WAEC Agriculture 2018 Paper

Concept:Since brown is dominant over black, any offspring carrying the brown allele will show brown colour.Explanation:Represent the homozygous brown cowpea as $BB$ and the homozygous black cowpea as $bb$.The cross is: $BB \times bb$.The brown parent produces only $B$ gametes, and the black parent produces only $b$ gametes.Thus, every F1 offspring receives one $B$ allele and one $b$ allele, giving the genotype $Bb$.Because $B$ is dominant over $b$, every $Bb$ plant will express the brown phenotype.Therefore, all F1 offspring are brown.Answer:$100\%$ of the F1 will have brown colour.Option A.