Sweetpotato breeding priority and preferred traits to increasing its utilisation in Niger and Nigeria

Sweetpotato is an important food, feed and vegetable crop in Niger and Nigeria. The adoption of a new variety depends on famers and consumers preferences. The objective of this study was to identify sweetpotato preferred traits by end-users in Niger and Nigeria. The study was conducted in two countries through participatory rural appraisal. The results revealed that sweetpotato is produced by men in Niger, while it is mostly produced by women in South-East Nigeria. In Niger, 100% of cultivated varieties were landraces, while 75.00% in Nigeria were landraces. Results showed that in Niger, farmers preferred high yielding, white flesh colour, and drought tolerant varieties, while in Nigeria they preferred high yielding, white flesh colour, and earliness cultivars. Traders and consumers in both countries preferred healthy, white flesh colour and big storage root size varieties. There is a need of effective breeding program in Niger, and both countries should turn toward developing cultivars with high yield, drought tolerant, and pest and disease resistant.


INTRODUCTION
Roots and tubers are part of diet for majority of the global population, with world average per capita consumption of 19.4 kg/year (2013-2015) and projecting to achieve 21.0 kg/year by 2025 (OCED and FAO, 2016).Among roots and tubers, sweetpotato [Ipomoea batatas (L.) Lam] is an important food, feed and vegetable crop in most tropical developing countries.Sweetpotato is an important root crop grown in more than 115 nations (FAOSTAT, 2019).Sweetpotato has wide production geography, from 40° north to 32° south latitude of the globe.It possesses special attributes such as adaptability in wider topography, the ability to grow in subsidiary circumstance, good productivity in short durations, and balanced nutritional composition (Trancoso-Reyes et al., 2016).Sweetpotato global production of 2021 was 88,867,913 tons, with area of production of 7,410,026 ha (FAOSTAT, 2023).In West Africa, Nigeria was the first sweetpotato producer (3,943,046 tons), while Niger ranks fifth (224,017 tons) during 2021 (FAOSTAT, 2023).Sweetpotato is an important food, feed and vegetable crop in most tropical developing countries.It has high minerals (K, P, Ca, Mg, Fe, Mn, Cu).The roots have high nutritional value and sensory versatility in terms of taste, texture, and flesh colour (white, cream, yellow, orange, purple).B-carotene content is crucial because vitamin A deficiency is a serious health problem that results in blindness, weakness and death (Gurmu et al., 2014;Wang et al., 2016).
Due to its favourable profile, sweetpotatoes have been the focus research in recent years (Wang et al., 2016).The decision to adopt a new cultivar is complexly related to field and yield performance as well as consumer taste acceptability (Sugri et al., 2012).The most important criteria of smallholder farmers in Sub-Saharan Africa to adopt sweetpotato variety are yield, drought tolerant, maturity period, resistant to pathogens and pests, taste, nutritive value, multipurpose used, market demand and external appearance of leaves and roots (Low et al., 2017).Meanwhile, end-used preferred traits are never constant but change in the long run due to many factors, mainly changing food preferences, and new food forms, cultural dynamics industrial application, new information that impact utilisation among others (Afuape et al., 2021).The acceptation of new sweetpotato cultivar in Niger and Nigeria must fulfil both famers and consumers preference.This preference varies from one state to another.Moreover, traders also play an intermediate and important role between sweetpotato production and utilisation.A variety that fails to satisfy agronomic trait for production will not accept by farmers, and the one that fails to fulfil consumers' preferences will also loose the market value.
Considering these perception and preference of farmers, traders and consumers in sweetpotato production, marketing and utilisation; the breeding program should involve the client at each step to meet their need for easy adoption of newly released variety.This can be addressed through participatory plant breeding (PPB) (Tufan et al., 2018;Ceccarelli and Grando, 2019); participatory variety selection (PVC), and participatory rural appraisal (PRA) (Gibson et al., 2007;Gasura et al., 2008;Baafi et al., 2015).Therefore, this study was conducted through participatory rural appraisal (PRA) to identify sweetpotato breeding priority and preferred traits by farmers' traders and consumers in Niger and Nigeria.This will allow establishing a scientific database of sweetpotato for consideration for an ongoing and future breeding program activity that can help facilitating breeding for acceptable cultivar for both farmer and consumer.

