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Urban (1873) characterized Medicago L. division Intertextae Urb. as having black seeds. An exception to this was found among M. granadensis Willd.; there were accessions with black as well as with brown seeds. Black seed color was dominant over brown and segregated in F2 in ratio 3:1. Two other M. granadensis marker characters: colored vs. green stems, hairy stems vs. smooth stems similarly segregated in a 3:1 ratio, the first named characters being dominant. The colored and white patch in the middle of leaflets appeared to be determined by a gene P for patching, a gene C being responsible for the presence of color. No recombinations were found between colored patch in leaflets, colored stems, and black seeds, indicating that there is only one gene for color with pleiotropic action, or that the genes are closely linked M. granadensis did not hybridize with M. intertexta and M. ciliaris. It clearly is a separate species.M. intertexta Mill., M. ciliaris All. and M. muricoleptis Tin. could be intercrossed. Marker characters, red basal patch vs. no patch in leaflets and hairs vs. no hairs on pods, segregated in F2 in a normal 3:1 ratio, the first named characters being dominant, Segregation did not indicate that there was any linkage between the two characters. Seed weight difference was determined by two genes acting in an additive manner. Distribution of leaf marking in seed weight classes indicated an independent segregation. Pollen fertility of F1's was less than 50%. There were observed irregularities in 30% of meiotic metaphases studied in F1 of M. muricoleptis × M. ciliaris. Because of some interbreeding barrier the taxa may be considered separate species though their hereditary material can be interchanged.

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