Relationship in annual species of Medicago. IV. Interspecific graft affinities between selected species

Abstract

Ten annual species representing each level of chromosome number and each subsection of sections Spirocarpos and Orbiculares were grafted in all possible combinations.

There was a high degree of compatibility, and if the data from reciprocal combinations are pooled, the only unsuccessful one was that of M. laciniata × M. Orbicularis, which suggests that despite incompatibility in hybridization the species are related.

Various hypotheses on graft compatibility are discussed.