Description of study area
The survey was conducted in nine villages selected across three states each from Niger (Tahoua, Dosso, and Tillaberi) and Nigeria (Ebonyi, Abia, and Kaduna) as presented in Table 1.A total of 18 villages (9 villages per country) were the study areas and were known as sweetpotato production areas.Tahoua State is situated in the middle-East part of Niger, while Dosso, and Tillaberi States are situated in the Western part of the country.In Nigeria, Ebonyi and Abia states are located in the South-East, while Kaduna is in the Northern part of the country.

Nature of participants
Farmers, traders, consumers and agricultural extension agents were the nature of the participants.During focus group discussion, the number of attended participants to the focus group discussion ranged from 5 to 40, with a total of 246 persons (Figure 1).The lower number was due to the restriction during COVID-19 pandemic in both countries.However, there were 135 participants in Niger against 111 in Nigeria.The highest number of 40 participants recorded in Niger was gotten before the restriction of COVID-19 started.
Based on Semis Structure Questionnaire (SSQ), a multistage sampling was used.Three states in each country were sampled, and then 1 to 2 district(s) were subsampled.In each district 1 to 3 village (s) was sub subsampled in order to get 3 villages per state.This provided 180 farmers (10 from each village), 180 consumers (10 from each village) and 60 traders (10 from each state) for SSQ.

Data collection
Data were collected for both Focus Group Discussion (FGD) and Semi-Structured Questionnaire (SSQ) from Niger and Nigeria republics.Focus Group Discussion was used to collect general information such as current cultivated varieties, sweetpotato production system, and preferred traits.This was done by a team where, and other village key informants with broad knowledge on diverse social issues.
Based on Semis Structure Questionnaire (SSQ), date were collected using established Participatory Rural Appraisal (PRA) tools followed (Baafi et al., 2015).The following data were collected from farmers: participant identification information, sweetpotato production and management, and sweetpotato preferred traits.From marketers and consumers, data were collected on identification information, sweetpotato preferred traits and some aspects related to cooking, consumption, and root conservation.Participatory rural appraisal was applied to identify the role of gender in production and marketing of sweetpotato.

Data analysis
Data were first converted to numerical values for both FGD and SSQ, then analysed using "R" software version 3.1.5and Microsoft Excel (Windows 8).Cross tabulations were used and results were summarized into frequencies and percentages, and represented in tables for discussion.Barplot simple and barchart group were constructed by R using lattice and ggplot2 packages.Data were analysed in different forms across states and countries.Pearson's Chi-squared test was performed by R software using library ''FactoMineR" to draw the inference of relationships between variables.

Farmer demography profile and socio-economic characteristics in Niger and Nigeria
The description of farmers in both countries was presented in Table 2. Hundred percent of farmers interviewed in Niger were males, whereas, 56.67% were females in Nigeria.Kaduna located in northern part of Nigeria; 100% of interviewed were males making difference with the South-East with 85% females as producers.Only less than 1% of respondent was below 20 years old in both countries.In Niger 78.89% were above 40 years old, while in Nigeria 52.22% were between 20 to 40 years old.Thirty percent of famers had family size varied from 0.5 to 1 ha, with Nigeria having the highest 37.78%, and Niger 22.22%.Moreover, 30% had farm size above 1 ha with also Nigeria with 32.22% and Niger 27.78% of total respondents.
The study also revealed that 41.78, 38.89 and 18.33% had family size less than 8, from 8 to 14, and above 14 persons, respectively.In Niger, 51.11% had from 8 to 14 family size, whereas in Nigeria 67.78% had less than 8 persons.

Current varieties cultivated by farmer
Different varieties were cultivated by farmers in Niger and Nigeria (Table 3).Variety preferences varied by state and country.In Niger, 17 varieties were cultivated with eight in Tahoua, while in Nigeria, 16 were being cultivated with eight cultivated in Ebonyi state.Majority (87.87%) of the varieties cultivated were landraces.In Niger, 100% of cultivated varieties were landraces, while 75.00% in Nigeria were landraces.
In Tahoua, varieties ''Bera'' and ''Dakantamini'' were the most cultivated varieties, while in Dosso ''Dan Tchadi'' and Tillaberi ''Dan Cameroon''.In Ebonyi state, ''Oyorima'' took the first place, while ''Butter Milk" and "Mother Delight'' in Abia state, and ''Pure water'' variety in Kaduna state.Some varieties cultivated but not mentioned during focus group discussion such as ''Dan Galmi'' in Tahoua, ''Ovoleba topia'' (which means this gives me joy and laugh), in Ebonyi state and ''Dakanta Zawara'' (which means wait for me widowed) in Kaduna.The most cultivated varieties in Niger are white/cream flesh colour as well as in Nigeria except in Abia state.

