Fertilization involves the union of sperm and egg with different characteristics. The new plant thus created is different and diverse in size, shape and structure.
Fertilization results in the development of disease-resistant plants from susceptible plants. Disease resistant plants are of different characteristics and varieties.
Mating of two different plants through fertilization results in varieties that are antagonistic. All these plants have a collection of various adverse resistance properties. These diverse plants can easily tolerate drought, flood, salinity, heavy rain, no rain etc.
Fertilization process produces various traits in crop plants. The grain size, color, smell, taste etc. of these plants are different.