Cytogenetic Studies of Oenothera mollissima L

The cytogenetic behavior of six of the races of Oenothera mollissima and their hybrids has been presented. Five of the races viz.-Argentina, Buenos Aires, Canelones, Montevideo and Uspallata were found to be complex-heterozygotes with _??_ 14. The sixth race viz.-Carrasco had _??_ 10, _??_ 4. In some instances there was evidence for the existence of gametic lethals, which were operative, at least, in the pollen parent. On the assumption that similarity in segmental arrangement is an indication of relationship between gene complexes, the phylogenetic relationships between races within O. mollissima have been pointed out. It has been concluded that complexes of O. mollissima. in general, are only distantly related to each other with respect to their segmental arrangements.