Sweetpotato preferred traits by farmer in Niger and Nigeria
The distribution obtained from dimension 1 and dimension 2 was presented in Figure 2. Results classified the study area as well as the farmer preferred traits in four groups.All the Niger states were classified in group 1.However, Kaduna state was separately classified in group 2 with specific trait (that is, easy to cultivate), while, Abia in group 3, and Ebonyi state in group 4 (Figure 2).In this study, 17 traits were listed across 6 states of Niger and Nigeria as traits preferred by farmers (Table 4).The results from correspondence analysis showed highly significant difference (χ 2 = 394.86;p<0.001) in the choice of farmer in different traits (Table 4).The criteria that  The number in parentheses represents the percentage of participants.
Source: Author Source: Author has been described mostly in Nigeria as white, orange and yellow flesh colour.Farmers considered white or cream colour as white.

Sweetpotato preferred traits by traders and consumers in Niger and Nigeria
Eleven traits were listed across 6 states of Niger and Nigeria as marketer traits preferred (Table 5).The results showed high significant difference (χ 2 = 82.38;p<0.01) in the choice of trader in different traits (Table 5).Various characteristics of good sweetpotato storage roots were identified by sellers.Thirty traders in each country were interviewed through Semi-Structured Questionnaire (SSQ).In Niger, healthy/clean root (83.33%), white/cream flesh colour (83.33%), big root (80.00%), high sugar taste (26.26%) and conservation (10.10%) were the first preferred traits by traders across the states as well as across countries (Figures 5 and 6).The order of importance was as follows in Nigeria: big root (90.00%), white/cream colour (83.33%), healthy/clean (76.67%), orange-fleshed (16.16%), and low sugar taste (10.10%).Ninety consumers in each country were interviewed which made it one hundred and eighty consumers.From these consumers, eleven traits were listed as traits preferred (Table 5).The results showed highly significant difference (χ 2 = 207.48;p<0.001) in the choice of consumer in different traits (Table 5).Consumer preferred traits in Niger were white/cream fleshed (81.11%), healthy (74.44%), big root (32.22%), high sugar (30.00%), and powder taste (13.33%).Similar trend was observed in Nigeria as healthy/clean (87.78%), white/cream fleshed (70.00%), big root (55.56%), orange-fleshed (27.78%), and low sugar (25.56%) (Figures 7 and 8).In sugar taste, Niger consumers mentioned high sugar as preferred trait, while in Nigeria low sugar was preferred.Other traits have been mentioned like powder taste.Besides, orangefleshed as well as yellow-fleshed was mentioned in Abia state.

Demography profile and socio-economic characteristics based on SSQ
In Niger, sweetpotato management is a man business in term of production, and marketing since it requires too much labour and financial resources.This is due to its large area of cultivation by farmers and it is for cash crop in all the villages.Sweetpotato however is men's crop in Niger.The highest percent of large production area obtained from Nigeria was increased by those from Kaduna state.In Niger, the raw or boiled sweetpotato is sold at the market by males, but young female could be sellers (of boiled or processed potato) after buying from the wholesalers.In Nigeria, Kaduna is similar to Niger due to huge production and purpose of which was to export to Lagos for other uses.In the South-East of Nigeria, women are more willingly producers and marketers because it is produced as food crop and  The involvement of more married females in sweetpotato production in Abia and Benue states could be due to the role of sweetpotato as a food security crop (Afuape et al., 2021).In general, the crop is more important for men than women in Nigeria (Olagunju et al., 2013).Other reports indicated the importance of women than men in sweetpotato production in Western Tanzania (Filson et al., 2018), and implication of 52.00% of female (as farmers, traders and consumers) in Ghana (Baafi et al., 2015).However, (Stathers et al., 2013) grouped gender roles and their responsibilities in sweetpotato production chain into three categories, namely sweetpotato as i) a male's crop with few or no women growing it, ii) female's crop with few or no men growing it, and iii) sweetpotato grown by both men and women on individually or family-owned plots.The increasing role of sweetpotato as a cash crop in South Nyanza in Kenya has attracted male involvement in sweetpotato production (Low, 2004), and increased sweetpotato market demand has brought changes in the roles and responsibilities of gender in Eastern Tanzania (Ngailo et al., 2016).Market demand can greatly influence men participation in sweetpotato production.In Niger 78.88% were above 40 years old, while in Nigeria 52.22% were between 20 to 40 years old, indicating that sweetpotato farmers were still in their active year of production.Similar age range of 20-60 years for over 90% was reported in Nigeria (Afuape et al., 2021) and above 40 years for over 52.00% was reported in Ghana (Baafi et al., 2015).For consumers, in Niger and Nigeria, sweetpotato consumption is not related to sex or age group.However, the tendency of males or females from one state to another is due to their availability during the administration of questionnaire, and or the management status of the crop in such area.

