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Potentials of Hausa Potato (Solenostemon rotundifolius (Poir.) J. K. Morton and Management of its Tuber Rot in Nigeria



Solenostemon rotundifolius (Poir) J. K. Morton commonly called Hausa potato in Nigeria, is a herbaceous, annual crop, with distinctive fragrance and peculiar tuber taste. Ethnomedicinally, leaves of the crop are used to treat dysentery, blood in urine and eye disorders. The tubers are eaten as a main starchy staple or part of it in combination with legumes, vegetables or cereals. The crop which is popular in the middle belt and Northeastern Nigeria, is constrained by edaphic factors, extremes of climatic variables and biotic pressures resulting in tiny tuber formations, tuber branching, low yields and poor tuber storability due to rots and poor storage methods. Amongst these, rots have been identified as the greatest constraint; followed by dearth of documented information on proper methods of its storage. Synthetic fungicides are veritable agents of fungal rot control; however their use is being deemphasized due to ecological and human health concerns occasioned by residues in crops as well as development of resistance to chemical control agents in pathogens. Phytopesticides have been advocated as viable alternatives for tuber rot control. However, their use has not been sufficiently researched on Hausa potato. Besides, the phytochemical constitution of the leaves and tubers of the crop underpinning their fragrance, peculiar taste and ethnomedicinal uses have not been fully documented. So are the mineral and vitamins composition of the tubers. Poor scientific research attention is considered as the reason for the poor performance of some tuber crops in Africa, both in the field and store. If given adequate and focused research attention, Hausa potato as a delicate vegetable crop holds prospects for enlarged adoption into other agro-ecological zones of Nigeria, and thereby contribute to food security. This communication therefore enumerates the importance of Hausa potato and presents significant researchable opportunities on the crop.
ISSN: 2354-2306
Potentials of Hausa
Potato (Solenostemon
rotundifolius (Poir.) J.
K. Morton and
Management of its
Tuber Rot in Nigeria
Enyiukwu D. N
Awurum A. N.
Nwaneri J. A.
Greener Journal of Agronomy, Forestry and Horticulture ISSN: 2354-2306 Vol. 2 (2), pp. 027-037, April 2014. 27
Review Article
Potentials of Hausa Potato (Solenostemon
rotundifolius (Poir.) J. K. Morton and Management of
its Tuber Rot in Nigeria
*1Enyiukwu D. N., 1Awurum A. N. and 2Nwaneri J. A.
1Department of Plant Health Management, Michael Okpara University of Agriculture, Umudike, P.M.B 7269
Umuahia, Abia State Nigeria.
2Lesser and Minor Root Crops Unit, National Root Crop Research Institute Umudike, PMB 7006 Umuahia,
Abia State, Nigeria.
*Corresponding Author’s Email:, Tel: +234 803 744 6891
Solenostemon rotundifolius (Poir) J. K. Morton commonly called Hausa potato in Nigeria, is a herbaceous, annual
crop, with distinctive fragrance and peculiar tuber taste. Ethnomedicinally, leaves of the crop are used to treat
dysentery, blood in urine and eye disorders. The tubers are eaten as a main starchy staple or part of it in
combination with legumes, vegetables or cereals. The crop which is popular in t he middle belt and Northeastern
Nigeria, is constrained by edaphic factors, extremes of climatic variables and biotic pressures resulting in tiny tuber
formations, tuber branching, low yields and poor tuber storability due to rots and poor storage methods. Amongst
these, rots have been identified as the greatest constraint; followed by dearth of documented information on proper
methods of its storage. Synthetic fungicides are veritable agents of fungal rot control; however their use is being de-
emphasized due to ecological and human health concerns occasioned by residues in crops as well as development
of resistance to chemical control agents in pathogens. Phytopesticides have been advocated as viable alternatives
for tuber rot control. However, their use has not been sufficiently researched on Hausa potato. Besides, the
phytochemical constitution of the leaves and tubers of the crop underpinning their fragrance, peculiar taste and
ethnomedicinal uses have not been fully documented. So are the mineral and vitamins composition of the tubers.
Poor scientific research attention is considered as the reason for the poor performance of some tuber crops in
Africa, both in the field and store. If given adequate and focused research attention, Hausa potato as a delicate
vegetable crop holds prospects for enlarged adoption into other agro-ecological zones of Nigeria, and thereby
contribute to food security. This communication therefore enumerates the importance of Hausa potato and presents
significant researchable opportunities on the crop.
Keywords: Solenostemon rotundifolius, C oleus rotundifolius, Plectranthus rotundifolius, Hausa potato, Frafra
potato, rots.
Solenostemon rotundifolius (Poir) J. K. Morton (Synonyms: Plectranthus rotundifolius Poir, Coleus rotundifolius A.
Chev and Perrot, C. parviflorus Benth, C. dysentericus Buk., Plectranthus tenatus Sims, Germania rotundifolius
Poir) (Common names: Hausa potato, Frafra potato, Sudan potato, Zulu round potato. Coleus potato, Chinese
potato) is a member of the Family Lamiatae (Labiatae) (Mint family) which consists of heterogeneous
assemblage of over 300 plants. According to Blench and Dendo (2004) there is a confusing plethora of taxonomy
about this crop, being reported under the genera Coleus, Plectranthus and Solenostemon. Its local names also
vary with geographic locations, for instance while in Ghana it is known as Salanga potato, in Nigeria it is called
Hausa potato. Hausa potato is a small herbaceous annual crop (Alleman, 2002; Dupriez and De Leener, 1989;
PROTA, 2013). The crop is thought to have originated in Kenya or Ethiopia in East Africa from where it spread
throughout tropical Africa through the savannas of Togo, Guinea and then into Southeast Asia including India, Sri
Lanka, Malaysia and Indonesia (Harlan et al., 1976). Hausa potato is a small herb that has prostrate or
ascending succulent stems and branches. It attains a height of 15-30 cm and presents a distinctive, distractive,
lighten odour due to presence of volatile oils in the glands or sacs of its leaves (Alleman, 2002; Phungpanya et
al., 2013). The flowers are small and may be white, blue, pinkish or pale violet in colour, being borne on distal
inflorescences with slender false spikes measuring up to 15 cm in length. These flowers are hermaphroditic and
the fruits consist of four nutlets which rarely develop. In Africa today, cultivation of this crop is mostly limited to
Burkina Faso, Eastern Mali, Northern Ghana and South Africa. In Nigeria, Hausa potato is still popular in the
middle belt and Northeastern regions of the country especially around the states of Bornu, Taraba, Nasarawa,
Jos Plateau and Kaduna. On the world scale , the crop is the most widespread of the cultivated Lamiatae
Greener Journal of Agronomy, Forestry and Horticulture ISSN: 2354-2306 Vol. 2 (2), pp. 027-037, April 2014. 28
(Labiatae) and is believed to be of more economic importance in tropical Asia particularly in India where it is
grown as a monsoon crop as well as in Sri Lanka, Madagascar, Malaysia, Indonesia and Southern Thailand
(Nkansah, 2004; Blench and Dendo, 2004; PROTA, 2013). In ethnobotany, preparation of boiled leaves of Hausa
potato is used to treat such disorders as dysentery, blood in urine and eye disorders including glaucoma
(Schipper, 2000; Irvine, 1990).
