Ethno-ecological knowledge of tiger nut (Cyperus esculentus L.) across contrasted climate zones: uses, diversity, production system, and perception of climate change in Togo (West Africa)

Abstract

Background 

Cyperus esculentus a perennial sedge, has been cultivated since ancient times for its nutritious and versatile tubers, which are used in cooking, traditional medicine, and various industries. Despite its potential, the crop remains underutilized in Togo and is grown in limited areas. Moreover, there is a lack of information on its genetic diversity, cropping systems, uses, and the impact of climate change on its productivity; factors essential for effective breeding and sustainable cultivation. This study aimed to document and compare existing knowledge on the uses and production systems of tiger nuts, as well as tiger nut producers’ perceptions of climate change and its impact on tiger nut cultivation in two regions of Togo with contrasting climatic conditions.

Methods

A total of 206 tiger nut producers from six ethnic groups were selected across 26 villages located in the Savanes region (Sudanian climate) and the Plateaux region (Guinean climate) were selected following the snowball method during a survey conducted from July to September 2023. Data on tiger nut uses, diversity, production systems, and producers’ perceptions of climate change and its impact on the species’ productivity were collected using participatory rural appraisal methods. The data were analyzed using descriptive statistics, Fisher’s Exact Test to examine the relationship between region and sociodemographic factors, and multinomial logistic regression to identify which sociodemographic characteristics influence tiger nut growers’ perceptions of climate change and their views on its impact on production.

Results

A significant difference was observed in the gender distribution of tiger nut producers between the two regions. In the Savanes region, most producers were male (75%), whereas in the Plateaux region, most were female (84%). The area dedicated to tiger nut production also varied significantly between the regions. In the Savanes region, no more than 0.25 ha was allocated to the crop, whereas in the Plateaux region, 58% of producers dedicated more than 0.25 ha of their land to tiger nut cultivation. Seven distinct uses were identified: tuber consumption, commercialization, medicinal applications, soil fertilization, traditional beverage preparation, weed control, and livestock feeding. The last three were reported exclusively in the Savanes region. Eight major constraints were identified across the two regions. The most critical in the Plateaux region was harvesting difficulties, while in the Savanes region it was pest attacks. Regarding climate change, chi-square tests showed a significant association between climatic zones and farmers’ perceptions, as well as between regions and the reported effects of climate change on tiger nut cultivation (P < 0.001). Perceived climate change indicators included irregular rainfall, delayed onset of rains, drought spells, and early rainfall. Reported effects on the crop included reduced yields, abnormal growth patterns, premature yellowing of leaves, seedling desiccation, and small tubers.

Conclusion

The ethno-ecological knowledge captured in this study provides a foundational resource for the sustainable management and conservation of tiger nut, and for the development of effective breeding strategies in Togo.

Background

Tiger nut (Cyperus esculentus L.), also known as chufa, yellow tiger nut, or aya in West Africa, is a time-honored tuber of considerable nutritional, economic, and cultural significance [1–3]. Though sometimes regarded as a weed in certain regions, it is an increasingly valuable crop, gaining global recognition for its health benefits and adaptability [4, 5]. Tiger nuts have served as a food source since ancient times and played a notable dietary role in ancient Egypt. Today, they are cultivated in countries such as Nigeria, Niger, Mali, Senegal, Ivory Coast, Ghana, Burkina Faso and Togo, where they are primarily consumed raw [2, 4, 6, 7]. Nutritionally, the tiger nut tuber contains, on average, 30.01% fat, 14.18% crude fiber, 5.08% protein, 2.23% ash, and 45.73% carbohydrate [8]. It is also rich in minerals, notably potassium (K), phosphorus (P), silicon (Si), chlorine (Cl), sulfur (S), and magnesium (Mg) [9]. In addition, tiger nut oil has high nutritional value, with a fatty acid profile similar to that of olive, avocado, and hazelnut oils [7, 8]. It contains polyunsaturated fatty acids, vitamin E, and plant sterols, which contribute to its exceptional oxidative stability [7]. Beyond its nutritional content, tiger nut is also recognized for its therapeutic properties. It has been associated with lowering cholesterol, reducing the risk of heart disease and atherosclerosis, and providing relief for individuals experiencing slow digestion, flatulence, and diarrhea [10]. Despite its nutritional value, tiger nut contains antinutrient factors such as tannins, flavonoids, and alkaloids. However, Okorie et al. [11] reported relatively low levels of these compounds, except for flavonoids. According to the authors, the overall antinutrient content in the two studied tiger nut varieties (brown and yellow) was even lower than that reported for peanuts.

In addition to antinutrients, tiger nuts and their derived products have also been found to contain certain levels of heavy metals, including cobalt, copper, lead, and cadmium. This accumulation may result from the presence of heavy metals in the soil, especially when tiger nuts are grown in acidic soils [12] or may be introduced during processing, such as through contaminated water, as suggested by Abajue & Obong [13] in the case of tiger nut juice collected from parts of Port Harcourt, Nigeria. However, in the studied cases, some of these heavy metals were found to be below the permissible limits set by health organizations such as the World Health Organization (WHO) [13, 14] posing minimal health risks. Still Odubo & Izah [14] reported concerning levels of cadmium and copper in food drinks randomly purchased from commercial vendors across the Yenagoa metropolis in Nigeria, raising potential public health concerns.

Tiger nut can play a significant role in improving food security, particularly in developing regions where malnutrition and food scarcity are prevalent. It serves as an affordable source of nutrition for low-income communities. Moreover, tiger nuts can thrive in less fertile soils that are unsuitable for other crops, require minimal water, and have a long shelf life, allowing them to be stored for several months, making them a reliable food source during periods of scarcity [15]. In Togo, tiger nut cultivation is primarily reported to be carried out by women [16], contributing significantly to household income. The tubers are commonly consumed in raw, dried, or roasted forms and are also processed into liqueur and flour. This crop makes a notable contribution to both dietary intake and economic well-being [17]. Despite its considerable potential, the species remains neglected, with limited research efforts aimed at improving and sustaining its production. Currently, there is no available data on its production systems or genetic diversity. These data are crucial for enhancing productivity and promoting tiger nut cultivation on a national scale, particularly in light of the Togolese government’s initiative to use local consumption (“consommer local”) as a lever for economic transformation.

