# Assessment of Production and Utilization Practices of Orange-Fleshed Sweet Potatoes (Ipomoea Batatas L.) in Sidama Region, Ethiopia

Authors: Miheret Hendebo; Ali Mohammed Ibrahim; Fekadu Gurmu; Hussien Mohammed Beshir
Journal: International Journal of Agronomy
 (2022)

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## Abstract

Sweet potato (Ipomoea batatas L.) is an important crop which ensures food security in developing countries. It can be harvested at any stage as needed, thereby providing a flexible source of food and income for rural families that are most vulnerable to crop failures and cash income fluctuations. The production and consumption of orange-fleshed sweet potatoes (OFSP) by smallholder farmers in the Sidama region of Southern Ethiopia were explored in this study to identify key problems and opportunities in OFSP production. A preliminary investigation and rudimentary data collection were used to gather data. The data were analyzed using descriptive statistics, multiple linear regression, and index grading. Based on the descriptive analysis, smallholder farmers have small landholdings of 0.51 ha per family. Farmers conserve their planting materials by leaving them in the field. This causes the materials to be extensively infested with diseases, insects, and other vertebrate pests. Farmers (54.4%) do not apply inorganic fertilizersassuming that it stimulates more vegetative growth and results in tasteless storage roots. The continuous cultivation of OFSP without fertilizer application results in nutrient depletion and reduced yield. Further, the production and utilization of OFSP in the Sidama region is constrained by factors such as diseases, lack of storage facilities, lack of planting materials, drought, insect pests, low market price, and shortage of money to purchase inputs. According to the index ranking, drought, shortage of planting material, diseases, and insect pests were the most important. Combinations of social, ecological, and economic factors limit the production of sweet potatoes and therefore, a stronger extension system on agronomic practices and credit system should be made accessible to the farmers.


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## Body

## 1. Introduction

Sweet potato (Ipomoea batatas L.) is a crucial food security crop for millions of people in Sub-Saharan Africa and Asia. The crop is among the world's most important crops, ranking fifth and seventh in production in Africa and the World, respectively [1–3]. It is mainly grown for human food and animal feed. It produces carbohydrate-rich storage roots with a substantial amount of vitamins A, B complex, C, and E, as well as minerals including calcium, potassium, and iron. According to Zhang et al. [4] and Gichuki et al. [5], Central America is considered the primary center of diversity of sweet potatoes based on molecular markers study and most likely the center of origin since the highest diversity was found in this region. However, in Sub-Saharan Africa, the majority of sweet potatoes are white-fleshed which are poor yielding (6 t·ha−1) and deficient in beta-carotene [6]. Sweet potato has a wide range of use and benefits, among them, chipped and milled into flour for making snakes and baby foods and boiled and eaten as food for families [7]. Orange-flesh sweet potato (OFSP) is rich in pro-vitamin A, which contributes to normal eyesight, healthy skin and mucous membranes, healthy cell growth, reproduction, and immunity to diseases such as malaria, measles, and respiratory diseases [8].Sweet potatoes can be harvested in piecemeal as needed as a food security crop, thus providing a variable source of food and income to rural people who are prone to crop failure. There are some cultivars with a short maturing period of 3 to 5 months. The crop is drought tolerant and has a wider ecological adaption [9]. In 2017, the total production of sweet potatoes was 112.8 million tons in around 115 countries, with China being the leading producer, followed by Nigeria and Tanzania [10]. Most of the world’s sweet potato production comes from developing countries [11].Sweet potato is commonly produced in Ethiopia by smallholder farmers with limited land, manpower, and capital in the south, southwestern, and eastern regions. Ethiopia is among the world's largest producers of sweet potatoes. Sweet potatoes occupied roughly 53,499 hectares of land, with an annual production of 1.85 million tons during the main production season only [12]. Sweet potato is chiefly produced in Southern Nations, Nationalities, and Peoples’, Sidama and Oromia regions of Ethiopia [13] with a trend of expansion in other regions. However, the average yield is very low at about 8 t·ha−1 compared to the potential yield of 30–73 t·ha−1 [14, 15].Sweet potato is grown and primarily eaten fresh in Ethiopia.Because of their high-carotene (provitamin A) content, the need to promote OFSP cultivars is critically important[13, 16]. Although sweet potatoes have many potential uses and benefits, its yield in many areas of Ethiopia is below the potential yield of 30–73 t·ha−1 due to abiotic, biotic, and socioeconomic constraints before and after harvest. The biotic stresses include diseases, insect pests, and weeds, whereas the abiotic factors are drought, heat, and low soil fertility [17, 18]. Constraints related to socioeconomic and quality attributes include unavailability of improved varieties, poor planting material, the low β-carotene content in the white-fleshed sweet potatoes, and a low dry matter content (DMC) in the OFSP varieties that are currently available [14, 16, 17, 19]. Poor postharvest handling techniques are among the key factors that reduce the quality and value of the crop. Site-specific information is lacking on the production management of OFSP in the study area. Consequently, evaluating OFSP production and its utilization is critically important to identify the main challenges and opportunities for sustainable OFSP production. Therefore, it is imperative to assess production and utilization practices of OFSP under smallholder farmers in Sidama region to elucidate and document major constraints of production of the OFSP.


## 2. Materials and Methods

### 2.1. Site Descriptions

During the 2019/2020 growing season, the study was carried out in Hawassa Zuria and Boricha districts of the Sidama region. According to the 2014 SNNPRS-BOFED [20], the Sidama region has a population of 3, 677, 370 people. The region is in the country's central-eastern corner, bordered on the north, east, and southeast by Oromia, the south by Gedeo Zone, and the west by Wolayita Zone. The region is located between 5′ 45″ and 6′ 45″ north latitude and 38′ and 39′ east longitude. The region's overall area is 6981.9 km2 [21]. Maize, coffee, enset, sweet potatoes, chat, and fruits are among the major crops produced in the study sites. The region is located between 1500 and 2500 meters above sea level, with an average annual rainfall of between 1200 and 1599 mm and average annual temperatures ranging from 15 to 19.9 degrees Celsius.


### 2.2. Techniques for Sampling and Sample Size

The study was carried out in four kebeles from two rural districts where sweet potato is substantially produced. Samples for the investigation were taken from the population of family heads, both men and women. Two kebeles in Hawassa Zuria rural district, namely Jarra dadoo and Doyo otolcho, and two kebeles in Boricha rural district, namely Aldaad deda and Hanja cafaa, were chosen using a purposive sampling approach (Figure1). The number of farmers (n) in each kebele was used to compute the sample size using [22](1)n=N1+Ne2,where n is the sample size, N is the population size, and e is the precision level (0.05).Figure 1
Total number of kebele households (N), number of sampled households (n), and the proportion of sampled households (C).HouseholdHeads were chosen using a systematic selection procedure that divided N byn (N/n = i) and every ith head of the home was chosen from a list at the kebele level, commencing with the first name of the head household. The sampling procedure is illustrated in Figure 1. The first household was selected using a lottery approach from the i ranges. The percent of the sampled population (C) was calculated [23].(2)C=nN×100,where n is the number of farmers chosen and N denotes the total number of farmers in a district.


### 2.3. Data Management and Statistical Analysis

A predesigned questionnaire was used to obtain primary data in two stages. First, a prelude assessment was required to obtain general knowledge about the kebeles, as well as to adjust and forward the study objectives to the kebele organization. A list of relevant criteria and questions was utilized to lead the talks with the center groups and key informants throughout the prelude assessment. Ten to fifteen members from each kebele were interviewed to ensure reliability. Pretesting was designed to identify any inadequacies and assist in making changes to a few questions before the actual data gathering. Thereafter, basic data on household demographics, production familiarity, production effectiveness, and proper production use were collected (better variety sources and assortments, option intervals, manipulation of soil fertility, pest management methods, postharvest management actions, and supervision OFSP production and consumption by gender). During data collection, the observation method was also applied. This involved recording observed facts on what happened in the field, OFSP storage, the site’s general appearance, and reference during data analysis.The Statistical Package for the Social Sciences was used to analyze the data (SPSS, version 20). To summarize and organize the research data, descriptive statistics such as percentage, frequency, and mean were used. The effect of each variable on the productivity of OFSP under smallholder farmers at the study site was investigated using multiple linear regression analysis with average yield (t ha−1) as a dependent trait (Y) and other studied variables as independent variables (X). In addition, the main factors affecting sweet potato production were ranked using an index ranking system based on the formula: Index = sum of (8X number of household heads ranked first + 7X number of household heads ranked second + 6X number of household heads ranked third + 5X number of household heads ranked fourth + 4X number of household heads ranked fifth + 3X number of household heads ranked sixth + 2X number of household heads ranked seventh + 1X number of household heads ranked eighth for each constraint divided by the sum of (8X Total number of household heads rated first + 7X Total number of household heads rated second + 6X Total number of household heads rated third + 5X Total number of household heads rated fourth + 4X Total number of household heads rated fifth + 3X Total number of household heads rated sixth + 2X Total number of household heads rated seventh + 1X Total number of household heads rated eighth) for all constraints mentioned.