Tubers of the crop provide essential dietary and energy requirements to the populace during the lean
periods. The tubers taste similar to Irish potato and trifoliate yam, and can be eaten as the main starchy staple or
part of it in combination with legumes, rice and vegetables. It can also be prepared in Indian and African cuisines
as boiled, baked or fried (Schipper, 2000; Wulueng et al., 2000). Some workers reported that the tubers of Hausa
potato can be used to make aromatic, alcoholic beverages (Schipper, 2000; Phungpanya et al., 2013) while the
leaves sometimes may also be eaten as pot-herbs (PROTA, 2013). Compared to other tuberous staples in
Nigeria, the tubers of this crop are rich in protein, vitamins and minerals. One hundred grams of the raw tubers
contain water 76%, carbohydrate 21%, protein 1.4%, fibre 0.7%, fat 0.2%, and ash 1.0% amongst other important
nutrients (PROTA, 2013).
Yields averaging 5-15 MT/ha have been reported from the crop in Ghana and Nigeria. The potential yield
of the crop could be up to 18-20 MT/ha (PROTA, 2013). A study in South Africa however, indicated that potential
yield from the crop may amount up to 45 MT/ha under favourable conditions of rains, soil fertility and texture
(Jansen, 1996; Nkansah, 2004). Such optimum yields could be obtained on well drained light sandy loams while
heavy soils prone to waterlogging are unsuitable for the crop. Hausa potato may be propagated vegetatively by
suckers or like cassava by soft woody stem cuttings as well as by tubers as yams and cocoyams. However stem
cuttings are scarcely used. Plantings are done on mounds, ridges and on flats in well drained locations at the
beginning of the rains as sole crop or intercrop with maize, yam, millet, melon, groundnut, sorghum and Bambara
groundnut (Apobol, 1997; PROTA, 2013). The ridges are incorporated with farmyard manure, wood ash, cattle
dung and urine or inorganic fertilizers (Tetter and Guo, 1993; Olojede et al., 2005).
Tuber yield from the crop have been reported to correlate strongly with amount and regularity of rain
(Nkamah, 2004). A well distributed rainfall of 1000mm have been reported sufficient for the crop while excessive
rainfall which could lead to waterlogging is detrimental to its tuber development (Gubber and Denton, 2004;
Alleman, 2002). Besides these climatic constraints, Hausa potato is attacked by various pathogens leading to
tuber quality reduction, yield losses and rots. These diseases include nematode infestations, virus mottling, scab
and tuber rot (Okorocha et al., 2006; PROTA, 2013). Root knot nematodes have wide host ranges and have
been associated with lesser root crops including Hausa potato (Okorocha et al., 2006). It galls affected roots,
impairs water and nutrient uptake by the crop, reduce marketable root yield and quality, and results in total crop
failure in severe cases (Jonathan and Hedwig, 1991; Asawalam and Adesanya, 2001). Infestation of root tubers
by root knot nematodes in the field in addition to abrasions sustained during harvesting, strongly predispose
tubers to rapid decay during transit and storage (Okigbo, 2004; Okigbo and Nmeka, 2005; Okigbo et al., 2009). A
variety of fungi are known to cause important diseases in crops. For instance, besides causing charcoal root rot,
stem cankers, stalk rot etc. in 500 plant species, Macrophomina phaseolina incites tuber rots in a number of
tropical tuber crops such as sweet potato and yam (Amienyo and Ataga, 2007; Nahunnaro, 2008). Postharvest
rots and spoilages represent the greatest constraints to tuber production in Nigeria (Alexandratus, 1995; Taiga,
2011). According to Taiga (2011), 40% of yams are lost to postharvest spoilage organisms and rots. Some of
these organisms include species of Fusarium, Colletotrchum, Geotrichum, Penicillium, Heminsthoporium,
Alternata, Pythium, Phytophtora, Erwinia and Staphylococcus. Recent investigations in Yola, Northeast Nigeria
showed that Fusarium oxysporium, Aspergillus niger, Penicillium expansum and Rhizopus stolonifer were
implicated with tuber rot of Hausa potato (Mohammed et al., 2013a; 2013b). Preliminary studies into the cause of
rot of tubers of the crop in Southeast Nigeria suggested the association of Colletotrichum spp. with rot of the
tubers in storage in the zone (Nwaneri, 2013). However organisms responsible for the spoilage and rot of Hausa
potato have not been fully documented.
Tuber rot diseases are controlled using synthetic chemical agents such as captan, borax, naphtalene
acetic acid and orthiophenylphenate (Okigbo and Nmeka, 2005). Synthetic chemicals remain the most popular
and effective means of controlling plant diseases. However, following their obvious demerits such as residues in
crops and environment, and the attendant mammalian toxicity and development of pathogen resistance to some
of the most effective fungicides etc., alternatives are being sought in agriculture. Such alternatives include
microbial antagonist and plant-based pesticides. The challenge with bio-control however, lies in developing safer
and acceptable formulations and application methods that can be used on a broad scale in agriculture (Suprapta,
2012). Many higher plants on the other hand in plant health management are being screened for pesticidal
properties and their effects against storage fungi (Amadioha, 2004; Enyiukwu and Awurum, 2013). These plant-
based preparations are cheap, easy to prepare and use by all classes of growers especially in the developing
countries of the tropics (Awurum and Enyiukwu, 2013).
Hausa potato is an important crop which has contributed immensely in alleviating poverty, hunger and
starvation in various farm-families. Properly directed researches to find solutions to the many agronomic and
storage-health challenges besetting the crop are imperative; towards making the crop to achieving its full
quantitative and qualitative yields potentials and contributing immensely to the drive for food security in Nigeria .
Greener Journal of Agronomy, Forestry and Horticulture ISSN: 2354-2306 Vol. 2 (2), pp. 027-037, April 2014. 29
Therefore this work reviews the potentials of Hausa potato (Solenostemonrotundifoius Poir) J. K. Morton and
management of its storage tuber rot in Nigeria.
Source of important nutrients
Recent anthropological proposal assumes that human evolution is significantly tied to dependence on tubers
(Schoeninger et al., 2000). Hausa potato is one of the lesser root crops and is generally a women-grown crop
(NRCRI, 2006; Dung et al., 2010). The tubers are thin skinned, cylindrical in shape and weighs approximately
less than 100g (Ukpabi et al., 2011). Others are Plectranthus esculenthus (Rizga), Ampelocissus granti (Rogon
Daji), Curcuma longa (Tumeric) and Tacca leotapetaloidae (Arrow root). Consumption of root and tuber crops are
higher in developing economies where food problems are not only quantitative (food production being less than
food demands) but qualitative (deficient in nutrients and calories) as well. It is now increasingly realized according
to Idusigie and Olayide (1975) that inadequacy of food calories in diets as well as protein deficiency contributes
to malnutrition in Nigeria. Lesser root crops can contribute to food security being high in calorific values and other
essential nutrients (Kana et al., 2012). Hausa potato plays a very significant role in providing the dietary and
energy requirements of the local people during lean periods. The crop is rich in major and minor nutrients and all
the nutrients are reported to be essential for proper functioning of the body (Kana et al., 2012). In addition, Hausa
potato plays the role of a substitute for sweet potato in most parts of Africa. Aside of being quantitative, food
problems remarked Kana et al. (2012) could be qualitative in which case the ingested food fails to meet the
calorific and nutrients demands of an individual. According to Alleman (2002) the content of 14% protein in Hausa
potato on dry matter basis, for instance compares well with Irish and sweet potatoes as well as other tuber crops.
