Creeping rootedness (CR) is the capacity of some lucerne (Medicago sativa L. complex) genotypes to form adventitious shoots from roots with horizontal habit. Satellite plants origin from adventitious shoots conferring greater tolerance to grazing and livestock trampling. Greater vegetative vigour has been reported to correlate with CR. However, phenotypic selection for CR in lucerne is severely hampered by the complex inheritance and incomplete penetrance of the trait. Moreover, the selection is further complicated by the autotetraploidy of the species, which makes it necessary to establish large segregating populations to uncover recessives. Finally, it has been reported that the CR trait in lucerne can take as long as 3 years after plant establishment to express itself. Therefore, there is a need to develop molecular markers for the assisted selection of CR in lucerne. Marker-assisted selection may help to introgress the CR trait in locally adapted variety, facilitating the selection of the additive (and, hence, heritable) component of the trait and allowing for a more effective and fast selection at the genotype level. The aim of this research is to isolate molecular markers linked to the CR trait in lucerne to be used for the marker-assisted selection of CR. Two segregating populations for CR were established: these two populations shared the CR donor whereas the two non-CR parents differed among them for the level of genetic relatedness with the CR parent. Markers associated with CR in both populations are good candidates for marker-assisted selection. Here we report preliminary results on the selection of AFLPs putatively linked to the CR trait. Fifty primer combinations were screened along the parental lines and eight 5-plant bulks (2 for each phenotype and for each population) each prepared by pooling together the DNA of 5 plants showing the same extreme phenotype (CR or non-CR). Bulk analysis showed 31 bands specifically present in bulks of CR plants in one or in the other population only, and 4 bands present in CR bulks of both populations. Linkage to CR of the putatively associated markers will be verified by co-segregation in single-plant analysis.
AFLP analysis of creeping rootedness in Lucerne
2006-01-01
Abstract
Creeping rootedness (CR) is the capacity of some lucerne (Medicago sativa L. complex) genotypes to form adventitious shoots from roots with horizontal habit. Satellite plants origin from adventitious shoots conferring greater tolerance to grazing and livestock trampling. Greater vegetative vigour has been reported to correlate with CR. However, phenotypic selection for CR in lucerne is severely hampered by the complex inheritance and incomplete penetrance of the trait. Moreover, the selection is further complicated by the autotetraploidy of the species, which makes it necessary to establish large segregating populations to uncover recessives. Finally, it has been reported that the CR trait in lucerne can take as long as 3 years after plant establishment to express itself. Therefore, there is a need to develop molecular markers for the assisted selection of CR in lucerne. Marker-assisted selection may help to introgress the CR trait in locally adapted variety, facilitating the selection of the additive (and, hence, heritable) component of the trait and allowing for a more effective and fast selection at the genotype level. The aim of this research is to isolate molecular markers linked to the CR trait in lucerne to be used for the marker-assisted selection of CR. Two segregating populations for CR were established: these two populations shared the CR donor whereas the two non-CR parents differed among them for the level of genetic relatedness with the CR parent. Markers associated with CR in both populations are good candidates for marker-assisted selection. Here we report preliminary results on the selection of AFLPs putatively linked to the CR trait. Fifty primer combinations were screened along the parental lines and eight 5-plant bulks (2 for each phenotype and for each population) each prepared by pooling together the DNA of 5 plants showing the same extreme phenotype (CR or non-CR). Bulk analysis showed 31 bands specifically present in bulks of CR plants in one or in the other population only, and 4 bands present in CR bulks of both populations. Linkage to CR of the putatively associated markers will be verified by co-segregation in single-plant analysis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
