Understanding physiological processes associated with yield–trait relationships in modern wheat varieties

New insights into changes in physiological processes associated with genetic gains in yield potential are essential for improved understanding of yield-limiting factors. Our field study was conducted at two sites with three N levels and 15 modern wheat (Triticum aestivum L.) varieties. The goal was to evaluate yield components, time courses of dry matter production, and N accumulation among different yield categories, and to determine physiological processes associated with yield–trait relationships. Close correlations were observed between yield and dry matter production after the stem elongation stage, particularly post-anthesis. Similar close correlations were observed between grain yield and N accumulation over the whole growing season, except for the re-greening stage. No positive correlation was found between yield and harvest index. Differences in dry matter production among different yield categories began at anthesis; differences in N accumulation emerged even earlier. We conclude that consistent increases in dry matter production (especially post-anthesis) and N accumulation are crucial for further improvements in wheat yield–trait relationships.

► We evaluate physiological process associated with wheat yield gains.
► No positive correlation was found between yield and harvest index.
► Consistent increases in dry matter production and N accumulation (especially post-anthesis) are crucial for further improvements in wheat yield gains.