TETRASOMIC INHERITANCE OF ISOZYMES IN SAINFOIN (ONOBRYCHIS-VICIAEFOLIA SCOP)

The genetic basis of the variation observed at five well-resolved enzy me systems (PGI, PGM, MDH, GOT, and ADH) was studied in the offspring of 10 self-fertilized sainfoin plants. The results of the progeny test s suggest the existence of seven isozyme loci: Pgi-2, Pgm-2, Got-2, Go t-3, Got-4, Mdh-2, and Adh-1. Preliminary evidence was also obtained a bout the genetic basis of the variability observed in two more isozyme s (Adh-2, Pgm-3) and also of a modifier gene affecting the mobility of the MDH bands (Mmm: modifier of the mitochondrial MDH), Evidence supp orts tetrasomic inheritance in three of the genes (Pgi-2, Mdh-2, and A dh-1) and disomic inheritance in two tightly linked genes (Got-3 and G ot-4), confirming previous observations on the tetraploid nature of O. viciaefolia, In eight progenies some individuals had allele dosages d ifferent from those predicted for tetrasomic inheritance and were iden tified as possibly arising from double reduction events. This observat ion implies that equational segregation occurs to some extent in O. vi ciaefolia.