EMBRYO CULTURE AND GEL-ELECTROPHORETIC IDENTIFICATION OF NUCELLAR ANDZYGOTIC SEEDLINGS OF CITRUS-LIMON (L) AND CITRUS-SINENSIS (L)

Five enzyme systems: peroxidase, esterase, glutamate oxaloacetate tran saminase, malate dehydrogenase and malic were assayed in Citrus limon (rough lemon) and Citrus sinensis (Valencia) by polyacrylamide gel ele ctrophoresis. Isozyme profiles were used to distinguish nucellar from zygotic seedlings produced from in vitro culture of preformed embryos. The frequency of zygotic seedlings resulting from open-pollination va ried between 0.0% and 9.0%. Embryo culture significantly enhanced the recovery of zygotic seedlings in Rough lemon but not in Valencia. Plan tlets produced via in vitro nucellar embryogenesis were genetically un iform. The isolation and culture of preformed embryos resulted in the production of up to 13 and 9 seedlings per seed in Valencia and Rough lemon, respectively. The use of tissue culture and isozymes as tools i n citrus breeding is discussed.