Climate change is a critical environmental issue that warrants special attention in the preservation of plant genetic resources. Growing evidence indicates that shifts in factors such as rainfall and temperature will significantly impact biodiversity [18]. According to a preliminary survey, tiger nut is cultivated in three of Togo’s five regions: Maritime and the Plateaux in the south, and the Savanes in the north. These regions experience contrasting climatic conditions. The Maritime and the Plateaux regions fall under a Guinean climate, characterized by two rainy and two dry seasons, while the Savanes region is under a Sudanian climate, which has one rainy season and one dry season. Additionally, occasional droughts occur in the northern regions [19], potentially increasing the vulnerability of tiger nut producers in the Savanes compared to those in the Plateaux. Therefore, it is crucial to document the challenges faced by tiger nut farmers across these differing climatic zones, along with their perceptions of climate change and its impact on the crop, in order to develop a sustainable and adaptive promotion strategy.

Additionally, tiger nut farmers may apply their own unique selection criteria when choosing which varieties to cultivate, often based on the specific climatic conditions of their regions. Because farmers experience climate variability differently depending on their geographic location and climatic zone, they adopt diverse cultivation practices tailored to their local environmental, community, and economic contexts [20]. Gaining a deeper understanding of these farmer-driven selection standards is essential for designing effective, climate-responsive breeding programs and scaling up tiger nut cultivation at the national level.

Therefore, we hypothesized that: (i) farmers’ varietal preferences and the constraints they face in tiger nut production vary across different climatic zones; (ii) the tiger nut production system, from land selection to post-harvest conservation, exhibits distinct characteristics in each region due to the specific climatic conditions of the growing zones; and (iii) although rooted in local contexts, growers’ perceptions of climate change and its impacts on tiger nut cultivation reflect the major climatic risks identified at the national level in Togo.

Materials and methods

Study environment

Two administrative regions were selected for this study: the Savanes region in the extreme north of Togo and the Plateaux region in the south (Fig. 1). These regions were chosen due to their contrasting climatic conditions. The Savanes region, located over 600 km inland in northern Togo, has Dapaong as its administrative capital. Geographically, it lies between 0° and 1° East longitude and 10° and 11° North latitude, covering an area of 8,533 km², which represents approximately 15% of the national territory. It shares borders with Burkina Faso to the north, Benin to the east, Ghana to the west, and the Kara region to the south. As its name implies, the region consists primarily of savannah landscapes, characterized by relatively flat high plains and plateaus with dominant horizontal surfaces. The tropical Sudanian climate features one short rainy season and one long dry season, with annual rainfall ranging between 850 mm and 1,400 mm, high solar radiation, and an average temperature of 28 °C [21]. The Plateaux region, with its capital in Atakpamé, is the largest of Togo’s five regions, covering an area of 16,800 km². It is located between 6°9′ and 8°5′ North latitude, and bordered by the Central Region to the north, the Maritime Region to the south, Ghana to the west, and Benin to the east. The region has a nuanced climate, influenced by equatorial, and humid tropical conditions. It experiences two rainy seasons and two dry seasons, with annual rainfall ranging from 1,000 mm to 1,600 mm and an average temperature of 27 °C [22, 23]. The major rainy season occurs from April to July, while a shorter rainy season spans September to October. Togo’s main soil types include hydromorphic soils, vertisols, ferralitic soils, and tropical ferruginous soils, collectively accounting for more than half of the country’s soil composition [19].

Fig. 1.

Sampled villages

Data collection

For the purposes of this work, two prefectures were selected in each region based on the information provided by Agricultural extension services agents on C. esculentus production. These prefectures were Tône, and Kpendjal-ouest in the Savanes region, Wawa and Danyi in the Plateaux region. In each prefecture, villages were selected on the basis of the presence of tiger nut producers and their accessibility, using the “snowball” method [24]. The surveys were carried out with the support of ICAT (Institut de Conseils et d’Appui Technique) agents in charge of the various cantons in which the villages were selected. A total of twenty-six (26) villages were selected and 206 people were interviewed in the selected villages. Prior to the survey, ICAT’s Farm Business Management Technical Advisors, who are the first ICAT agents in direct contact with farmers at village level, are responsible for bringing together tiger nut producers in the targeted village on the day of the interview, and asking them to bring samples of the tiger nut they produce. In this study, the use of the snowball sampling method is justified by the lack of available data on the size and composition of the target population. Under these conditions, it was not possible to establish a comprehensive sampling frame that would allow for a conventional random selection. The snowball method enabled us to overcome this limitation by beginning with a small group of informants identified by ICAT’s Farm Business Management Technical Advisors and progressively expanding the sample through referrals. This approach facilitated access to relevant actors despite the absence of precise demographic information. The study adhered to the guidelines outlined in the International Society of Ethnobiology’s Code of Ethics [25]. On the day of the interview, after the presentation of the objectives of the survey and the verbal obtained consent of tiger nuts growers, two questionnaires (one for individual surveys and one for focus groups) were administered to the producers. The focus group discussion was designed to gather information related the different tiger nut varieties grown in the village, their characteristics, the meaning of their local names, growers’ preferences for tiger nut varieties and the reasons for these preferences, the cultural use of tiger nut in the village, the different uses of the different parts of the plant and the production constraints.

The individual survey questionnaire was designed to collect information on:

• The producers’ socio-demographic characteristics (gender, age, education level, ethnicity, and land size dedicated to tiger nut production).

• The tiger nut farming system (agricultural practices, challenges, methods of tuber storage and conservation).

• The perceived effects of climate change on the region and its impact on tiger nut production.

For the last aspect, the method used by Adjacou et al. [18] was applied. First, respondents were introduced to the concepts of climate change. Then, they were invited to share their views, which were transcribed verbatim to capture perceptions and highlight the impacts of climate change on tiger nut production.

Data analysis

In each locality, the households surveyed were classified by ethnic group, gender, age category, and level of education. The age groups were divided into three categories: under 30, 30–60, and over 60. Land size dedicated to tiger nut cultivation was grouped into four categories: less than 0.1 ha, 0.1–0.25 ha, 0.25–0.50 ha, and greater than 0.5 ha.

Statistical analyses were conducted using R version 4.3.2 and SPSS version 22.0 (SPSS Inc., Chicago, Illinois, USA). Frequencies were calculated to determine the percentage of respondents for each category of tiger nut usage. Additionally, to examine the relationship between the different uses of tiger nut and ethnic group, the frequency data were subjected to Principal Component Analysis (PCA). A multinomial logistic regression [²⁶] was also performed to assess which socio-demographic characteristics influence tiger nut growers’ perceptions of climate change and their views on its impact on tiger nut production.