The principal amino acids present in the protein of the crop are arginine, aspartic and glutamic acids
(Appropedia, 2013). The tubers are also a rich source of dietary energy and 100g of the tubers provides 392-
394KJ of metabolisable energy (Schoeninger et al., 2000; PROTA, 2013) and mean starch percentage of 28.62
on dry matter basis of less than 100 gram tuber (Ukpabi et al., 2011). A standard serving dish of the crop is
reported to provide in addition, a large proportion of the daily requirements of calcium, vitamin A and iron. Dietary
iron, calcium and vitamin C for instance have been recommended in preventing lead poisoning especially for
those living in industrialized areas (Afolabi et al., 2012). Inadequate quantity of food (those deficient in calories)
and not merely protein deficiency is reported as the cause of widespread protein-calorie malnutrition, since with
insufficient calories, protein in diets is used to supply energy instead of fulfilling its body building roles (Idusigie
and Olayide, 1975).
The comparative yield of nutrients and minerals of major tuber staples are presented in Table 1. The crop
holds potentials as seen from Table 1 to meet the calorific needs of an average Nigerian. Besides, recent organo-
leptic evaluation of the mealy boiled tubers and crispy fried French fries from the tubers were found generally
acceptable by sensory assessors (Ukpabi et al., 2011). Hausa potato can be used in the confectionery industries
where it could act as colouring agent in bread production. At 10% substitution of wheat with its flour, no
significant difference was observed in all the sensory attributes of taste, texture, and general acceptability of the
bread produced from the composited flour (Aniedu and Agugo, 2010). Disintegrants such as starch and cellulose
aids in breaking of tablets into smaller fragments in a fluid environment prior to dissolution of the active principle
of the drug and its absoption in the gastro-intestinal tract. A trial in Maiduguri by Muazu et al. (2012) found that
the starch of Hausa potato compared well to Maize starch BP in the formulation of paracetamol tablet excipient
both in disintegration and dissolution times. A viable raw material no doubt in pharmaceuticals. However, being a
starch-rich staple biochemical studies to determine its tolerance by diabetics is urgently warranted for the
Generally, several researchers agree that there is strong need to give greater prominence to root and
tuber crops development especially the under-utilized and neglected species, in the agricultural scheme of things
to meet economic, quantitative and qualitative nutritional needs of the nation (Idusigie and Olayide, 1975;
Olojede, 2013).
Table 1: Comparison of nutrient contents of major tuber staple foods in Nigeria
Component/100g portion Yam Cassava Cocoyam Sweet potato Potato Hausa potato
Energy (KJ) 494 670 594 360 322 394
Protein (g) 1.5 1.4 0.52 1.6 2.0 1.3
Fat (g 0.17 0.28 0.11 0.05 0.09
Carbohydrate (g) 28 38 34.6 20 17 21
Fibre (g) 4.1 1.8 5.1 3.0 2.2 1.1
Sugar (g) 1.5 1.7 0.49 4.18 0.78 -
Calcium (mg) 17 16 18 30 12 17
Vitamim C (mg) 17.4 20.6 2.4 24 19.7
Thiamine (mg) 0.11 0.09 0.11 0.08 0.08 0.05
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Riboflavin (mg) 0.03 0.05 0.28 0.06 0.03 0.02
Niacine (mg) 0.55 0.85 0.51 0.56 1.05 1.0
Iron (mg) 0.54 0.85 0.72 0.61 0.78 6.0
Vitamin A (IU) 138 13 - 14138 2.0 -
Beta-carotene (mcg) 87 8.0 - 8509 5.0 -
Vitamin B6 (mg) 0.29 0.09 0.331 0.21 0.30 -
Pantothemic acid (mg) 0.31 0.11 0.336 0.80 0.30 -
Folate (Vit. B9) (mg) 23 25 9 11 16 -
Vitamin E (mg) 0.39 0.19 2.93 0.26 1.10 -
Magnesium (mg) 0.40 0.38 30 0.26 0.15 -
Potassium (mg) 816 271 484 337 421 -
Phosphorus (mg) 55 27 76 47 57 -
Zinc (mg) 0.24 0.34 0.27 0.30 0.29 -
Sources: Schoeninger et al., 2000; Wikipedia, 2013; PROTA, 2013
Key: - = not determined
Yield of the crop
Hunger reported by Kana et al. (2012) stares most third world economies in the face because of their inability to
modernize their agriculture. Due to extreme poverty remarked this source chronic hunger is commonplace in
these nations. It is a known fact that nearly 1 billion people the world over are seriously affected by hunger, out of
which 10 million hunger-related deaths occur annually. Many of these low-income, food deficient nations
particularly in Asia and SSA may have relied on few crop species for their food supply to the detriment of lesser
known crop plants. Lesser root crops hold potentials to serve as sources of foods, raw materials, animal feed,
medicines and industrial raw materials for these nations. Hausa potato like aerial yam can be cultivated with very
little attention. They require low inputs hence contributing to sustainable agricultural production (Blench and
Dendo, 2004; Kana et al., 2012). The crop takes 5-6 months to mature in the field and like cassava provides a
wide harvesting window since it can be left in-field for ½-2 years post-maturation and can be relied upon during
famine or civil unrest (Kana et al., 2012) However, farmers usually grow this crop around homesteads, long farm
boundaries and marginal lands with little agronomic attention paid to them. They also follow indigenous crop
husbandry methods which culminate ultimately to low yields. Reasons behind the low yields are traceable to
farmers’ non-adoption of improved crop production techniques and lack of improved and high yielding varieties of
the crop as well as lack of capital for acquiring improved inputs (Dung et al., 2010; Abate et al., 2011). Lack of
cultivars tolerant or resistant to water logging, submersion or flooding has been advanced as other yield non-
enhancing factors (Bill and Melinda Gates Foundation, 2011). Comparative yield values of the various tuber
crops in Nigeria are presented in Table 2.
Hausa Potato
Hausa Potato on Display at Gombi
Market, Adamawa State.
Hausa Potato Farm in Manchok,
Kaduna State Hausa Potato Field at NRCRI,
Greener Journal of Agronomy, Forestry and Horticulture ISSN: 2354-2306 Vol. 2 (2), pp. 027-037, April 2014. 31
Table 2: Comparative yield values (MT/ha) of major tuber staples grown in Nigeria
Cassava Cocoyam
potato Potato
Mean world yield (t/ha) 11.5 12.5 6.7 13.7 16 7.0 4.7 6
Potential yield (t/ha) 110 90 110 120 80 45 35 -
Price/kilogram (Naira) 150 250 250 200 700 300 500 200
: Iksan, 2000; Fang, 2008; Lebot, 2013; Wikipedia, 2013; PROTA, 2013, Agriechange, 2013.