## 2.1. Site Descriptions

During the 2019/2020 growing season, the study was carried out in Hawassa Zuria and Boricha districts of the Sidama region. According to the 2014 SNNPRS-BOFED [20], the Sidama region has a population of 3, 677, 370 people. The region is in the country's central-eastern corner, bordered on the north, east, and southeast by Oromia, the south by Gedeo Zone, and the west by Wolayita Zone. The region is located between 5′ 45″ and 6′ 45″ north latitude and 38′ and 39′ east longitude. The region's overall area is 6981.9 km2 [21]. Maize, coffee, enset, sweet potatoes, chat, and fruits are among the major crops produced in the study sites. The region is located between 1500 and 2500 meters above sea level, with an average annual rainfall of between 1200 and 1599 mm and average annual temperatures ranging from 15 to 19.9 degrees Celsius.


## 2.2. Techniques for Sampling and Sample Size

The study was carried out in four kebeles from two rural districts where sweet potato is substantially produced. Samples for the investigation were taken from the population of family heads, both men and women. Two kebeles in Hawassa Zuria rural district, namely Jarra dadoo and Doyo otolcho, and two kebeles in Boricha rural district, namely Aldaad deda and Hanja cafaa, were chosen using a purposive sampling approach (Figure1). The number of farmers (n) in each kebele was used to compute the sample size using [22](1)n=N1+Ne2,where n is the sample size, N is the population size, and e is the precision level (0.05).Figure 1
Total number of kebele households (N), number of sampled households (n), and the proportion of sampled households (C).HouseholdHeads were chosen using a systematic selection procedure that divided N byn (N/n = i) and every ith head of the home was chosen from a list at the kebele level, commencing with the first name of the head household. The sampling procedure is illustrated in Figure 1. The first household was selected using a lottery approach from the i ranges. The percent of the sampled population (C) was calculated [23].(2)C=nN×100,where n is the number of farmers chosen and N denotes the total number of farmers in a district.


## 2.3. Data Management and Statistical Analysis

A predesigned questionnaire was used to obtain primary data in two stages. First, a prelude assessment was required to obtain general knowledge about the kebeles, as well as to adjust and forward the study objectives to the kebele organization. A list of relevant criteria and questions was utilized to lead the talks with the center groups and key informants throughout the prelude assessment. Ten to fifteen members from each kebele were interviewed to ensure reliability. Pretesting was designed to identify any inadequacies and assist in making changes to a few questions before the actual data gathering. Thereafter, basic data on household demographics, production familiarity, production effectiveness, and proper production use were collected (better variety sources and assortments, option intervals, manipulation of soil fertility, pest management methods, postharvest management actions, and supervision OFSP production and consumption by gender). During data collection, the observation method was also applied. This involved recording observed facts on what happened in the field, OFSP storage, the site’s general appearance, and reference during data analysis.The Statistical Package for the Social Sciences was used to analyze the data (SPSS, version 20). To summarize and organize the research data, descriptive statistics such as percentage, frequency, and mean were used. The effect of each variable on the productivity of OFSP under smallholder farmers at the study site was investigated using multiple linear regression analysis with average yield (t ha−1) as a dependent trait (Y) and other studied variables as independent variables (X). In addition, the main factors affecting sweet potato production were ranked using an index ranking system based on the formula: Index = sum of (8X number of household heads ranked first + 7X number of household heads ranked second + 6X number of household heads ranked third + 5X number of household heads ranked fourth + 4X number of household heads ranked fifth + 3X number of household heads ranked sixth + 2X number of household heads ranked seventh + 1X number of household heads ranked eighth for each constraint divided by the sum of (8X Total number of household heads rated first + 7X Total number of household heads rated second + 6X Total number of household heads rated third + 5X Total number of household heads rated fourth + 4X Total number of household heads rated fifth + 3X Total number of household heads rated sixth + 2X Total number of household heads rated seventh + 1X Total number of household heads rated eighth) for all constraints mentioned.


## 3. Results and Discussion

### 3.1. Household Demographic Information

The majority of the family leaders interviewed (80.5%) were men, while the rest (19.5%) were female family heads (widowed or divorced) (Table1). Males are typically the family resource leaders, which is similar to other African countries. Our results agree with those reported by Ahmad et al. [24] in Nigeria where 71% of the respondents were men.Table 1
Socioeconomic characteristics of the respondents.
CharacteristicsFrequencyPercentageGender of household headMale29380.5Female7119.5Age of the household head15–65 years old24968.4>65 years old11531.6Education level of household headNo education12534.3Primary education20456.0Secondary education277.4Postsecondary education82.2Respondent’s family sizeFrequencyPercentMean standard deviationMinimumMaximumHawassa Zuria18951.94.6 ± 1.72.0010.00Boricha17548.15.7 ± 1.72.0011.00Total364100.05.1 ± 1.82.0011.00SD: standard deviation; HH: household.Approximately 68.4% of family respondents were in the active farming age group (15 to 65 years old), while 31.6% were elderly (>65 years old) (Table1). This indicates that this community has efficient and autonomous workers who are recognized to have the physical strength required for OFSP production. This result is consistent with the findings of Negasi et al. [25], who reported the active age group (15–65 years old) to be primarily involved in onion production in Ethiopia's rift valley regions. Similarly, Ahmad et al. [24] stated that most of the farmers are young people who are still strong and full of energy to make a meaningful impact on agricultural production. In Nigeria, Okoruwa and Ogundele [26] depicted that the average age of sweet potato farmers to be 42 years. The average household size of Hawassa-Zuria districts was ≈5, whereas that of Boricha was about 6 (Table 1). This result suggests that there is a sufficient supply of family labor in the study area. Similar to this study, Simonyan and Obiakor [27] reported that the majority of rural dwellers had families with more than five members. Several authors have attributed the growth of family size to easily finishing family agricultural tasks in time due to the division of responsibilities among family members [24, 28]. According to Okoye et al. [29] and Udensi et al. [30], relatively high family size is more likely to supply more labor for farm operations such as weed management and fertilizer application. However, Simonyan and Obiakor [27] reported that a large household size does not ensure higher labor efficiency since it is comprised of mostly children who go to school during working hours. Results from this study revealed that most of the farmers (56%) had completed primary school (Table 1), which was higher than the national average adult literacy rate (46.7%) [31]. This indicates that the majority of the farmers had a reasonably high degree of education and were familiar with fundamental farming practices. This is further supported by Doss [31], who stated that one of the factors that influence farmers' acceptance of agricultural technologies is their high literacy level. Farmers can make better sweet potato production operations as a result of high literacy levels using published materials such as booklets, leaflets, posters, and other items [32].


### 3.2. Production Experience

The mean number of years of farming experience of the farmers in the two districts was 21.5 (Table2). About 51.9% of the respondents have been planting sweet potatoes for the past more than 20 years. This result is similar to that of Gebru et al. [28] who found that the average farm experience of households in their study was more than 20 years. This result shows that the farmers are highly experienced in the cultivation of OFSP. The average farm size grown by each household was about 0.51 ha, with OFSP cultivation accounting for roughly 0.094 ha (19%). The higher number of years of farmers growing sweet potato implies a wealth of production knowledge which can be further improved and taught to other farmers to increase OFSP production in their farms.Table 2
Farming experience and land size of households.
ValuesFrequencyPercentageMean ± standard deviationMinimumMaximumHousehold head’s farm experience (year)Hawassa Zuria woreda18951.921.1 ± 7.68.0043Boricha woreda17548.121.9 ± 11.108.0046Total364100.021.5 ± 9.48.0046Total land size of household (ha)Hawassa Zuria woreda18951.91.0 ± 0.60.453.38Boricha woreda17548.10.8 ± 0.40.253.00Total364100.00.9 ± 0.50.253.38HH: household; SD: standard deviation.


