Incompatibility in someSolanum crosses

Conclusions and Summary

There are four conclusions: (1)Solanum kurtzianum, S. simplicifolium andS. michoacanum possess an ordinary one locus system; (2) the three species ofMegistacroloba investigated are sufficiently closely allied to express, with little irregularity, a common incompatibility system; (3) several crosses involvingS. infundibuliforme, four wild species of the seriesTuberosa and certain cultivated diploids show a highly irregular expression of the incompatibility system which is much influenced by erratic female sterilities; and (4) the combinationS. simplificifolium x Phureja cultivar group shows an entirely anomalous behaviour (which is consistent in reciprocal) in which only three compatibility groups can be recognized in the approximate numerical ratio 1∶2∶1; for this there is yet no explanation.