**3. Research on citrus**

Scientific production about citrus is equally important in different areas of human knowledge. From the search for the term "citrus" in the "all fields" option in the Scopus and Web of Science databases in the last 5 years (2018–2022), there was an increasing number of publications in both databases [3, 4]. Although the search with the term "all fields" retrieves in very broad number of publications, the Scopus database included a much larger number of publications. In year of 2022, from Scopus database were retrieved 31,103 documents while for Web of Science database a lower number was recovered (2,839 publications) (**Figure 2A**).

Then, a new, more restrictive search was performed in Scopus database, from 2018 to 2022 searching the term "citrus" in the "article title, abstract, and keywords" option. A total of 21,954 results were retrieved, where 66% of these publications are from the last three years (from 2020 to 2022). Therefore, citrus research is a topic of current relevance (**Figure 2A**).

Regarding to the countries that most contributed to publications about citrus in the last 5 years, there are China, United States, India, Brazil, Spain, Italy, Iran, South Korea, Japan, and Pakistan. Of these, six were also the top 10 citrus fruit producers in

*Introductory Chapter: World Citrus Production and Research DOI: http://dx.doi.org/10.5772/intechopen.110519*

#### **Figure 2.**

*(A) Number of publications retrieved from Scopus and Web of Science databases searching for the term "citrus" in all fields (ALL(citrus); (B) Most relevant countries when searching for term "citrus" in "article title, abstract and keywords" (TITLE-ABS-KEY(citrus)) in Scopus database; (C) Main knowledge subject areas when term "citrus" was search in article title, abstract and keywords (TITLE-ABS-KEY(citrus)). The searches were performed in the last 5 years (2018 to 2022).*

2021, namely: China, Brazil, India, Spain, United States, and Iran [1]. China is the biggest contributor, with 28.66% of the total published. Researchers from USA and India have published more than 2,000 articles, standing for 11.82% and 10.12% of the total articles produced in the period, respectively. Further, with more than 1,000 publications are Brazil, Spain, and Italy. Besides, Iran, South Korea, Japan, and Pakistan had around 600–1,000 publications. Additionally, the great importance of Asian countries to knowledge production related to "citrus" can be noted as they account for more than 50% of total publications (**Figure 2B**) [3].

As to the subject areas by Scopus database classification, 43.4% of the publications were from Agricultural and Biological Sciences. The second most important area was Chemistry (19.6%), followed by Biochemistry, Genetics and Molecular Sciences (17.9%). Also, there was a significant number of publications addressing citrus in other areas of knowledge: Environmental Science, Material Science, Engineering, Chemical Engineering. Yet, some part of publications was applied to the medical and pharmacological area (**Figure 2C**).

Furthermore, many patents are report on citrus. In a search in the Derwent Innovations patent database over the last 5 years (2018–2022) [5], using the term "citrus" as a topic resulted in 6977 patents. The majority of these publications cover the following areas: chemistry, agriculture, biotechnology, instruments, food science, pharmacology. Hence, research on citrus is directed to several areas of knowledge, which shows its importance and the need of continuous increase in its knowledge.