### 3.3. Sweet Potato Varieties Grown by Farmers

The varieties currently grown most by smallholder farmers in the area include: Kulfo (65.7%) and Tulla (32.4%) (Table3). Studies have shown that Kulfo is the best variety in terms of marketable yield and other agronomic attributes [33]. This could be the main reason for its dominance in production in the study areas.Table 3
Sweet potato production management in the study site.
CharacteristicsFrequencyPercentageOrange-fleshed sweet potato cultivars were usedKulfo23965.7Tulla11832.4Alamura71.9Sweet potato planting material conservation methodPlant on soil embankment256.9Plant after harvest133.6Left on-farm30082.4Do not conserve267.1Use of recommended spacingYes28578.3No7921.7Types of fertilizer they useOrganic10829.7Inorganic4712.9They did not use any fertilizer19854.4The integration of both113.0Types of beds they useRidges24667.6Flats11832.4Land-use typePure stand30283.0Intercropping6217.0Important orange-fleshed sweet potato pests in the areaDisease11331.0Insect21158.0Weed4011.0Disease control strategies they usedCultural184.9Chemical31285.7Both318.5None30.8


#### 3.3.1. Method for Preserving Sweet Potato Planting Material

The majority of farmers (82.4%) kept planting materials in situ in the field, while the rest utilized different methods (Table3). These methods result in materials being extensively infected with viruses and other diseases, as well as insect and vertebrate pests. This could explain the significant drop in productivity, quality roots, and biomass compared to the preceding crop. Of the 318 sweet potato samples of different varieties that were collected and tested for virus, 62.8% were affected by sweet potato feathery mottle virus infection [34]. The virus incidences were highest (86%) and lowest (32%), respectively, in samples collected from Humbo and Sodo Zuria District of the Wolaita zone [34]. These findings are consistent with those of Namandaa et al. [35], who found that sweet potato planting materials obtained from waterlogged agricultural plots were infected with virus, and that acquiring it from volunteer plants after rains caused planting delays. Planting materials for sweet potatoes were mostly recycled from previous crops since just a tiny percentage of farmers utilized certified planting materials. This indicates that either the majority of farmers are unaware of the need of utilizing clean, certified planting materials or that they do not have access to improved planting materials. This could explain why sweet potato yields are still poor. In a review of sweet potato production constriantsassesments conducted across numerous nations, Fuglie [36] reported the lack of clean and sufficient planting materials was a prominent barrier in most African countries.The majority of farmers (78.3%) adopted appropriate spacing for OFSP production (Table3), demonstrating that they chose intensive farming to maximize the yield of their limited area. According to Adubasim et al. [37], the highest root yield was achieved at a plant spacing of 60 cm × 30 cm. The yield values under these plant spacing exceed the African average root yield of sweet potatoes, which is estimated at 7.0 t ha−1 FAOSTAT [38]. This implies that farmers who plant in rows at such specific dense spacing could have higher yields than the African average yield and those who use arbitrary plant spacing. Similar to our observation, Sen et al. [39] reported higher sweet potato tuber yields of 20 t·ha−1 where the vine cuttings were closely planted.In this survey, nearly 30% of smallholder farmers (29.7%) preferred to utilize manure over artificial fertilizers like DAP and urea, whereas a considerable number of farmers (54.4%) did not use fertilizer. According to the farmers, inorganic fertilizers support extensive vegetative growth resulting in tasteless storage roots. Some farmers claimed that sweet potato does not require applied soil nutrients and can thrive on poor soils. This result agrees with those of Stephan et al. [40], who report farmers do not utilize fertilizers in the production of sweet potatoes. The authors suggested that although the reasons for not using fertilizer may be far from reality, more studies are needed in order to design a fertilization approach that could increase sweet potato yields while maintaining root quality. The higher cost of inorganic fertilizer is one of the major reasons for the none or low use not only in sweet potato cultivation but also in other crops.The sweet potato was grown on ridges by 68% of the farmers interviewed, similarly, Githunguri et al. [41] found that most farmers employed ridges to grow sweet potatoes, presumably because this planting method produces higher yields than other methods. The study revealed that 83% of farmers grew sweet potatoes under monocropping and 17% under intercropping with other crops (Table 3). According to Benjamin et al. [42], the most preferred strategy was mixed cropping with other food crops, which means farmers prefer growing crops in a mixture to reduce the risk of harvest failure in the event of drought or other unanticipated constraints. However, in the research area, a high number of farmers planted sweet potatoes as a monoculture, indicating that those farmers’ perceptions of the crop's worth are improving. Insects were regarded as a major pest by the majority of farmers (58%) in this study, followed by disease (31%), while weeds were identified as a major limitation by 11% of farmers. Adane [43] observed viral incidences of up to 80% and 100% in samples taken from farmers' fields and germplasm collection locations, respectively. One or more viruses were found in those samples according to Benjamin et al. [42]. Similarly, Tesfaye et al. [44] recorded viral occurrences of 75% in farmer’s fields and 100% in experimental stations in their study. In the same study, the authors recommended that cultural practice was the cheapest control strategy for resource-poor farmers. However, data obtained in this study showed that a number of farmers were unaware of sweet potato pests and diseases. This indicates that farmers must be educated about sweet potato diseases, pests, and other cultural practices. Degu et al. [45] suggested the necessity to increase farmers’ ability to adopt and maintain innovative varieties and technology.The unavailability of disease- and pest-free sweet potato planting materials and lack of resistant types appear to be the key pest and disease control difficulties. To boost sweet potato production, it is critical to find resistant varieties and promote the production of clean seeds. Sweet potato virus disease has also been identified as a key barrier to sweet potato production in Ethiopia as reported by Adane [43]. Some farmers suggested utilizing clean planting materials as a coping strategy to boost output. This indicates that farmers are open to adopting research innovations aimed at increasing sweet potato yields.


### 3.4. Production and Postharvest Management of Sweet Potato in the Study Site

#### 3.4.1. Orange-Fleshed Sweet Potato Yields

The majority of respondents (48.1%) obtained on-farm yields of sweet potato ranging from 6.0 to 7.5 t·ha−1, which is lower than the average yield of 10 t·ha−1 at the farmer level in Ethiopia (Table 4). According to Zhang et al. [4], the average yield of sweet potato in Ethiopia is about 8 t·ha−1 compared to 18 t ha−1 in Asian countries. This suggests that production constraints must be addressed in order to increase sweet potato yield in Ethiopia. In Ethiopia, sweet potato has a potential yield of 50 to 60 t·ha−1, however, farmers obtain about 6 to 8 t·ha−1 [45]. A number of variables contribute to the yield gap, including a lack of high-yielding, virus-free planting materials, lack of effective insect pest management, and absence of the utilization of enhanced crop management alternatives. Data concerning postharvest management show that 69.5% of the respondents have an understanding of the importance of sweet potato storage (Table 4). After physiological maturity, most (89.8%) of smallholder farmers store OFSP roots by leaving them in the soil of the farm (in situ) to store and use them when the need arises, which exposes the roots to various diseases and pest attacks. According to Gurmu et al. [46], most of the respondents (98.4%) stored the storage roots in situ in the soil, harvesting them when they were needed for food. The major constraints that affect the storage of sweet potato roots in situ leaving them in the soil were described by the respondents as heat (31.6%), insect pests (mainly weevil) (25.6%), diseases (21.8%), and rodents (20.9%) [47]. A similar trend was reported in Uganda where farmers practiced harvesting sweet potatoes in a piecemeal manner by storing them in pits [48].Table 4
Yield and postharvest management of orange-fleshed sweet potatoes.
CharacteristicsFrequencyPercentYield (t·ha−1)<613837.96–7.517548.17.5–10349.3>10174.7Awareness on sweet potato storageYes25369.5No11130.5Place of storageIn the soil113.0In the bright room102.7Leaving in the field32789.8In modified diffused light storage (DLS)10.3Not stored154.1Preference to growWFSP10729.4OFSP6618.1Both19152.5WFSP, white fleshed sweet potato; OFSP, orange fleshed sweet potato.The respondent farmers believed that some rain was favorable for prolonging the lives of the storage roots in the soil, which was an unexpected observation [46]. As a result, postharvest limitations have remained a major constraint in Ethiopia for agricultural products in general and horticulture production. In the study site, 52.5% of respondents grow both white-fleshed sweet potatoes (WFSP) and orange-fleshed sweet potatoes (OFSP), whereas 29.4% grow WFSP and 18.1 grow OFSP types (Table 4). This preference could have arisen as a result of the cultivar's genetic dissimilarity. Similarly, Gurmu et al. [46] reported that 78.3%, 83.1%, and 67.7% of the respondents were familiar with OFSPs in Sidama, Wolayta, and Gamo Gofa, respectively. These authors indicated that, given a chance to choose and grow among the WFSP and OFSP, 54.7% responded to grow both WFSP and OFSP, while 27.6% indicated WFSP and 17.8% preferred OFSP only. Among the respondents who were aware of OFSPs, 77.7% disliked the varieties due to the inherent wateriness on cooking (low root dry matter content) and associated poor taste [46].


