After studying peas, Mendel investigated plants in the genus Phaseolus, including common beans. These experiments tested whether the inheritance patterns he had observed in Pisum, the garden-pea genus, also appeared in another plant group.
In his 1866 paper, Mendel described two small Phaseolus experiments. One cross involved Phaseolus vulgaris and Phaseolus nanus. Their offspring displayed numerical ratios and combinations of traits that corresponded closely with the results he had obtained in peas. This gave Mendel some support for the idea that his inheritance principles were not limited to Pisum.
The work also showed Mendel’s broader scientific method: he did not want to rely on a single species, so he tried to test his proposed laws through hybridization in other plants. Later, he studied many additional genera, including Hieracium, where the results were more difficult to interpret because of unusual reproductive biology.
A common confusion is Zea, the genus of maize. Mendel considered or investigated several other plants, but Phaseolus is the genus specifically associated with the early bean experiments that produced results agreeing with his pea findings.