PHENOTYPIC CHARACTERIZATION AND CLASSIFICATION OF NODULATION MUTANTS OF PEA (PISUM-SATIVUM L)

Seven mutants of pea, altered in nodulation, were isolated following ethyl methanesulphonate mutagenesis. Biochemical, cytological and histological approaches have been used to phenotypically characterize and classify the mutants. Seed exudates of all mutants induced nod Rhizobium genes. However, mutants could be distinguished according to their infection patterns. In one group, comprised of P6, P53, P54, P55 and P56 lines, root hairs were shown to be resistant to infection. In the second category, containing the line DK24, the arrest of the nodulation process occurred during infection thread development. In the third group, containing the line P57, root hair infection seemed normal but early nodule development was affected.