### 3.5. Major Causes and Constraints That Influence Production Management of Orange-Fleshed Sweet Potatoes

The farmers' ability to produce and consume OFSP in the assessment site was limited due to a variety of factors. According to the index ranking, drought, lack of planting material, diseases, and insect pests were the most significant (first to the fourth rank) constraints affecting the production of OFSP in the study site (Table5). This result is consistent with those of Emana and Gebremedhin [49] who reported pests, drought, a scarcity of desirable seed varieties, and the cost of gasoline for driving water for irrigation and fertilizer restrictions, as the main horticulture production restraints in Ethiopia. Similar to this study, Negasi et al. [25] also reported the unavailability of storage facilities as a major problem affecting onion production. Gurmu et al. [46] reported heat and drought at 21.6%, shortage of planting materials (20.1%), shortage of land (15.7%), diseases (10.0%), insect pests (9.4%), a lack of draft power (oxen, donkeys, horses, and mules) (8.1%), shortage of money to cover input costs (7.9%), a lack of labor (5.1%), and weeds (2.0%) as the major sweet potato production constraints in Ethiopia. Abigail et al. [50] reported the shortage of labor as the most prominent limitation affecting sweet potato production in Nigeria. The authors attribute the inefficacies in labor to be due to the reliance on hoe and cutlass in Nigeria. However, a large number of able-bodied people in most parts of the country have abandoned farming in favor of a motorbike transport industry, which pays a somewhat consistent daily wage, causing a labor shortage. According to the farmers, the second major productivity constraint on sweet potato farms is the lack of access to updated technologies. For example, most farmers relied on basic equipment such as a cutlass and a hoe with a poor adoption rate of the improved vine for planting. Similar to this study, Abigail et al. [50] reported poor yield to be linked to the usage of rudimentary equipment and the sort of locally grown vines [50]. Okonya et al. [51] found insect infestations as the fourth ranked among the obstacles in the production process. The fifth major barrier in sweet potato production was the lack of finance. Most formal credit sources and certain informal credit sources made it difficult for farmers to meet the requirements for obtaining a loan [52]. Diseases are the sixth major barrier in sweet potato production and affect crop yield. Bad roads, poor output prices, lack of processing facilities, and expensive transportation costs were also noted as factors affecting production.Table 5
The area’s major orange-fleshed sweet potato production constraints.
ConstraintPrioritization1st2nd3rd4th5th6th7th8thIndexRankShortage of planting materials38108432200.01492Shortage of land2454100000.02945Disease30103221100.02043Drought562313962200.00901Insect pest14106321110.02634Storage problem1653210000.03706Low market price932221110.04767Shortage of money to purchase inputs743111000.05888Total19470422417872Results of the multiple linear regressions show that the independent variables utilized in the model clarify differences in OFSP production (Table6). The coefficients were considerably different from zero, resulting in significant F-values (15.8) and R2 principles of 15%, which demonstrate the model’s goodness of fit. The predominance of market, storage, insect pest, and planting materials remained in the equation as significant variables. The market and storage factors positively significantly (p=0.001) affected OFSP, whereas the insect pest and planting materials negatively significantly (p=0.001) affected the OFSP yield (Table 6).Table 6
Multiple regression outcomes for causes affecting the yield of OFSP.
Independent charactersRegression coefficientsSEt-valuep valueMarket0.3190.0823.902∗∗∗0.000Storage0.2820.0684.134∗∗∗0.000Insect pest-0.2230.062−3.609∗∗∗0.000Planting materials-0.1610.051−3.122∗∗0.002Constant1.1280.2973.803∗∗∗0.000Number observation364R20.150F-value15.803∗∗∗∗∗Significant at 99% level of significance.


### 3.6. Major Consumption and Utilization Method of Orange-Fleshed Sweet Potatoes in the Area

#### 3.6.1. Frequency of Eating OFSP

It was shown that the majority of the respondents (44.5%) commonly ate OFSP once in a week, while 32.7% and 15.7% of the respondents consumed it once a month and daily, respectively. Only 7.1% ate OFSP twice a day (Table 7).Table 7
Method of consumption and utilization of orange-fleshed sweet potato in the area.
VariablesFrequencyPercentageHow often do you eat sweet potatoTwice a day267.1Daily5715.7Once a week16244.5Once a month11932.7Common processing method of OFSP sweet potato products for consumption in your householdBoiling28578.3Steaming369.9Roasting4311.8Which products are you familiar withWhite-fleshed sweet potato23765.1Orange-fleshed sweet potato13734.9Are you aware that OFSP has a high vitamin A contentNo5114.0Yes31386.0You promoted the consumption of OFSP by your youngsters and pregnant ladiesNo4412.1Yes32087.9According to Nungo [53], over 80% of the sweet potatoes produced in SSA is consumed fresh. When in season, it is a secondary staple in most other rural areas, eaten 2–4 times per week with breakfast frequently served with boiled or steamed roots. Sweet potato is not commonly used as a morning or snack dish in metropolitan diets. There is a common cultural perception in Africa that sweet potato is a “sweet” food that is best suited for women and children [54]. Adults prefer high-starch types of food while youngsters prefer softer, lower-starch roots, according to Low et al. [55].


### 3.7. Common Processing Method of OFSP Sweet Potato Products for Consumption in the Household

Most respondents (78.3%) consumed fresh OFSP after boiling or processed for other purposes, while 11.8% and 9.9% consumed roasted and steaming, respectively (Table7). This result is consistent with those of Fawole [56] who reported boiling and roasted sweet potato processed forms are the most consumed products. However, alternative use methods such as manufacturing chips and combining sweet potato flour with wheat flour for goods like chapatti, Mandazi, or porridge have not yet been fully developed in African countries [57].


### 3.8. OFSP Product Familiar at Household Level

The most prevalent sweet potato products at the household level were from WFSP (65.1%) and OFSP (34.9%). The low percentage of OFSP varieties in comparison to WFSP types could be attributable to their low dry matter content (DMC). This is consistent with the findings of Gurmu et al. [13], who found that farmers and consumers dislike OFSP cultivars due to their low storage root DMC. WFSP cultivars have high storage roots which are preferred by farmers. Currently, OFSP types are frequently promoted due to their high-carotene (provitamin A) content, similar to the findings of Tofu et al. [16] and Gurmu et al. [13]. The root DMC of the OFSP cultivars is low, which has a direct impact on taste and influences its adoption. According to the results of several authors, varieties with high storage root DMC are preferred by most African households since this trait is correlated with a good taste [16, 17, 19, 58]. Therefore, the WFSP varieties are more accepted by farmers than the OFSP varieties due to their high DMC. However, the problem of low root DMC can be reduced through the crossing and development of OFSP varieties with high root DMC of WFSP varieties in Ethiopia [59, 60].The majority of farmers (86%) said they were aware that OFSP is high in vitamin A. Meanwhile, 14% stated that they were not aware that OFSP is high in vitamin A.Awared respondants preferred sweet potatoes over vitamin-fortified foods since it was readily available, relatively inexpensive, and simple to prepare [61]. In the present study, farmers who knew about the nutritional value of OFSP were nearly three times more likely to use it than those who did not. This is consistent with a prior expectations and knowledge of OFSP’s nutritional value which is anticipated to encourage its use, particularly for home use. This indicates that any program that includes effective instruction on the nutritional advantages of OFSP is more likely to be adopted.


