Male-sterility and heterosis in hybrid varieties: from the genetic hypothesis of Jones to the genomics era (in Italian with English summary)

Heterosis, after a century from its discovery, is still today the greatest biological phenomenon existing in nature that can be exploited for breeding plant varieties through the constitution of F1 hybrids. The actions and interactions of genes linked in chromo- some blocks allow to explain heterosis in diploids, fixed heterosis in allopolyploids of selfing species and progressive heterosis in autopolyploids of outcrossing species. With the advent of the genomic era, experimental data are now shedding light on the genetic factors and molecular networks that control the expression of heterosis in plants. The discovery of male-sterility was crucial because it enables to control fertilization through the selection of pure lines or inbreds to be used as seed parent in controlled crosses with genetically divergent pollinators.