The courgette plant, Cucurbita pepo, produces edible fruits that vary in colour and shape. Fruit colour in courgettes is controlled by the gene A/a. Fruit shape in courgettes is controlled by the gene B/b. • A yellow fruit is produced when the dominant allele A is present. • A round fruit is produced when the dominant allele B is present. Genes A/a and B/b occur on different chromosomes. Table 1.1 shows the genotypes and phenotypes of four different varieties of courgette with respect to their fruit colour and shape. Table 1.1 name of variety | genotype | fruit colour | fruit shape ---|---|---|--- Defender | aabb | green | long Floridor | AABB | yellow | round Golden Dawn | AAbb | yellow | long Tondo di Piacenza | aaBB | green | round