To assess the association between region and sociodemographic variables, as well as between region and perceived manifestations and effects of climate change, the Fisher’s Exact Test was used.

For constraints and preference criteria, producers were first asked to list the relevant elements. They were then instructed to rank these constraints or criteria in order of importance. The resulting hierarchical list was submitted to the growers for validation [27]. The identified constraints and selection criteria were subsequently prioritized at both the regional and national levels using the following formula:

where TNV represents the total number of villages in which the constraint or criterion was cited; MAC, the number of villages where it was ranked first; and PCO, the number of villages where it was ranked among the top five [28].

Results

Socio-demographic characteristics of tiger nut producers across climate zones

Approximately 56% of respondents were female, with males constituting the remaining 44%. The gender distribution varied significantly across regions (χ² = 64.71, p < 0.001). For instance, in the Savanes region, located in the Soudanian climatic zone, the majority of tiger nut producers were male (75%). In contrast, in the Plateaux region, situated in the Guinean zone, the majority of producers were female (84%).

80% of the respondents were between 30 and 60 years old, while 13% were under the age of 30. Again, a significant association was found between region and age group (χ² = 14.12, p = 0.001). Farmers over the age of 60 were found exclusively in the Savanes region.

Regarding educational level, 54% of tiger nut growers had no formal education. This trend was particularly evident in the Savanes region, where 68% of farmers were not formally educated. Conversely, in the Plateaux region, the majority of farmers (57%) had attained primary school education.

In terms of land use, 66% of respondents reported dedicating between 0.10 and 0.25 hectares to tiger nut cultivation. Land size was also significantly associated with region (χ² = 110.95, p < 0.001). In the Savanes region, no farmer cultivated tiger nut on land larger than 0.25 hectares, with most plots ranging from 0.10 to 0.25 hectares. However, in the Plateaux region, most cultivated areas (46%) ranged between 0.26 and 0.50 hectares, and 12% of farmers dedicated more than 0.5 hectares to tiger nut production (Table 1).

Table 1.

Tiger nut producers’ socio-demographic characteristics across region

Variables	Categories	Regions		Mean (%)	df	χ2	P-value
		Savanes (%)	Plateaux (%)
Sex	Male	75	16	44	1	64.71	< 0.001
	Female	25	84	56
Age (years)	< 30	17	6	13	2	14.12	0.001
	30–60	72	94	80
	> 60	11	0	7
Level of education	Not formally educated	68	27	54	2	34.50	< 0.001
	Primary	20	57	33
	Secondary	12	16	13
Land size dedicated to tiger nut production	< 0.10	12	21	15	3	110.95	< 0.001
	0.10–0.25	88	22	66
	0.26–0.50	0	46	15
	> 0.5	0	12	4

Uses of tiger nut

In the regions surveyed, food use emerged as one of the primary reasons for cultivating tiger nut. This use takes two forms: the tubers are either consumed raw or used as an ingredient in the preparation of traditional local beverages. In the Plateaux region, only raw consumption was reported, cited by 100% of respondents. In the Savanes region, in addition to raw consumption (reported by 97% of respondents), tiger nut is also combined with sorghum to make the traditional beverage Tchakpalo, as reported by 11% of interviewees. Beverage producers use juice extracted from crushed tiger nut to increase the sugar content of this sorghum-based drink. According to the interviewees, this process accelerates fermentation and enhances alcohol yield.

Beyond human consumption, tiger nut was also used as animal feed in the Savanes region (reported by 4% of respondents). In this region, the vegetative part of the plant is fed to livestock after tuber harvest, while unsellable or inedible tubers are crushed or ground to produce fodder for poultry or cattle during the dry season, when natural forage is scarce (Fig. 2).

Fig. 2.

Tiger nut different uses across the climate zones

Other uses cited by interviewees included commercialization, medicinal applications, soil fertilization, and weed control (Fig. 2). While commercialization and medicinal use were reported in both regions, soil enrichment and weed control were mentioned exclusively in the Savanes region. Overall, commercialization appears to be the second most important reason for tiger nut cultivation. In the Savanes region, however, it is along with weed control (both cited by 99%) the main motivation for growing the crop, ahead of consumption.

According to farmers, tiger nut helps control weeds due to the rapid growth of its vegetative parts. Once established, the dense plant cover suppresses weed development on the plot. Additionally, tiger nut leaves are used as compost or green manure to enrich the soil, a use reported by 20% of interviewees.

The only medicinal use reported by respondents was for the treatment of sexual weakness. In the Plateaux region, raw tubers are infused in Sodabi, a traditional alcoholic beverage mainly produced in the southern part of the country. In the Savanes region, tubers are pounded or crushed, and the resulting paste is strained through a fine cloth to extract the juice, which is then mixed with milk. In both cases, the resulting mixture is consumed as needed.

Relationship between socio-demographic variables and tiger nut food uses

The chi-square test revealed a significant association between regions, ethnic groups, and respondents’ perceptions of tiger nut use for food purposes (p < 0.01). Principal Component Analysis (PCA) was employed to further explore the relationship between different food uses and the ethnic groups within each region. The first two axes of the factor map accounted for 100% of the total variance (Fig. 3), indicating that they fully capture the information contained in the variables.

Fig. 3.

Relation between tiger nut food uses and the different ethnic groups across climate zones. The circles represent the different clusters based on the ethnic groups and the tiger nut food uses

Human consumption of tiger nut was more closely associated with the Akposso, Ewe, and Kabyè ethnic groups from the Plateaux region. In contrast, the use of tiger nut as animal feed was primarily associated with the Moba ethnic group in the Savanes region. Additionally, the use of tiger nut as an ingredient in traditional beverages was more strongly linked to the Gourma ethnic group, also from the Savanes region.

Between socio-demographic variables and alternative uses of tiger nut

The chi-square test revealed a significant association between regions, ethnic groups, and other uses of tiger nut (p < 0.01). The first two axes of the Principal Component Analysis (PCA) explained nearly 100% of the total variance (Fig. 4), indicating that they effectively summarize the information contained in the dataset.

Fig. 4.

Relation between tiger nut other uses and the different ethnic groups across climate zones. Green circles represent the different clusters based on the ethnic groups and the tiger nut uses

Commercialization and medicinal use of tiger nut were more strongly associated with the Akposso, Ewe, and Kabyè ethnic groups from the Plateaux region, as well as the Peulh ethnic group from the Savanes region. In contrast, the use of tiger nut for weed control and soil fertilization was more closely linked to the Gourma and Moba ethnic groups in the Savanes region.

