Socio demographic characteristics of respondents
In total 500 pigeonpea producing households including 190 in the Guinean zone, 200 in Sudano-Guinean zone and 110 in the Sudanian zone were surveyed. The age of the surveyed pigeonpea farmers ranged from 21 to 76 years with an average of 45.9±9.2 years old. The majority (62.4%) of farmers were men. The majority of pigeonpea farmers were found to be illiterate (43.4%), while 31.6% and 25% were found to have primary and secondary levels of education, respectively. The average household size was 6.4±2.1 members (ranging from 3 to 11 members). The experience year old was 15±8 years, on average (Table 2).
Significant differences in age of the surveyed pigeonpea farmers were observed across ecological zones. On average, farmers in the Guinean zone are older (48.7 years against 44 years) and more experienced than those in the Sudano-Guinean zone (18.4 years of experience against 16.5). The number of farmers with none, primary and secondary level of education varied between ecological zones.
Local nomenclature
Across the thirteen sociolinguistic groups surveyed in the study area, 50 different pigonpea local names were recorded in the local dialects. Referring to the various vernacular names identified, the generic name of pigeonpea varied according to sociolinguistic group and ecological zones (Table 3).
In the Guinean and Sudano-Guinean zones, pigeonpea is called Hounkoun, Kloué or Klouékoun referring to Cowpea by farmers belonging to Fon and Mahi sociolinguistic groups while in the Guinean and Sudanian zones, pigeonpea is called Otili in reference to a pod-producing tree by farmers belonging to Nago and Dendi sociolinguistic groups. However, Bariba and Peulh sociolinguistic groups designated pigeonpea by Wotiri in reference to a pod-producing erected tree. Moreover, in Guinean zone, farmers belonging to Holly and Yoruba sociolinguistic groups call pigeonpea Otini. Pigeonpea is called Ekloui or Kloui by Adja sociolinguistic group. In Sudano-Guinean zone, pigeonpea is called Colo (meaning is unknown to farmers) by Idaasha sociolinguistic group while pigeonpea is called Tissi Tounan and Itoun by Biali and Somba sociolinguistic groups respectively, referring to a cowpea.
Folk taxonomy
In the study area, 5 criteria were used by surveyed farmers to identify pigeonpea landraces. The great majority of names (90.7%) given to pigeonpea had a meaning. More than half pigeonpea vernacular names correspond to morphological aspect (71%) of seeds. Such as seed coat colour (85.5%), seed coat and eyes colour (9.2%), seed size (1.3%), seed coat colour and size (4%). Plant type (3.7%), seed origin (8.4%), vegetative cycle (10.3%) and referring to cowpea (3.7%) were also among the criteria used by farmers to name pigeonpea (Table 4).
The folk taxonomy of pigeonpea has a hierarchical structure with two hierarchy levels as found in several sociolinguistic groups (Adja, Bariba, Fon, Holly, Idaasha, Mahi, Nago, Peuhl and Yorouba). For example, in the Adja sociolinguistic group, the generic name of pigeonpea Ekloui or Kloui is subdivided into 5 infra-specific pigeonpea taxa (Ekloui djou, Ekloui koudji, Ekloui ri, Ekloui wlanwlan, Ekloui wliwlito). In the Fon sociolinguistic group, the generic name of pigeonpea Klouékoun is subdivided into 6 infra-specific pigeonpea taxa (Klouékoun vôvô, Klouékoun wéwé, Klouékoun wéwé tété, Klouékoun wéwé noukoun vôvô, Klouékoun wéwé noukoun wiwi, Klouékoun wlanwlan). While in the Bariba sociolinguistic group, the generic name of pigeonpea Wotiri is subdivided into 4 infra-specific pigeonpea taxa (Wotiri gbika, Wotiri goukorou, Wotiri wonka, Wotiri souan).
Diversity of cultivated pigeonpea landraces
Based on seed characteristics, fifteen pigeonpea landraces were idesntified in the study area (Figure 2). At village level, the number of pigeonpea landrace ranges from 1 to 5 with an average of 2.7 ± 1. The highest number of landrace (5) per village was reported at Ouèssènè in the department of Alibori. At the household level, the number of pigeonpea landrace held by producers ranges from 1 to 3 with an average of 1.3 ± 0.5. Seventy two point two (72.2%), 27.6% and 0.2% of the producers cultivated 1, 2 and 3 landraces respectively. The highest number of landrace (3) per household was reported at Ouèssènè in the department of Alibori and maintained by only one producer. The Sudano-Guinean zone contained the highest number of landraces followed by the Guinean and Sudanian zones (11, 9 and 7 landraces respectively) while the highest number of landraces (5) per village and per household (3) was recorded in the Sudanian zone.
