CYTOKININ EFFECTS ON TOMATO SEED QUALITY, FRUIT YIELD, AND RIPENING IN TRANSGENIC PLANTS CARRYING THE ipt GENE

Abstract

Lycopersicon esculentum cv. UC82b cotyledons were co-cultivated with A. tumefaciens carrying vectors with modified isopentenyl transferase (ipt) genes. The ipt gene was placed under the control of the RUBISCO promoter in both the sense and antisense orientation. Over 50 transformants were recovered on kanamycin-containing media. Seeds from RO plants were germinated on selective media and R1 plants transformed with the ipt gene identified by PCR and Southern blot hybridization. Phenotypes of the R1 plants, whether transformed with the ipt gene in the sense or antisense orientation, were comparable to the control plants transformed with an inactive cytokinin gene. Fruit weights from both were similar to those from control plants, however, yields were reduced and ripening delayed. Most fruit had no seeds or very few small seeds. Cytokinin levels are being determined in order to correlate them to the observed phenotypes.