Current varieties cultivated by farmer based on FGD
Seventeen varieties were cultivated in the study area of Niger.A previous study reported 36 varieties cultivated in Western Niger (Ayerou, Gaya and Balleyara) (Harouna et al., 2015).The use of ''Bera'' variety could be explained by its introduction (into two villages that is, Guidan Magagi and Kamakamo) by agricultural extension agent, which is why farmers do not have a choice since they are new growers.The third village of Tahoua (Bangui) is the most experimented one and 'Tourist'' and "Dan Pateka'' are the most cultivated.This choice if was due to the high yield of ''Tourist'' variety but ''Dan Pateka'' variety is more consistent.In Western Niger, ''Dan Tchadi'' and ''Dan Cameron'' varieties were the most cultivated in Dosso (Gaya), and Tillaberi (Balleyara), respectively because of their high yield, big root and white flesh colour.Earliness varieties with big storage roots were the most appreciated, which explained the cultivation of ''Dan Maradi'' variety by about 50% of farmers (Harouna et al., 2015).Previous report (Harouna et al., 2015) did not mention ''Dan Cameron'' as a variety, which suggests that ''Dan Cameroon'' was not introduced at that time.In Ebonyi state, ''Oyorima was the most cultivated because of its high yield, and as the name implies ''plenty storage roots''."Butter Milk" and "Mother Delight" which were improved varieties were the most cultivated in Abia state, while "Pure water" was mostly cultivated in Kaduna state.The choice of ''Pure water'', could be explained by its less requirement of practice, drought tolerant, and it can be harvested twice, but it is less conservable compared to other varieties (that is, "Dakanta Zawara" variety which is better in conservation).The most cultivated varieties in both countries are either white or cream-fleshed except "Mother Delight" which is orange-fleshed.This study revealed that variety preferences depend on state and country.Similar result was reported that variety preferences in Tanzania vary by district and sex (Mulwa et al., 2021).

Sweetpotato preferred traits by farmers in Niger and Nigeria
There was highly significant difference (χ 2 = 394.86;p<0.001) in the choice of farmer in different traits among study areas.As confirmed by the Figures, yield was the most preferred trait following by white/cream coloured and drought tolerant cultivar.The choice of yield as first trait in both countries explained that farmer firstly focuses to high yield in choosing genotype.This confirmed the usual first breeding objective which is high yield.The study revealed five important traits viz.high yield, white/cream colour, drought tolerant, earliness, and resistance to pest and disease.Similar results were found where stated that yield, drought tolerant, maturity period, resistant to pathogens and pests, taste, nutritive value, multipurpose used, market demand and external appearance of leaves and roots constituted the criteria of smallholder farmers to adopt sweetpotato varieties in Sub-Sahara Africa (Low et al., 2017).Study in Niger discovered that the most preferred traits in Western part were earliness, taste, root size and resistant to pests and  (Harouna et al., 2015).Other researchers in Tanzania reported the first three preferred agronomic traits were yield, drought tolerant and pest and disease resistant (Ngailo et al., 2016;Filson et al., 2018).In Rwanda, the selection of cultivar by farmers is tightly linked to farmers' preferred traits cultivar and this cultivar should be high yield, early maturity and drought tolerant (Rukundo et al., 2015).
The drought tolerant trait as 3rd preferred trait in Niger could be explained by the production of sweetpotato under irrigation (65.55%).Therefore, farmers need to save time and energy for other works as well as fuel money which is expensive in Niger (1 litre at 0.98 US Dollar).Such kind of variety can be highly accepted by farmer.Earliness as 3 rd trait in Nigeria could be explained by the high percentage of the production of sweetpotato under rain (92.22%).Thus, earliness genotype can be easily accepted in Nigeria since it can escape drought to complete its cycle before the end of rain (Levitt, 2012).Resistance to pests and disease is due to the influence of these enemies in the productivity.In fact, sweetpotato weevil is the first pest in Niger (Doumma et al., 2008), and in Southern Nigeria (Uwaidem et al., 2018) with 61.11 and 33.33%, respectively.Orange fleshed mentioned in Abia state can be explained by the membership of the producers to Sweetpotato Producers Association of Nigeria (SPAN).This was explained by their relationship with the NRCRI of Nigeria which can be easy to access to more benefit.In Kaduna, farmers mentioned ''easy to cultivate'' as trait because of their variety "Pure water" which is highly preferred and very easy to manage.Sweetpotato breeding programs should consider the preference of farmers in developing new varieties for easy adoption.

