Isozyme analysis and phylogenic relationship of citrus.

Abstract

Isozymes of GOT and MDH in leaves of 105 citrus biotypes were analyzed using acrylamide gel electrophoresis. At least 3 loci were detected on these two enzymes. From the analysis, Natsumikan (Citrus natsudaidai), Hassaku (C. hassaku) and some other citrus cultivars are considered to be hybrids of pummelo (C.grandis) and mandarin as suggested. Moreover, Iyo (C.iyo), which has been assumed to be a hybrid of sweet orange (C.sinensis) and mandarin, was found to have a genetic effect from pummelo. Sour oranges (C.aurantium) had unique allele A at Got-1. In addition to the sour orange, the same allele was found only in lchang lemon (C.wilsoni), Bergamot (C. bergamia) and 'Hirado' pummelo. While, Tachibana (C.tachibana), Shiikuwasha (C. depressa), and Korai-tachibana (C. nippokoreana), which are reported to be native to Japan and its neighboring areas, had an unique allele A at Got-2. This allele was also found in Hyuganatsu (C.tamurana) and some biotypes originated in Japan, but not found in mandarins originated in mainland China, India, Philippines and other areas. While, Yuzu (C.junos) and its relatives had B at Got-2 and B at Mdh-1.