Legumes belonging to the family Fabaceae (Leguminosae) are essential to global food security, human nutrition and sustainable agricultural systems. Major grain legumes include chickpea, pigeon pea, lentil, mung bean, urd bean, cowpea, field pea, soybean, common bean and faba bean. Their grains provide protein, essential amino acids, dietary fibre, minerals, vitamins and bioactive compounds. Legumes also contribute to agricultural sustainability through symbiotic nitrogen fixation, improving soil fertility and potentially reducing dependence on synthetic nitrogen fertilisers
(Kebede et al., 2021; Jat et al., 2024; Erol et al., 2026). In contrast to major cereals, however, investment in legume research and genetic improvement has lagged behind and has led to ongoing yield gaps and relatively smaller genetic advances
(Foyer et al., 2016; Rubiales and Mikic, 2015). With the rising consumer interest in plant-based proteins and the growing importance of crops and agriculture that are resilient to climate change, researchers are once again making legumes the focus of their studies.
Bibliometric analysis offers a quantitative means for analyzing publication performance, impact of citations, scientific collaboration networks and the evolution of scientific knowledge
(Donthu et al., 2021). These approaches are becoming more common to assess research trends and scientific contributions in various fields of agriculture, such as agriculture
(Kamali et al., 2020) and organic agriculture
(Naik et al., 2025, 2026). It helps to identify the top producers, research trends, new science horizons and geographical distribution of the production of scientific knowledge. There are some studies that have explored the research trends on a single species of legume or a single research area, but a comprehensive study on overall research and collaboration patterns in major grain legumes is still useful.
Thus, the current study aims at creating a global map of legume research based on publications published between 2016 and 2025 in Scopus. It covers publication trends, top authors and institutions, citation trends, global collaborations, thematic shifts and new trends. The study combines research performance with social and intellectual frameworks to give a clear picture of the state of legume research internationally and to highlight future research priorities, legume breeding and sustainable agriculture.
In this study, bibliographic data was from the Scopus database by applying a scientometric approach. The study was carried out at the ICAR-National Academy of Agricultural Research Management (ICAR-NAARM), Hyderabad, India. The research period covered publications published from 2016 to 2025. Bibliographic data were retrieved from the Scopus database up to 29 May 2026.
Search string development
The Scopus search strategy combined the names and synonyms of major grain legumes with agricultural and agronomic terms. Searches were conducted in the title, abstract and keyword fields and restricted to English-language journal articles published from 2016 to 2025. The complete search string is provided below.
The final scopus search query was as follows
(TITLE-ABS-KEY) chickpea OR pigeonpea OR “pigeon pea” OR lentil OR mungbean OR “green gram” OR urdbean OR “black gram” OR cowpea OR “field pea” OR soybean OR groundnut OR peanut OR mothbean OR lathyrus OR “faba bean” OR frenchbean OR “common bean” OR rajmash) AND TITLE-ABS-KEY (agriculture OR agronomy OR cultivation OR farming OR crop OR yield) AND [LIMIT-TO (SUBJAREA, “AGRI”)] AND [LIMIT-TO (DOCTYPE, “ar”)] AND [LIMIT-TO (LANGUAGE, “English”)] AND PUBYEAR > 2015 AND PUBYEAR < 2026.
Document screening
Only peer-reviewed journal articles that were written in English and indexed under Agricultural and Biological Sciences were included. The first search returned 20,186 results in Scopus database. Records were then screened for inclusion/exclusion of information not directly related to legume agronomy and crop science. The data set excluded publications that were mainly devoted to animal nutrition, clinical investigations, pharmacology, non-agricultural uses of legumes, or uses of non-leguminous cereal crops. The retrieved records were then exported in CSV format for further processing and analysis. Data cleaning processes were used to eliminate unnecessary information and make the data set consistent. After screening, validation, data-cleaning, a total of 19,996 articles were retained for scientometric analysis, which means that 190 articles were excluded.
Data analysis
The cleaned data set was analysed extensively using scientific research analysis techniques involving an array of complementary tools that are scientifically tested and proven
(Donthu et al., 2021). The Bibliometrix R Package
(Aria and Cuccurullo, 2017) was applied through RStudio (version 4.3.2) and the user-friendly Biblioshiny interface in extracting important scientific indicators such as yearly publications, citation rates, author productivity, ranking of sources, institutional production, production by countries and the h-index of the authors involved in producing the literature. For constructing complex networks and creating thematic maps. This allowed an extensive examination of collaborative networks within legume crop research and the evolution of the thematic content during the specified period.
The final dataset comprised 19,996 articles published across 1,016 sources between 2016 and 2025 (Table 1). Annual publication growth was 16.92%, with an average of 13.93 citations per document. The dataset included 60,977 authors, an average of 6.25 co-authors per document and an international co-authorship rate of 23.11%. These indicators provide an overview of the scale and collaborative character of global legume research.
