A segregation distortion factor linked to Iys3a on chromosome 7 has been reported (Doll, 1991) which influences the frequency of homozygous recessive segregants by the frequency of homozygous recessive segregants by decreasing the proportion transmitted through the male gamete. The distorted frequency of mutant phenotypes varied from 1.2 to 7.3% in certain crosses compared to the expected frequency of 1:3.

Franckowiak (1991) tested 45 male sterile mutants against R. I. Wolfe's multiple marker stocks in order to find their chromosome location by estimating linkages between the mutants and chromosome specific markers. Seven of the 45 mutants tested were shown to be linked to the r locus (semi-smooth awn) located on the long arm of chromosome 7. Two of these mutants had previously been shown to be linked to the T2-7a translocation breakpoint (Ramage and Eslick, 1975) and thus the two methods were shown to be complementary.

A 21% recombinant interval on the long arm of chromosome 7 controlled QTLs for 37-68% of the variation for three estimates of cold tolerance, 47% of the variation for growth habit and 28% of the variation for crown fructan content (Hayes et al., 1993).

Using telosomic wheat-barley addition lines, 23 characterized cDNAs and 2 genomic clones from barley were assigned to barley chromosomes by means of southern blotting and hybridization analysis (Cannell et al., 1992). The cDNAs for probably an amylase-protease inhibitor (Mundy and Rogers, 1986) and a 10.8 kDA photosystem I polypeptide (Okkels et al., 1988) were assigned to the long arm of chromosome 7 by this means.

References:

Cannell, M. A., A. Karp, P. G. Isaac, and P. Shewry. 1992. Chromosomal assignment of genes in barley using telosomic wheat barley addition lines. Genome 35:17-23.

Doll, H. 1990. A factor on barley chromosome 7 causing distorted male segregation of gene Iys3a. BGN 20:23.

Franckowiak, J. D. 1990. Association of male sterility genes with a specific chromosome using multiple marker stocks. BGN 20:31-36.

Hayes, P. M., T. Blake, T. H. H. Chen, S. Tragoonrung, F. Chen, A. Pan, and B. Liu. 1993. Quantitative trait loci on barley (Hordeum vulgare) chromosome 7 associated with components of winterhardiness. Genome 36:66-71.

Mundy, J., and J. C. Rogers. 1986. Selective expression of a probable amylase/protease inhibitor in barley aleurone cells: comparison to the barley amylase/subtilising inhibitor. Planta 169:51 -63.

Okkels, J. S., L. B. Jepson, L. S. Honberg, et al. 1988. A cDNA clone encoding a 10.8 kDa photosystem I polypeptide of barley. FEBS Lett 237: 108- 112.

Ramage, R. T., and R. F. Eslick. 1975. Translocation linkage tests - T2-7a x male sterile genes. BGN 5:46-48.