Distribution and extent of pigeonpea landraces
Within each ecological zone, the production was limited to specific districts and departments. In the Guinean zone, the production was restricted to the districts of Adja-Ouèrè, Kétou and Pobè in the department of Plateau and to the districts of Aplahoué, Klouékanmè and Lalo to the districts of Couffo. In the Sudano-Guinean zone, pigeonpea was cultivated in the districts of Dassa-Zoumè, Ouèssè, Savalou and Savè in the department of Collines and the districts of Covè, Djidja, Zakpota and Zangnannado in the department of Zou. Lastly, in the Sudanian zone, pigeonpea was cultivated in the districts of Bembèrèkè and Kalalé in the department of Borgou and the district of Gogounou in the department of Alibori. The Four Squares Analysis revealed that in the Sudanian zone, among the 9 landraces presents, 1 (Klouékoun wéwé noukoun vôvô (Mahi and Fon sociolinguistic groups)) was cultivated by many households on a large area, 1 (Otili founfoun kékélé (Idaasha sociolinguistic group)) was cultivated by few households on large area while the 7 remaining ((Ekloui djou (Adja sociolinguistic group), Wlétchivé kloui (Adja sociolinguistic group), Carder ekloui (Adja sociolinguistic group), Otili founfoun lakoun (Idaasha sociolinguistic group), Klouékoun wéwé tété (Mahi sociolinguistic group), Otili kpoukpa (Nago sociolinguistic group) and Klouékoun vôvô (Fon and Mahi sociolinguistic groups)) were grown by few households on small area. In the Sudano-Guinean zone, the Klouékoun wéwé nounkoun wiwi (Mahi and Fon sociolinguistic groups) was cultivated by many households on large area, Klouékoun wéwé tété (Mahi sociolinguistic group) and Otili founfoun kékélé (Idaasha sociolinguistic group) were cultivated by few households on large area, and the Wlétchivé kloui (Adja sociolinguistic group) and Klouékoun wlanwlan (Fon sociolinguistic group) by many households on small area while the Klouékoun wéwé nounkoun wiwi (Mahi and Fon sociolinguistic groups), Otini kpoukpa (Holly sociolinguistic group), Colo kpikpa (Idaasha sociolinguistic group), Otili founfoun lakoun (Idaasha sociolinguistic group), Otili kpoukpa (Nago sociolinguistic group) and Klouékoun vôvô (Fon and Mahi sociolinguistic groups) were cultivated by few households on small area. Finally, in the Sudanian zone, 2 landraces ((Klouékoun wéwé nounkoun wiwi (Mahi and Fon sociolinguistic groups) and Otili founfoun kékélé (Idaasha sociolinguistic group)) were cultivated by many households on large area while 1 landrace ((Klouékoun wlanwlan (Fon sociolinguistic group)) is cultivated by few households on large area, 4 landraces ((Ekloui djou (Adja sociolinguistic group), Wotiri wonka (Bariba sociolinguistic group), Wotiri souan (Bariba sociolinguistic group) and Klouékoun vôvô (Fon and Mahi sociolinguistic groups)) were cultivated by few households on small area. Thus, in the Guinean zone, 7 landraces were threatened of disappearance, 6 in the Sudano-Guinean zone against 4 in the Sudanian zone. In areas where landraces were threatened of disappearance, the frequency of disappearance varied between 50 and 100% (Table 5).
The distribution analysis revealed that the Otini kpoukpa (Holly sociolinguistic group), Colo kpikpa (Idaasha sociolinguistic group) and Klouékoun wéwé nounkoun wiwi (Mahi and Fon sociolinguistic groups) were specific to the Sudano-Guinean zone; Wotiri souan (Bariba sociolinguistic group) and Wotiri wonka (Bariba sociolinguistic group) were specific to the Sudanian zone and Carder ekloui (Adja sociolinguistic group) was specific to the Guinean zone while the Klouékoun wéwé nounkoun wiwi (Mahi and Fon sociolinguistic groups), Otili founfoun kékélé (Idaasha sociolinguistic group) and the Klouékoun vôvô (Fon and Mahi sociolinguistic groups) were cosmopolitan for the three ecological zones (Table 12). The Wlétchivé kloui (Adja sociolinguistic group), Otili founfoun lakoun (Idaasha sociolinguistic group), Klouékoun wéwé tété (Mahi sociolinguistic group) and Otili kpoukpa (Nago sociolinguistic group) were present in the Guinean and Sudano-Guinean zones, Ekloui djou (Adja sociolinguistic group) in the Guinean and Sudanian zones while the Klouékoun wlanwlan (Fon sociolinguistic group) was present in the Sudano-Guinean and Sudanian zones (Table 12).
