INHERITANCE OF NON-NODULATION AND INEFFECTIVE NODULATION MUTANTS IN COMMON BEAN (PHASEOLUS-VULGARIS L)

Two nodulation mutants lacking effective nodules were induced in common bean (Phaseolus vulgaris L.) by treating seeds with ethyl-methane sulfonate. Inheritance of ineffective nodulation (IN) and non-nodulation (NN) was determined in crosses with wild types (W). Both nodulation characteristics were controlled by single recessive genes. Complementation tests, including nitrate-tolerant supernodulation (NTSN) mutants, revealed that all three nodulation types were under nonallelic control with distinct function. The gene symbols nie and nnd-2 were assigned for IN and NN types, respectively. A gene nod previously assigned for NTSN of common bean lines R32 and SV145 is changed to nts. Recessive epistasis occurred with nie being epistatic to nts, and nnd-2 being epistatic to nts and nie.