Knowledge of local varieties of tiger nut across climate zones

In the study area, four local varieties of tiger nut were identified (Fig 5; Table 2). Local populations distinguish these varieties based on morphological characteristics such as tuber color, shape, and size.

Fig. 5.

Dried tubers of identified tiger nut local varieties across the two regions. A: local variety 4, B: local variety 3; C: local variety 2 and D: local variety 1

Table 2.

Local name and morphological characteristics of the local varieties of tiger nut grow across the survey area

Ethnic groups	Local varieties	Local names	Meaning	Morphological characteristics of the tubers
				Tuber shape	Tuber size	Tuber colour	Tuber taste
Gourma	Local variety 1	Apiéna	The action of harvesting (tearing off the tiger nut tuber from the rhizomes)	Round	Big	Yellow	Sweet
Peulh		-		Round	Big	Yellow	Sweet
Moba		Sinsa koga	Cultivated tiger nut	Round	Big	Yellow	Sweet
Gourma	Local variety 2	Apiéna	The action of harvesting (tearing off the tiger nut tuber from the rhizomes)	Round	Small	Yellow	Sweet
Kabyè	Local variety 3	Amona		Round	Big	Black	Sweet
Ewé, Akposso		Efio		Round	Big	Black	Sweet
Kabyè	Local variety 4	Amona		Elongated	Big	Yellow	Sweet
Ewé, Akposso		Efio		Elongated	Big	Yellow	Sweet

In the Savanes region, two local varieties were recorded. The first is characterized by large, yellowish, rounded tubers. The second, reported by a single producer, has small, yellowish, rounded tubers. In the Plateaux region, two other varieties were identified. One is distinguished by large, yellowish, elongated tubers, while the other features large, rounded black tubers (Table 2; Fig 5).

In the Savanes region, both varieties are referred to as “Apiéna” by the Gourma ethnic group, whereas the Moba ethnic group uses the local name “Sinsa koga”. The term Apiéna is derived from a local word describing the action of tearing tubers from the plant’s rhizome. In contrast, Sinsa koga refers specifically to cultivated tiger nut varieties, distinguishing them from the smaller, wild-growing types commonly found in the area.

A similar situation was observed in the Plateaux region, where tiger nut, regardless of variety, is referred to by a single local name. The Kabyè ethnic group uses the term “Amona,” while the Akposso and Ewe ethnic groups use “Efio.” Unlike in the Savanes region, producers in Plateaux could not explain the meaning of these names, stating that they were inherited from previous generations.

Tiger nut production system and post-harvest management across climate zones

Tiger nut is cultivated in pure stands in both the Savanes and Plateaux regions. With a few exceptions, the technical itinerary for its production is largely similar across the two zones. In both regions, once a suitable site is identified typically one with light, moist soil the land is cleared and ploughed into ridges using a daba (a traditional West African agricultural tool similar to a hoe, used for plowing, aerating, weeding, harvesting, and cutting) or animal-drawn ploughs (common in the Savanes region).

Planting occurs during the rainy season: from April to early June in the Savanes region, and from March to April in the Plateaux region. Under adequate moisture conditions, emergence occurs around the fourth day after planting. Sowing is done in holes or stakes, with one tuber per hole, and plant spacing ranges from 10 to 15 cm.

Two weeks after emergence, the first weeding is performed, followed by the application of NPK fertilizer. This may be followed by a second weeding (hoeing), which is optional, and then ridging before the final harvest.

Tiger nut tubers are considered mature when the leaves begin to yellow or when the plants start to flower. Harvesting is done from late August to early October in the Savanes region, and from August to December in the Plateaux region. On average, the crop takes about three months from sowing to harvest.

Seeds for the next season are collected once the plant has completely dried, typically between November and December. Most tasks, from field preparation to harvesting, are performed manually, making the process labor-intensive.

After harvesting, tubers are washed by hand using river sand and water to remove residual soil. A portion of the harvest is sold fresh at local markets, while the remainder is preserved for household consumption, later sale, or other uses. For storage, tubers must be sun-dried for at least 15 days, then kept in bags placed in dry conditions to prevent rotting or moisture damage. Black tiger nuts, which are produced in the Plateaux region, do not store well and are generally sold fresh for immediate consumption.

In the Savanes region, tubers intended for planting in the next season are not washed. Instead, they are dried and stored in plastic bags or in canaries (traditional clay containers) filled with sand and kept in dry locations. In the Plateaux region, however, tubers are stored in bags suspended above the kitchen chimney. According to farmers, smoke from the chimney helps to repel post-harvest pests by penetrating the storage bags.

Constraints to tiger nut production

Farmers across both regions cited eight major constraints affecting tiger nut production. Based on the criteria outlined in the Materials and Methods section, the most significant constraint overall was the difficulty of harvesting, followed by pest attacks (primarily termites), climatic hazards (such as delayed rainfall, drought, and prolonged dry spells), production-stage challenges, limited access to agricultural inputs (including quality seeds, fertilizers, and pest control products), labor shortages, rodent attacks, and fungal diseases (Table 3).

Table 3.

List and importance of tiger nut production constraints in the two surveyed regions in Togo

Constraints	Number of villages			IMV	Rank	Rank per region
	TNV	PCO	MAC			Plateaux	Savanes
Pest attack	25	14	14	17.67	2	5	1
Climatic hazards	23	23	0	15.33	3	2	3
Fungal diseases	1	0	0	0.33	8		7
Difficult harvest	23	23	9	18.33	1	1	2
Production stage challenges	20	20	0	13.33	4	4	5
Limited access to agricultural inputs	17	17	0	11.33	5	3	4
Rodents attack	8	0	0	2.67	7	5
Labor shortage	12	1	0	4.33	6	6	6

However, the nature and relative importance of these constraints varied across climate zones, as confirmed by Fisher’s Exact Test (p = 0.013). For instance, fungal diseases were reported only in the Savanes region and not mentioned at all in the Plateaux region. Conversely, rodent attacks were cited as a major constraint in nearly all surveyed villages in the Plateaux region but were not reported in any villages in the Savanes.

In terms of ranking, pest attacks, harvest difficulty, and climatic hazards were identified as the top three constraints in the Savanes region. In contrast, in the Plateaux region, the top three were harvest difficulty, climatic hazards, and limited access to agricultural inputs.

