When a true-breeding strain of sweet pea is allowed to self-fertilize, the offspring will exhibit traits identical to the parent plant. This is because true-breeding means that the plant is homozygous for the traits in question, so self-fertilization will produce offspring with the same genotype and phenotype consistently. Thus, the true breeding strain will "breed true," producing offspring that all show the same traits as the parent without variation due to dominant or recessive alleles segregating in the offspring.
In summary:
- True-breeding strains are homozygous for specific traits.
- Self-fertilization in such a strain produces genetically identical offspring.
- The phenotypic traits do not vary and remain consistent generation after generation.
This is a fundamental concept demonstrated by Mendel in his pea plant experiments, where true-breeding lines always gave offspring with the same traits through self-fertilization.
