on the performance of hybrids between isogenic lines of barley. Genetics 84:765-775.
In the "Materials and Methods" (P. 766) of the above-cited paper the
authors mentioned that (line 3 to 5):
"among four marker loci : Vv (two-versus six-rowed spikes, linkage group 1) ; Bl bl (blue versus white aleurone color, linkage group 4) ; Rr (rough versus smooth awn, linkage group 6) ; Oo (white versus orange lemma color, linkage group 7)."
Also in the lines 7 and 6 from the bottom of p. 766, these authors described:
"v v bl bl r r O o ms1ms1 This male-sterile line was produced and made available to us by Dr. C.A. Suneson, who used 19 backcrosses to transfer the ms allele (linkage group 5)..."
As most of the barley geneticists are familiar with the revision of the old system of designating linkage groups and chromosomes to the new one more than 15 years ago, it was quite a surprise to see this kind of confusion still existing among barley workers.
In the new system chromosome and linkage group are designated by the same numerals as shown in the table below. Vv alleles now belong to chromosome and linkage group 2 (formerly linkage group I, not 1). Rr is located in chromosome (linkage group) 7 (formerly linkage group V, but not 6), and Oo on chromosome (linkage group) 6. The Oo alleles have never been located in the old linkage groups, I - VII until 1963 when linkage relation was found between o and uc2 (Shands, 1963), o and ea7 (ec) by Ramage (1963) and o and xn (Robertson et al. 1965). Oo has never been located in linkage group 7.
The old linkage group IV became the new linkage group (and chromosome) 4 and carries Blbl alleles. Ms1ms1 alleles are associated with linkage group (and chromosome) 5 (but not with the old group V). Therefore these authors are right for these two cases.
This indicates that these authors confused the old and new systems of designating linkage groups. Also the relation between chromosome (linkage group) and marker gene was confused in some cases.
The readers of this issue will see the revised linkage map for chromosome 1 on the cover and a brief explanation of this revision. The system to show relationships between chromosomes and linkage groups with key marker genes was established by Kramer and Blander (1961, Crop Science 1:339-342) and Tsuchiya (1961, Jap. J. Genet. 36:444-451) as shown in the following table.
I hope this will help some of the workers who are still not familiar with the new system.
prepared by T. Tsuchiya
Department of Agronomy
Colorado State University
Ft. Collins, Colorado 80523
BGN 8 toc
BGN Main Index