### 3.9. Sensitivity of Children or Pregnant Women to Consuming OFSP

About 87.9% of the respondents encouraged their youngsters and pregnant ladies to consume OFSP and only 12.1% were not encouraged. This is attributed to the nonawareness of vitamin A content of OFSP. Vitamin A deficiency is a severe health problem in Sub-Saharan Africa affecting young children aged from 0 to 6 years and pregnant women. Meanwhile, the orange-flesh variety is high in beta-carotene, which the body uses to make vitamin A. Vitamin A is a wonderful source of energy and key nutritive components, and it can help rural inhabitants improve their nutritious status [62].


## 3.1. Household Demographic Information

The majority of the family leaders interviewed (80.5%) were men, while the rest (19.5%) were female family heads (widowed or divorced) (Table1). Males are typically the family resource leaders, which is similar to other African countries. Our results agree with those reported by Ahmad et al. [24] in Nigeria where 71% of the respondents were men.Table 1
Socioeconomic characteristics of the respondents.
CharacteristicsFrequencyPercentageGender of household headMale29380.5Female7119.5Age of the household head15–65 years old24968.4>65 years old11531.6Education level of household headNo education12534.3Primary education20456.0Secondary education277.4Postsecondary education82.2Respondent’s family sizeFrequencyPercentMean standard deviationMinimumMaximumHawassa Zuria18951.94.6 ± 1.72.0010.00Boricha17548.15.7 ± 1.72.0011.00Total364100.05.1 ± 1.82.0011.00SD: standard deviation; HH: household.Approximately 68.4% of family respondents were in the active farming age group (15 to 65 years old), while 31.6% were elderly (>65 years old) (Table1). This indicates that this community has efficient and autonomous workers who are recognized to have the physical strength required for OFSP production. This result is consistent with the findings of Negasi et al. [25], who reported the active age group (15–65 years old) to be primarily involved in onion production in Ethiopia's rift valley regions. Similarly, Ahmad et al. [24] stated that most of the farmers are young people who are still strong and full of energy to make a meaningful impact on agricultural production. In Nigeria, Okoruwa and Ogundele [26] depicted that the average age of sweet potato farmers to be 42 years. The average household size of Hawassa-Zuria districts was ≈5, whereas that of Boricha was about 6 (Table 1). This result suggests that there is a sufficient supply of family labor in the study area. Similar to this study, Simonyan and Obiakor [27] reported that the majority of rural dwellers had families with more than five members. Several authors have attributed the growth of family size to easily finishing family agricultural tasks in time due to the division of responsibilities among family members [24, 28]. According to Okoye et al. [29] and Udensi et al. [30], relatively high family size is more likely to supply more labor for farm operations such as weed management and fertilizer application. However, Simonyan and Obiakor [27] reported that a large household size does not ensure higher labor efficiency since it is comprised of mostly children who go to school during working hours. Results from this study revealed that most of the farmers (56%) had completed primary school (Table 1), which was higher than the national average adult literacy rate (46.7%) [31]. This indicates that the majority of the farmers had a reasonably high degree of education and were familiar with fundamental farming practices. This is further supported by Doss [31], who stated that one of the factors that influence farmers' acceptance of agricultural technologies is their high literacy level. Farmers can make better sweet potato production operations as a result of high literacy levels using published materials such as booklets, leaflets, posters, and other items [32].


## 3.2. Production Experience

The mean number of years of farming experience of the farmers in the two districts was 21.5 (Table2). About 51.9% of the respondents have been planting sweet potatoes for the past more than 20 years. This result is similar to that of Gebru et al. [28] who found that the average farm experience of households in their study was more than 20 years. This result shows that the farmers are highly experienced in the cultivation of OFSP. The average farm size grown by each household was about 0.51 ha, with OFSP cultivation accounting for roughly 0.094 ha (19%). The higher number of years of farmers growing sweet potato implies a wealth of production knowledge which can be further improved and taught to other farmers to increase OFSP production in their farms.Table 2
Farming experience and land size of households.
ValuesFrequencyPercentageMean ± standard deviationMinimumMaximumHousehold head’s farm experience (year)Hawassa Zuria woreda18951.921.1 ± 7.68.0043Boricha woreda17548.121.9 ± 11.108.0046Total364100.021.5 ± 9.48.0046Total land size of household (ha)Hawassa Zuria woreda18951.91.0 ± 0.60.453.38Boricha woreda17548.10.8 ± 0.40.253.00Total364100.00.9 ± 0.50.253.38HH: household; SD: standard deviation.


## 3.3. Sweet Potato Varieties Grown by Farmers

The varieties currently grown most by smallholder farmers in the area include: Kulfo (65.7%) and Tulla (32.4%) (Table3). Studies have shown that Kulfo is the best variety in terms of marketable yield and other agronomic attributes [33]. This could be the main reason for its dominance in production in the study areas.Table 3
Sweet potato production management in the study site.
CharacteristicsFrequencyPercentageOrange-fleshed sweet potato cultivars were usedKulfo23965.7Tulla11832.4Alamura71.9Sweet potato planting material conservation methodPlant on soil embankment256.9Plant after harvest133.6Left on-farm30082.4Do not conserve267.1Use of recommended spacingYes28578.3No7921.7Types of fertilizer they useOrganic10829.7Inorganic4712.9They did not use any fertilizer19854.4The integration of both113.0Types of beds they useRidges24667.6Flats11832.4Land-use typePure stand30283.0Intercropping6217.0Important orange-fleshed sweet potato pests in the areaDisease11331.0Insect21158.0Weed4011.0Disease control strategies they usedCultural184.9Chemical31285.7Both318.5None30.8


