Challenges and Opportunities for Further Improvements in Wheat Yield

Wheat is one of the most critical food crops. Globally wheat yield has been growing slower than wheat demand. Further improvements in yield are required. Due to environmental concerns, much of these improvements must come from genetic gains. As wheat yield potential is expressed across a wide range of environments, breeding cultivars of higher-yield potential than that of most modern cultivars is critical. The challenge is that the main physiological avenues for improving yield in the future must be different than that on which past breeding (including the “green revolution”) was based. Major improvements in yield potential were achieved by increased harvest index based on plant height reduction, but any further reductions in plant height would bring about yield penalties rather than gains. In this paper I will discuss alternative opportunities for future improvements beyond modifications in height or partitioning of dry matter.