Inheritance of isozymes in pedunculate oak (Quercus robur L.)

Fourteen full-sib families of pedunculate oak (Quercus robur L.) were utilized in order to study the segregation of isozymes and to verify their mode of inheritance. Based on standard gel electrophoresis and isoelectric focusing, a total of 12 enzymes systems were analyzed in seeds, radicles (germinated seeds) and bud tissue. Tissue-specific expression of isozymes was evident for one system. Fourteen enzyme systems were controlled genetically by 15 polymorphic gene loci. A nomenclature with respect to 76 codominant alleles is suggested. This nomenclature includes polymorphism that was verified in various oak populations in France and Germany. Confirmation of the genetic control of isozyme banding pattern was based on single-locus segregation data. In most of the cases, the expected 1:1 or 1:2:1 Mendelian ratios were confirmed. Deviations from Mendelian segregation proportions were found when parent trees were bearing rare alleles. The exceptions to these cases are discussed. Analyses of two-locus genotypes revealed linkages in 20 out of 83 tested crosses and resulted in the identification of two linkage groups (Dia-A and Mr-A for group I and Aap-A, Lap-A, Idh-B, Pgi-B, and Acp-C for group II).