Submitted to: Journal of Agricultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/31/2000
Publication Date: N/A
Interpretive Summary: Providing food and fiber for the 21st century while preserving the quality of the environment will require that plant breeders develop higher yielding plants which also have natural resistance to pest and pathogens. A major concern with pest resistant cultivars of crops is the development of biotypes of pests or pathogens that can reproduce on the resistant cultivar, thus rendering the cultivar ineffective for controlling the pest or pathogen. A strategy is proposed that is similar to what happens in a natural ecosystem where many genetically diverse host plants and many biotypes of pests or pathogens co-exist in nature without any one pest biotype becoming dominant enough to destroy the host plants. The proposed strategy is to develop F2 hybrids for crop plants from parents that differ in their genes for pest resistance. The resulting F2 population will be planted by growers and thus the various biotypes of pests or pathogens will experience a similar situation in grower fields that it experiences in nature. This should delay or minimize the selection for a resistant biotype of pest or pathogen that can overcome the resistance of the F2 hybrid. This strategy also envisions developing F2 hybrids that show hybrid vigor for yield and quality. Thus, these hybrids would be desired by growers for these advantages as well as for the built-in pest control afforded by the plant resistance genes. This strategy should increase the sustainability of the system, while increasing yield, and improving the environment by reducing the use of organic pesticides for pest and pathogen control.
Technical Abstract: A novel and general strategy for the management of plant genes for pest or pathogen resistance is presented. The strategy utilizes F2 hybrids produced from two parents similar in agronomic and quality traits but which differ in their plant genes for resistance to a pest or pathogen. The grower would plant F2 hybrid seed that should allow for the expression of hybrid vigor for agronomic and quality traits while presenting a diverse population of plants to the pest or pathogen in which individual plants differ for their pest resistance genotype. This simulates nature where the pest or pathogen is exposed to a population of host plants that differ in resistance genes. This strategy should delay or minimize the selection of a dominant pest or pathogen biotype that can damage and reproduce on the resistant plants resulting in the loss of the usefulness of the resistant genes. Careful selection of individual genes should allow this strategy to utilize the advantages of strong vertical resistance genes while maintaining the sustainability advantages of horizontal resistance. This strategy also provides for a refuge of a small percentage of the plants in an F2 population which do not carry any resistance genes.