Final answer:
The predominating genotype in the progeny of a test cross between a female double heterozygote in cis configuration and a male homozygous for recessive alleles will likely be the parental genotypes p+b+ or pb if the genes are linked.
Step-by-step explanation:
When a female double heterozygote with a cis configuration (p+b+/pb) is test crossed with a male who is double homozygous recessive (pb/pb), the genotype that will predominate in the progeny will likely be the parental genotypes, either p+b+ or pb, with the exact proportions depending on the frequency of recombination between the two genes if they are linked.
Because the female is double heterozygous in cis configuration, this means that one chromosome carries both dominant alleles (p+ and b+), while the other carries both recessive alleles (p and b). When crossed with a male homozygous for the recessive alleles, the expected offspring would be 50% p+b+ (if genes are tightly linked and no recombination occurs) and 50% pb.
However, if recombination occurs between the two genes, recombinant genotypes may also appear in the offspring but in smaller proportions than the parental genotypes.