Bei Pisum wurde es durch Versuche erwiesen, dass die Hybriden verschiedenartige Keim- und Pollen-Zellen bilden, und dass hierin der Grund für die Veränderlichkeit ihrer Nachkommen liegt.
In Pisum it was shown by experiments that the hybrids form germ and pollen cells of different kinds, and that herein lies the reason for their variability.
Mendel refers to the back-crossing experiments that he reports on in Section 9 of his paper. The sentence repeats the explanation of the “law of combination of differing traits” given in the concluding sentence of that section, but in much more general terms (see p. 32, s. 2).