Dilemma between yield and quality: Multigenerational effect of elevated CO2 and nitrogen supply on wheat cultivars

Studying the long-term effect of elevated atmospheric CO2 concentration (e[CO2]) on wheat (Triticum aestivum L.) over multiple generations has received increasing attention. Here, five wheat cultivars were grown under ambient CO2 concentration (a[CO2], 400 ppm) and e[CO2] (800 ppm), respectively, for three consecutive generations (G1 to G3) under two nitrogen (N) levels (1N and 2N). Compared to plants grown under a[CO2], e[CO2] increased shoot biomass and grain yield (GY) over three generations and the enhancement was greater in G3 than in G1. However, plant N concentration was lowered by e[CO2] and the reduction was not mitigated by higher N supply. The carbon (C) concentration significantly increased in leaf and stem but decreased in grain, indicating an inhibited C translocation to grain under e[CO2]. Most importantly, these negative impacts were exacerbated in G3. Concentrations of mineral nutrients in grain were significantly lowered by e[CO2] with larger reduction in G3 than in G1 in some micronutrients such as Zn, Cu and Fe. These findings suggest that long-term exposure to e[CO2] sustained the positive effects on plant growth and production but aggravated the reduction of grain quality over multiple generations. Among the five cultivars, 325Jimai showed the greatest increase in shoot biomass and GY, and a greater sink capacity compared with the other cultivars, indicating its potential for future breeding strategies.

Automated summary

The long-term effect of elevated atmospheric CO2 concentration (e[CO2]) on wheat over multiple generations was studied. The results showed that e[CO2] increased shoot biomass and grain yield over three generations, with a greater enhancement in the third generation. However, e[CO2] reduced plant N concentration and inhibited C translocation to grain, resulting in lower grain quality. The negative impacts of e[CO2] were exacerbated in the third generation, and micronutrient concentrations in grain were significantly lowered. The cultivar 325Jimai exhibited the greatest increase in shoot biomass and grain yield, suggesting its potential for future breeding strategies.