LONG-TERM CHILLING OF YOUNG TOMATO PLANTS UNDER LOW-LIGHT .7. INCREASING CHILLING TOLERANCE OF PHOTOSYNTHESIS IN LYCOPERSICON-ESCULENTUM BYSOMATIC HYBRIDIZATION WITH LYCOPERSICON-PERUVIANUM

The inheritance of the chilling tolerance of photosynthesis in a somat ic hybrid between the chilling-sensitive cultivated tomato (Lycopersic on esculentum) and the chilling-tolerant wild species L. peruvianum wa s studied by comparison of photosynthesis and chlorophyll fluorescence data after a defined chilling stress with those of the parental lines . The hybrid was superior to L. esculentum and equal or superior to L. peruvianum with respect to photosynthesis rates, chlorophyll content, specific activity of ribulose-1,5-bisphosphate carboxylase, reduction state of the photosynthetic electron transport chain and development of energy-dependent chlorophyll fluorescence quenching under chilling conditions. It is concluded that somatic hybridization can be a useful tool for introducing germplasm related to chilling tolerance from L. peruvianum into (possibly polyploid) new tomato lines.