In corn plants, plant height is controlled by one gene with two alleles how many alleles that control the trait for height are present in each cell nucleusof a corn plant

2 alleles

The number of the allele that a gene contains could be various. The allele will determine the phenotype of the organism, so more allele means more possible combination. There is only 1 gene that control the corn height and that gene only has two alleles. So, the total allele that controls the corn height should be: 1 gene * 2 alleles/gene= 2 alleles