Plant Breeding Research



CULTIVAR DEVELOPMENT

North Carolina State University has one of the largest concentrations of public plant breeders involved in cultivar development in the world. Several of the N.C. State breeding programs provide the sole source of cultivars for North Carolina farmers because there is no private company investment in breeding cultivars. These include peanuts, tobacco, turfgrass and several horticultural crops such as sweet potatoes, potatoes, cucumbers, peaches, tomatoes, blueberries and Fraser Fir Christmas trees. Even for major crops such as corn, soybean and small grains, the amount of private company breeding in North Carolina and the Southeast has been greatly reduced in recent years. Focuses of the cultivar development programs at N.C. State include incorporation of genes that provide resistance to biotic stresses caused by disease and insect pests, genes that provide resistance to abiotic stresses such as heat tolerance, drought and freeze damage, genes for specialty products such as novel fatty acids and proteins, and genes that provide higher quality and greater yield of grain, fruit, fiber and other plant constituents. Both traditional and DNA-based marker-facilitated selection schemes are being utilized.
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GENETIC BASIS OF AGRONOMIC AND HORTICULTURAL TRAITS

Studies of the genetic bases of economically important agronomic and horticultural traits provide new knowledge that enhances the efficiency and ultimate responses to selection for improved cultivars. These studies are being conducted in all of the major field crops and many of the horticultural crops grown in North Carolina. Gene mapping using DNA-based genetic marker approaches is conducted in a number of species in several laboratories at N.C. State, although traditional genetic and quantitative genetic methods are also used. A novel gene-mapping approach in forest tree genetics quantifies the intensities of the spots on a micro-array analysis and then uses quantitative genetic methods to evaluate the association of these spot intensities with phenotypic trait measurements from field trials. Functional genomics techniques are also being used to elucidate key points of cellular and metabolic control of plant processes important for crop quality and yield.
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GENETIC BASIS OF RESISTANCE TO DISEASE AND INSECT PESTS

None of the field, horticultural or forest tree crops is devoid of disease and insect pests, and all successful breeding programs must include resistance to these pests in their improvement strategies. A number of researchers, particularly in the plant pathology and entomology departments are searching for new sources of resistance to disease and insect pests. In addition, they are evaluating the nature and genetic basis of these resistance traits using traditional and molecular population genetic approaches. In collaboration with plant breeders, they are developing novel strategies for incorporating resistance factors into elite cultivars. 
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STRATEGIES FOR INCORPORATING PEST RESISTANCE FACTORS INTO ELITE GERMPLASM

Transformation technology is being used in several crop species to transfer virus resistance, nematode resistance, drought tolerance and other desired traits into breeding populations and elite germplasm. One of the novel strategies under development involves the isolation of genes from fungi that encode resistance and the characterization of these genes for their functions and ability to impart resistance. Those pathogen genes with desired characteristics would then be targeted for the genetic engineering of disease-resistant plants. 
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GENETIC TRANSFORMATION AND DEVELOPMENT OF TRANSGENIC PLANTS

The development of transgenics is being accomplished in several breeding programs. N.C. State also has a Plant Transformation Laboratory (PTL) with state-of-the art equipment that serves as the local provider for incorporating the most advanced gene delivery and molecular analysis technologies into plant science programs at the university. The PTL collaborates with researchers who seek to use transgenes in their programs. These researchers are using genetic transformation technology for introgressing genes, such as virus resistance genes and drought resistance genes, into breeding populations and elite germplasm. 
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MAINTENANCE AND EVALUATION OF GERMPLASM COLLECTIONS

A major component of many of the N.C. State plant breeding programs is the collection, active maintenance and evaluation of germplasm collections. The prevention of the erosion of genetic diversity and the maintenance of diverse germplasm pools is imperative to provide sources of useful genes, including genes for pest resistance and genes for improving oil, protein, starch, flavor and other quality components of field and horticultural crops. 
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