In Nigeria mean yield range of 7-15 MT has been reported from Hausa potato. As seen from Table 2, at N300
(nearly US$2.00) per kilogram of tubers of Hausa potato, the crop could impart the farm economy to the tune of
2.1-4.5 million Naira (US$ 14,000-30,000) all things being equal. Similarly, its potential yield in Nigeria has also
been reported at 18-20 MT/ha, in which case it translates to 5.4-6.0 million Nigerian currency (US$ 36,000-
40,000). Higher potential yield of 45 MT has been reported from the crop in South Africa. And besides its
nutritional attributes the crop holds strong economic potentials and could be financially rewarding to the farm
economy (Table 2). Being a mid-duration crop two cycles of its production in both sole and intercrop production
systems are feasible in our agro-ecological zones. Which no doubt would translate to several millions of financial
returns to its growers. From the foregoing therefore, one agrees with Olojede (2013) that Hausa potato holds
strong potential to becoming a commodity crop for food security, poverty alleviation and economic growth in
Nigeria. However, neglect of scientific research attention, funding and capacity building with reference to Hausa
potato and other lesser root crops informed their neglect and under-utliization. According to Anonymous (2004)
neglected and underutilized crops have great potential in the future sustainable food system. Many workers
argue that they can contribute to improved and increased farm economy (Kana et al., 2012; Mohammed et al.,
2013b). Especially if given adequate research focus remarked some investigators (Talwana et al., 2010). The use
of resistant varieties is the first major way of tackling recalcitrant abiotic and biotic constraints to crop production.
It is considerably cheap, easy to use and integrable with wide ranging crop production systems. The tuber yield
and production of Hausa potato can be increased by breeding the crop for resistance to edaphic and climatic
extremities such as water logging or aridity and drought. This has been achieved in some companion crops. For
instance in the Sudan and Sahel agro-ecologies Bill and Melinda Foundation (2011) reported that maize varieties
suitable for growers in the region that are tolerant or resistant to extreme aridity have been developed while rice
cultivars capable of tolerating and surviving submersion under floods for up to 2 weeks are currently being
circulated in South Asia.
With respect to Hausa potato breeding for increased tuber size is imperative. Tuber size tends to put the
crop at a disadvantage vis-a-viz rizga (P. esculentus). Besides, tuber branching is another discouraging
parameter against the crop. It behoves breeders to develop high yielding varieties with non-tuber branching
capacity in addition to withstanding the vagaries of the weather. Many varieties of Hausa potato in circulation
today produce tiny and/or branched tubers. Branched, tiny tubers make the crop unattractive and reduce the
marketability of the tubers. In general, average yield of the crop is grossly small and does not compare to yields
of other tuber crops such as Irish potato, sweet potato, yams, cocoyams and cassava in most farm situations.
Cumulatively these constrain the adoption, spread and distribution of the crop in Nigeria. Overcoming these
drawbacks through proper germplasm selection, conventional breeding research, genetic engineering and crop
modification, human capacity development, education and awareness creation of the benefits of the crop through
buttressed agricultural extension services will undoubtedly translate to attaining the potential tuber yield of the
crop, higher incomes and improved farm economy (Dung et al., 2010; Talwana, 2012; Olodeje, 2013).
Phytochemical constituents of Hausa potato
The Genus Plecthranus contain 300 plant species which occur in Africa; around half are distributed within SSA
while 70% occur in Asia and Australia. The genus is plagued with numerous nomenclatural disharmonies that
make it difficult to collate accurate data. Coleus is considered as an old name for most members of the genus.
The crops in this genus may be used as food; food additives for flavouring and marinating beef, chicken, masking
strong smells associated with goat, sheep and spicing tomato-rich dishes. The genus serves also as dry season
fodder for domestic animals like cattle, camel, rabbit and wild species such as elephant. Most members of the
genus are frequently used as medicines and are used to treat a range of ailments especially those relating to
digestive, skin, infective and respiratory problems (Lukhoba et al., 2006). Hausa potato besides agricultural
importance has ornamental, medicinal, curlinary and many other uses including perfume making and alcoholic
beverages. The plant in addition as reported by Kana et al. (2013) can be used as food protectants in just the
same manner as neem (Azadirachta indca) and pepper (Capsicum sp.). The crop contains saponins and
anthraquinones. Saponins have been reported to reduce blood cholesterol levels in humans, and ward off fungal
and viral infections. They also impair cell membrane integrity and ensure translocation of macromolecules across
cells (Okwu and Njoku, 2009; Kana et al., 2012; Enyiukwu and Awurum, 2013). Hausa potato finds topical
application as cicatrizants and antiseptics. In the ethnomedicine of African and Asian countries members of the
Coleus genera have been reported useful for treating dysentery , blood in urine , insomnia , convulsion , lung
Greener Journal of Agronomy, Forestry and Horticulture ISSN: 2354-2306 Vol. 2 (2), pp. 027-037, April 2014. 32
diseases, intestinal muscular spasms, glaucoma and heart diseases (Alleman, 2002; Kana et al., 2012;
Phunganya et al., 2013; My Agricultural Information Bank, 2013). Monoterpenoids, sesquiterpenes, diterpenes
and phenolics have been reported as some of the phtochemicals present in species of the genera Coleus with
the abietane diterpenoids being the most isolated from Plectranthus spp. Forskolin a high profile cardiographic
labdane diterpenoid has been extracted from the roots of the india-gown relative of Hausa potato Coleus forskolin
(Lukhoba et al., 2006; My Agricultural Information Bank, 2013). Hausa potato has been reported to contain
volatile oils, sesquiterpenes and diterpenes. For instance, 11-Hydroxy-12oxo-7,9(11), 13-abietatriene isolated
from Plectranthus elegans inhibited the spore germination of the fungus Cladosporium cucumerinum.
Monoterpenoids including humulene and β–caryophellene are known for their antimicrobial properties while
limonene, β-bisabolene and β–cubelene have anti-febrifuge properties (Lukhoba et al., 2006). In a recent
investigation, some researchers have isolated a number of biologically active ingredients from the leaves, stems
and tubers of Hausa potato. These are γ–muurolene (21%), α-humolene (12.5%), E-caryophyllene (5.67%), n-
dodecane (5.55%) and 1-octene-3-ol (4.63%). From the tubers however were obtained epi-α-cardinol (15.52%),
sesquiceneole (9.36%), cyperene (4.88%), epi-α-bisabolol (3.0%) and α-santalene (2.25%). These compounds
exhibited significant antibacterial activity against Pseudomonas aeroginosa, Escherichia coli and Staphylococcus
aereus (Phunganya et al., 2013). It follows therefore that these compounds are the underpinning reasons which
explain the ethno-medicinal and plant protection uses of Hausa potato plant leaves. Assessment of the above
ground tissues effect of the plant to rots of its tubers in storage is suggested in vitro and in vivo. In an evaluation
Okoko and Ere (2012) reported that leaf extract of Solenostemon monostachyus exhibited antioxidant activities
against free radicals, hydrogen peroxide, and hydroxyl radicals in vitro. And thus, the mode of action of leaf
extract of the species Solenostemon may be linked to the antioxidant properties of the plant. Subjection of the
plant to f urther screenings for active materials in our own environment may proof useful since presence and
concentration of these secondary metabolites in a plant are environment-mediated. Secondary metabolites from
spices and medicinal plants command on a worldwide scale US$14-20 billion, India alone makes US$60-72
million from them (Sofia et al., 2007; Trade Portal of India, 2013) with EU and the USA being the major importers.
