Intercepting more radiation or higher use efficiency: pathways to enhancing biomass and yield in two wheat cultivars with distinct spike types under wide-belt sowing.

Background: In north China, wide-belt sowing (WBS) is widely used in wheat production because it increases the yield by improving the plant distribution and reducing the competition for resources compared with conventional narrow-drill sowing (NDS). Yield formation is also different for wheat varieties with distinct spike types. Therefore, it is important to explore the effects of WBS on the yields of wheat varieties with different spike types.

Results: We conducted a field experiment using Shannong20 (SN20, a multi-spike variety) and Shannong30 (SN30, a heavy-spike variety) for three seasons under WBS and NDS. WBS increased yields of both varieties by 9.3-11.1% than NDS. The yield increase for SN20 came from improvement in pre-anthesis biomass, whereas the post-anthesis biomass improved for SN30. Before anthesis, the increased biomass for SN20 by WBS was due to higher radiation interception because of the increased population size and leaf area index. After anthesis, WBS increased the biomass via improving radiation use efficiency (RUE) for SN30. WBS improved the radiation intensity in the sub-top and middle canopy layers which was beneficial for increasing RUE. In addition, the higher maximum leaf net photosynthesis rate (A) also contributed to the increase in RUE for SN30. The increased A for SN30 was due to the increased specific leaf nitrogen and leaf antioxidant capacity.

Conclusion: In short, the radiation interception before anthesis was mainly responsible for the yield increase for the multi-spike variety, whereas for the heavy-spike variety, the yield improvement only came from the increased RUE after anthesis under WBS. © 2024 Society of Chemical Industry.