A cross between parents that differ in a single character is known as mono hybrid cross. Mendel crossed pure tall plants with pure dwarf plants . He called them parental generation (P) . He removed the anthers of tall variety and pollinated them with pollen from dwarf plants . The removal of anthers from flowers is called emasculation . He collected the seeds produced by this cross and raised them into tall plants . He called this first generation as the first filial generation ( F1) . Only hybrid tall plants are produced in F1 generation . No dwarf plants are developed even though one parent had been pure for dwarf character . This experiment was repeated several times and every time Mendel got the same result .

Reciprocal crosses were carried out . This time, flowers of dwarf plants were emasculated and pollinated with pollen from tall tall plants . But the results were same , i.e, all the plants of F1 generation were tall . Mendel concluded that tallness of pea plants is dominated over dwarfness .