Reasons for pigeonpea production and uses category
Our study revealed that pigeonpea is produced for three main reasons depending on the ecological zones (Table 6).
In the Guinean and Sudano-Guinean zones, nutritional value is the main source of motivation while in the Sudanian zone land fertilizing power is the main source of motivation. The third reason is the market value. The different pigeonpea uses categories were mainly concentrated on grains. Based on their fidelity level, pigeonpea is more used in medicine in the Guinean (FL = 19.5%) and Sudanian (FL = 23.9%) zones. According to famers, boiled leaves are used by oral route to treat malaria. Also, the decoctate of the leaves is used in bath to treat measles and is also used as an antibiotic to treat mouth’s sores or tooth decay. The roots, when chewed, prevent the rise of snake venom, in the case of snake bite. The use of pigeonpea grains as an offering for food or symbolic purposes and in sacrifice to divinity was specific to the Sudano-Guinean and restricted to Holly and Nago sociolinguistic groups. While grain processing into donuts is specific to Guinean (FL = 4.3%) and Sudano-Guinean (FL = 2%) zones and restricted to Holly and Adja sociolinguistic groups. In these zones, pigeonpea are roasted and reduced to flour to sprinkle sauces as nutritional supplement by the first one or to make donuts by the second one. Consumption, weed control and land fertilization are common to all three ecological zones (Table 6).
Cultural practices
Pigeonpea was considered as an annual plant by most of surveyed farmers (93.2%). Only 6.2% of farmers considered this legume as a perennial plant. For the last one, plant is left in the field and is harvested the following year. The main pigeonpea farming activities included: ploughing, sowing, weed control, pod harvest, pod plugging and winnowing. Seeding and weed control were practiced by all the farmers. Pigeonpea is sown between April, May, June (73.6%) in intercropping with other seasonal crops (82.8%) or in pure stand (17.2%). Three sources of labour were observed. For farming activities, 13.2% of farmers used family labour, 73% combined family and friends labour while 13.8% used a combination of family, friends and jobber labour (Table 7).
Land fertilization was not reported while only 14% of farmers included in this study used pesticide. The average grain yield in farmers’ fields was estimated at 553.4±36.3 kg/ha. According to farmers, during the three last years, Sudano-Guinean zone were the largest cropping area followed by the Guinean zone while farmers in the Sudanian zone produced pigeonpea on a small cropping area (Table 7). Sowing was more realized between April, May and June in the Guinean and Sudano-Guinean zones (97.9% and 91% respectively) whereas it was more realized between June, July and August in the Sudanian zone (68.2%). Intercropping with other seasonal crops such as maize and millet was specific to Guinean (100%) and Sudano-Guinean (98.5%) zones while pigeonpea was more cultivated in pure stand in Sudanian zone (75.4%). Family and the friends was the main source of labour for various farming activities in the Guinean and Sudano-Guinean zones (87.9% and 61.5% respectively) while it was family (49.3%) in the Sudanian zone. Our results revealed that the average pigeonpea yield in the Sudanian zone is lower (522.3 ± 44kg/ha) compared to the Guinean and Sudano-Guinean zones (557.5 ± 15.9 kg/ha and 566.6 ± 35.8 kg/ha respectively).
Seed system
Three sources of seeds were observed. Farmers used seeds from previous harvest (60.2%) or friends (22%) or local market (17.8%). After each harvest, 67.8% of farmers stored seeds until scarcity at market while 32.2% of them sell seeds in local markets. Comparing seed system between ecological zones, previous harvest was the main source of seed in the Guinean and Sudano-Guinean zones (70% and 62.9% respectively) while friends was the main source (50.4%) in Sudanian zone and after each harvest, farmers stored more grains in the Guinean and Sudano-Guinean zones (70% and 84% respectively) while they were more immediately sold in Sudanian zone (65.5%) (Table 7).
Pigeonpea production constraints
In total, 10 constraints were identified as affecting pigeonpea production. The long vegetative cycle was ranked as the major constraint in Benin following by pests and diseases and rainfall irregularity (Table 8). According to farmers descriptions, pigeonpea production is faced by Low productivity is seventh among the constraints followed by the sensitivity to storage insects. All constraints have been reported in the three ecological zones. However, their relative importance varied from one zone to another. The most important constraint in the Guinean and Sudano-Guinean zones is the long vegetative cycle followed by the sensitivity to pests and diseases, while in the Sudanian zone pest and diseases followed by soil poverty were the most important constraints (Table 8).