### 3.3.1. Method for Preserving Sweet Potato Planting Material

The majority of farmers (82.4%) kept planting materials in situ in the field, while the rest utilized different methods (Table3). These methods result in materials being extensively infected with viruses and other diseases, as well as insect and vertebrate pests. This could explain the significant drop in productivity, quality roots, and biomass compared to the preceding crop. Of the 318 sweet potato samples of different varieties that were collected and tested for virus, 62.8% were affected by sweet potato feathery mottle virus infection [34]. The virus incidences were highest (86%) and lowest (32%), respectively, in samples collected from Humbo and Sodo Zuria District of the Wolaita zone [34]. These findings are consistent with those of Namandaa et al. [35], who found that sweet potato planting materials obtained from waterlogged agricultural plots were infected with virus, and that acquiring it from volunteer plants after rains caused planting delays. Planting materials for sweet potatoes were mostly recycled from previous crops since just a tiny percentage of farmers utilized certified planting materials. This indicates that either the majority of farmers are unaware of the need of utilizing clean, certified planting materials or that they do not have access to improved planting materials. This could explain why sweet potato yields are still poor. In a review of sweet potato production constriantsassesments conducted across numerous nations, Fuglie [36] reported the lack of clean and sufficient planting materials was a prominent barrier in most African countries.The majority of farmers (78.3%) adopted appropriate spacing for OFSP production (Table3), demonstrating that they chose intensive farming to maximize the yield of their limited area. According to Adubasim et al. [37], the highest root yield was achieved at a plant spacing of 60 cm × 30 cm. The yield values under these plant spacing exceed the African average root yield of sweet potatoes, which is estimated at 7.0 t ha−1 FAOSTAT [38]. This implies that farmers who plant in rows at such specific dense spacing could have higher yields than the African average yield and those who use arbitrary plant spacing. Similar to our observation, Sen et al. [39] reported higher sweet potato tuber yields of 20 t·ha−1 where the vine cuttings were closely planted.In this survey, nearly 30% of smallholder farmers (29.7%) preferred to utilize manure over artificial fertilizers like DAP and urea, whereas a considerable number of farmers (54.4%) did not use fertilizer. According to the farmers, inorganic fertilizers support extensive vegetative growth resulting in tasteless storage roots. Some farmers claimed that sweet potato does not require applied soil nutrients and can thrive on poor soils. This result agrees with those of Stephan et al. [40], who report farmers do not utilize fertilizers in the production of sweet potatoes. The authors suggested that although the reasons for not using fertilizer may be far from reality, more studies are needed in order to design a fertilization approach that could increase sweet potato yields while maintaining root quality. The higher cost of inorganic fertilizer is one of the major reasons for the none or low use not only in sweet potato cultivation but also in other crops.The sweet potato was grown on ridges by 68% of the farmers interviewed, similarly, Githunguri et al. [41] found that most farmers employed ridges to grow sweet potatoes, presumably because this planting method produces higher yields than other methods. The study revealed that 83% of farmers grew sweet potatoes under monocropping and 17% under intercropping with other crops (Table 3). According to Benjamin et al. [42], the most preferred strategy was mixed cropping with other food crops, which means farmers prefer growing crops in a mixture to reduce the risk of harvest failure in the event of drought or other unanticipated constraints. However, in the research area, a high number of farmers planted sweet potatoes as a monoculture, indicating that those farmers’ perceptions of the crop's worth are improving. Insects were regarded as a major pest by the majority of farmers (58%) in this study, followed by disease (31%), while weeds were identified as a major limitation by 11% of farmers. Adane [43] observed viral incidences of up to 80% and 100% in samples taken from farmers' fields and germplasm collection locations, respectively. One or more viruses were found in those samples according to Benjamin et al. [42]. Similarly, Tesfaye et al. [44] recorded viral occurrences of 75% in farmer’s fields and 100% in experimental stations in their study. In the same study, the authors recommended that cultural practice was the cheapest control strategy for resource-poor farmers. However, data obtained in this study showed that a number of farmers were unaware of sweet potato pests and diseases. This indicates that farmers must be educated about sweet potato diseases, pests, and other cultural practices. Degu et al. [45] suggested the necessity to increase farmers’ ability to adopt and maintain innovative varieties and technology.The unavailability of disease- and pest-free sweet potato planting materials and lack of resistant types appear to be the key pest and disease control difficulties. To boost sweet potato production, it is critical to find resistant varieties and promote the production of clean seeds. Sweet potato virus disease has also been identified as a key barrier to sweet potato production in Ethiopia as reported by Adane [43]. Some farmers suggested utilizing clean planting materials as a coping strategy to boost output. This indicates that farmers are open to adopting research innovations aimed at increasing sweet potato yields.


## 3.3.1. Method for Preserving Sweet Potato Planting Material

The majority of farmers (82.4%) kept planting materials in situ in the field, while the rest utilized different methods (Table3). These methods result in materials being extensively infected with viruses and other diseases, as well as insect and vertebrate pests. This could explain the significant drop in productivity, quality roots, and biomass compared to the preceding crop. Of the 318 sweet potato samples of different varieties that were collected and tested for virus, 62.8% were affected by sweet potato feathery mottle virus infection [34]. The virus incidences were highest (86%) and lowest (32%), respectively, in samples collected from Humbo and Sodo Zuria District of the Wolaita zone [34]. These findings are consistent with those of Namandaa et al. [35], who found that sweet potato planting materials obtained from waterlogged agricultural plots were infected with virus, and that acquiring it from volunteer plants after rains caused planting delays. Planting materials for sweet potatoes were mostly recycled from previous crops since just a tiny percentage of farmers utilized certified planting materials. This indicates that either the majority of farmers are unaware of the need of utilizing clean, certified planting materials or that they do not have access to improved planting materials. This could explain why sweet potato yields are still poor. In a review of sweet potato production constriantsassesments conducted across numerous nations, Fuglie [36] reported the lack of clean and sufficient planting materials was a prominent barrier in most African countries.The majority of farmers (78.3%) adopted appropriate spacing for OFSP production (Table3), demonstrating that they chose intensive farming to maximize the yield of their limited area. According to Adubasim et al. [37], the highest root yield was achieved at a plant spacing of 60 cm × 30 cm. The yield values under these plant spacing exceed the African average root yield of sweet potatoes, which is estimated at 7.0 t ha−1 FAOSTAT [38]. This implies that farmers who plant in rows at such specific dense spacing could have higher yields than the African average yield and those who use arbitrary plant spacing. Similar to our observation, Sen et al. [39] reported higher sweet potato tuber yields of 20 t·ha−1 where the vine cuttings were closely planted.In this survey, nearly 30% of smallholder farmers (29.7%) preferred to utilize manure over artificial fertilizers like DAP and urea, whereas a considerable number of farmers (54.4%) did not use fertilizer. According to the farmers, inorganic fertilizers support extensive vegetative growth resulting in tasteless storage roots. Some farmers claimed that sweet potato does not require applied soil nutrients and can thrive on poor soils. This result agrees with those of Stephan et al. [40], who report farmers do not utilize fertilizers in the production of sweet potatoes. The authors suggested that although the reasons for not using fertilizer may be far from reality, more studies are needed in order to design a fertilization approach that could increase sweet potato yields while maintaining root quality. The higher cost of inorganic fertilizer is one of the major reasons for the none or low use not only in sweet potato cultivation but also in other crops.The sweet potato was grown on ridges by 68% of the farmers interviewed, similarly, Githunguri et al. [41] found that most farmers employed ridges to grow sweet potatoes, presumably because this planting method produces higher yields than other methods. The study revealed that 83% of farmers grew sweet potatoes under monocropping and 17% under intercropping with other crops (Table 3). According to Benjamin et al. [42], the most preferred strategy was mixed cropping with other food crops, which means farmers prefer growing crops in a mixture to reduce the risk of harvest failure in the event of drought or other unanticipated constraints. However, in the research area, a high number of farmers planted sweet potatoes as a monoculture, indicating that those farmers’ perceptions of the crop's worth are improving. Insects were regarded as a major pest by the majority of farmers (58%) in this study, followed by disease (31%), while weeds were identified as a major limitation by 11% of farmers. Adane [43] observed viral incidences of up to 80% and 100% in samples taken from farmers' fields and germplasm collection locations, respectively. One or more viruses were found in those samples according to Benjamin et al. [42]. Similarly, Tesfaye et al. [44] recorded viral occurrences of 75% in farmer’s fields and 100% in experimental stations in their study. In the same study, the authors recommended that cultural practice was the cheapest control strategy for resource-poor farmers. However, data obtained in this study showed that a number of farmers were unaware of sweet potato pests and diseases. This indicates that farmers must be educated about sweet potato diseases, pests, and other cultural practices. Degu et al. [45] suggested the necessity to increase farmers’ ability to adopt and maintain innovative varieties and technology.The unavailability of disease- and pest-free sweet potato planting materials and lack of resistant types appear to be the key pest and disease control difficulties. To boost sweet potato production, it is critical to find resistant varieties and promote the production of clean seeds. Sweet potato virus disease has also been identified as a key barrier to sweet potato production in Ethiopia as reported by Adane [43]. Some farmers suggested utilizing clean planting materials as a coping strategy to boost output. This indicates that farmers are open to adopting research innovations aimed at increasing sweet potato yields.


