• Farmers began cross breeding plants in the 1700s to perpetuate ideal plant characteristics.¹
• Herbicide- and insect-resistant crops began introduction and adoption in 1996 using the science of transgenesis.²

Plant breeding and the domestication of plants dates back 9,000 to 11,000 years ago⁴ when humans initially began the practice of farming. The introduction of farming allowed civilizations to stay in one place, rather than hunting and gathering their food on a constant move. Early farmers selected food plants with desirable characteristics to cultivate and provide their food supply. With each generation, plants with the best characteristics were chosen and crops improved. Knowledge of science and genetics advanced through the work of scientists such as Gregor Mendel. Modern plant breeding uses the same principles with the addition of advanced technology and ever-advancing knowledge of genetics. The average diet consists of food produced by plants that have been developed and improved through a variety of plant modification methods.

Cross breeding has been practiced since the beginning of farming and utilizes the laws of inheritance to guide the specific selection of desirable traits in plants.⁵ After a desirable plant is selected, the pollen from one plant is placed on the female portion of the flower of another desirable plant which leads to the production of seeds that are hybrids of the two parent plants. This process is repeated with each generation of plants slowly moving toward an improved species. Plants with chosen characteristics are perpetuated and those without are removed. Genetic mutations occur naturally and randomly in the genomes of plants and animals. These result from the spontaneous deletion, addition, or insertion of base units in DNA. Mutagenesis is a plant breeding method which utilizes mutations as a method of creating genetic diversity. Plant breeders expose plants to mutating chemicals or radioactivity to increase the likelihood of mutations to occur which may create desirable characteristics in plants.⁵ Polyploidy is the occurrence of more than two sets of chromosomes. It can occur naturally or be induced through the use of chemicals. Polyploidy can increase fruit size or be used to create sterile varieties of a plant such as a seedless watermelon.⁵ Protoplast fusion is an artificial version of cross breeding that fuses the pollen of one plant species with the ova in the flower of another species. This allows the moving of beneficial traits from one species to another by fusing the protoplasts.⁶ Transgenesis is the process of introducing one or more genes into an organism from another entirely separate organism by finding and isolating a chosen gene and adding it to the genome. Genome editing uses an enzyme to change the DNA of a cell at a specified sequence. CRISPR-Cas9 is a specific gene editing tool that helps plant breeders integrate desirable traits with more efficiency and precision than before. It is a promising and developing technology.⁵ The understanding of the CRISPR system began in 1987, but it did not gain momentum until 2012 when scientific research began being published about it.⁷ CRISPR is now being studied for its medical benefits to decrease human diseases as well as to improve the food we eat.

Plant breeders often use one or more modification methods before ultimately achieving their goal. Each method of plant modification comes with both advantages and disadvantages or limitations. Not every method will be effective in every situation. Regardless of the method or methods used, all plants are screened for overall safety before a seed variety is available on a commercial level.⁸