Annual scientific production
Annual scientific output on legume research gradually increased between 2016 and 2025, as shown in Fig 1. Annual scientific production generally increased during 2016-2025, rising from 756 publications in 2016 to 3,087 in 2025 (Fig 1). Despite minor fluctuations, the overall trend indicates substantial growth in the volume of research captured by the search strategy.
Legumes have attracted considerable interest because of their ability to fix biogenic nitrogen, improve soil health and decrease the need for artificial fertilizers. In addition, the development of genomics, molecular breeding, precision agriculture and digital technologies has opened the door to research opportunities and brought multidisciplinary scientific interest
(Stagnari et al., 2017; Spatti et al., 2022; Calia et al., 2024). The publication trajectory is generally in accord with the scientific growth as outlined by
Price (1963) and that, as a research field grows, so does the number of scientific publications grow, albeit in a steady manner.
Most relevant sources
The most relevant sources given in the Fig 2 reveal the key journals contributing to legume research during the period of study. Among the contributed sources, Legume Research is the most productive journal, publishing 960 articles, highlighting its central role disseminating research on legumes. Frontiers in Plant Science ranked second (804 publications), indicating the growing integration of legume research within broader plant science research. With 723 publications, Agronomy occupying the third position. The dominance of legume research is a significant illustration of the need for specialised journals on specific crops and specific situations in the dissemination of the results of applied research for legume production, breeding, crop protection and management. The distribution of the publications in the different sources shows that the legume research is supported by both specialized and interdisciplinary journals. The diversification reflects the increasing scientific and societal relevance of legumes in the context of global food security and environmental issues
(Foyer et al., 2016; Stagnari et al., 2017).
Most relevant authors
The most relevant authors presented in Fig 3 represent the researchers who have made the greatest contributions to scientific output in legume research during the study period. Rajeev K. Varshney emerged as the most productive author with 132 publications. His high ranking is a reflection of his extensive contributions to legume genomics, molecular breeding, crop improvement and translational research for enhancing productivity and resilience in legume crops
(Varshney et al., 2021). Among other researchers, Yang Wenyu ranked second with 118 publications. A high proportion of publications by a limited number of highly productive scientists suggests that there is a compact group of core scientists at the forefront of innovation and knowledge development in legume research. The international nature of current legume research will be emphasized by leading researchers from Asia, North America and Australia. This geographical diversity highlights the global relevance of legumes for food security, nutritional value, climate resilience and sustainable agricultural development
(Foyer et al., 2016; Stagnari et al., 2017). It also indicates the presence of strong international research networks facilitating scientific collaboration and knowledge exchange across regions.
Most globally cited documents
The most cited document (Table 2) was “Evolution of Gene Duplication in Plants” by
Panchy et al., (2016) with 1,330 citations. This paper has received many citations because gene duplication studies are important for understanding plant evolution, genome organization and crop improvement. Several studies on soybean production systems were among the highly cited publications, reflecting the dominant position of soybean in the global legume research.
One of the remarkable characteristics among the most powerful documents is the high number of studies related to remote sensing, machine learning, artificial intelligence and digital agriculture
(Zhang et al., 2002; Mulla, 2013;
Wolfert et al., 2017). Publications by
Maimaitijiang et al., (2020), Khaki et al., (2020); dos Santos Ferreira et al. (2017);
Cai et al., (2018); Gao et al., (2017); Schwalbert et al., (2020); Nagasubramanian et al., (2019); Mulla, 2013;
Wolfert et al., 2017, show the growing application of advanced computational approaches for crop monitoring, yield prediction, disease diagnosis and precision agricultural management.
The presence of well-cited publications on iron oxide nanoparticles and crop diseases further underscores the multi-disciplinary nature of the current legume research, which extends beyond the traditional agronomy to nanotechnology, plant pathology, biotechnology and digital phenotyping.
Most relevant institutions in legume research
The analysis of institutional productivity revealed that several universities and agricultural research organizations have played a major role in advancing global legume research during the study period (Fig 4). Tamil Nadu Agricultural University emerged as the most productive institution with 770 publications, highlighting its significant contribution to legume crop improvement, agronomic management and sustainable production systems. The Iowa State University, ICAR-Indian Agricultural Research Institute (419 publications) and Punjab Agricultural University (415 publications) followed closely behind. Multiple institutions from India, China and the USA in the top 10 list. Asia was found to be the most important region in terms of the role of legumes in food and agriculture, with institutions from that region dominating the rankings. The institutional productivity analysis reveals that there are already well-developed research hubs which stimulate research innovation, knowledge generation and networked and collaborative relationships across international boundaries in the world of legume science.
