Final answer:
True-breeding plants in Mendel's experiments are those that are homozygous for a specific trait, with possible genotypes being either homozygous dominant (YY) or homozygous recessive (yy).
Step-by-step explanation:
The student's question relates to Gregor Mendel's experiments with pea plants, specifically regarding the possible genotypes of true-breeding (homozygous) plants. True-breeding plants are those that, when self-fertilized, produce offspring identical to themselves. Therefore, their genotypes must contain identical alleles for a specific trait. In Mendel's experiments, a homozygous dominant plant would have a genotype of YY, and a homozygous recessive plant would have a genotype of yy. These are the plants that would never express any other phenotype aside from the one related to their homozygous state when self-fertilized or crossed with plants of the same genotype.
Therefore, the possible genotypes for true-breeding plants in Mendel's experiments are:
- Homozygous dominant (YY)
- Homozygous recessive (yy)
In Mendel's true-breeding plants experiments, the possible genotypes are:
Homozygous recessive: represented by the genotype yy, where both alleles are lowercase and recessive.
Homozygous dominant: represented by the genotype YY, where both alleles are uppercase and dominant.
Heterozygous recessive: represented by the genotype Yy, where one allele is uppercase and dominant, and the other is lowercase and recessive.
Heterozygous dominant is not possible in true-breeding plants because both alleles need to be the same for breeding true.