RELATIVE POSITION OF Adh-1 AND Gal-3 ON CHROMOSOME 3

PNL Volume 17 1985

RF,SEARCH REPORTS

Weeden, N. F., G. A. Marx, NYS Agricultural Experiment Station

Geneva, NY USA

and E. Pagowska Experiment Station of Plant Breeding

and Acclimatization, Przebedowo, Poland

Previous mapping studies have identified three Loci which code (or

specific enzymes (Lap-1, Lap-2, and Acp-3) on chromosome 1 (1, 2).

These loci span most of the known linkage map ol this chromosome and

should be useful markers for further mapping studies. In this communi-

cation we report the position of two additional enzyme loci, Adh-1 and

Gal-3, relative to those already mapped and to the two morphological

markers St and B.

Starch gel electrophoresis was performed on seed, young leaf, and

flooded root tissue as described previously (2, 3, 4). Seed extracts

were primarily used to obtain acid phosphatase (AcP), beta-galactosidase

(Gal) and leucine aminopeptidase (Lap) phenotypes. Alcohol

dehydrogenase phenotypes were determined using extracts from root tissue

which had been submerged in water for 12 hours. Young leaf tissue was

used to confirm the Acp, Gal and Lap phenotypes. Only small amounts of

tissue were required for each sampling so that a single plant could be

assayed for all isozyme systems and still be grown to maturity in the

greenhouse.

The results of our analysis of five different F2 populations are

presented in Table 1. All results are consistent with a gene order of

Lap 2 — Gal-3 — (Adh-1 , Acp-3) -- St -- (Lap-1, B).

Despite the significant recombination frequency observed between Adh-1

and Acp-3 in crosses #3 and #4, we were not able to determine which of

these loci was closer to St. We therefore place the two 1oci together

within parentheses to indicate that their relative sequence is unknown.

The loci Lap-1 and B were treated similarly although previous work

suggests that Lap-1 should be on the St side of B (2).

The map distances calculated between loci were relatively

reproducible when results from different crosses were compared. The St,

— (Adh-1, Acp-3) was calculated as 10, 20, and 10 recombinant units in

crosses 1, 4, and 5, respectively. Similar consistency was observed for

the St — Gal-3 and Gal-3 — (Adh-1, Acp-3) map distances. Ihe greatest

source of error probably was in the scoring of the Acp 1 phenotypes, for

these are faint in leaf tissue extracts and relatively poorly resolved

in seed extracts. Thus Adh-1 would appeal to be a better genetic marker

than Acp-3 for this particular region of chromosome 3.

1. Almgard, G. and K. Ohlund. 1970. PNL 2:9.

2. Weeden, N. F. and G. A. Marx. 1984. I. Hered. 75: 365-370.

3. Weeden, N. F. 1985. PNL 17:76-78.

4. Weeden, N. F. and E. Pagowska. 1985. PNL 17:79+80.