LINKAGE GROUPS WITH S-GENES IN THE SUGAR-BEET (BETA-VULGARIS) AND THELIKES IN OTHER PLANTS

Segregation in the Tc locus controlling the red color of the sugarbeet (Beta vulgaris) floral bracts has been studied. Deviations from mende lian ratio indicate there must be linkage between Tc and one of the ga metophytic incompatibility locus, S(d). Analysis of segregations in th e marker isozymic loci, Adh1 and Gpi2, showed that S(d) is not identic al to S(a) linked with Adh1, or to S(c) linked with Gpi2. linkage grou ps with S loci known for sugarbeet are compared with analogous ones in a number of other plants. Data obtained support an idea that one-locu s incompatible plants are in fact species with one polymorphic and sev eral monomorphic S loci.