Which of the following best defines 'plant breeding'?

The chosen definition of 'plant breeding' emphasizes the science behind modifying and selecting plant traits to achieve specific desired characteristics. Plant breeding involves utilizing various techniques, including traditional crossbreeding, molecular biology, and genetic engineering, to improve traits such as yield, disease resistance, drought tolerance, and nutritional value. This scientific approach allows breeders to deliberately introduce or enhance traits that benefit agricultural productivity and food security.

In contrast to the correct answer, cultivating plants in gardens pertains more to horticulture than plant breeding. Likewise, growing plants without any genetic intervention does not capture the essence of plant breeding, which inherently involves manipulating genetics in various ways. Lastly, using synthetic chemicals to enhance plant growth reflects agri-chemical practices, which are separate from the fundamental goals and processes of plant breeding, thus reinforcing that the heart of plant breeding lies in its focus on altering plant genetics.