Leaf photosynthetic properties and biomass accumulation of selected western Canadian spring wheat cultivars

Current studies indicate wheat straw as a viable source for the production of cellulosic ethanol. Since photosynthetic performance impacts the overall success of the mature plant, this study aimed to measure the photosynthetic vigour of 11 spring wheat cultivars during field development as well as their biomass composition at maturity to determine which would be optimum for ethanol production. All cultivars had similar maximal quantum yields of photosystem II photochemistry (F-V/F-M), normalized difference vegetation index and biomass composition in the field. However, differences were observed in photosynthetic rate, with McKenzie having the highest light-saturated maximal rate of CO2 uptake (A(max)) and apparent quantum yield of CO2 uptake (Phi(app) CO2), while also having the best water use efficiency. Snowbird was found to have the lowest CO2-compensation point (Gamma*) and A(max). Upon subjecting wheat samples to photoinhibitory conditions, McKenzie and Kyle were found to be the most resistant and susceptible, respectively, with a difference of 11% in F-V/F-M. Abundance of xanthophyll pigments were not found to be a contributing cause to differential photoinhibitory resistance as there was not a noticeable difference between cultivars. Although some cultivars were found to have enhanced photosynthetic traits over others, these were slight and did not contribute to changes in plant biomass. However, McKenzie did present a higher cellulose content, which would be favourable for ethanol production.