Project description:Green manure is widely advocated as a sustainable alternative to chemical fertilizers in crop systems, yet the mechanisms underlying its yield benefits remain unclear. Moreover, vigorous vegetative growth under green manure can elevate lodging risk, undermining yield and harvest efficiency. Here, we describe mechanisms by which hairy vetch–based green manure enhances yield and evaluate the practical value of deploying functionally weak alleles of gibberellin 20-oxidase (GA20ox) in this management context. We conducted field comparisons of green manure and conventional chemical fertilization to evaluate effects on rice productivity, grain appearance quality, and canopy physiology. Green manure significantly increased grain yield and grain appearance quality in the leading Japanese cultivar ‘Koshihikari’, accompanied by higher lodging. By contrast, high-yielding cultivars homozygous for a single-copy GA20ox1 allele and/or a non-functional GA20ox2 allele maintained superior lodging resistance under green manure treatment while improving yield and grain appearance quality, indicating an effective combination of its treatment and genotypes. Physiologically, green manure increased chlorophyll index during vegetative growth and at the reproductive stage, and nitrogen (N) concentration on the whole plant. Furthermore, green manure increased flag-leaf width and tiller number; these canopy changes were associated with reduced panicle temperature at the ripening stage. Green manure treatment induced upregulation of OsNADH-GOGAT2, a known gene associated with increased N loading to grains, and more grain storage proteins, providing a positive link to improved grain appearance quality. Collectively, this study demonstrates that integrating hairy vetch with functionally weak GA20ox alleles can enhance productivity and grain appearance quality while mitigating lodging risk. This sheds light on the importance of aligning green-manure treatment with targeted allelic selection to stabilize performance across intensive-farming systems and reduce chemical fertilizer dependency.
Project description:<p>Common vetch (Vicia sativa L.) is an important annual leguminous forage crop commonly used for green manure, fodder, and soil improvement. It is widely cultivated as a green manure and forage crop in Yunnan Province during winter and spring. However, the dry conditions and minimal rainfall during these seasons greatly limit common vetch growth. Therefore, screening for drought-tolerant, high-yielding common vetch varieties is a critical objective in breeding programs.</p>