Use of four isozymatic systems in lemon and lemon-like citrus cultivars todetect their genetic diversity

Leaf tissue samples of seven cultivars of Citrus limon, one of Citrus auran tifolia, one cultivar of Citrus latifolia, one cultivar of Citrus meyeri an d two cultivars of local selections were analyzed for isozyme variation for malate dehydrogenase (MDH), glutamate oxaloacetate transaminase (GOT), tet razolium oxidase (T.O.) and esterase (EST) to examine the biodiversity of f armers' selections and commercial cultivars. The GOT zymograms consisted of bands in two zones. The GOT isozymes are characterized by co-dominant expr ession. The enzyme differences were found to be adequate for distinction at the species level. MDH isozymes showed one or three bands. Two major areas of T.O. activity were identified. Zymograms for EST should prove useful as a diagnostic tool for cultivar identification in view of the extensive pol ymorphism of this enzyme.