Selection criteria for local tiger nut varieties

Farmers across the surveyed areas identified ten preference criteria for selecting local tiger nut varieties. Of these, six were agromorphological (high yield, short growth cycle, tuber color, tuber shape, adaptability to soil, and tuber size). One criterion was biochemical (sweetness, related to sugar content), one technological (long shelf life), one economic (market value), and one cultural (knowledge of only one local variety).

Across both regions, “high yield” and “tuber color” were commonly cited as the most important selection criteria. However, regional differences were evident. In the Savanes region, all ten criteria were mentioned by farmers, whereas only six were cited in the Plateaux region. Fisher’s Exact Test confirmed a significant association between region and selection criteria (p < 0.001).

In the Plateaux region, “high yield” was ranked as the top priority. In contrast, “tuber color” was the leading criterion in the Savanes region. There, black tiger nut varieties are not cultivated due to their poor shelf life and low market demand. The latter reason constituted along with sweetness, the third most important criterion overall. According to growers, black varieties are highly perishable and prone to rapid fermentation, which diminishes their market value. As a result, they must be consumed or sold immediately after harvest. In certain villages, yellow tubers are the only known local variety. Regarding tuber shape, farmers expressed a preference for round tubers over elongated ones (Table 4).

Table 4.

Farmers’ preferred traits of tiger nut local varieties and their importance in the two surveyed regions

Criteria	Number of villages			IMV	Rank	Rank per region
	NTV	PCr	MCr			Plateaux	Savanes
High yield	16	16	14	15.33	1	1	2
Short growth cycle	14	14	0	9.33	4		4
Knowledge of a single variety	14	0	0	4.67	5		9
Long shelf life	6	0	0	2.00	6		10
Sweetness	15	15	0	10.00	3	4	5
Market demand	15	15	0	10.00	3	6	3
Tuber Colour	23	12	12	15.67	1	2	1
Tuber Shape	25	12	0	12.33	2	3	8
Adaptability to soil	16	12	0	9.33	4	5	7
Tuber size	14	14	0	9.33	4		6

Local perceptions of climate change and its effects on tiger nut production across climate zones

Based on the survey, four main perceptions of climate change were identified in the study area. The perceptions cited by tiger nut growers included irregular rainfall (35%), late onset of rains (33%), prolonged dry spells (31%), and early onset of rains (2%). Fisher’s Exact Test revealed a significant association between producers’ perceptions and their respective regions (p < 0.001).

In the Plateaux region, the most frequently cited perception was irregular rainfall (44%), followed by late onset of rains (30%), prolonged dry spells (22%), and early onset of rains (4%). In the Savanes region, growers reported only three perceptions. The most cited was prolonged dry spells (40%), followed by late onset of rains (35%) and irregular rainfall (25%) (Table 5).

Table 5.

Local perception of climate change manifestations and their impact on tiger nut across climate zones

Variables	Categories	Regions		Total
		Savanes (%)	Plateaux (%)	(%)
Local Perception of climate change	Irregular rainfall	25	44	35
	Early onset of rains	0	4	2
	Late onset of rains	35	30	33
	Prolonged dry spells	40	22	31
Local perceptions of the effects of climate change on Tiger nuts	Yield reduction	52	47	51
	Premature of yellowing leaves	14	0	7
	Abnormal Plant development	15	1	8
	Seedlings Drying	9	0	4
	Small tubers	9	0	4
	No observed effects	1	52	26

Regarding the perceived effects of climate change on tiger nut production, five effects were identified. The most commonly cited was yield reduction (51%), followed by abnormal plant development (8%), premature yellowing of leaves (7%), seedling drying (4%), and small tubers (4%). Notably, 26% of respondents indicated that they had not observed any effect of climate change on the crop’s development or productivity.

There was a statistically significant association between perceived effects and region (p < 0.001). In particular, the proportion of producers who reported no observable effects was markedly higher in the Plateaux region (52%) compared to the Savanes region (1%). Furthermore, effects such as premature leaf yellowing, small tubers, and abnormal development were reported only in the Savanes region and not at all in Plateaux (Table 5).

The multinomial logistic regression analysis revealed a strong association between gender and the perception of climate change manifestations. Specifically, men were significantly less likely to cite “early onset of rain” as an indicator of climate change.

Level of education was also significantly associated with farmers’ perceptions. Farmers with primary or secondary education were more likely to report a variety of climate change manifestations compared to those with no formal education.

Regarding ethnic affiliation, producers from the Kabyè ethnic group in the Plateaux region were less likely to cite “early onset of rain” as a manifestation of climate change. In contrast, members of the Peulh ethnic group were less likely to associate climate change with the “late onset of rain.”

No significant association was observed between farmers’ perceptions of climate change and age (Table 6).

Table 6.

Determinants of tiger nut grower’s perception of climate change

	Dependent Variables
	EOR	LOR	IR	PDS
Region_Savanes	11.385***	8.206***	15.745***	16.408***
	(2.572)	(1.921)	(1.926)	(1.935)
Age	0.211	−0.060	−0.078	−0.058
	(0.207)	(0.059)	(0.059)	(0.059)
Sex1	−19.352***	0.442	0.457	0.367
	(0.580)	(1.076)	(1.078)	(1.088)
Level_education2	3.601	2.120***	2.886***	2.346***
	(3.014)	(0.822)	(0.831)	(0.837)
Level_education3	38.390***	33.222***	33.641***	33.540***
	(3.451)	(1.183)	(1.186)	(1.183)
Ethnic.GroupEwe	−0.480	−0.416	−1.169	−1.131
	(3.021)	(1.046)	(1.006)	(1.068)
Ethnic.Group_Gourma	1.399	2.537	−6.006***	−5.414***
	(2.571)	(1.912)	(1.918)	(1.919)
Ethnic.Group_Kabye	−7.955***	13.193***	11.966***	11.866***
	(0.00001)	(0.645)	(0.668)	(0.793)
Ethnic.Group__Moba	8.409***	21.541***	13.027***	13.369***
	(0.003)	(0.151)	(0.226)	(0.224)
Ethnic.Group_Peulh	1.577	−15.873***	8.724***	8.453***
	(0.000)	(0.548)	(0.548)
Household.size	−2.616*	−0.230*	−0.186	−0.245*
	(1.577)	(0.136)	(0.136)	(0.136)
Marital.Status2	1.217	−0.979	−2.366***	−0.910
	(0.598)	(0.767)	(0.570)
Marital.Status3	−3.905***	3.202***	2.988***	2.581***
	(0.0003)	(0.592)	(0.769)	(0.638)
Area.Cultivable.Land	1.521	0.142	0.128	0.163
	(1.037)	(0.391)	(0.391)	(0.392)
Area.actually.cultivated	−1.473	−1.046*	−0.973	−0.991*
	(0.994)	(0.592)	(0.592)	(0.592)
Area.dedicated.tiger nut	−8.793	−0.539	−0.490	−0.553
	(5.746)	(0.710)	(0.711)	(0.710)
Constant	1.750	5.268*	5.807*	5.052
	(9.292)	(3.143)	(3.135)	(3.151)
Akaike Inf. Crit.	868.990	868.990	868.990	868.990
Note:	*p < 0.1;	**p < 0.05;	***p < 0.01