Incidence of pests on pigeonpea yield and control methods
According to farmers, the impact of pests and diseases in pigeonpea production in farmers’ fields varied from one zone to another (Table 9). The impact is low in the Guinean and Sudano-Guinean zones (52.6% and 42.5% respectively) while it is high in the Sudanian zone (81.8%). Pests control was only reported in the Sudanian zone (63.7%). Three reasons justified the non-control of pest reported by farmers: the high price of pesticides (49.6%), the risk of intoxication (29.6%) and the lack of sprayers (20.8%).
Evolution of pigeonpea production in Benin
Overall, the majority of farmers (69.4%) reported a decrease in pigeonpea production in Benin. According to farmers, this downward trend was the fact to the Guinean and Sudano-Guinean zones (75.79 % and 85.5% respectively). In these zones, the decrease in cropping area is highly significant (p ˂ 0.001). Indeed, the average of cropping area was 0.9 ±0.2 ha in 2015, 0.8 ± 0.1 ha in 2016 and 0.5 ±0.1 ha in 2017, in the Guinean zone (Table 7). Similarly, in the Sudano-Guinean zone, average cropping area was 1.3 ± 0.8 ha in 2015, 0.9 ± 0.4 ha in 2016, 0.7 ± 0.3 ha in 2017, in the Sudano Guinean zone (Table 7). In contrary, in the Sudanian zone, pigeonpea cultivation is increasing (70.91%). In this zone, the cropping area increasing is highly significant (p˂0.001). The average cropping area was 0.3 ± 0.1 ha in 2015, 0.4 ± 0.1 ha in 2016 and 0.4 ± 0.1 ha in 2017 (Table 7). According to farmers, the reasons for this increasing are the fertilizing power of the plant (89.1 %) and weeds control (10.9%).
Farmers’ preference criteria of pigeonpea
Through the study area, 11 criteria depending on the ecological zones and different sociolinguistic groups underlined the choice of pigeonpea landraces to be cultivated by the farmers. The most important criteria were precocity, resistance to pests and diseases, rapid for cooking, adaptability to any types of soil, good taste and high productivity (Table 10).
In Guinean and Sudano-Guinean zones, precocity was the most important criterion followed by the resistance to pests and diseases while in the Sudanian zone, the resistance to pests and diseases was ranked first followed by the adaptability to any type of soil (Table 10). Precocity appeared at the front of the criteria of all sociolinguistic groups except for Nago sociolinguistic group for whom adaptability any types of soil was the first criterion. Moreover, in addition to precocity, resistance to pests and diseases, rapid for cooking, adaptability to any types of soil and good taste were the choice criteria for farmers belonging to Bariba sociolinguistic group (Table 11).
In addition to the choice criteria for Bariba sociolinguistic group, farmers belonging to Boo sociolinguistic group had strong tendency to varieties cultivable at any time of the year and resistant to storage insects while those belonging to Dendi sociolinguistic group preferred varieties with high productivity and cultivable at any time of the year and those belonging to Peuhl sociolinguistic group preferred high productive and resistant to storage insects varieties. Lastly, precocity, resistance to pests and diseases, rapidity for cooking and adaptability to any type of soil were farmers belonging to Yoruba sociolinguistic group criteria.
Participatory evaluation of pigeonpea landrace grown in Benin
The results revealed that for landraces identified simultaneously in the three ecological zones, none of them were performing for a given character simultaneously in the three ecological zones (Table 12). Moreover, none landrace were performing simultaneously for all 5 evaluated characters. Nevertheless, the Carder ekloui (Adja sociolinguistic group) only identified in Guinean zone combined 4 good performances (high productivity, rapid for cooking, resistant to pests and diseases, resistant to storage insects). Moreover, Carder ekloui (Adja sociolinguistic group) and Otili founfoun kékélé (Idaasha sociolinguistic group) showed high productivity in Guinean and Sudano-Guinean zone but showed low productivity in the Sudanian zone. These two landraces, however, showed resistance to pests and diseases. In addition, Klouékoun vôvô (Fon and Mahi sociolinguistic groups) showed high productivity, rapid for cooking, resistant to pests and diseases, resistant to storage insects and short vegetative cycle in Guinean and Sudano-Guinean zone, however, showed low productivity and susceptible to pests and diseases in the Sudanian zone (Table 12).