Explanation

Mendel cross-pollinated a pure tall pea plant (100-120 cm hight) and a pure dwarf pea plant. (only 22 to 44 cm hight). He called them parental generation, expressed now-a-days by symbol P. This hybridization popularly called as monohybrid cross [image:5c_image47.emf] This three generations of pea plants after crossing a pure tall plant with a dwarf one. The plants of $F_{1}$-generation are all tall, of $F_{2}$-generation three tall and one dwarf. One third of the tall plants are pure, while the remaining behave as hybrids $\mathbf{F}_{\mathbf{1}}$-generation Seeds collected from the parental generation called first filial generation or $F_{1}$-generation $\mathbf{F}_{\mathbf{2}}$-generation $F_{1}$-plants pollinated among them self (self breeding or inbreeding) and seed produced by $F_{1}$-plants called $F_{2}$-generation. They were in ratio 3:1 (three tall and one dwarf). $\mathbf{F}_{\mathbf{3}}$-generation Mendel allowed $F_{2}$-plant to form seed by self-pollination called $F_{3}$-generation. Mendel observed that tall and dwarf plant behave differently (i) Dwarf plant produced dwarf plant on self-pollinated (ii) In tall plants one third plants breed true so they were pure (iii) Other two third plant behave like parents and give tall to dwarf plants 3 : 1 indicate that their parents have dwarf genes also