ISOZYME INHERITANCE AND VARIATION IN ACTINIDIA

Isozyme inheritance and variation in Actinidia was investigated using 23 enzyme systems. Ten isozyme loci from six enzyme systems, Acp-2, Es t, Prx-1, Prx-2, Prx-3, Prx-4, Prx-5, Pgi-2, Pgm-2 and Tpi, were found to be inherited as single Mendelian genes in families of two interspe cific crosses. Disomic inheritance detected at 10 loci in progenies of a cross between the hexaploid A. deliciosa and the diploid A. chinens is (Jingkui x Moshan no. 4) provided convincing evidence that A. delic iosa is an allohexaploid. Allelic segregation for tetrasomic inheritan ce at the 10 isozyme loci was demonstrated in the progenies of a cross between the tetraploid A. chinensis and the diploid A. eriantha, a re sult suggesting autoploid origin of the tetraploid A. chinensis, which apparently originated from its diploid ancestor A. chinensis. A high level of isozyme variation and heterozygosity was observed in the 22 c ultivars and 56 plants from 28 Actinidin taxa. Allozyme phenotype can be used effectively for cultivar identification. The application of is ozyme markers in the study of phylogeny could still be difficult in po lyploids of natural populations in which estimations of gene frequenci es are a prerequisite.