Abstract
Intraspecific variation in crop responses to global climate change conditions would provide opportunities to adapt crops to future climates. These experiments explored intraspecific variation in response to elevated CO2 and to high temperature during anthesis in Chenopodium quinoa Wild. Three cultivars of quinoa were grown to maturity at 400 (“ambient”) and 600 (“elevated”) μmol·mol−1 CO2 concentrations at 20/14 °C day/night (“control”) temperatures, with or without exposure to day/night temperatures of 35/29 °C (“high” temperatures) for seven days during anthesis. At control temperatures, the elevated CO2 concentration increased the total aboveground dry mass at maturity similarly in all cultivars, but by only about 10%. A large down-regulation of photosynthesis at elevated CO2 occurred during grain filling. In contrast to shoot mass, the increase in seed dry mass at elevated CO2 ranged from 12% to 44% among cultivars at the control temperature. At ambient CO2, the week-long high temperature treatment greatly decreased (0.30 × control) or increased (1.70 × control) seed yield, depending on the cultivar. At elevated CO2, the high temperature treatment increased seed yield moderately in all cultivars. These quinoa cultivars had a wide range of responses to both elevated CO2 and to high temperatures during anthesis, and much more variation in harvest index responses to elevated CO2 than other crops that have been examined.
Highlights
The yearly mean concentration of carbon dioxide in the atmosphere has increased from about320 μmol·mol−1 in 1965 to about 400 μmol·mol−1 currently, and continues to increase rapidly
Most main stem leaves had senesced and seeds were mature at about 90 days after planting, except that the high temperature treatment at the lower CO2 concentration resulted in a slower progression of anthesis up the main stem in Salcedo, which prolonged seed filling and delayed maturity by about
The failure of seed development resulting from the high temperature treatment was evident in Cherry Vanilla grown at the lower CO2 concentration, but not in other cases
Summary
The yearly mean concentration of carbon dioxide in the atmosphere has increased from about320 μmol·mol−1 in 1965 to about 400 μmol·mol−1 currently, and continues to increase rapidly. At elevated CO2 , the high temperature treatment increased seed yield moderately in all cultivars. There is little information about differences among cultivars in response to high temperature and elevated CO2 treatments [28].
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