Global research trends in finger millet (Eleusine coracana L.) research: A scopus-based bibliometric analysis

Introduction

Finger millet (Eleusine coracana L.) is a major and extensively grown small millet in the semi-arid and rainfed regions of Asia and Africa with India being the major (Upadhyaya et al., 2006; Gupta et al., 2017) [20,15] producer and consumer. It is the most important among the pulses mainly due to its great mineral and vitamin content, especially the high calcium, iron, fiber, and amino acids, thus, making it an integral part of the human diet and consequently, one of the major contributors to food and nutrition security of the underprivileged populations (Saleh et al., 2013; Devi et al., 2014; Chandra et al., 2016) [19,10,9] . Furthermore, finger millet is extremely tolerant to drought, poor soil fertility, and marginal growing conditions, thus, it can significantly contribute to the development of sustainable and climate-resilient agricultural systems (Dida et al., 2007) [11] . Concerns about climate change, land degradation, and malnutrition have sparked worldwide interest in the past and current use of resilient crops such as fingerprint millet (Padulosi et al., 2015; FAO, 2018) [16,13] . Consequently, the research on finger millet has been considerably widened to cover a variety of topics like genetic enhancement, cultivation, tolerating abiotic and biotic stress, improving nutrition, and food technology (Ceasar et al., 2018; Goron and Raizada, 2015) [8,14] . A systematic appraisal of the scientific literature on finger millet has not yet occurred despite the abundant scientific literature. Bibliometric analysis is a method that provides the ability carry out the quantitative assessment of research by using the statistical and mathematical approaches to characterize the publications, authorship, alliances, and thematic trends in research area (Pritchard, 1969; Broadus, 1987; Donthu et al., 2021) [18,6,12] . The availability of comprehensive and high-quality bibliographic records through databases like Scopus allows for a thorough appraisal of research at both global and regional levels, i.e., showing the connectivity of ideas across different scales (Bergman, 2012; Aghaei Chadeganet al., 2013; Afgan and Bing, 2021) [4,1,3] . In such a situation, the present study is aimed at investigating the global research trends in finger millet (Eleusine coracana L.) based on Scopus data and its bibliometric implications. The research covers areas such as the growth of publications, the types of documents, the main journals, the authors collaborating the most, the institutions, and the countries contributing the most, and the prevailing research themes. This analysis points out the progress of finger millet research and the identification of areas where future research and policy interventions for sustainable agriculture can take place.

Materials and Methods:

The bibliometric data for the present study were retrieved from the Scopus database, which is recognized as one of the largest and most reliable abstract and citation databases covering peer-reviewed literature across scientific disciplines. Data were retrieved from the Scopus database using the search query: TITLE-ABS-KEY ("Finger millet" OR "Ragi" OR "Eleusine coracana"). The search was conducted in June 2025 covering publications from 1990 to 2024. In total, two thousand six hundred and sixty eight (n=2,668) articles were found during the first phase of the search. Further screening was done by limiting the selection to include articles, reviews and conference papers n=2456. Then selection is limited to papers written in English language resulting in n = 2417 papers. After refinement, the final study database is comprised of 2412 research publications

Results and Discussion

Classification of documents

Figure 1 shows the breakdown of the publications into different document types. Research articles made up nearly 92% (2219) of the total publications, which indicates that the research conducted on finger millet is mainly based on original experimental and analytical studies. Review articles made up around 5-6% (135) of the total output, which means that there is consistently coming through the literature the periodic synthesis and consolidation of the advancements in the research field. Conference papers accounted for a smaller share around 2-3% (58), thus implying that there is a limited but upcoming dissemination of the research on finger millet through the conference platforms. The same pattern of publication has been reported in other similar agricultural bibliometric studies (Price, 1963; Donthu et al., 2021) [17,12] .

Year-wise Growth of Publications

The year-wise increase in the number of scientific publications on the research of finger millet (Eleusine coracana L.) from 1990 to 2024 can be seen in the graph Figure 2. The output of research during the period of the study was increasing and it was steadily progressive, which is an indication of the growing worldwide interest in this particular crop. Initially (1990-2000), publications were very few, and the figure fluctuated from 13 to 30 documents per year. This era demonstrates scarce scientific interest, and the gradual growing pattern indicates that little finger millet was noticed or the crop was even neglected. The first decade of the 21st century saw a slow but steady rise in publication output. This period corresponds to the start of the acknowledgment of millets as resilient crops that can be grown in rainfed and harsh environments.

It is more likely that the scientific fields of crop enhancement, stable yields, and nutrition were the main drivers of this upward trend. Starting from 2011, on the whole, there was a very clear and sudden boost in research output, especially after 2016. The number of publications more than doubled, and a peak was reached in 2024. One of the main reasons for this rapid growth is increased global concern over the adaptation to climate change, climatesmart agriculture, food and nutrition security, and editing of cereal systems (Bornmann and Mutz, 2015; Varshney et al., 2017) [5,21] . Besides, policy support for millets in India and the development of technologies like molecular breeding, genomics, and value addition have been big contributors to research activity. The unprecedented rise in recent years serves as a marker for the transition of finger millet from an underutilized crop to one that is strategically significant for sustainable agriculture.

Performance of Authors

The contribution of the most productive authors in the field of research on finger millet (Eleusine coracana L.) is shown in Figure 3. Among the leading authors, Kumar, A. came forth as the most prolific researcher with 63 publications which reflect the continuous and wide-ranging participation in researching finger millet. His research was mainly on crop improvement, genetics, and related areas thereby contributing significantly to the advancement of knowledge in this field. Among the most significant contributors are Malleshi, N.G. (34 documents) and Sood, S.

