Development and research trends of stay-green biology in legumes: a bibliometric and visual analysis over...

The stay-green trait, which manifests as a delayed leaf senescence in plants, is increasingly viewed as a valuable target for improving crop resilience, quality and yield stability. While most of the progress in this area has been made in cereals, research in legumes remains less consolidated, despite their importance for nutrition and sustainable agriculture.

Bibliometric and structured literature reviews were combined to examine the evolution, thematic structure, and research frontiers of stay-green research in legumes over the past 3 decades. Using the Web of Science Core Collection and Dimensions database, 157 relevant articles published between 1993 and 2025 were identified following PRISMA guidelines and analyzed using VOSviewer and the Bibliometrix R framework to assess publication trends, collaboration networks, thematic evolution, and to classify reported stay-green phenotypes into functional and non-functional categories.

The results show a steady rise in publications with a growth rate of 8.6% per year, involving 883 authors across 96 journals, and a strong pattern of international collaboration. Most publications were original research articles, with only 11 review articles, indicating a lack of integrative work in this field. Foundational work by Thomas and colleagues remains highly influential, while recent studies increasingly emphasize molecular genetics and functional analyses in soybean, common bean, pea, and other grain legumes. The keyword analysis highlighted five main research hotspots: drought tolerance, molecular regulation of senescence, photosynthesis related mechanisms, trait mapping and genomics, and pathological stay-green syndromes. Research emphasis has shifted from descriptive physiology toward molecular breeding applications, with increasing focus on distinguishing functional from non-functional stay-green.

This is the first comprehensive study to apply bibliometric approaches to analyze the trends and research frontiers of stay-green traits in legumes, offering valuable insights and reference points for advancing future research and breeding applications.