II. 24. Supplementary and new evidence on the location of five enzyme loci on barley chromosomes.
Gunnar Nielsen, Agricultural Research Department, Risø National Laboratory, DK-4000 Roskilde, Denmark.
By starch gel electrophoresis F2-populations comprising trisomics for chromosomes 3, 4, 5L, and 7 were found to segregate for 6-phospho-gluconate-dehydrogenase. Forty heterozygotes were found in the 5L-population. Twelve of these showed a clear dosage effect suggesting that an extra chromosome was carrying the enzyme gene. The plants were chromosome counted. All 12 plants showing the dosage effect had a telocentric chromosome. No sign of a dosage effect was observed in zymogrammes from disomic plants or from plants trisomic for other chromosomes than 5L. It is concluded that the locus, designated Pgd 2, is located on chromosome 5L. Two allelic variants were observed.
An enzyme from barley leaves with properties suggesting that it is a fructose-phosphate-dehydrogenase has been shown to be located on chromosome 6 by means of a set of wheat-barley addition lines obtained from Dr. A.K.M.R. Islam, Adelaide. The zymogrammes from the barley-chromosome 6 addition line showed a clear band at the same position as the band from the barley reference. The other addition lines and the wheat reference did not show bands at this position. The locus is designated Fpd 1. Three allelic variants were observed.
The two esterase loci, Est 3 and Est 5 (Hvid and Nielsen, 1977) were both shown to be located on chromosome 1 by F2-segregations of trisomic lines. This location has been further confirmed by electrophoresis of wheat-barley addition lines.
A locus coding for beta-amylases in germinating seeds has been reported to be located on chromosome 4 by means of wheat-barley addition lines (Powling et al., 1981). This location was confirmed using immature endosperms and mature kernels, likewise from wheat-barley addition lines. We propose the locus designation Bam 1. Two allelic variants were observed.
The results are summarized in Table 1.
Table 1. Location and designation of 5 enzyme loci in barley.
BGN 12 toc
BGN Main Index