Author
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Havey, Michael |
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Submitted to: Plant Breeding Reviews
Publication Type: Book / Chapter Publication Acceptance Date: 11/15/2017 Publication Date: 12/21/2018 Citation: Havey, M.J. 2018. Onion breeding. Plant Breeding Reviews. 42:39-85. https://doi.org/10.1002/9781119521358.ch2. DOI: https://doi.org/10.1002/9781119521358.ch2 Interpretive Summary: Technical Abstract: The bulb onion (Allium cepa L.) is grown on all continents except Antarctica, and prized by essentially all cultures for its flavor and health-enhancing attributes. Onion is sensitive to length of the night required to induce bulb formation and germplasm is traditionally classified by length of days under which bulbing occurs, such as short, intermediate, or long-day types. This bulbing requirement limits the use in breeding of germplasm across different day length responses. Both open-pollinated and hybrid cultivars are commonly grown, with hybrids predominating in regions of the world with mechanized production. Hybrids are produced using systems of cytoplasmic male sterility (CMS) and two main sources of CMS (S and T cytoplasms) are commercially used. Onion breeders focus primarily on bulb characteristics, such as color, shape, soluble-solids content, pungency and flavor, storage ability, health benefits, and resistances to diseases, pests, and bolting. Important characteristics for seed production include uniform flowering, straight seed stalks, stable expression of male sterility, and yields. Most of these traits show moderate to high heritabilities and therefore respond to selection. Due to the biennial generation time of onion, development of value-added populations and hybrids is a time-consuming and expensive process. The use of biotechnological approaches, such as marker-aided selection, production of doubled haploids, gene editing, and cytoplasmic conversions offer great promise to advance population and hybrid improvement to address changes in consumer preference and production environments. |