## 3.4. Production and Postharvest Management of Sweet Potato in the Study Site

### 3.4.1. Orange-Fleshed Sweet Potato Yields

The majority of respondents (48.1%) obtained on-farm yields of sweet potato ranging from 6.0 to 7.5 t·ha−1, which is lower than the average yield of 10 t·ha−1 at the farmer level in Ethiopia (Table 4). According to Zhang et al. [4], the average yield of sweet potato in Ethiopia is about 8 t·ha−1 compared to 18 t ha−1 in Asian countries. This suggests that production constraints must be addressed in order to increase sweet potato yield in Ethiopia. In Ethiopia, sweet potato has a potential yield of 50 to 60 t·ha−1, however, farmers obtain about 6 to 8 t·ha−1 [45]. A number of variables contribute to the yield gap, including a lack of high-yielding, virus-free planting materials, lack of effective insect pest management, and absence of the utilization of enhanced crop management alternatives. Data concerning postharvest management show that 69.5% of the respondents have an understanding of the importance of sweet potato storage (Table 4). After physiological maturity, most (89.8%) of smallholder farmers store OFSP roots by leaving them in the soil of the farm (in situ) to store and use them when the need arises, which exposes the roots to various diseases and pest attacks. According to Gurmu et al. [46], most of the respondents (98.4%) stored the storage roots in situ in the soil, harvesting them when they were needed for food. The major constraints that affect the storage of sweet potato roots in situ leaving them in the soil were described by the respondents as heat (31.6%), insect pests (mainly weevil) (25.6%), diseases (21.8%), and rodents (20.9%) [47]. A similar trend was reported in Uganda where farmers practiced harvesting sweet potatoes in a piecemeal manner by storing them in pits [48].Table 4
Yield and postharvest management of orange-fleshed sweet potatoes.
CharacteristicsFrequencyPercentYield (t·ha−1)<613837.96–7.517548.17.5–10349.3>10174.7Awareness on sweet potato storageYes25369.5No11130.5Place of storageIn the soil113.0In the bright room102.7Leaving in the field32789.8In modified diffused light storage (DLS)10.3Not stored154.1Preference to growWFSP10729.4OFSP6618.1Both19152.5WFSP, white fleshed sweet potato; OFSP, orange fleshed sweet potato.The respondent farmers believed that some rain was favorable for prolonging the lives of the storage roots in the soil, which was an unexpected observation [46]. As a result, postharvest limitations have remained a major constraint in Ethiopia for agricultural products in general and horticulture production. In the study site, 52.5% of respondents grow both white-fleshed sweet potatoes (WFSP) and orange-fleshed sweet potatoes (OFSP), whereas 29.4% grow WFSP and 18.1 grow OFSP types (Table 4). This preference could have arisen as a result of the cultivar's genetic dissimilarity. Similarly, Gurmu et al. [46] reported that 78.3%, 83.1%, and 67.7% of the respondents were familiar with OFSPs in Sidama, Wolayta, and Gamo Gofa, respectively. These authors indicated that, given a chance to choose and grow among the WFSP and OFSP, 54.7% responded to grow both WFSP and OFSP, while 27.6% indicated WFSP and 17.8% preferred OFSP only. Among the respondents who were aware of OFSPs, 77.7% disliked the varieties due to the inherent wateriness on cooking (low root dry matter content) and associated poor taste [46].


## 3.4.1. Orange-Fleshed Sweet Potato Yields

The majority of respondents (48.1%) obtained on-farm yields of sweet potato ranging from 6.0 to 7.5 t·ha−1, which is lower than the average yield of 10 t·ha−1 at the farmer level in Ethiopia (Table 4). According to Zhang et al. [4], the average yield of sweet potato in Ethiopia is about 8 t·ha−1 compared to 18 t ha−1 in Asian countries. This suggests that production constraints must be addressed in order to increase sweet potato yield in Ethiopia. In Ethiopia, sweet potato has a potential yield of 50 to 60 t·ha−1, however, farmers obtain about 6 to 8 t·ha−1 [45]. A number of variables contribute to the yield gap, including a lack of high-yielding, virus-free planting materials, lack of effective insect pest management, and absence of the utilization of enhanced crop management alternatives. Data concerning postharvest management show that 69.5% of the respondents have an understanding of the importance of sweet potato storage (Table 4). After physiological maturity, most (89.8%) of smallholder farmers store OFSP roots by leaving them in the soil of the farm (in situ) to store and use them when the need arises, which exposes the roots to various diseases and pest attacks. According to Gurmu et al. [46], most of the respondents (98.4%) stored the storage roots in situ in the soil, harvesting them when they were needed for food. The major constraints that affect the storage of sweet potato roots in situ leaving them in the soil were described by the respondents as heat (31.6%), insect pests (mainly weevil) (25.6%), diseases (21.8%), and rodents (20.9%) [47]. A similar trend was reported in Uganda where farmers practiced harvesting sweet potatoes in a piecemeal manner by storing them in pits [48].Table 4
Yield and postharvest management of orange-fleshed sweet potatoes.
CharacteristicsFrequencyPercentYield (t·ha−1)<613837.96–7.517548.17.5–10349.3>10174.7Awareness on sweet potato storageYes25369.5No11130.5Place of storageIn the soil113.0In the bright room102.7Leaving in the field32789.8In modified diffused light storage (DLS)10.3Not stored154.1Preference to growWFSP10729.4OFSP6618.1Both19152.5WFSP, white fleshed sweet potato; OFSP, orange fleshed sweet potato.The respondent farmers believed that some rain was favorable for prolonging the lives of the storage roots in the soil, which was an unexpected observation [46]. As a result, postharvest limitations have remained a major constraint in Ethiopia for agricultural products in general and horticulture production. In the study site, 52.5% of respondents grow both white-fleshed sweet potatoes (WFSP) and orange-fleshed sweet potatoes (OFSP), whereas 29.4% grow WFSP and 18.1 grow OFSP types (Table 4). This preference could have arisen as a result of the cultivar's genetic dissimilarity. Similarly, Gurmu et al. [46] reported that 78.3%, 83.1%, and 67.7% of the respondents were familiar with OFSPs in Sidama, Wolayta, and Gamo Gofa, respectively. These authors indicated that, given a chance to choose and grow among the WFSP and OFSP, 54.7% responded to grow both WFSP and OFSP, while 27.6% indicated WFSP and 17.8% preferred OFSP only. Among the respondents who were aware of OFSPs, 77.7% disliked the varieties due to the inherent wateriness on cooking (low root dry matter content) and associated poor taste [46].


## 3.5. Major Causes and Constraints That Influence Production Management of Orange-Fleshed Sweet Potatoes

The farmers' ability to produce and consume OFSP in the assessment site was limited due to a variety of factors. According to the index ranking, drought, lack of planting material, diseases, and insect pests were the most significant (first to the fourth rank) constraints affecting the production of OFSP in the study site (Table5). This result is consistent with those of Emana and Gebremedhin [49] who reported pests, drought, a scarcity of desirable seed varieties, and the cost of gasoline for driving water for irrigation and fertilizer restrictions, as the main horticulture production restraints in Ethiopia. Similar to this study, Negasi et al. [25] also reported the unavailability of storage facilities as a major problem affecting onion production. Gurmu et al. [46] reported heat and drought at 21.6%, shortage of planting materials (20.1%), shortage of land (15.7%), diseases (10.0%), insect pests (9.4%), a lack of draft power (oxen, donkeys, horses, and mules) (8.1%), shortage of money to cover input costs (7.9%), a lack of labor (5.1%), and weeds (2.0%) as the major sweet potato production constraints in Ethiopia. Abigail et al. [50] reported the shortage of labor as the most prominent limitation affecting sweet potato production in Nigeria. The authors attribute the inefficacies in labor to be due to the reliance on hoe and cutlass in Nigeria. However, a large number of able-bodied people in most parts of the country have abandoned farming in favor of a motorbike transport industry, which pays a somewhat consistent daily wage, causing a labor shortage. According to the farmers, the second major productivity constraint on sweet potato farms is the lack of access to updated technologies. For example, most farmers relied on basic equipment such as a cutlass and a hoe with a poor adoption rate of the improved vine for planting. Similar to this study, Abigail et al. [50] reported poor yield to be linked to the usage of rudimentary equipment and the sort of locally grown vines [50]. Okonya et al. [51] found insect infestations as the fourth ranked among the obstacles in the production process. The fifth major barrier in sweet potato production was the lack of finance. Most formal credit sources and certain informal credit sources made it difficult for farmers to meet the requirements for obtaining a loan [52]. Diseases are the sixth major barrier in sweet potato production and affect crop yield. Bad roads, poor output prices, lack of processing facilities, and expensive transportation costs were also noted as factors affecting production.Table 5
The area’s major orange-fleshed sweet potato production constraints.
ConstraintPrioritization1st2nd3rd4th5th6th7th8thIndexRankShortage of planting materials38108432200.01492Shortage of land2454100000.02945Disease30103221100.02043Drought562313962200.00901Insect pest14106321110.02634Storage problem1653210000.03706Low market price932221110.04767Shortage of money to purchase inputs743111000.05888Total19470422417872Results of the multiple linear regressions show that the independent variables utilized in the model clarify differences in OFSP production (Table6). The coefficients were considerably different from zero, resulting in significant F-values (15.8) and R2 principles of 15%, which demonstrate the model’s goodness of fit. The predominance of market, storage, insect pest, and planting materials remained in the equation as significant variables. The market and storage factors positively significantly (p=0.001) affected OFSP, whereas the insect pest and planting materials negatively significantly (p=0.001) affected the OFSP yield (Table 6).Table 6
Multiple regression outcomes for causes affecting the yield of OFSP.
Independent charactersRegression coefficientsSEt-valuep valueMarket0.3190.0823.902∗∗∗0.000Storage0.2820.0684.134∗∗∗0.000Insect pest-0.2230.062−3.609∗∗∗0.000Planting materials-0.1610.051−3.122∗∗0.002Constant1.1280.2973.803∗∗∗0.000Number observation364R20.150F-value15.803∗∗∗∗∗Significant at 99% level of significance.