Country-wise Distribution of Publications

India was the foremost contributor with 1711 publications taking a lion's share of the worldwide research output (Table 1). This very much is the case since India is the main center of growing, eating, and producing the most diverse types of finger millet genetically. The strong research output is a sign of national agricultural research systems, universities, and international collaborations focusing on crop improvement, nutrition, climate resilience, and value addition investing over a long period of time. The United States came second with 175 publications, even though finger millet is not a major crop in the country. The present work is mostly a result of collaboration between millet-growing countries in nutrition, food science, genomics, and global food security. Ethiopia (90 documents) and Kenya (89 documents) are listed as the third and fourth most productive countries, respectively, which indicates the significance of finger millet in the diet of East Africa and the capacity of the region in agronomy and crop adaptation research is growing. The increasing involvement of African nations points to the escalating acknowledgment of finger millet in food security and climate change adaptation tactics (FAO, 2018) [13] . The United Kingdom (79 documents) and Japan (77 documents) were also leading to the forefront, mainly by their excellent research in plant science, food technology, and biotechnology accompanied by strong global partnerships. The contributions from South Africa, China, Canada, and Germany are also indicative of the growing global interest in finger millet, particularly in terms of climate-smart agriculture and functional foods. The analysis of countries clearly shows that the millet research is predominantly supported by those countries that have direct agricultural and nutritional relevance with this crop, while the research-intensive nations provide advanced scientific methods. The strengthening of South-South and North-South collaborations could further magnify the global impact of research and facilitate the development of better finger millet varieties for sustainable agriculture. [22,2] Moreover, the institution-wise variation shows that research on finger millet is mainly supported by public-sector research institutions, revealing their indispensable position in fostering eco-friendly and climatesmart farming practices. [11,8,21] .

Source-wise Distribution of Publications

The leading journals where finger millet (Eleusine coracana L.) research is published are listed in Table 4. The findings suggest that research on finger millet is published in a wide variety of journals which cuts across agricultural, food science, plant breeding and interdisciplinary fields. The Journal of Food Science and Technology was the leading source of research (86 publications) which indicates the great interest in finger millet's nutritional quality, food processing, value addition, and development of functional foods. The above findings suggest that the health-promoting and nutraceutical aspects of millet are becoming more and more popular. The second position was taken by Food Chemistry which had 36 publications, and it also helped to draw attention to the importance of the composition, bioactive compounds, antioxidant properties, and nutritional profile of finger millet. The hierarchy of the food science journals among the main sources shows that research on finger millet has moved from crop production to human health through the use of the crop traits.

Keyword Frequency and Research Focus

A keyword analysis offers a comprehensive view of the main research themes, areas of focus, and the conceptual framework of the scientific literature. The most frequently used keywords in the study of finger millet (Eleusine coracana L.) are presented in Table 6. The most frequently used keyword "Finger millet" occurred 842 times, followed by "Eleusine coracana" with 740 occurrences, which are almost the same. This implies the publications had both the common and scientific names appearing simultaneously. It also indicates that there was a common ground in the identification of the crop which consequently led to the consistency in subject matter of literature. The mention of related terms such as "Finger millets" and "Millet" even more confirms that research on this crop is in the core of the millets research area. [7] . The changing keyword pattern in this regard illustrates the gradual shifting of finger millet research from the original disciplinary boundary to becoming a globally relevant research area.

Declining or Mature Research Themes

On the other hand, a few research themes seem to have grown already or are at least on the way downwards. Studies that relied on the traditional methods of basic agronomy, varietal evaluation, and conventional cultivation practices, which were the main focus during the early research phases (1990 -2005), are now having slower growth when compared to other areas. However, these studies still have great importance; they have simply come to a point where there are no new questions to ask and no new approaches to apply in terms of methods. In the same way, descriptive taxonomic and morphological studies, marked by earlier frequent use of generic botanical keywords, have lost their prominence with the adoption of molecular and genomic tools. Instead of being isolated research areas, these themes are increasingly incorporated into wider genetic and breeding frameworks.

Conclusion

The current Scopus-based bibliometric study has presented an extensive picture of the global research trends in finger millet (Eleusine coracana L.) from 1990 to 2024. The findings indicate a consistent and considerable rise in the amount of scientific output, especially after 2016, which is a sign of a revival of the global interest in finger millet as a climate-resilient and nutritionally rich crop. The prevalence of research articles shows that there was a strong focus on original experimental work, and the presence of review papers indicates that the knowledge in this field has been periodically consolidated. India was recognized as the foremost contributor in terms of publications, authors, and institutions, which indicates its crucial role in the areas of production, conservation, and research of finger millet. The significant contribution from African countries and those with intensive research are additional proofs of the increasing global significance of finger millet that is being acknowledged. The analyses that were conducted in terms of institutions and sources pointed out the essential participation of agrarian universities, national research institutions, and food science journals in releasing the research. The identification of the subject area and the keywords confirmed the multi-dimensionality of the research done on finger millet, which included agriculture, genetics, nutrition, environmental science, and human health.

The volume of research is increasing but, still, the future studies in this field should be concentrated on cutting-edge genomics, pre-breeding, and trait-based development strategies that would lead to yield stability and climate resilience. In total, this bibliometric analysis has revealed the scientific landscape of finger millet research that is changing and has provided a lot of information to researchers, policymakers, and funding agencies. The research, which is conducted in a way that it meets the goals of sustainability, nutrition, and climate adaptation, will further strengthen the position of finger millet in the development of resilient and sustainable agricultural systems.

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