Therefore screening and isolation of useful metabolites could improve not only our local pharmaceutical
industries but will amount to saving scarce foreign exchange for our local economy.
Storability of Hausa potato tubers
Hausa potato in general, has been reported as difficult to store crop (PROTA, 2013; Southern Times, 2013).
According to Alleman and Coertze (1997) tubers of the crop do not store well. This may be due to influences from
pathogenic rot organisms or enzymes-mediated deteriorations (Okigbo, 2004; Okigbo et al., 2009) particularly in
hot tropical sub-saharan Africa (SSA) where lack of storage facilities especially hi-tech storage facilities are
unavailable (Dung et al., 2010). Many methods have been devised in traditional farmsteads for storing the tubers.
In such systems tubers can be stored in the sand in well ventilated sheds (Appropedia, 2013) or in the ground
under a tree where it is cooler than the open, in this way the tubers could retain their aromatic flavour for up to 2
months post-harvesting (PROTA, 2013). In some cases remarked this source tubers of the crop are stored in
sacks in-laid with straws though it does not store long with this practice in hot farm conditions of SSA, or in
sealed earthen vessels especially in highland regions or South Africa (PROTA, 2013).
Rots lead to reduction in the quality of tubers and storable periods of the crop (Amadioha, 2012). Fungi
associated with the rot of Hausa potato tubers are Apergillus niger, Fusarium oxysporium, Rhizoctonia stolonifer
and Penicillium expansum with frequencies of occurrence as 19.69%, 16.4%, 14.38% and 12.81% respectively
(Mohammed et al., 2013a). Infection of the tubers as noted by Mohammed et al. (2013a) leads to discoloration,
change in flavor, emission of unpleasant odour and in some cases deposits of mycotoxins in the tubers.
Mycotoxins can cause cancer, birth defects, liver diseases and several other health problems (Bankole and
Adebanjo, 2003). In a recent investigation Mohammed et al. (2013b) evaluated the response of the tubers to ash
of Anogeiossus leiocarpus wood, saw dust, and chaff of Sorghum bicolor as storage media for the crop. They
reported A. leiocarpus ash to significantly reduce rots of the tuber from 78.81% in the control to 1.56% and
remarked that the pathogen A. niger was the most resistant to the other treatments. As mentioned earlier,
breeding for extended storable period of the tubers is imperative towards achieving food sufficiency and security
in Nigeria. Conventional breeding, Marker-assisted breeding and molecular/genetic modification of the crop
should be fervently researched and pursued to bring about the development of varieties capable of producing
tubers that can resist rot pathogens and/or enzymatic deteriorations and store longer after harvesting. Such
breeding programs may be collaborative with professionals from other scientific disciplines and will endeavour to
prolong the peculiar taste of Hausa potato tubers which is reportedly lost 2 weeks post harvesting in storage
(PRORA, 2013). These constraints have consigned the crop to minor root crop and confined its popularity to the
middle belt and Northeastern agro-ecological zones of Nigeria. Hence with focused research into the
pathologies, agronomic practices and techniques for storing Hausa potato tubers, its popularity and extent of
adoption will grow beyond its traditional areas of cultivation, given that the crop has good potential yield values
and the tubers have acceptable taste similar to that of Irish potato and trifoliate yam.
Chemical control of pathogenic diseases is one of the most effective means besides use of resistant
varieties in the management of diseases of plants. However this approach to disease control has many attendant
Greener Journal of Agronomy, Forestry and Horticulture ISSN: 2354-2306 Vol. 2 (2), pp. 027-037, April 2014. 33
drawbacks. According to Tripathi and Dubey (2004) the most important of these drawbacks are the stimulation of
development of resistance to fungicides by the pathogens and fungicides residues in crops which leads to
intermittent ingestions of toxic chemical compounds from foods. These compounds in the long run get
accumulated in the adipose tissues and milk of humans till toxic mammalian levels are attained and death ensues
(Enyiukwu, 2002; Taiga, 2011). Other demerits of synthetic pesticides include disruption of the food chain and
ecological health (Awurum and Nwaneri, 2010). Plant-based fungicides have been advocated as viable
alternatives by several investigators (Enyiukwu and Awurum, 2011; Amadioha; 2012). However relative to Hausa
potato and many other minor root crops investigations in this regard are lacking.
A vast range of research opportunities exist therefore in the evaluation of some tropical species against
rot and storage pathogens of Hausa potato. In addition, prospect also exist in molecular identification and
characterization of the pathogenic entities responsible for rot of the tubers. A similar feet was achieved recently
with regard to novel bacterial rot organisms of vegetable sweet potato in southwest Nigeria (Oladoye et al.,
2013). Proper pathogen identification is reported essential to tailoring effective management approaches to a
given disease problem (Than et al., 2008). For instance, proper pathogen identification is crucial to delaying of
appearance of resistance to a fungicidal formula against the pathogen; allowing for proper selection of fungicides
with different modes of action to combat the given pathogen than reliance on broad-spectrum, multi-site
fungicides (Brown, 2006) which are eco-disruptive (Taiga, 2009; Enyiukwu and Awurum, 2013).
