Abstract
Three-factor crosses in both Rhizopus stolonifer and R. microsporus gave results which supported the hypothesis that normal sexual functions (karyogamy and meiosis) were operating in these species. However, not all meiotic products are recovered in the germsporangium of each germinating zygospore. When the number of germsporangia containing each genotype were scored, the sizes of the eight possible genotypes obtainable from a three-factor cross were found to be approximately equal. Likewise, allelic recovery values were approximately equal. Parental/recombinant figures indicate that none of the loci studied (3 in R. stolonifer and 4 in R. microsporus) were linked. Classification of each germsporangium according to the number and kinds of genotypes recovered revealed that 35% of those in R. stolonifer and 17% of those in R. microsporus contained products of more than one meiosis.
