THE INHERITANCE OF ALCOHOL-DEHYDROGENASE ISOZYMES IN SEEDS OF HEXAPLOID ECHINOCHLOA-CRUS-GALLI BEAUV

To clarify the mode of inheritance of alcohol dehydrogenase (ADH) isoz ymes in Echinochloa crus-galli, we induced single-banded mutant lines for ADH by gamma-ray irradiation; the irradiation of the 5-banded E. c rus-galli var. formosensis (phenotype A(1)A(2)A(3)A(4)A(5)) produced t wo single-banded mutant Lines, A(1) and A(5). All pairwise reciprocal crosses were made among the single-banded mutant lines and the natural ly occurring single-banded type E. crus-galli var, praticola that disp lays only band A(3). The ADH zymograms from the resulting F-1 progenie s were identified by polyacrylamide gel electrophoresis and the relati ve staining densities of the bands were determined by densitometer sca nning for several important E. crus-galli phenotypes and F-1 individua ls. All F-1 seeds displayed both parental bands plus an additional ban d located intermediate to the parental bands. Moreover, the ratios of the band densities were in agreement with those expected from the kine tics of ADH dimer formation. The results can be accounted for by three loci encoding three ADH subunits. Also, the data indicate that the A( 3) band of the 5-banded phenotype consists of two different dimeric pr oducts, homo- and hetero-dimers.