Trend topics in legume research (2016-2025)
The findings (Fig 5) show a distinct shift from traditional breeding and crop improvement research to sustainability-oriented, climate-resilient and technology-driven approaches. During the initial years of the study period, 2016-2018, scientific focus was centered on crop-specific and genetic improvement aspects. During 2016-2018, trend topics mainly reflected germplasm characterisation, genetic diversity, breeding and crop improvement, alongside varietal evaluation and agronomic management. During 2019-2022, soybean, chickpea, yield and crop production were prominent topics, indicating a strong emphasis on crop productivity. Cropping systems and diversification also appeared in the keyword patterns, reflecting interest in improving resource use and production-system performance.
The most prominent change that was observed after 2020 is the appearance of sustainability and climate change themes. The phenomenon of climate change (237 occurrences) emerged as median year of 2023 reflecting growing scientific concern regarding the impacts of changing climatic conditions on legume productivity, adaptation and sustainability. Another trend observed during the years between 2021 and 2025 is the appearance of terms such as sustainability (152 times) and sustainable agriculture (141 times). Legumes are considered to be important components of strategies to increase agricultural resilience and environmental sustainability because they can fix atmospheric nitrogen, improve soil fertility, reduce fertiliser dependence and support sustainable cropping systems
(Foyer et al., 2016; Stagnari et al., 2017; Soumare et al., 2025. Mohamed et al., 2026).
From 2023 to 2025, trend topics increasingly included climate change, sustainability, deep learning and microbial communities. These patterns suggest expanding research interest in climate-resilient production, digital methods for crop monitoring and prediction and plant-microbe interactions. The thematic progression points from genetic improvement and productivity towards a broader combination of sustainability, climate adaptation and technology-enabled research
(Mulla, 2013;
Wolfert et al., 2017).
The growing attention on the various themes associated with intercropping reflects the importance that is placed on sustainable intensification strategies aiming at improving the productivity of cropping systems within an environmentally friendly framework
(Lithourgidis et al., 2011). The temporal evolution of keywords indicates that research on legumes has shifted from mainly focusing on genetic improvement and productivity to a more comprehensive and integrated approach.
Collaboration network among the author in legume research
The researcher collaboration network (Fig 6) provides evidence of an extremely well-connected scientific community for legume research. Amongst all the authors, P. V. Vara Prasad had the highest value of betweenness centrality (360.17) while Rajeev K. Varshney had the second-highest betweenness centrality (336.85). Authors with high betweenness centrality tend to be the knowledge intermediaries of scientific networks, allowing the flow of information between otherwise disconnected research communities.
Cluster-1, revolves around breeders and geneticists such as Rajeev K. Varshney, P. V. Vara Prasad, Kadambot H. M. Siddique, Manish K. Pandey, as well as others. The significant prominence of this cluster indicates the increasing importance of genomics-assisted breeding, climate resilient crop improvement and translational research in solving the contemporary challenges faced by the legume production
(Varshney et al., 2021). Cluster 2 mainly includes authors from China such as Yang Wenyu, Yang Feng, Yong Taiwen and others. Particularly, Yang Wenyu showed high betweenness (160), which denotes that he is playing a key bridging role both inside and outside the cluster. Cluster 3 consists of researchers from Nguyen Henry T., Chen Pengyin, Li Zenglu and Song Qijian. The group is related to soybean genetics, tolerance to stresses and molecular breeding. The members of Cluster 4 are Ignacio A. Ciampitti, Sotirios V. Archontoulis, Shawn P. Conley, Seth L. Naeve and others. Its research areas include agronomic management and precision agriculture. These network structures have been recognized as important contributors to scientific productivity, innovation and knowledge sharing
(Newman, 2001;
Wagner and Leydesdorff, 2005).
Collaboration network among the countries in legume research
The country collaboration network (Fig 7) reveals three major clusters, highlighting the geographically structured and internationally connected nature of legume research. Cluster 1 is centred on India and China, connecting Asian and Middle Eastern countries, including Pakistan, Bangladesh, Japan, Australia, Egypt and Saudi Arabia. This cluster reflects strong scientific cooperation across Asia and neighbouring regions. Cluster 2 is led by the United States and Brazil, linking Canada, Argentina, Mexico and several African countries, including Nigeria, Ethiopia, Kenya and South Africa. These partnerships support collaborative efforts to address productivity constraints, climate resilience and sustainable agricultural development.
Cluster 3 comprises predominantly European countries, including Germany, France, the United Kingdom, Spain, the Netherlands and Switzerland, reflecting established regional research collaboration focused on sustainable agriculture and environmental protection.
The central positions of the United States, India, China, Brazil and Germany indicate their potential roles in connecting regional research communities. Overall, the network demonstrates the importance of international partnerships in advancing legume research
(Newman, 2001;
Wagner and Leydesdorff, 2005).
