BREEDING SELECTION AND MOLECULAR CHARACTERIZATION FOR IMPROVED SUGAR BEET GERMPLASM
Location: Sugarbeet and Bean Research
Title: Molecular and Morpho-Physiological Characterization of Sea, Ruderal and Cultivated Beets
| Saccomani, Massimo - |
| Stevanato, Piergiorgio - |
| Trebbi, Daniele - |
McGrath, J Mitchell
| Biancardi, Enrico - |
Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 14, 2009
Publication Date: September 1, 2009
Citation: Saccomani, M., Stevanato, P., Trebbi, D., Mcgrath, J.M., Biancardi, E. 2009. Molecular and Morpho-Physiological Characterization of Sea, Ruderal and Cultivated Beets. Euphytica. 169(1):19-29.
Interpretive Summary: Sugar beets have been bred for a very specific purpose, to provide sucrose at economically recoverable levels for human consumption. During this process, the genetic diversity of sugar beets has been reduced relative to the total genetic diversity in its wild progenitors. This reduction has implications for continued genetic improvement of sugar beet, and the genetic diversity of both cultivated and wild beets was measured with molecular markers and by examining the architecture of their poorly characterized root systems and their responses to nutrient limitation. With all measures, significant variability was seen in wild beets compared with sugar beet, and these differences will be useful for improving sugar beet and other cultivated beets. Particularly, the identification of root character responses to nutrient limitation will allow scientists and breeders to understand and select for more robust root systems.
Beta vulgaris genetic resources are essential for broadening genetic base of sugar beet and developing cultivars adapted to adverse environmental conditions. Wild beets (sea beets, B. vulgaris spp. maritima and their naturalized introgressions with cultivated beets known as ruderal beets) harbor substantial genetic diversity that could be useful for beet improvement. Here, we compared molecular and morpho-physiological traits of wild beets collected on the Adriatic coast of Italy with sugar beet using eight primer-pairs amplifying 194 polymorphic fragments and four root traits (glucose and fructose content in the root tip, root elongation rate, number of the of root tips, and total root length). Genetic diversity was higher in the sea beet accession, which may be due to the highly variable selection pressures that occur in ecological niches, compared with the ruderal and cultivated beets. Sea and sugar beet accessions showed contrasting root patterns in response to sulfate deprivation where sugar beet showed an increase of reducing sugars in the root tips and higher root elongation rate whereas the sea beet accession showed an increase in root tip number, total root length and fine root length (average diameter < 0.5 mm). The ruderal beet showed intermediary responses to sea and sugar beet accessions. Cluster analyses showed sea, ruderal and cultivated beets to be genetically distinct groups. The results of this study indicate variability in response to sulfate deprivation is present in undomesticated beets that could be deployed for sugar beet improvement.