Plant Breeding, Genetics, and Biotechnology

Esther van der Knaap

University of Georgia, Athnes, GA

“Domestication and selection driving fruit quality traits in tomato”

Abstract: The process of domestication and selective breeding has played a crucial role in shaping tomato fruit quality traits, making it one of the most popular and widely cultivated crops today. Wild tomato feature fruits that are small, round, full of seeds, and produce an aroma that, collectively, has evolved to attract seed dispersers in native habitats. The evolutionary process from wild to contemporary fruit types was driven by human preferences for increased sizes, variable shapes, characteristic tastes, and other attributes, where selective breeding further refined these traits. This resulted in a phenotypically diverse germplasm that produces fruits varying in morphological and aromatic properties. The emergence of genomics and molecular biology has allowed for a much deeper understanding of the processes, including the genes, that regulate the transition from wild to cultivated types in the regulation of fruit quality. This knowledge enables breeding strategies that are targeted at specific market classes by enabling the selection of beneficial haplotypes. The research in our laboratory delves into the molecular genetic basis of these forces that have influenced the evolution of the tomato plant, with extensions to other fruit and vegetable crops. Examples include SUN, TRM, and OVATE that regulate fruit shape; CSR and SlKLUH that regulate fruit size; and various genes that regulate fruit aroma.

Jen Jaqueth

Corteva Agriscience

“Deploying Genome Editing for Native Disease Resistance: Maize Disease Super Locus”

Abstract: Corteva Agriscience uses innovative genome editing technology to package multiple disease-resistant genes into a single location in the genome to better address devastating corn diseases facing farmers today. By using genome editing to combine and reposition disease-resistant genes that already exist within the corn genome, Corteva is able to bolster disease tolerance and increase yield potential. The Disease Super Locus concept is intended to simplify disease management and improve sustainability by reducing the need for additional fungicide applications.

Paul Gepts

University of California, Davis

“The Natural History of a Wild Crop Relative: Its Applications in Domestication Studies, Conservation, and Genetic Improvement”

Abstract: For most of its existence, the hominin evolutionary lineage leading up to Homo sapiens has procured food and other biological necessities as hunter-gatherers. In a major subsistence transition (which, as yet, is not fully understood), modern humans initiated the crop cultivation process (and animal rearing). One cannot exaggerate the importance of this transition as it affected, in the most significant way, crop properties through domestication, biodiversity, ecosystems, and habitats, and the activities, organization, and health of human societies. Within this broader context, I will focus on the natural history of a crop wild relative (CWR)  - namely, wild common-bean (Phaseolus vulgaris) - and what this knowledge tells us about this crop's domestication process. I will discuss various aspects, like its vast geographic distribution in the Americas and how it came to be, the issue of gene flow between wild and domesticated types despite its predominant autogamy, and the molecular basis of its transformation into the most widely cultivated pulse in the world, through a remarkable diversification in pod and seed types and photoperiod insensitivity. In turn, this knowledge guides the process of genetic conservation, both in-situ and ex-situ, and the use of this CWR in breeding more resilient cultivars.

David Van Tassel

The Land Institute

“Farmers need new tools. Wild plants have impressive adaptations. Domestication could bring them together. Everyone will have to help”

Abstract: Farmers face more erratic weather, fiercer competition for irrigation water, increased fertilizer cost, rising sea levels, and more social pressure to help conserve biodiversity. The plant kingdom is immensely species-rich and contains a wealth of evolutionary adaptations: deep roots, mutualisms with beneficial insects and fungi, perennial regrowth in the spring, heat and flooding tolerance, an array of defensive structures and chemistry. These adaptations could help farmers conserve soil, produce during droughts, and use applied nutrients more efficiently. However, bringing completely new species to the farm requires major investment in genetic improvement, horticultural and ag. engineering innovation, and social/economic/cultural capacity-building: a truly transdisciplinary challenge. Genetic innovations including gene editing and genomic selection could accelerate yield gains during de novo domestication, but do not overcome concerns that strong directional selection will lead to loss of the “wild adaptations” that attracted us to these plants in the first place. I will illustrate these general domestication challenges and opportunities using examples from The Land Institute’s work to domesticate perennial cereal, legume, and oilseed grains, including my work domesticating Silphium integrifolium (Asteraceae)--a North American prairie perennial.