## 3.6. Major Consumption and Utilization Method of Orange-Fleshed Sweet Potatoes in the Area

### 3.6.1. Frequency of Eating OFSP

It was shown that the majority of the respondents (44.5%) commonly ate OFSP once in a week, while 32.7% and 15.7% of the respondents consumed it once a month and daily, respectively. Only 7.1% ate OFSP twice a day (Table 7).Table 7
Method of consumption and utilization of orange-fleshed sweet potato in the area.
VariablesFrequencyPercentageHow often do you eat sweet potatoTwice a day267.1Daily5715.7Once a week16244.5Once a month11932.7Common processing method of OFSP sweet potato products for consumption in your householdBoiling28578.3Steaming369.9Roasting4311.8Which products are you familiar withWhite-fleshed sweet potato23765.1Orange-fleshed sweet potato13734.9Are you aware that OFSP has a high vitamin A contentNo5114.0Yes31386.0You promoted the consumption of OFSP by your youngsters and pregnant ladiesNo4412.1Yes32087.9According to Nungo [53], over 80% of the sweet potatoes produced in SSA is consumed fresh. When in season, it is a secondary staple in most other rural areas, eaten 2–4 times per week with breakfast frequently served with boiled or steamed roots. Sweet potato is not commonly used as a morning or snack dish in metropolitan diets. There is a common cultural perception in Africa that sweet potato is a “sweet” food that is best suited for women and children [54]. Adults prefer high-starch types of food while youngsters prefer softer, lower-starch roots, according to Low et al. [55].


## 3.6.1. Frequency of Eating OFSP

It was shown that the majority of the respondents (44.5%) commonly ate OFSP once in a week, while 32.7% and 15.7% of the respondents consumed it once a month and daily, respectively. Only 7.1% ate OFSP twice a day (Table 7).Table 7
Method of consumption and utilization of orange-fleshed sweet potato in the area.
VariablesFrequencyPercentageHow often do you eat sweet potatoTwice a day267.1Daily5715.7Once a week16244.5Once a month11932.7Common processing method of OFSP sweet potato products for consumption in your householdBoiling28578.3Steaming369.9Roasting4311.8Which products are you familiar withWhite-fleshed sweet potato23765.1Orange-fleshed sweet potato13734.9Are you aware that OFSP has a high vitamin A contentNo5114.0Yes31386.0You promoted the consumption of OFSP by your youngsters and pregnant ladiesNo4412.1Yes32087.9According to Nungo [53], over 80% of the sweet potatoes produced in SSA is consumed fresh. When in season, it is a secondary staple in most other rural areas, eaten 2–4 times per week with breakfast frequently served with boiled or steamed roots. Sweet potato is not commonly used as a morning or snack dish in metropolitan diets. There is a common cultural perception in Africa that sweet potato is a “sweet” food that is best suited for women and children [54]. Adults prefer high-starch types of food while youngsters prefer softer, lower-starch roots, according to Low et al. [55].


## 3.7. Common Processing Method of OFSP Sweet Potato Products for Consumption in the Household

Most respondents (78.3%) consumed fresh OFSP after boiling or processed for other purposes, while 11.8% and 9.9% consumed roasted and steaming, respectively (Table7). This result is consistent with those of Fawole [56] who reported boiling and roasted sweet potato processed forms are the most consumed products. However, alternative use methods such as manufacturing chips and combining sweet potato flour with wheat flour for goods like chapatti, Mandazi, or porridge have not yet been fully developed in African countries [57].


## 3.8. OFSP Product Familiar at Household Level

The most prevalent sweet potato products at the household level were from WFSP (65.1%) and OFSP (34.9%). The low percentage of OFSP varieties in comparison to WFSP types could be attributable to their low dry matter content (DMC). This is consistent with the findings of Gurmu et al. [13], who found that farmers and consumers dislike OFSP cultivars due to their low storage root DMC. WFSP cultivars have high storage roots which are preferred by farmers. Currently, OFSP types are frequently promoted due to their high-carotene (provitamin A) content, similar to the findings of Tofu et al. [16] and Gurmu et al. [13]. The root DMC of the OFSP cultivars is low, which has a direct impact on taste and influences its adoption. According to the results of several authors, varieties with high storage root DMC are preferred by most African households since this trait is correlated with a good taste [16, 17, 19, 58]. Therefore, the WFSP varieties are more accepted by farmers than the OFSP varieties due to their high DMC. However, the problem of low root DMC can be reduced through the crossing and development of OFSP varieties with high root DMC of WFSP varieties in Ethiopia [59, 60].The majority of farmers (86%) said they were aware that OFSP is high in vitamin A. Meanwhile, 14% stated that they were not aware that OFSP is high in vitamin A.Awared respondants preferred sweet potatoes over vitamin-fortified foods since it was readily available, relatively inexpensive, and simple to prepare [61]. In the present study, farmers who knew about the nutritional value of OFSP were nearly three times more likely to use it than those who did not. This is consistent with a prior expectations and knowledge of OFSP’s nutritional value which is anticipated to encourage its use, particularly for home use. This indicates that any program that includes effective instruction on the nutritional advantages of OFSP is more likely to be adopted.


## 3.9. Sensitivity of Children or Pregnant Women to Consuming OFSP

About 87.9% of the respondents encouraged their youngsters and pregnant ladies to consume OFSP and only 12.1% were not encouraged. This is attributed to the nonawareness of vitamin A content of OFSP. Vitamin A deficiency is a severe health problem in Sub-Saharan Africa affecting young children aged from 0 to 6 years and pregnant women. Meanwhile, the orange-flesh variety is high in beta-carotene, which the body uses to make vitamin A. Vitamin A is a wonderful source of energy and key nutritive components, and it can help rural inhabitants improve their nutritious status [62].


## 4. Conclusion

The combinations of social, ecological, and economic factors influence the OFSP production in the Sidama region in the southern part of Ethiopia. In this region, factors such as diseases, lack of storage facilities, lack of planting materials, drought, insect pests, low market price, and lack of currency to achieve inputs existed as the main constraints affecting OFSP production and productivity. To increase OFSP production and consumption under resource-poor farmers, improved cultural practices are the most important ways in developing a cost-effective disease management strategy that should focus on planting bed types (sweet potato planting on ridges), use of recommended spacing for good plant population, and farmer collaboration. Furthermore, the extension system should prioritize the OFSP as an essential and specialized commodity in order to increase productivity and consumption. Academics and nongovernmental organizations (NGOs) need to research the diversity of farmers’ expertise to increase crop yields through site-specific and recommended fertilizer practice packages and applicable terrestrial-use structures. To enhance soil productivity, collaboration with nearby stakeholders such as higher education institutions and research centers is required. Planting materials that are free from diseases should be made readily available to increase the production and consumption of orange-fleshed sweet potatoes. Finally, the food and nutrition security policy will gradually achieve its goal, when similar food security packages are promoted.



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*Source: 4922864-2022-09-30.xml*