A survey of the genetic resources of kava (Piper methysticum
Forst. f. and P. wichmannii C. DC.) was conducted throughout the Pacific. Leaf
tissues of more than 300 accessions, collected on 35 islands, were analyzed for
isozyme variation in eight enzyme systems including ACO, ALD, DIA, IDH,
MDH, ME, PGI, and PGM. Isozymes in P. methysticum cultivars from Polynesia
and Micronesia were monomorphic for all enzyme systems examined;
however, cultivars from Melanesia were polymorphic for ACO, DIA, MDH,
and PGM. The genetic base of this crop is much narrower than previous
morphological and biochemical studies suggest. Most of the morphotypes and
chemotypes apparently originated through human selection and preservation of
somatic mutations in a small number of original clones. Isozymes of P.
wichmannii confirmed its status as the wild progenitor of kava. Piper methysticum
cultivars and P. wichmannii and P. gibbilimbum C. DC. wild forms were all found
to be decaploids with 2n = lOx = 130 chromosomes, but there was no firm
evidence that interspecific hybridization has played a role in the origin of P.
methysticum