Energy efficiency can be increased either by increasing the production per m2 or by reducing the energy input per m2, e.g. by reducing temperature set-points in the greenhouse. So far, in Dutch glasshouse tomatoes energy efficiency was almost exclusively raised by yield increases. To study the role of tomato breeding in this production increase, yield and underlying components of 7 cultivars released between 1950 and 2002 were studied. Furthermore, variation in temperature response between cultivars was studied. In three experiments yield and biomass production of in total 11 cultivars were evaluated at two temperature regimes (17/15°C and 21/19°C day/night temperature set-points). Breeding has resulted in a remarkable increase in production. Under current conditions, yield of modern cultivars was on average 40% higher than yield of `Moneymaker¿, released in 1950. This increase in production resulted from a higher light use efficiency. Although the fraction of assimilates partitioned to the fruits showed small differences between cultivars, this trait was not related to year of release. Furthermore, more recently introduced cultivars produced larger fruits rather than more fruits. All cultivars responded similar to both temperature regimes for all important characteristics, limiting the possibilities of using existing cultivars in a breeding program for improved yield at lower temperatures.
van der Ploeg, A., van der Meer, M., & Heuvelink, E. (2007). Breeding for a more energy efficient greenhouse tomato: past and future perspectives. Euphytica, 158(1-2), 129-138. https://doi.org/10.1007/s10681-007-9437-z