MP Board · Class 10 · Science · HeredityExplain the monohybrid cross experiment conducted by Mendel by taking plant height as the characteristic.

A monohybrid cross is a genetic breeding experiment that tracks the inheritance of a single pair of contrasting characters, such as plant height. Mendel conducted a monohybrid cross by taking a pure-breeding tall pea plant (genotype TT) and crossing it with a pure-breeding dwarf pea plant (genotype tt). The plants used as parents constitute the parental or P generation. When these two plants were cross-pollinated, all the resulting seeds grew into plants that were tall. This first filial generation is known as the F1 generation. Interestingly, no dwarf plants were observed in the F1 generation, leading Mendel to conclude that the trait for tallness is dominant while the trait for dwarfism is recessive. Next, Mendel allowed the F1 generation tall plants (genotype Tt) to undergo self-pollination. The offspring resulting from this self-pollination formed the second filial generation, or F2 generation. In the F2 generation, both tall and dwarf plants reappeared in a distinct mathematical ratio. Out of four plants statistically analyzed, approximately three were tall and one was dwarf, yielding a phenotypic ratio of 3:1. However, when examining their underlying genetic makeup or genotype, the ratio was found to be 1 TT (pure tall) : 2 Tt (hybrid tall) : 1 tt (pure dwarf). This classic monohybrid experiment successfully established the fundamental concept of allele segregation.