Fungicides have remained a popular and effective input in agriculture following the discovery of boudeaux
mixture. They reduce attacks and infection from photosynthesis, water and nutrient uptake impairing-organisms
in the field, arrest the development of rot of produce in transit and storage as well as discourage or minimize
deposition of mycotoxins on stored food products (Suprapta, 2012). According to Amadioha (2004), extracts of
Azadirachta indica, Cymbopogon citratus and Ocimum gratissimum effectively checked charcoal rot of potato
caused by Rhizoctonia solani. Similarly Amadioha and Markson (2007a; 2007b) reported that phytochemicals
derived from Ageratum conyzoides and Piper nigrum checked the rot and deterioration of fresh cassava tuber in
storage induced by Botrydiplodia acerina and Rhizopus oryzae in vivo. In a parallel study, Ocimum gratissimum
was reported to check the rot of Egusi melon in storage incited by R. stolonifer, Aspergillus niger and Penicillium
italicum (Chuku et al., 2011). Taiga (2011) found that 40% aqueous extracts of Nicotinia tabacum inhibited the
growth and development of R. stolonifer causing postharvest rot of yams in Northern Nigeria. With regard to
sweet potatoes, Tijjani et al. (2013) reported that phytochemicals derived from Moringa sp. and A. indica retarded
the growth of R. stolonifer, an incitant of rot of yam tubers in Northern Nigeria. In a trial Anukworji et al. (2012)
demonstrated the effectiveness of Allium sativum, Garcinia kola, Azadirachta indica and Carica papaya on rot of
cocoyam corms caused by Penicillium spp and other pathogens. Similarly extracts from Dennettia tripetala
according to Nwachukwu and Osuji (2008) were fungitoxic and seriously prevented the rot of cocoyam corms in
storage. Da Costa et al. (2010) reported that neem seed oil effectively retarded production of aflatoxins B1 and
B2 by Aspergilus flavus for up to 95% in culture and the authors emphasized that the extracts possessed strong
anti-aflatoxigenic activity. In a related study, Reddy et al. (2010) found that solvent extracts of Zingiber offficinale
and Oxalis cornuculata suppressed both growth and aflatoxin production by the fungus A. flavus while Trigonella
foenum-graecum only checked production of aflatoxin by the fungus effectively without inhibiting significantly the
growth of the fungus. A comprehensive review of essential oils fungitoxic against aflatoxigenic fungi have been
done by Shukla et al. (2012). In like manner, a review of extracts and phytochemicals fungitoxic against rots and
rot inducing organisms are presented in Enyiukwu et al (2014a) and the mycotoxins they produce along with their
implications on animal and human health have been enumerated (Enyiukwu et al., 2014b). According to
Mohammed et al. (2013b) studies in Adamawa state of Northern Nigeria, with ash from Anogeiossus leiocarpus
wood revealed that it significantly inhibited the development and spread of tuber rot (Apergillus niger, Fusarium
oxysporium, Rhizoctoniastolonifer and Penicillium expansum) on Hausa potato (Solenostemon rotundifolius Poir)
in storage for four months. This pioneering research is indicative of prospects of controlling rots and rot-inducing
organisms with plant-derived pesticides in this crop. A parallel study demonstrated the fungitoxic properties and
antifungal activities of dehydrozigerone (DZ) from ginger on these pathogenic organisms. This compound
inhibited their spore germination, reduced their mycelial biomass and lysed or altered their hyphal morphology
(Kubra et al., 2012). However, investigations on the control of rots and aflatoxination of Hausa potato tubers; to
the best of our Knowledge are scanty and have not been fully documented. And therefore needs to be vigorously
researched and adopted.
Comparatively little is known about this interesting crop vis-a-viz other tuber crops such as sweet potato,
cassava and yams etc. However, the crop has good prospects as a delicate vegetable crop (PROTA, 2013).
Improvements in agronomic technologies for the crop is recommended as well as other high target areas such as
increased tuber size, developing non-branching tubers, tubers that store longer and retain their peculiar taste,
crop tolerance to waterlogging, aridity, and drought. These research prospects into Hausa potato improvements
have become inviting given the challenges of green house gas ( G H G ) emissions and climate change with
Greener Journal of Agronomy, Forestry and Horticulture ISSN: 2354-2306 Vol. 2 (2), pp. 027-037, April 2014. 34
pronounced constraints against crop production and food security; so as to enable the crop contribute its quota to
food security in Nigeria and elsewhere. To achieve all these will entail:
Renewed interest by governments and NGOs to fund scientific research in breeding for Hausa potato
Studies on the biochemical properties of the nutrient components of the tubers especially carbohydrate to
determine its tolerance by diabetics.
Improved agronomic and management technologies for the crop to increase yields.
Intensive and aggressive extension services to encourage the crop adoption.
Incentives to the growers such as zero interest loans to boost their production.
Value addition in time and utilityfor the crop,
Low-tech integrable storage methods and practices for tubers of the crop.
Low-tech tuber rot control techniques and phyto-pesticides use in its tuber rot management.
Exploitation of the aromatic and medicinal properties of the crop for pharmaceutical and culinary products
Organized market economy to elevate the crop to cash earning status.
Hausa potato holds potential to become an important crop which could be cultivated beyond its present areas of
adoption. However, the issues of determining and improving its production techniques demand urgent research
attention. Above all, its tubers have been noted as difficult to store due to pathogenic influences. Therefore
studies to address these issues to proffer best-practices at overcoming them are imperative. There is need, to
develop value chains for the crop to reduce wastages, make available foods of better quality and permit fuller and
better utilization of the tubers in national dietaries to ensure food security and improved farm economy.
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... This maturity period is in line with the results of Kana et al. [21] and Enyiukwu et al. [2] that frafra potatoes mature within 5-6 months after planting. The number of days to maturity correlated negatively with the tuber yield (r = -0.21), ...
... The tuber yield of the six varieties in this study under the rainfall condition, without the addition of manure or fertilizers is encouraging (plate 6). This was higher than the projected 5-15 t/ha under favorable growth conditions [3], which was an even lower value than the postulated 45 MT/Ha [2,22]. It is, therefore, obvious that a very high yield of frafra potatoes is achievable at the study site under optimum growth conditions. ...
... Though there was a decrease in rainfall by the 8 th WAP, and consequent decline in leaf growth; the rate of increase in leaf area within 4-8 WAP was higher than from 10-12 WAP, when rains were rather heavier (Fig 2A). The reduction in leaf expansion within that growth phase could be due to plants approaching maturity, and leaves attaining their maximum sizes or due to excessive soil moisture [2]. ...
... Black potato originates from tropical Africa, where it is still found as a native plant in East Africa, but can now be found cultivated in other parts of the world including countries like Sri Lanka, India, Indonesia, Thailand and Malaysia [6], [7], [9], [11], [21], [22], [23], [24], [25], [26]. Common names of this potato include Black potato, Hausa potato, Country potato, Coleus potato, Chinese potato, Zulu potato, Frafra potato, Sudan potato and "ubi kemili" [6], [17], [22], [24], [27]. ...
... Black potato originates from tropical Africa, where it is still found as a native plant in East Africa, but can now be found cultivated in other parts of the world including countries like Sri Lanka, India, Indonesia, Thailand and Malaysia [6], [7], [9], [11], [21], [22], [23], [24], [25], [26]. Common names of this potato include Black potato, Hausa potato, Country potato, Coleus potato, Chinese potato, Zulu potato, Frafra potato, Sudan potato and "ubi kemili" [6], [17], [22], [24], [27]. Black potato is a perennial herbaceous crop belonging to the Lamiaceae mint family [17], [21], [24]. ...
... Due to its low glycaemic index, black potato can also reduce the risk of diabetes and obesity [19], [23], [25]. It has been reported that 100 g of black potato has 21 g of carbohydrate, slightly higher than the same portion of potato (17 g) and sweet potato (20 g) [9], [22], [23], [25]. Compared with other tubers, a standard serving provides a large percentage of the daily required calcium, vitamin A and more than the daily required iron [9], [12], [24]. ...
