|MCGRATH, J MITCHELL|
Submitted to: Journal of Sugarbeet Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 2000
Publication Date: N/A
Interpretive Summary: Determining the genetic basis for disease resistance and other agronomic traits in sugarbeet is hampered by the lack of germplasm containing well- defined traits. One way to overcome this limitation is to inbreed sugarbeets. A generalized strategy is presented that will utilize inbreeding to develop populations for genetic analyses. Additionally, the strategy is applicable to a variety of traits and will allow better evaluation of traits derived from beet relatives and related species. Using this strategy is expected to have a beneficial impact by more precisely understanding the genes required for economical sugarbeet production, and using this information to efficiently develop improved germplasm for sugarbeet growers.
Technical Abstract: Variety and germplasm development and release has been the main goal of the USDA-ARS sugarbeet breeding program at East Lansing, MI for over 70 years. Progress has been made in improving tolerance to Aphanomyces seedling disease, Cercospora leaf spot tolerance, Rhizoctonia root rot tolerance, herbicide resistance, and low tare root morphology. The genetic basis of these traits is not well defined, and the current program seeks to provide information on the genes and their location on beet chromosomes that influence the expression of disease, quality and morphological traits. The out-crossing nature of sugarbeet is not well suited for large-scale genetic analyses, and a common strategy has been adopted which should allow genetic dissection of a variety of traits through standard genetic analyses. In addition, this strategy allows relatively rapid introduction of traits from wild and unadapted germplasm while simultaneously determining the genetic basis for novel traits introduced through such crosses. Briefly, a common genetic male sterile seed parent that also carries a dominant self- fertility gene is paired with germplasm of interest. The resulting self- fertile hybrid is self-pollinated to give a segregating F2 population, which is simultaneously evaluated for segregation of the targeted traits and linkage of these traits with molecular markers. Segregation of the male-sterility and self-fertility genes in the F2 gives a range of options for further characterization. Increased use of newer technologies will allow higher-throughput in germplasm enhancement based on this scheme.