His theories are the basis for modern breeding techniques of plants and animals?

The person whose theories are the basis for modern breeding techniques of plants and animals is Gregor Mendel.

He is known as the "father of modern genetics" for his groundbreaking work on inheritance patterns in pea plants. Mendel's experiments led to the discovery of fundamental principles of heredity, including:

* Law of Segregation: Each inherited trait is determined by two factors (now known as alleles) that separate during gamete formation.

* Law of Independent Assortment: Different traits are inherited independently of each other.

These principles form the foundation of modern genetics and breeding practices. Breeders use Mendel's laws to selectively breed plants and animals for desired traits, leading to significant improvements in agriculture and animal husbandry.