EOR= Early onset of rains; LOR = Late onset of rains; PDS = Prolonged Dry Spells; IR= Irregular rainfall; Sex1 (women), Level_educatio2 (Secondary school); Level_education3 (University); Marital.status2 (single); Marital.Status3 (widower). p = p value; coef = coefficient. ***, **, * significant at 0.01%, 1% and 5% probability level respectively. The coefficients in bold reflect the significant influence of the socio-demographic variable on the concerned use.

The five locally identified perceptions of climate change effects on tiger nut production were strongly associated with the Savanes region. Furthermore, farmers’ perceptions were significantly influenced by ethnic group affiliation. For instance, producers from the Kabyè ethnic group in the Plateaux region primarily cited “yield reduction” as the only observed effect of climate change. In contrast, Moba and Gourma growers in the Savanes region reported a broader range of perceived impacts, including “yellowing of leaves,” “plant drying,” and “reduced tuber size,” in addition to yield reduction. The Ewe ethnic group tended to associate climate change with “premature leaf yellowing” and “yield reduction,” while Peulh farmers frequently cited “abnormal development,” “premature leaf yellowing,” and “plant drying” as key climate-related effects on tiger nut. Regression analysis also revealed a significant association between marital status and the perception of climate change impacts. Single producers were less likely to report any noticeable effects of climate change, while married producers were more likely to cite “abnormal development,” “premature leaf yellowing,” and “yield reduction” as the primary effects on the crop (Table 7).

Table 7.

Determinants of grower’s perception of climate change impacts on tiger nut

	Dependent variables
	SD	APD	PLY	YR	ST
Region_Savanes	14.517***	8.658***	23.234***	1.030	25.272***
	(0.897)	(1.197)	(0.880)	(0.827)	(0.928)
Age	−0.033	−0.070**	−0.067**	−0.053**	−0.062*
	(0.031)	(0.030)	(0.030)	(0.026)	(0.032)
Sex1	0.123	−0.063	−0.275	−0.788	−0.243
	(0.944)	(0.853)	(0.870)	(0.669)	(0.967)
Level_education2	−1.121	0.049	0.865	0.627	−0.002
	(1.191)	(0.815)	(0.781)	(0.553)	(0.971)
Level_education3	0.419	1.378	0.481	1.794**	1.909
	(1.382)	(1.058)	(1.389)	(0.851)	(1.178)
Ethnic Group_Ewe	−2.455***	−14.130***	1.326***	1.433**	−0.188***
	(0.000)	(0.00000)	(0.00000)	(0.677)	(0.000)
Ethnic Group_Gourma	12.014***	−0.880	3.987***	6.832***	4.384***
	(0.790)	(0.868)	(0.807)	(0.767)	(0.821)
Ethnic Group_Kabye	−3.348***	−16.387***	−3.132***	0.624	−5.141***
	(0.000)	(0.00000)	(0.000)	(1.302)	(0.000)
Ethnic Group_Moba	9.368***	−3.721***	0.809	4.579***	1.691***
	(0.572)	(0.606)	(0.607)	(0.447)	(0.624)
Ethnic Group_Peulh	−6.865***	13.259***	18.437***	−10.381***	19.197***
	(0.000)	(0.695)	(0.653)	(0.000)	(0.666)
Household size	−0.086	−0.118*	−0.130*	−0.128**	−0.192**
	(0.067)	(0.067)	(0.069)	(0.056)	(0.084)
Marital Status2	−50.800***	−45.124***	−46.384	−4.252**	−2.934
	(0.000)	(0.000)	(1.700)	(2.082)
Marital Status3	−11.805***	11.517***	11.621***	11.423***	−11.333***
	(0.000)	(0.821)	(0.821)	(0.627)	(0.000)
Area.Cultivable.Land	0.488**	0.443*	0.379	0.396*	0.411
	(0.241)	(0.241)	(0.253)	(0.229)	(0.262)
Area.actually.cultivated	−0.939***	−0.718***	−0.603**	−0.688***	−0.501*
	(0.294)	(0.278)	(0.286)	(0.256)	(0.285)
Area.dedicated.tiger nut	0.884	0.327	1.072	−0.010	−1.278
	(1.378)	(1.506)	(1.368)	(1.085)	(1.608)
Constant	−19.933***	0.749	−19.038***	1.733	−21.487***
	(0.897)	(1.921)	(0.880)	(1.411)	(0.928)
Akaike Inf. Crit.	838.626	838.626	838.626	838.626	838.626
Note:	*p < 0.1;	**p < 0.05;	***p < 0.01

APD= Abnormal Plant Development; PLY = Premature leaf yellowing; SD: Seedling drying; ST: Small tubers; YR: Yield reduction; Sex1 (women), Level_educatio2 (Secondary school); Level_education3 (University); Marital.status2 (single); Marital.Status3 (widower). p = p value; coef = coefficient. ***, **, * significant at 0.01%, 1% and 5% probability level respectively. The coefficients in bold reflect the significant influence of the socio-demographic variable on the concerned use

A chi-square test indicated a significant relationship between region, ethnicity, marital status, and farmers’ perceptions of other uses of tiger nut (χ² = 139.43, df = 32, p = 2.288e-15). The first two axes of the factorial map explained 93.21% of the total variance (Fig. 6), indicating that these dimensions effectively summarize the variability in responses. In the Plateaux region, married respondents from the Akposso, Ewe, and Kabyè ethnic groups largely reported no observable effects of climate change on tiger nut. In the Savanes region, factorial analysis revealed two distinct respondent groups. The first group, comprising married Peulh, married Gourma, and single Moba farmers, associated climate change effects with “small tubers,” “premature leaf yellowing,” and “seedling drying.” The second group, consisting of married Moba, widowed Gourma, and single Gourma farmers, primarily perceived climate impacts through reduced yields (Fig. 6)

Fig. 6.

