The locus Estl2 controls of differences between esterase zymotypes in the lowest mobility area of zymogramme using electrophoretic separation according to Netsvetaev (1992a, b). Alpha-amylases are controlled by loci Amyl and Amy2. The locus Amy2 is located on chromosome 1 (Brown and Jacobsen, 1982).

Alpha-amylase was separated in PAGE with tris-glicine buffer, pH 8.3 (Netsvetaev, 1993) and placed in the gel with 5M urea added for inactivation of beta-amylase activity. On seed zymogramme of addition wheat-barley stocks with barley chromosome 1, a single band of var. Betzes was identified. The alpha-amylase band in barley had a secondary position compared to the fastest isozyme for this electrophoretic mobility. Barley varieties were monomorphic for this band. The fastest Betzes isozyme and one of the Chinese Spring alpha-amylase enzymes had similar gel positions. Spring barley had three isoenzyme variants in this electroshoretic area.

In the Donetsky 4 × Jau Kabutak cross, which was studied for linkage estimates, the parents were different for alleles at the Nn (covered vs naked caryopsis), and Est5 (Esterase 5) in chromosome 1 and the Vv (two- vs six-rowed) locus in chromosome 2. Donetsky 4 had the alleles V, N, Est5Te, Estl2Be, Amy2Do and Jau Kabutak had v, n, Est5Pi, Estl2Hi, Amy2Ja. The results are presented in Table 1.

The fastest alpha-amylase isozymes were linked with caryopsis characters. Thus, the isoenzymes are controlled probably by the Amy2 loci. The Est5 alleles were inherited independently of alleles at the Amy2 and N loci. These data don't permit orientation of the N, Amy2, and Est5 in the linkage map. Probably Amy2 and n are arranged in the long arm of chromosome 1.

A recombination value of 31.0 ± 2.7 was found between the Estl2 and V loci (Table 1). Therefore, locus Estl2 is located in chromosome 2, not in chromosome 3 as reported previously (Netsvetaev, 1992b).

References:

Brown, A. H. D., and J. V. Jacobsen. 1982. Genetic basis and natural variation of aamylase isozymes in barley. Genet. Res., Carnb. 40, 315-324.

Netsvetaev, V. P. 1992a. Use of double ditelosomics for gene location in barley. (In Russian). Cytology and Genetics (Kiev) 26:26-30.

Netsvetaev, V. P. 1992b. Identification of the barley leaf esterase 11, 12 and their genetic control. (In Russian). Genetika (USSR) 27:105-119.

Netsvetaev, V. P. 1993. Location of alpha-amylase coding locus (Bmy 1) on barley chromosome 4. (In Russian). Cytology and Genetics (Kiev) (in press).