Submitted to: Horticulture Scientia
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/29/1996
Publication Date: N/A
Citation: Interpretive Summary: Molecular marker data for many tropical fruit crops has not been previously collected. A cooperative effort between USDA, ARS, N.C.G.R. - Hilo and the University of Hawaii, Department of Horticulture has undertaken generating this genetic relatedness study for seven known species and two unknown accessions in the genus Canarium. Fifty-two accessions from USDA, ARS, N.C.G.R. - Hilo collection were evaluated for isozyme polymorphisms using enzyme electrophoresis and stained for fourteen enzymes. Gels were scored for presence or absence of electromorphs and relative positions. Only six of the fourteen enzymes gave consistent zymographs. Cluster analysis showed eight distinct groups at a 50% level of genetic similarity.
Technical Abstract: Fifty-two accessions of Canarium involving seven species, C. ovatum, C. album, C. megalanthum, C. harveyi, C. indicum, C. mehenbethene and C. odontophyllum were studied for isozyme polymorphisms. Starch gel electrophoresis with a histidine-citrate buffer system (pH 6.5) was employed to assay six enzymes, LAP, MDH, PGI, PGM, TPI and UGPP. Species were polymorphic for most of the six enzyme systems assayed and the level of phenotypic polymorphism for different species and enzymes assayed ranged from 0 to 0.88, with an overall average of 0.28. The weighted average of polymorphisms across different enzyme systems for different species ranged from 0.16 for C. indicum to 0.47 for C. ovatum, with an overall average of 0.26. On average, LAP was the most polymorphic enzyme (0.43) followed by PGI (0.38), MDH (0.27), UGPP (0.26), PGM (0.18) and TPI (0.13). The complexity of isozyme phenotypes indicate that interspecific hybridization and polyploidy might have played a role in the evolution of Canarium species. Geographic speciation in Canarium was not apparent from the phenetic analysis of the isozyme data.