An allotetraploid species has a genome composed of two ancestral genomes, A and B, each of which have a basic chromosome number (  ) of seven. In this species, the two copies of each chromosome of...

An allotetraploid species has a genome composed of two ancestral genomes, A and B, each of which have a basic chromosome number (
 ) of seven. In this species, the two copies of each chromosome of each ancestral genome pair only with each other during meiosis. Resistance to a pathogen that attacks the foliage of the plant is controlled by a dominant allele at the
 locus. The recessive alleles
 and
 confer sensitivity to the pathogen, but the dominant resistance alleles present in the two genomes have slightly different effects. Plants with at least one
 allele are resistant to races 1 and 2 of the pathogen regardless of the genotype in the B genome, and plants with at least one
 allele are resistant to races 1 and 3 of the pathogen regardless of the genotype in the A genome. What proportion of the self-progeny of an
 plant will be resistant to all three races of the pathogen?