Leaf gas-exchange characteristics of four Japanese and four Dutch tomato cultivars grown in a greenhouse

• Leaf gas-exchange rates of Japanese and Dutch tomato cultivars were surveyed.
• Dutch cultivars generally had higher photosynthetic capacity than Japanese cultivars.
• There is variation of photosynthetic capacity within Japanese and Dutch cultivars.

Modern Dutch tomato cultivars reportedly yield 1.2–1.6 times as much fresh fruit as Japanese cultivars. To analyze a factor potentially contributing to the yield difference, leaf gas-exchange characteristics were determined for four Japanese (‘Asabiyori 10’, ‘Momotaro York’, ‘Reiyo’ and ‘Renaissance’) and four Dutch (‘Dundee’, ‘Levanzo’, ‘Tomimaru Mucho’ and ‘Vinchy’) tomato cultivars and evaluated according to a C3 photosynthesis model. Plants were grown hydroponically with a high-wire system in a glass greenhouse, and leaf gas-exchange rates were measured at different photosynthetic photon flux and CO2 partial pressures with 130- to 140-d-old plants. Overall, Dutch cultivars generally had higher photosynthetic capacity than Japanese cultivars both under the light-limited and -saturated conditions, and both under the CO2-limited and -saturated conditions; thus, both capacities of ribulose-1,5-bisphosphate (RuBP) carboxylation and regeneration were relatively higher in Dutch cultivars. However, not all Dutch cultivars were superior than Japanese cultivars in terms of photosynthesis: although Dutch cultivars ‘Levanzo’ and ‘Tomimaru Mucho’ tended to have higher leaf photosynthetic capacity than Japanese cultivars ‘Asabiyori 10’ and ‘Renaissance’, Japanese cultivars ‘Momotaro York’ and ‘Reiyo’ and Dutch cultivars ‘Dundee’ and ‘Vinchy’ possessed comparable photosynthetic capacity. Thus, there is variation of photosynthetic capacity even within Dutch cultivars and within Japanese cultivars.