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Plectranthus rotundifolius (synonym: Solenostemon rotundifolius) (black potato) is an underutilised nutrient-rich crop that has the potential to contribute to food and nutritional security. We examined the macronutrient and selected mineral content of black potato bought at a morning market located in the state of Pahang, Peninsular Malaysia. The proximate composition of the tubers observed in % were, moisture (78.14 ± 0.84); crude protein (0.84 ± 0.06); crude fat (0.48 ± 0.06); crude fibre (2.03 ± 0.12); ash (1.63 ± 0.13); carbohydrate (18.92 ± 0.73) and energy in kcal/100g (83.32 ± 3.46). The mineral content observed in mg/kg were calcium (336.57 ± 21.71), iron (48.20 ± 3.64), potassium (12025.07 ± 485.33), magnesium (1346.63 ± 101.24), sodium (68.23 ± 2.62), manganese (6.67 ± 0.21) and phosphorus (978.00 ± 7.72). Comparison of black potato with some popular tubers such as potato, sweet potato and cassava found that black potato had less crude protein and crude fat. The carbohydrate and the energy contents of black potato were within the same range as potato and sweet potato but lower than those observed in cassava. The ash content of black potato was higher than that of potato, sweet potato and cassava and it also had a higher mineral content. Compared with popular tuber crops such as potato, sweet potato and cassava, black potato was observed to have higher mineral content that fulfils the requirements of the Recommended Nutrient Intake as outlined in the Dietary Guideline for American male and female aged between 31 to 50.
... Unlike cereals, tubers and roots contain relatively high amounts direct sunlight and can tolerant to marginal conditions such as high temperatures and rainfall. Aside from its productivity of crops, the ausa potato has ornamental, medicinal, culinary, and a variety of other purposes, including the production of perfume and alcoholic beverages ( Enyiukwu et al., 2014 ). Hausa potato is an underutilized nutrient-rich tuber that can contribute to food and nutritional security ( Sethuraman et al., 2020 ). ...
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The aim of this work was to characterize morphological, crystalline property, physicochemical, functional, thermal, pasting, rheological properties, and in vitro digestibility of starch and flour from Plectranthus rotundifolius (Hausa potato). Chemical composition analysis showed a significant difference (p ≤ 0.05) between the Hausa potato starch and flour, and the amylose content of starch (30.44 %) was substantially greater than that of flour (20.57 %). SEM study showed that Hausa potato starch granule size varies from 3.31 μm to 6.61 μm having a morphology of some truncated circular shapes on a smooth granule surface. Hausa potato starch and flour exhibited a similar FT-IR pattern and A-type crystallinity. Howbeit, the relative crystallinity (obtained from XRD) of starch was significantly higher (p ≤ 0.05) than flour. The functional properties, including water and oil absorption capacity and solubility of flour, were significantly higher (p ≤ 0.05) than starch. RVA analysis observed that Hausa potato starch had a higher value in pasting properties compared to its flour. Enthalpy of gelatinization calculated from DSC showed that Hausa potato starch was significantly higher (p ≤ 0.05) than the flour. Hausa potato flour has a significantly greater (p ≤ 0.05) slowly digestible starch and resistant starch value than its starch. The study showed that starch and flour of Hausa potato significantly differed from each other. Better physicochemical and structural properties of Hausa potato starch can be explored as a non-conventional source of starch for various applications, and flour can be used as a useful functional ingredient in the food industry.
... The ash content of black potato flour ranges from 4 to 5%. In Nigeria, black potatoes (Hausa potato) generally have mineral contents, such as calcium (17 mg/100 mg) and iron (6 mg/100 mg) (Enyiukwu et al., 2014). The ash content of black potatoes is higher than the ash content of taro (1.3%) and potatoes (1.9%), yet lower than that of sweet potatoes (4.4%) (Kaur et al., 2011;Kamal et al., 2014). ...
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Coleus tuberous (local name: kentang hitam/black potato) is widely available in Indonesia. Commonly, black potatoes are only boiled and made into side dishes. Black potatoes have the potential to be the ingredient of functional foods. However, black potatoes can only be harvested once a year. Therefore, a low moisture form (flour) storage is required for longer shelf life. Research on physicochemical and functional characteristics of black potato flour is expected to widen the use of black potato flour as raw materials in various food products. This study was aimed to analyze the chemical, physical, and functional characteristics of black potato flour originating from Sunthi (Jaten), Begal, and Kopenan Forest villages in East Java, Indonesia. All the measurements were carried out with three replications and analyzed using one-way ANOVA, then followed by the Tukey test to find the difference from each sample at a 0.05 significance level. The correlation analysis and principal component analysis were also subjected to study the relationship between each character of the samples. The result indicated that the tuber and starch have relatively high ash, amylose, and total phenol concentration. Several high correlations were found between the characteristics of the black potato flours. One of the high correlations was the water absorption index with starch, amylose, and total phenolic content. The principal component analysis (PCA) also found that the three samples were loading differently in the score plot. Two first principal components (PCs) were the contributing factor for 100% of the differences.
... Production constraints identified in some studies were limited access to planting materials, use of local varieties, pests and diseases damage, low yield, and high postharvest losses. In other studies, rapid tuber decay, small size of tubers, ease of peeling, and short period of availability, were the major challenges in Ghana, Nigeria and Burkina Faso [7,8]. In addition, the tubers break natural dormancy by 3 months after harvest and become fibrous, and thus less suitable for consumption. ...
... The infestations of pathogens and pests on the black potato plants were initially controlled by the usage of fungicides and insecticides. However, their use is being de-emphasized due to the ecological and human health consideration caused by its residues in the crops (Enyiukwu et al., 2014). ...
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Plectranthus rotundifolius (Lamiales: Lamiaceae) is an edible tuber that is widely distributed in Asia, covering India, Sri Lanka, Malaysia, and Indonesia. P. rotundifolius, which is commonly called black potato in Indonesia, has the potential to be developed for national food diversification due to its high carbohydrates. However, one of the challenges in black potato cultivation is the existence of leaf-eating caterpillar. This study aimed to evaluate the status of Paliga auratalis (Lepidoptera: Crambidae) larva as an insect pest in black potato plant and to develop the control strategy by using parasitoid as the natural enemies. Observation and collection of P. auratalis and other potential insect pests were conducted in 12 black potato plantations located in five provinces of Java island. The life cycle of P. auratalis was observed in the laboratory of Zoology Division, Research Centre for Biology, Indonesian Institute of Science. Rearing of unhealthy P. auratalis larvae was also conducted to observe the parasitoid. We identified five moth larvae species that infested black potato plants: Argyrograma sp., Pycnarmon cribata, Pleuroptya punctimarginalis, Rehimena diemenalis, and Paliga auratalis. Our results showed that P. auratalis larva is the main insect pest in Java island with the serious attack status and black potato was recorded as a new host plant. Paliga auratalis spends its lifecycle from eggs to adulthood between 25 – 32 days with a total number of eggs of about 60-80 per female individual. We also identified two parasitic wasps as the parasitoid of P.auratalis: Cryptopimpla sp. (Hymenoptera: Ichneumonidae) and Aspanteles sp. (Lepidoptera: Barconidae), which can potentially be developed as biological control agents for P. auratalis.
