Characterisation of amaranth accessions by isozymic patterns

Accurate and rapid methods for identification of germplasm accessions and g enotypic comparison have important practical applications in plant breeding . Polymorphic isozyme patterns were analysed in order to characterise eight commercial Varieties and 35 experimental strains obtained from the amarant h breeding program developed in our institution. These accessions belong to seven Awaranthus spp.: A. caudatus L., A. cruentus L., A. hypochondriacus L. Rob., A. mantegazzianus Pass., A. dubius Mart. ex Thell., A. tricolor L. and A. hybridus L. Of the 43 cultivars and strains, thirty-one were identi fied by electrophoresis of esterases, alcohol dehydrogenases, leucine amino peptidases, malate dehydrogenases, 6-phosphogluconate dehydrogenases, acid phosphatases, and malic enzyme from seed extracts. Some accessions could no t be characterised individually indicating that they may have similar genot ypes, forming separate groups. A Principal Coordinate Analysis was made bas ed on the presence or absence of 23 polymorphic bands. This provided a gene ral overview of genetic diversity within this germplasm. These multivariate approaches grouped mast cultivars and strains according to taxonomical cla ssifications and illustrated interrelationships among accessions. This stud y suggests that isoenzymatic seed characteristics can be a profitable compl ement of other morphological and biochemical markers for practical applicat ions in amaranth breeding programs allowing the characterisation of cultiva rs and new breeding lines.