Author
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Panella, Leonard |
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Lewellen, Robert |
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Submitted to: Euphytica
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 6/9/2006 Publication Date: 8/30/2006 Citation: Panella, L.W., Lewellen, R.T. 2006. Broadening the genetic base of sugar beet: introgression from wild relatives. Euphytica. 154(3):383-400. 2007.(Published online: 30 August 2006) DOI 10.1007/s10681-006-9209-1 Interpretive Summary: Sugar beet is, perhaps, the first field crop to be developed at a time when modern genetic principles were becoming understood. It was developed in the late 1700s from white fodder beet; therefore, the genetic base of sugar beet has been thought to be narrower than many open-pollinated crops. The wild sea beet is the progenitor of all domesticated beet and cross compatible with cultivated beet (domestic and cultivated are given subspecies level in the same species). Early breeding goals were to improve the concentration and extractability of sucrose and little pressure was placed on finding and maintaining high levels of host-plant resistance to insect, nematode, and disease pests but as production areas expanded, these pests limited production, sometimes severely. The first systematic attempts to screen exotic and wild beet germplasm for disease resistance were begun at the beginning of the 20th Century. In North America, a pivotal development in utilizing the genetic resources available for sugar beet breeding was the formation in 1983 of the Sugar Beet Crop Germplasm Committee. Since the Sugarbeet CGC identified enhancing the commercial sugarbeet germplasm pool as a high priority, there has been an aggressive evaluation of the NPGS Beet collection. This collection now has more than 2,500 populations of wild and cultivated beet. In 2002, it was estimated that close to 25,000 evaluation data describing the collection were available in the GRIN database. Over 3,000 evaluations described levels of resistance of sugarbeet and wild beet accessions to 10 major disease and insect pests of sugarbeet. As soon as the evaluation data are collected, they are used to select the sources for the pre-breeding programs. There is a lag time in sugarbeet of 6 to 10 years between starting a germplasm development program and releasing the first developed germplasm, but we are seeing the results of this program in the germplasm being made available to the commercial seed company breeders. Resistance genes from wild beet for rhizomania- and beet cyst nematode-resistance have been commercialized. Technical Abstract: Sugar beet is, perhaps, the first field crop to be developed at a time when modern genetic principles were becoming understood. It was developed in the late 1700s from white fodder beet; therefore, the genetic base of sugar beet has been thought to be narrower than many open-pollinated crops. The wild sea beet is the progenitor of all domesticated beet and cross compatible with cultivated beet (domestic and cultivated are given subspecies level in the same species). The breeding system of sugar beet is complex and the crop is biennial, which lengthens the generation time to almost one year. A CMS system is in place for commercial hybrid production. Early breeding goals were to improve the concentration and extractability of sucrose and little pressure was placed on finding and maintaining high levels of host-plant resistance to insect, nematode, and disease pests but as production areas expanded, these pests limited production, sometimes severely. The first systematic attempts to screen exotic and wild beet germplasm for disease resistance were begun at the beginning of the 20th Century. Many undesirable traits from wild beet were reportedly introgressed with the selected disease resistance and it was only in the late 1900s that the use of wild beet genetic resources became common place in public breeding programs. In North America, a pivotal development in utilizing the genetic resources available for sugar beet breeding was the formation in 1983 of the Sugar Beet Crop Germplasm Committee. Since the Sugarbeet CGC identified enhancing the commercial sugarbeet germplasm pool as a high priority, there has been an aggressive evaluation of the NPGS Beta collection. This collection now has more than 2,500 accessions from within the genus Beta. In 2002, it was estimated that close to 25,000 evaluation data (descriptors x accessions evaluated) describing the collection were available in the GRIN database. Over 3,000 evaluations described levels of resistance of sugarbeet and wild beet accessions to 10 major disease and insect pests of sugarbeet. As soon as the evaluation data are collected, they are used to select the sources for the pre-breeding programs. There is a lag time in sugarbeet of 6 to 10 years between starting a germplasm development program and releasing the first developed germplasm, but we are seeing the results of this program in the germplasm being made available to the commercial seed company breeders. Resistance genes from wild beet for rhizomania- and beet cyst nematode-resistance have been commercialized. |
