image: Conceptual framework for inflorescence architecture and yield improvement in wheat
Credit: ©Science China Press
Driven by both long-term natural evolution and human domestication, different cereal crops have evolved inflorescence architectures that share common features, most having a notably compact spike, while also exhibiting distinct variations in shape and structure. These architectural differences contribute significantly to the variation in grain number per spike among major crops such as wheat, rice, maize, and sorghum.
How can we unlock the genetic code for obtaining higher wheat yields through inflorescence design? The researchers proposed a multi-pronged strategy focusing on four key areas:
1. Unlocking the yield potential of branched wheat: In crops like rice and sorghum, branched inflorescences are a major factor contributing to the high grain number per panicle. Although wheat and barley are typically unbranched crops, some natural or mutanted branched varieties do exist and have showed potential on grain number increase. However, challenges remain existing, as branched wheat often suffers from poor fertility and lower grain weight, and the trait is usually controlled by recessive loci, which further complicating its application in breeding. But, the potential of branching to boost grain number is undeniable. The authors advocate for deeper exploration of the molecular mechanisms underlying wheat spike branching, identification of robust genetic loci controlling the trait, and the use of genetic engineering to balance branching with other agronomic traits. The goal is to achieve moderate branching wheat variaties that enhance grain number without compromising overall performance.
2. Maintaining inflorescence meristem activity: Differences in meristem activity among crops significantly influence the development of lateral organs, including branch and spikelet meristem. By manipulating stem cell activity to prolong the activity of the inflorescence meristem, wheat can form more spikelets without negatively affecting other traits. This approach can effectively increase both spikelet and grain number, leading to a higher yield.
3. Improving floret fertility: Enhancing the fertility of individual florets is a direct way to increase grain number per spike. This involves the understanding and optimizing the genetic and environmental factors that determine whether a floret successfully sets grain.
4. Enhancing nutrient transport via the rachis: Recent studies have increasingly focused on redesigning the source–sink–flow system to meet breeding goals. In the context of wheat, improving the photosynthetic capacity and nutrient distribution efficiency of the spike, especially the rachis, can significantly enhance floret fertility and overall yield. Fine-tuning the allocation of assimilates to developing grains represents a promising avenue for yield improvement.
To achieve these goals, the researchers advocates for a multi-omics approach by integrating genomics, metabolomics, single-cell transcriptomics, and phenomics, to conduct comprehensive comparative analyses of inflorescence development across cereal species. By combining genetic engineering with deep learning and AI-driven design, the ultimate aim is to re-engineer wheat inflorescence architecture to maximize grain number potential, break through current yield ceilings, and ensure global food security.
Journal
Science Bulletin