Tetrasomic inheritance of isozymes in sainfoin (Onobrychis viciaefolia Scop.)

Abstract

The genetic basis of the variation observed at five well-resolved enzyme systems (PGI, PGM, MDH, GOT, and ADH) was studied in the offspring of 10 self-fertilized sainfoin plants. The results of the progeny tests suggest the existence of seven isozyme loci: Pgi-2, Pgmo2, Got-2, Got-3, Got-4, Mdh-2, and Adh-1. Preliminary evidence was also obtained about the genetic basis of the variability observed in two more isozymes (Adh-2, Pgm-3) and also of a modifier gene affecting the mobility of the MDH bands (Mmm: modifier of the mitochondrial MDH). Evidence supports tetrasomic inheritance in three of the genes (Pgi-2, Mdh-2, and Adh-1) and disomic inheritance in two tightly linked genes (Got-3 and Got-4), confirming previous observations on the tetraploid nature of O. viclaefolia. In eight progenies some individuals had allele dosages different from those predicted for tetrasomic inheritance and were identified as possibly arising from double reduction events. This observation implies that equational segregation occurs to some extent in O. viciaefolia.