GENETIC-CONTROL OF KAVALACTONE CHEMOTYPES IN PIPER METHYSTICUM CULTIVARS

The chemical composition of 121 cultivars of Piper methysticum origina ting from 51 Pacific islands, were investigated using HPLC. The result s obtained for six major kavalactones (demethoxy-yangonin, dihydrokava in, yangonin, kavain, dihydromethysticin and methysticin) were submitt ed to cluster analysis and six distinct chemotypes were identified. Th ree field experiments demonstrated that chemotypes are not affected by environmental factors but are controlled genetically. Analysis of the isozyme variation for eight enzyme systems, revealed that these culti vars exhibited only three zymotypes. These are so similar that the dif ferences in malate dihydrogenase and diaphorase could be explained as mutations. Few genes are thought to be responsible for the chemotype v ariation between cultivated clones. Because all cultivars are decaploi ds and sterile, it is suggested that mutagenesis might be used to indu ce genetic variability and to improve cultivar chemotypes. Copyright ( C) 1996 Elsevier Science Ltd.