Ethyl-methane sulphonate (EMS) induced nodulation mutants of common bean (Phaseolus vulgaris L.) lacking effective nodules

Seed of white bean (Phaseolus vulgaris L. cv. OAC Rico) was treated with 0.04 M ethyl-methane sulphonate. Screening of the M₂ progeny from 175 M₁ lines in the presence of 1 mM nitrate revealed two nodulation mutants. One line was essentially non-nodulating in several tests, but small white nodules were observed occasionally in other tests with 16 separate Rhizobium strains. The other line formed tiny, creamy white, non-functional (ineffective) and tumor-like pseudo-nodules. The M₃ and M₄ progenies were fertile and bred true.