Studies of isozyme patterns in nullisomic-tetrasomic combinations of hexaploid wheat.

Thirty-eight wheat strains, each nullisomic for one chromosome and tetrasomic for a homoeologous (related) one, were analyzed electrophoretically for 12 different enzymes, and a gene (or genes) for alkaline phosphatase was localized to chromosomes 4B and 4D. The other 11 enzymes showed no significant electrophoretic variation. The fact that the only mutants observed affect the same enzyme favors the concept that rigorous selection operates in the polyploids both to preserve certain types of variants and to eliminate others.