Relation between producers’ perception of climate impacts on tiger nut and ethnic groups. Green circles represent the different clusters based on the ethnic groups and perception of climate change impacts on tiger nut

Discussion

Socio-demographic characteristics of tiger nut producers

The findings of this study revealed significant differences in the socio-demographic profiles of tiger nut producers across the two surveyed regions. In the Savanes region (northern Togo), producers were predominantly male, while in the Plateaux region (southern Togo), producers were mainly female. This contrast is largely explained by the distinct cultural and socio-economic contexts of the two regions. In the Plateaux region, women typically have the autonomy to cultivate and manage plots of land independently and are actively engaged in the production of horticultural crops. Conversely, in the Savanes region, the higher proportion of male farmers can be attributed to a patriarchal social structure, where men dominate household decision-making, including decisions related to agricultural activities. In this context, women are primarily involved in distribution, marketing, and processing of harvested produce, rather than direct cultivation. Across both regions, the majority of tiger nut producers belonged to the adult age group (30–60 years), considered the most active demographic for farm labor and household decision-making [29]. The limited presence of both youth and older adults among producers may be due to the labor-intensive nature of tiger nut cultivation, which can discourage younger individuals and pose physical challenges for the elderly.

Nutritional composition and ethno-economic significance of tiger nut in local communities of Togo

Tiger nut is utilized for a variety of purposes by local populations, including food, commercial, medicinal, and soil fertilization uses. The high nutritional value of tiger nut may explain its significant role in local diets. The tubers have been reported to be rich in proteins (5.08%), fats (30.01%), digestible carbohydrates (45.73%), ash (2.23%), and fiber (14.18%) [8]. They are also abundant in essential minerals, including potassium, calcium (important for bone and dental development, especially in infants), magnesium, and iron. Additionally, tiger nuts contain important vitamins such as A, C, and D, and the oil extracted from the tubers contains essential amino acids [30, 31].

Beyond home consumption, commercialization is the most widespread use of tiger nut across both regions. The tubers are primarily sold by women at local markets or to traders, many of whom travel directly to production areas to purchase supplies. These traders then resell the product to retailers or processors based in Lomé, where demand is equally strong for locally grown tiger nuts as it is for imported varieties. Given the economic potential of the tiger nut sector, structuring the value chain has become a key priority. In response, a project was launched under the Project to Support the Development of a Short Agroecological Supply Chain (PASFA), implemented by Écosystème Naturel Propre (ENPRO) in partnership with GRET. This initiative aims to provide technical and organizational support to women involved in tiger nut production, who are now being organized into cooperatives. The project’s goals include: addressing the product conservation and quality challenges identified by processors; identifying new market outlets and distribution channels; advancing toward the labelling and certification of tiger nut products produced by these cooperatives [16]. All of these measures will facilitate access to regional and international markets, thereby contributing to the improved well-being of women producers. Such initiatives are expected to strengthen the tiger nut sector and promote its sustainable development and conservation.

The medicinal use of tiger nuts has been reported in other studies. In Benin, the species has been used to treat conditions such as sexual weakness and diarrhea [3]. In Burkina Faso, tiger nut is traditionally used to treat constipation and to address milk secretion problems in breastfeeding women [2]. In contrast, the only medicinal use reported in the present study was for the treatment of sexual weakness. The preparation methods vary by region. For example, in the southern region, the tubers are used as a base ingredient in the traditional alcoholic beverage “sodabi”, which is consumed for its perceived therapeutic effects. The various methods used to treat sexual weakness with tiger nut in Togo reflect the differing levels of knowledge about the plant’s use across regions. This suggests that specific insights into its applications may be preserved and transmitted within certain communities, likely through vertical knowledge transmission. The same observation was made by Kinhoégbè et al. [28] while studying pigeon pea, a neglected species in Benin.

Traditional knowledge and folk classification of tiger nut across ethnic groups in Togo

This study revealed that generic names for tiger nut vary across ethnic groups and regions. These findings are consistent with those reported by Yamwemba et al. [2] in their study of cultivated yellow tiger nut in Burkina Faso, and by Adjahossou et al. [3] in their research on folk classification and traditional uses of the species in Benin. Although farmers are able to distinguish between different types of tiger nut based on color, shape, and size, these types are often referred to by the same generic name within a given region. For example, the term “Efio” is used by both the Akposso and Ewe ethnic groups. As noted by Kinhoégbè et al. [28], this shared terminology may result from the cohabitation of these groups, which has likely facilitated the transfer of habits and knowledge over time.

The recognition of different local varieties by farmers is a strong indicator of their knowledge of species diversity. This study revealed two levels of local variety identification. The first level is based on tuber color typically classified as yellow or black. The second level relates to tuber shape and size, including categories such as large and rounded, large and elongated, and small and rounded. This hierarchical classification system observed in our study is consistent with findings from other ethnobotanical research on species such as pigeon pea [28, 32] and common bean [26], and highlights farmers’ ability to recognize and categorize intraspecific diversity.

In our study, as in those of Adjahossou et al. [3] and Yamwemba et al. [2], the identification of local tiger nut cultivars was based on a combination of tuber characteristics, including tuber color, tuber shape, and in the latter study, sexual dimorphism, and in the former, the presence or absence of inflorescence. This approach contrasts with the findings of Bori et al. [33] where local cultivars were distinguished solely based on tuber size. The fact that farmers in our study did not mention either sexual dimorphism or the presence or absence of inflorescence may suggest a limited understanding of the species’ reproductive biology. Instead, their classification relies on readily observable morphological traits, which are more accessible and easier to recognize by local populations. It is also important to note that a single local variety may be known by different names across ethnic groups, and conversely, two distinct varieties may share the same generic name within a single ethnic group. This inconsistency in local nomenclature can lead to an underestimation of actual varietal diversity. As a result, there is a clear need for in-depth characterization, both agromorphological and molecular, to accurately assess the genetic diversity of tiger nut varieties at the national level.

Farmers’ perspectives on cultivation challenges and climate change impacts on tiger nut in Togo

Tiger nut producers face various limitations that hinder their production activities. At the national level, pest attacks, challenging harvest processes, and climatic hazards are the primary issues affecting tiger nut cultivation. According to growers, harvesting the tubers is especially labor-intensive and physically demanding. In fact, many farmers consider tiger nut production to be difficult overall. These constraints were also noted by Bori et al. [33] in their study on tiger nut cultivation in Niger. In that study, 64.8% and 49.3% of surveyed farmers identified cultivation and harvesting, respectively, as the main production challenges.

