How do Mendel’s experiments show that traits may be dominant or recessive?



Mendel performed breeding experiments on pea plants.


  • Mendel took pea plants with different characteristics of the same criteria.
  • He took a tall plant and a short plant and crossed them.
  • In the F 1 generation, only tall variants appeared.
  • On self-pollinating the F 1 generation, both tall and short plants appeared in the ratio 3:1. 
  • He concluded that the trait which appeared in the first generation is the dominant trait.
  • This trait appeared when at least 1 allele coding for it was present in the genotype (i.e Tt and TT).
  • The trait which only appeared when no other allele for another trait was present in the genotype of the 2nd generation is the recessive trait (i.e tt )
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CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo