Selezione assistita da marcatori molecolari in erba medica: costruzione di mappe genetiche e mappaggio genico.

Cultivated lucerne (Medicago sativa L.) represents one of the most important legume forages in temperate climates. The genus Medicago includes sexual species that reproduce prevalently through allogamous pollination. A genetic map for alfalfa was constructed by ordering the linkage values of 65 AFLP and 40 RAPD markers collected in an F1 segregating population generated by crossing two highly heterozygous parents. A bulked segregant analysis (BSA) was also carried out to detect and map AFLP markers linked to diplosporic apomeiosis in a M. falcata mutant. Up to now, the current research led to the following results: (1) the generation of highly informative and reproducibile RAPD and AFLP fingerprints was achieved and several genome-specific primers were selected; (2) one integrated RAPD and AFLP linkage map that includes 55 loci was developed; (3) the use of an F1 mapping population enabled to minimize segregation distortion; (4) one AFLP marker was located 10.1 cM from the gene that potentially controls the unreduced egg production in Medicago; (5) the BSA approach appeared to be feasible using the available apomeiotic/meiotic plant materials. The development of genetic linkage maps in lucerne and their importance for marker-assisted selection is discussed.