Millet (
Pennisetum glaucum (L.) R. Br) is a staple food crop in arid and semi-arid areas of Asia and Africa and remains one of the main sources of energy, protein, vitamins, and minerals for millions among the poorest people in these regions. This cereal is generally grown for grains, used in human and animal diet, and also for stubble used as fodder and silage [
1]. In addition to the dietary and forage use of millet, different parts of the plant are commonly used for multiple services including the treatment of various human and animal diseases [
2,
3], soil fertilization, and handicrafts [
4,
5]. Furthermore, as a result of climate change and population pressure, millet is increasingly being exploited as forage or a dual-purpose crop (grain and fodder) in order to ensure the food security of livestock [
6,
7]. This new trend towards the valuation of millet in animal food is not without consequences on the food security of the human local populations. Therefore, an ethnobotanical study appears to be a good approach in this area to understand the use as well as the sociocultural and economic perceptions of local populations about this crop [
8‐
10].
Ethnobotany is a science that is related to several disciplines such as biodiversity conservation, conservation genetics, ethno-pharmacology, food technology, ecology, etc. [
11]. The ethnobotanical assessment of millet would be then indispensable for its valuation, sustainable management, and conservation. This study documented indigenous knowledge of millet uses by ethnic groups in Niger. Past ethnobotanical studies in the West African Sahel have focused on wild woody and herbaceous plant species [
12,
13]. But this study was focused on a crop such as millet, given its importance as a major cereal for humans and as an additional source of forage for animals in Niger. However, little known work has been conducted on the ethnobotanical use of millet despite being considered as the staple food crop for local populations in the arid and semi-arid areas of the world [
14‐
16]. The objectives of our study were to document the endogenous knowledge of millet uses in Niger and to assess the effects of ethnicity, occupation, and age on botanical knowledge. Indeed, Indigenous knowledge is often unevenly distributed among those factors [
13]. Moreover, the level of individual knowledge of native plant species can be affected by many factors such as sex, age, ethnicity, occupation, religious and cultural beliefs, abundance, and the usefulness of the species [
13,
17]. In addition, research conducted in the West African Sahel reported that the
Fulani,
Kel Tamashek,
Bellah, and
Maure groups were the main major livestock-rearing groups, while the farmers were mainly from the
Bambara,
Hausa,
Djerma,
Gourmantche,
Mossi, and
Soninke [
13,
18]. Nowadays, professional specialization according to ethnic criteria is becoming increasingly blurred in the region [
13,
18]. Nevertheless, pastoral groups usually know more about livestock than farmer groups and vice versa. Robert et al. [
19] also reported that producers’ choice of millet varieties is generally based on agro-morphological traits, phenological, or organoleptic characteristics. Furthermore, the preservation of the cultural identity of a community requires knowledge to be passed on from generation to generation [
13]. Age therefore has an impact on the knowledge of plants within ethnic groups [
13,
20]. In this study, we tested three hypotheses. First, ethnicity affects knowledge about the uses of millet organs, so that farmers (
Zarma-Sonhrai,
Hausa,
Kanuri,
Gurmantche) tend to know the uses of millet better than pastoralists (
Fulani,
Tuareg,
Tubu). Secondly, the socio-professional category also influences the knowledge of uses of millet organs, so that ethnic groups such as
Zarma-Sonhrai,
Hausa,
Kanuri and
Gurmantche (farmers) tend to know the uses of the millet organs better than
Fulani,
Tuareg,
Tubu (pastoralists). And thirdly, there is a positive correlation between knowledge of millet organ use and age, that is, older people are more familiar with millet uses than younger people.