A comparative analysis of two parental pea cultivars, Rondo and Ramonskii 7
7; two supernodulating mutants, nod(3) and nod(4); and the Torsdag line wit
h a marker Nod(5) gene was conducted. The mutants had more than 1000 nodule
s per plant, which were small and evenly distributed along the root system.
In the Torsdag line, the number of nodules was smaller (200-230 nodules pe
r plant), but they were larger and were Located in the upper part of the ro
ots. By crossing the Torsdag line with supernudulating mutants, forms with
two types of nodules were isolated: very small, as in mutants, and large, a
s in the Torsdag line. It is concluded that two regulatory systems controll
ing nodulation may operate simultaneously in one plant.