GrainGenes
A Database for Triticeae and Avena
Nielsen and Hvid, pp. 45-46
II.22 Location of the esterase locus Est1 on barley chromosome 3.
Gunnar Nielsen and Søren Hvid, Agricultural Research Department, Danish Atomic Energy Commission Research Establishment Risø, DK-4000 Roskilde, Denmark.
The Est1 locus was previously shown by means of trisomics to be located on chromosome 3 (Nielsen and Frydenberg, 1971a, 1971b). The localization was further investigated by telotrisomic plants. A sample obtained of Triplo 3S (Tsuchiya, 1974) segregated for the Est1 alleles, Ca and Pr. In the zymogrammes telotrisomic heterozygotes showed either a double dose of Ca in relation to Pr or vice versa. This indicates that the plants had the allelic constitution Ca/Ca/Pr or Ca/Pr/Pr, respectively. A telotrisomic plant with the presumed constitution Ca/Pr/Pr was pollinated with pollen from a plant carrying a third Est1 allele, A1. A few of the telotrisomic progeny plants had all three alleles, Ca, A1 and Pr. This proves that Est1 is located on the telocentric chromosome.
The linkage of Est1 with the genes gs2 (glossy) and f2 (chlorina) was investigated by a three-point test. The F2 segregation shown in Table 1 yielded the following recombination percentages:
Est1 - f2 r = 11.5 + 2.2
Est1 - gs2 r = 50.7 + 4 0
f2 - gs2 r = 51.4 + 4.8
In other crosses, no linkage was found between Est1 and the genes an, ac, xc, xs, uz, wst, yst2, ert-c, and ari-a on chromosome 3.
The linkage between Est1 and f2 and the free recombination between Est1 and the other 10 marker genes indicates, that Est1 and f2 are located distally to gs2 on the short arm of the chromosome-3 linkage map (BGN 5: 93, 1975). Additional linkage tests with other genes on chromosome 3, cu2, als, zb, and al, are in progress for a more precise localization of Est1.
References:
Nielsen,G.and 0. Frydenberg, 1971a. Chromosome location of Est1 by analysing F1 trisomic plants. BGN 1: 35-36.
Nielsen, G. and 0. Frydenberg, 1971b. Chromosome localization of the esterase loci Est1 and Est2 in barley by means of trisomics. Hereditas 67: 152-154.
Tsuchiya, T., 1974. Coordinator's report: Trisomics. BGN 4: 110.