Explain pea plants in genetics?

Pea Plants :  In pea plants, sperm are located in the pollen grains produced by the anthers of the flower. Eggs are formed in ovules, structures in the center of the flower, within the ovary. Pollination refers to the transfer of a pollen grain to the stigma, which is the tip of the style, a tube leading to the ovary. Once the pollen grain attaches to the stigma, it sends down a pollen tube, which then transports two sperm cells to the ovule. Fertilization, or fusion of the sperm nucleus with the egg nucleus, then occurs. One sperm fertilizes the egg to form a zygote, while the other fuses with two polar nuclei in the central cell to form the endosperm which will develop into food for the developing embryo. This is called double fertilization.

Mendel found that plants grown from some yellow seeds produced only yellow peas, and those produced from some green seeds produced only green peas, but also that plants from some yellow seeds produced peas of a different color. By a process called self-pollination, that is, using pollen to fertilize the egg of the same plant, he was able to produce true breeding strains; that is, the parent generation (P1) always produced offspring with the same trait.

Mendel decided to concentrate his study on seven traits in peas: seed shape, seed color, flower color, pod shape, pod color, flower position (whether the flowers were located on the tip end of the plant or not) and stem height (tall or dwarf). He chose to study characteristics that were distinct and that did not produce intermediate results. For instance, a cross between tall plants and dwarf (short) plants was known to produce plants that were either short or tall, making interpretation of results easy.