Polyembryony, heterozygosis and chimeras in citrus

does not appear. First page follows. Introduction The genus Citrus is characterized by remarkable genetic variability, both in seed reproduction and within clonal varieties. An F1 hybrid progeny usually exhibits great genetic diversity (Swingle, 1913a), suggesting the F2 generation from a cross between races differing in many genes. Bud-variation types arise frequently, and involve changes in many characters of tree and fruit (Shamel et al., 1918), (1918b), (1920). With any tree fruit, considerations of time and expense seem to make thorough genetic analysis impracticable; with Citrus, polyembryony appears to render it even theoretically impossible. Such remarkable genetic phenomena, however, occurring in a group of such great economic importance, deserve the best interpretation possible on the basis of the theory of heredity worked out with organisms more suitable for genetic study. The present paper reports evidence, obtained from the pedigree cultures of Citrus at the Citrus Experiment Station, bearing on the relation of apogamy to genetic variation in Citrus. It also includes preliminary data which can best be presented in a general publication preceding detailed reports on limited problems.