S-GENE POLYMORPHISM IN PHLOX-DRUMMONDII

The genetic control of self-incompatibility and the number of S-allele s were studied in a population of Phlox drummondii from Lytle, Texas. Thirty-four seedlings were transplanted to the greenhouse. Each was se lf-fertilized (using bud pollination) to generate self families of 9-1 1 plants. Complete diallels were performed within each family. Twenty- four families contained three cross-compatibility phenotypes whose cro ssing relationships indicated that self-incompatibility was under game tophytic control and governed by one gene. Homozygotes from twenty-fou r families were crossed in a half-diallel for S-genotype assignment. T hirty S-alleles were detected. Allele frequencies did not deviate sign ificantly from equality.