In both climatic zones, the constraints cited by growers were largely the same, with one notable exception. Rodents were mentioned as a constraint in the Plateaux, while fungal diseases were identified in the Savanes. Although the relative importance of each constraint varies between zones, the core challenges remain consistent. For instance, the labor-intensive nature of harvesting tiger nut was identified among the top three production constraints in both regions ranked first in the Plateaux and second in the Savanes. These findings invalidate our initial hypothesis that constraints on tiger nut production differ significantly between climatic zones.

This situation remains fundamentally unchanged regarding producers’ perceptions of climate change. Apart from the early onset of rains cited only in the Plateaux, the other three perceptions were reported in varying proportions across both regions.

In the Plateaux, where growers are accustomed to abundant rainfall during the rainy season, the irregularity of rainfall was the most frequently mentioned indicator of climate change. In contrast, in the Savanes region, where annual rainfall ranges from 850 to 1,400 mm and the dry season typically lasts around six months, any dry spell is perceived as a major sign of climate change.

This heightened sensitivity in the Savanes can be attributed to the region’s chronic water scarcity; any factor that could worsen this situation is seen as a significant climatic shift by the population. The term “climatic hazards,” used by producers to describe production constraints, refers to disruptions such as drought, delayed rains, and irregular precipitation. Notably, these same phenomena were cited by farmers when asked how they perceive climate change.

Regarding the impact of climate change on the species, producers reported several effects, including reduced yields, early leaf yellowing, abnormal growth, seedling desiccation, and the production of smaller tubers. As previously noted, water availability is critical for tiger nut cultivation, particularly during germination and tuber formation [4]. Adequate irrigation during the tuber initiation and bulking stages is essential for achieving high yields. A lack of water during these phases results in fewer and smaller tubers, directly impacting both the quality and quantity of the harvest. The effects reported by farmers in the Savanes region are direct consequences of inadequate irrigation caused by climate change during the sensitive stages of the plant’s development. These impacts were more readily cited by farmers in the Savanes, as the region has experienced periodic droughts for decades. As a result, local growers have become familiar with the various manifestations of climate change and their effects on crops. Perceptions such as the late or early onset of rains, irregular rainfall, and the threat of drought correspond to the phenomena of “shifting seasons,” “poor rain distribution,” and “drought” identified as major climatic risks in Togo, according to a survey conducted by the Ministry of the Environment and Forest Resources [34]. This supports our hypothesis that producers’ perceptions of climate change align with its scientifically documented manifestations.

Tiger nut production systems, farmers’ preferred traits across climate zones, and implications for varietal development

The tiger nut production system is generally similar across the two climatic zones studied, with only minor differences. One notable distinction is the use of animal-drawn ploughs by some farmers in the Savanes region. This finding contradicts our hypothesis that cultivation practices for the species vary significantly by climatic zone.

Farmers’ variety choices are influenced by both socioeconomic and agroecological factors. These preferences are essential for breeding programs and play a key role in promoting the adoption of improved varieties. Ignoring these characteristics could undermine the effectiveness of breeding and dissemination efforts. Across the study area, high yield and tuber color are the primary criteria cited by farmers when selecting local varieties. Tuber color, in particular, is highly important in the Savanes region. Farmers there avoid cultivating the black variety due to the lack of market demand and the belief that it has a very short shelf life. Similarly, in Benin, producers reported that the black variety is less attractive to buyers because its price remains constant and it carries a high risk of financial loss due to its lower sweetness compared to the yellow variety [3].

Producers in the Plateaux region cultivate both black and yellow tiger nut varieties. All farmers recognize that the yellow tubers have high market demand and excellent productivity. In addition to these two traits, taste, market demand, and tuber shape are among the most important selection criteria. Based on these five criteria, the yellow, rounded tiger nut variety emerges as the most preferred local type across both regions and enjoys the highest market demand. Maduka & Ire [1] reported that, in terms of appearance, yellow tiger nut tubers are larger and have a more appealing color than the brown and black variants. Furthermore, yellow tubers yield a greater quantity of tiger nut milk, which contains higher fat and protein levels compared to milk produced from the black variety. Additionally, yellow tubers have lower levels of antinutritional factors particularly polyphenols than the black variant [35]. However, black tiger nut tubers have a higher oil content than yellow ones.

Given the diverse uses of tiger nuts in the country, and the distinct nutritional characteristics of each variety, it is unsurprising that yellow varieties are the most in demand on the market. Most of the criteria cited by producers in Togo were also reported by farmers in Benin [3].

Conclusion

This research provides valuable insights into the cultivation methods, varietal diversity, and uses of tiger nut in Togo. Organizing farmers into cooperatives could foster mutual support in addressing production challenges. Additionally, the development of effective pest management strategies targeting both insects and rodents would likely contribute to increased tiger nut yields.

Farmers rely on morphological traits to distinguish between local varieties and tend to prefer yellow types known for producing high yields and large tubers. Breeding programs that focus on these desirable characteristics would accelerate variety adoption and, in turn, enhance crop productivity.

Beyond developing improved varieties, researchers should also design comprehensive technological packages tailored to tiger nut cultivation, with the aim of reducing the production burden on farmers. Furthermore, the Ministry of Agriculture and Rural Development should work toward creating an enabling environment that improves access to agricultural inputs such as herbicides, fertilizers, and insecticides.

Lastly, a market study focusing on potential outlets and marketing channels could facilitate the sale of tiger nut and stimulate broader interest in its production.

Author contributions

PKK and BA: Conceptualization, PKK and AD: Formal analysis, Writing, JIKA and YGL: Investigation, Methodology, TDH and PKK: Funding acquisition, DMA and GNG: Review and editing, AKN: Project administration.

Funding

This work was supported by The World Academy of Sciences (TWAS) and the Islamic Development Bank (IsDB) through the TWAS-IsDB Postdoctoral Fellowship Program (Agreement No. 021/2024).

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

The study received ethical approval from the Pedagogic and Scientific Commission of Université de Kara. The research proposal was initially submitted to the commission, which confirmed its scientific and ethical validity. Prior to data and morphotype collection for the ethnobotanical survey, informed consent was obtained from all tiger nut growers involved in the study. Participants also provided their consent for the submission and publication of the survey results.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.