Starch synthesis in pea is an example of incomplete dominance. When the dominant allele is not completely able to mask the expression of a recessive allele it is called incomplete dominanace. The gene for starch synthesis in pea seeds has two alleles B and b. In BB genotype, large starch grains are produced. After maturation the seeds are round. In bb homozygous condition, smaller starch grains are produced and mature seeds are wrinkled. Bb heterozygous form round seeds so that B seems to be dominant allele. However, Bb seeds have starch grains of intermediate size, showing incomplete dominance.