Sweetpotato preferred traits by traders and consumers in Niger and Nigeria
There was high significant difference (χ 2 = 82.38;p<0.01) in the choice of traders, and highly significant difference (χ 2 = 207.48;p<0.001) in the choice of consumers in different traits across both countries.Healthy/clean root, white flesh colour, and big size of storage root were the first 3 most significant preferred traits by traders and consumers in Niger and Nigeria as confirmed by the Figures.Traders' traits depend to consumers' preferred traits.Consumers were more attracted by white/cream colour due to the beauty and consistence when frying or boiling.For the mouth-feel of boiled roots, Afuape et al. (2021) reported that more than half of the respondents in Benue state (70%) and Abia state (52%) preferred hard boiled sweetpotato storage roots (roots with boiled white yam texture).This is related to high dry matter which Source: Author contains high carbohydrate.In contrast, in Tanzania consumers preferred sweetpotato with medium to large storage root size, purple skin colour high dry matter content, sweet taste and well-shaped roots (Mulwa et al., 2021).Staple sweetpotato types typically have white to cream flesh with dry weight contents ranging from 30-35% (la Bonte et al., 2000), while dessert sweetpotato types generally have cream to orange flesh with dry matter ranging from 17.7 to 26.3 % (Picha, 1987).Carbohydrate is the most constituent of dry matter in sweetpotato with up to 80-90% (Mcharo and La-Bonte, 2007).This could explain the less choice of orangefleshed which contains high beta-carotene, but with less dry matter.However, the choice of orange-fleshed sweetpotato in Abia state could be explained by their relationship with NRCRI of Nigeria, and their appurtenance as membership of sweetpotato producers' association of Nigeria (SPAN).The selection of new cultivars by urban consumers depends on sensory profiles, knowledge, level of promotion of the crop, and previous experiences of consumers on similar crops among others (Birol et al., 2015).The storage root is mainly starch.Cooking method and utilization form have a critical influence on taste and consumptive quality (Sugri et al., 2012).Cooking leads to the changes in physical, sensory and chemical characteristics of the final product (Fontes et al., 2011).However, low dry matter content like orange flesh types lose their cooking quality (mealiness) when cooked affecting textural characteristics.Frying enhances sensorial characteristics such as texture, flavour, smell, colour, as well as overall palatability (Sugri et al., 2012).

Conclusion
Sweetpotato is among staple food in South-East of Nigeria in difference with Niger.The study revealed that in Niger farmers preferred high yielding white flesh colour and drought tolerant varieties, while in Nigeria farmers desired high yielding white flesh colour and earliness varieties.Consumers preferred white flesh colour with large storage root size.However, in Niger consumers' preferred high sugar, but in Nigeria low sugar was preferred.All the varieties cultivated in Niger were landraces, and majority in Nigeria were landraces too.Therefore, there is urgent need of sweetpotato breeding program in Niger, and the breeding program should adjust to breeding cultivars with high yield, white-fleshed colour and tolerance to drought stress.It is also important for an integrated team for introducing new varieties with high nutritional value like orange fleshed sweetpotato (OFSP).

Figure 1 .
Figure 1.Gender attended participants per village during focus group discussion.Source: Author

Figure 3 .
Figure 3. Farmers' preferred traits across States of Niger and Nigeria.Source: Author

Figure 5 .
Figure 5. Sweetpotato trader preferred traits across states of Niger and Nigeria.Source: Author

Figure 7 .Figure 8 .
Figure 7. Sweetpotato consumer preferred traits across states of Niger and Nigeria.Source: Author

Table 1 .
List of villages where the study was conducted in Niger and Nigeria.
Source: Author

Table 2 .
Description of farmers' characteristics in Niger and Nigeria.

Table 4 .
Chi-square in sweetpotato farmer preferred traits across study areas.

Table 5 .
Chi-square in sweetpotato farmer preferred traits across study areas.
Source: Author in South-East Nigeria.