INVERSION HETEROZYGOSITY IN THE HYBRID SOYBEAN X GLYCINE-SOJA - EVIDENCE FROM A PACHYTENE LOOP CONFIGURATION AND OTHER MEIOTIC IRREGULARITIES

Meiotic irregularities and partial sterility were found in the hybrid between the soybean, Glycine max and its presumed wild progenitor, Glycine soja. Chromosome bridges and fragments were believed to be caused by inversion heterozygosity. The presence of an inversion was confirmed by finding an inversion loop at pachytene. Other evidence for inversions came from bivalents that failed to separate in the first division. These bivalents acted as laggards or passed intact to one pole at anaphase I. Nondisjunction of the partners in the bivalents was believed to result from chiasmata occurring in the region of an inversion in the bivalents. The number of bridges, fragments, and lagging bivalents suggest the presence of more than two inversion differences between the two species.Chromosomal differentiation together with wide genetical and morphological differences provide evidence that G. max and G .soja are two distinctly separate species. © 1979 AMRICAN GENETIC ASSOCIATION.