Biochemical markers controlling isozymes and seed proteins are useful for linkage analysis in barley. Shepherd and Islam (1987) summarized that a total of 55 loci for biochemical characters have been assigned to barley chromosomes using wheat-barley addition lines. 0ut of them, 7 loci have been assigned on chromosome 3, but only a few loci have been localized on the chromosome. Three loci, Est1, Est2, and Est4, for esterase isozymes are closely linked (Kahler and Allard 1970; Nielsen and Frydenberg, 1971a), and located on chromosome 3 by means of trisomics (Nielsen and Frydenberg, 1971b). Furthermore, the loci are found to be located on the long arm of the chromosome by 3L telotrisomic analysis (Nielsen and Hvid, 1976), and finally it is made clear that the loci are located at the terminal of the long arm of chromosome 3 (Konishi and Matsuura, 1987). After this finding, two other loci are located near the esterase loci. They are Ym for resistance to Barley Yellow Mosaic Virus of 'Mokusekko 3' (Konishi et al., 1989) and Ga2 for certation (Konishi and Matsura, 1988). For aspertate aminotransferase, Aat3 is linked with two loci, al and uz, respectively, and located on the short arm of chromosome 3 (Konishi and Matsuura, 1989). The Itcl (or Cme) locus for trypsin inhibitor is located between uz and als on chromosome 3 (Nielsen and Hejgaard, 1985).
The f2 locus for chlorina seedling is linked with the Est1 locus with a distance of 11.7 + 2.2 cM (Nielsen and Hvid, 1976). Yano et al. (1991) also obtained a similar result that the f2 locus is linked with the Estl locus with the recombination value of 18.13%, and found that the f2 locus is tightly linked with the cu2 locus for curly growth on the lonq arm of chromosome 3.
References:
Kahler, A. L., and R. W. Allard. 1970. Genetics of isozymes variants in barley. I. Esterases. Crop Sci. 10:444-448.
Konishi, T., N. Kawada, H. Yoshida, and K. Sohtome. 1989. Linkage relationship between two loci for the Barley Yellow Mosiac resistance of Mokusekko 3 and esterase isozymes. Japan. J. Breed. 39:423-430.
Konishi, T., and S. Matsuura. 1987. Linkage analysis of Est4 locus for esterase isozyme-4 in barley. BGN 17:68-70.
Konishi, T., and S. Matsuura. 1988. A new certation gene, Ga-2, on the long arm of chromosome 3 in barley. BGN 18:33-37.
Konishi, T., and S. Matsuura. 1989. Chromosomal localization of two isozyme loci on chromosome 3 in barley. BGN 19:46-48.
Nielsen, G., and 0. Frydenberg. 1971a. The inheritance and distribution of esterase isozymes in barley. Barley Genetics II:14-22.
Nielsen, G., and 0. Frydenberg. 1971b. Chromosome localization of the esterase loci Est-1 and Est-2 by means of trisomics. Hereditas 67:152-154.
Nielsen, G., and J. Hejgaard. 1985. Linkage of a trypsin inhibitor locus (Itc1) and two esterase loci (Est1 and Est4) with marker loci in barley chromosome 3. BGN 15:16-18.
Nielsen, G., and S. Hvid. 1976. Location of the esterase locus Est1 on chromosome 3. BGN 6:45-46.
Shepherd, K. W., and A. K. M. R. Islam. 1987. Cytogenetic manipulation of barley chromosomes in a wheat background. Barley Genetics V:375-387
Yano, Y., K. Abe, and T. Konishi. 1991. Linkage analysis of the chlorina mutant qene (f2) in barley. BGN 20:68-71.