The noncultivated or nondomesticated food plants that are collected from the wild natural habitats for consumption are called wild food plants (WFPs). They enrich the dietary diversity and significantly contribute to the micro and macronutrients of the body. WFPs are popular as a potential source of income for the local communities, and they ensure food supply during famine periods. The capacity to survive in harsh environmental conditions contributes to the stress adaptation potential of the these plants. Therefore, WFPs can be explored as a climate change adaptation strategy or resilient plants for agriculture. In the scenario of climate change, nutritional and yield reduction of the staple crops, wide diversity of WFPs with regional adaptations can be utilized for crop improvement programs and can significantly improve food security. The popularity of WFPs among ethnic communities is a link between traditional knowledge and modern scientific systems. But the traditional knowledge related to WFPs is being lost. Loss of traditional knowledge related to the WFPs has also threatened their existence. Therefore, it is essential to document and conserve the WFPs and promote their consumption globally. The popularization of WFPs can help to eradicate the hidden hunger and malnutrition among the population since they are a cheap source of locally available nutrient-rich food. The genetic diversity of the WFPs should be protected, and several crop improvement programs can be applied to improve the traits of the plant. The effective exploration of the diversity of WFPs can directly contribute to achieving zero hunger by 2030.KeywordsWild food plantsFood securityClimate resilienceFood securityNutritional deficiency
Conference Paper
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Field experiments were carried out on Frafra potato (FP) during the 2019 and 2020 cropping seasons at the Manga Agricultural Station, near Bawku, in the Upper East Region of Ghana. The aim of the experiment was to determine the effects of different bed sizes, plant spacing and propagules on the yield and yield components of FP. The experimental design was spit-split-plot; where bed size (small, medium and large) was the main plot, propagules (stem cuttings and seed’ tubers) assigned to the sub-plot, and Intra-row spacing (20, 25 and 30cm) assigned to subsub plot. Data collected included days to 50% flowering, tuber count, tuber yield and tuber size distribution. The results did not show significant (P<0.05) interaction among the three factors) for all the traits evaluated. Flowering was significantly (P<0.05) earlier in treatments involving stem cutting compared to ‘seed’ tubers. Bed size significantly (P<0.05) affected tuber size distribution, with large beds recording the highest percentage of large tubers while the small beds accounted for the highest percentage of small tubers in both years. Stem cuttings accounted for higher percentage of large tubers while the ‘seed’ tubers recorded a higher percentage of small tubers. The highest percentage of small tubers was recorded at 20 cm while the highest percentage of large tubers was accounted for by the 30 cm spacing in both years. Where the production of large tubers is the top priority, this study found that large beds, stem cuttings and 30 cm spacing could be used.
Many indigenous Nigerian plant species that served as foods several years ago are presently neglected and going extinct. The major challenge is that they are considered as food for low-income earners because there is little or no knowledge of the value additions made to these crops. Most of these species of crops are highly nutritious and can produce under marginal growing conditions therefore, they can be used to combat hidden hunger and food insecurity. This work is a compilation of research work performed over the years on some neglected Nigerian root and tuber crops: sweet potato (Ipomoea batatas); Polynesian arrowroot (Tacca leontopetaloides); water yam (Dioscorea alata); arieal yam (Dioscorea bulbifera); cocoyam (Colocasia esculanta) and Hausa potato (Solenostemon rotundifolius). The nutritional contents or food qualities of the above crops were highlighted and also the various ways of adding value to some of the crops were identified and discussed along their value chains. The purpose of this work is to bring out the need to refocus attention on these crops for increased food production, conservation of the crops and subsequent food security in Nigeria.
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Laboratory experiment was conducted in the Microbiology to determine the antifungal effect of different concentrations of neem and moringa seed extracts on wet rot disease of sweet potato. Moringa and neem seed extracts each with four varying concentrations (30,60,90,and 120g/L) were evaluated along with carbendazim and untreated sweet potato serving as a control constittuted the treatments. The treatment were laid out in Completely Randomized Design (CRD) with three replications. The result showed that neem seed extact was significantly (P < 0.01) better than th moringa seed extract in controlling the disease. Treatment of the sweet potato with varying concentrations of neem and moringa seed extracts significantly (P < 0.01) inhibited radial mycilial growth of R. stolonifer and also reduce the weight loss of sweet potatoes caused by R. stolonifer compared with the control, except the application of 25g/1 of moringa seed extract. Preventive method of control significantly reduce the disease than the curative method. The effectiveness of the two plants seed extracts compared favourably with carbendzim. The study revealed that there exist a potential in natural plant products for the control of crop diseases, and if fully exploited, they can replace chemical pesticide in the control of crop diseses. It is therefore recommended that farmers should used 90g/1 or120g/1 as postharvest treatment for sweet potatoes before storage as control measure for R. stolonifer.
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Extracts of Piper guineense seeds and fungitoxicity against the radial growth of cowpea. The experiment was laid out in a co treatments and 5 replications and was repeated twice. the growth of the fungi irrespective of concentration of application. This was followed by roots extracts while C. papaya compared favourably (P≥0.05) with benomyl in fungitoxicity to the pathogen, hence a possible source of natural pesticide against the organism.
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Cowpea anthracnose (Colletotrichum destructivum the affected crop. Inappropriate use of synthetic fungicides for its control contributes to toxicological problems in the food chain and the environment. Rece of novel chemotherapeutants for plant health management. In previous studies, and Carica papaya roots and seeds extracts had inhibited the spores of the pathogen. However, their phytochemical compositions have not been fully documented. This study therefore, aims at determining the phytoconstituents of these plant materials. The results revealed the presence of alkaloids, flavonoids, tannins, saponins, phenols as well as glycosides, te materials. Quantitative tests showed that alkaloids ranged between (0.62 2.64%), flavonoids (0.34 – 1.11%), tannins (0.22 were absent in Piper gunieense seeds while seeds extract of and steroids. The significance of these bioactive compounds against evaluated on PDA-Extract medium in Petri dishes. The experiment consisted of 5 treatments and 5 replications.and was repeated twice being laid out in completely randomized design (CRD). Piperguineense severely inhibited the radial growth of the (p>0.05) with 95.644% obtained from benomyl. This was followed by seeds extract of C. papaya was the least in inhibition effect (24.20%) though they did not differ (p>0.05) statistically from each other. sources of natural pesticides against the pathogen.
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The most important losses in agricultural production which involve the greatest costs on the farm economy occur postharvest. It is estimated that worldwide between 10 and 40% losses of agricultural produce occur postharvest. Losses are more severe in developing than developed nations of the world. Several species of fungi and in some cases bacteria participate in postharvest deterioration and rots of tubers and agro-produce. These include species of Aspergillus, Fusarium, Colletotrichum, Macrophomina, Penicillium and Rhizopus amongst several others. In a bid to control these storage diseases several control techniques including physical, biological, and chemical and in recent times plant-based pesticides are employed. Chemical control has been identified as the most popular and most effective means of controlling plant diseases. However, it is being de-emphasized due largely to mammalian toxicity occasioned by chemical residues in crops. This in addition to many other demerits on ecological health and build-up of pathogens' resistance to some of the most effective fungicides have prompted search for alternatives. Recently in plant pathology many tropical plants are being screened for fungitoxic properties. This review presents highlights of the different control techniques and emphasized the efficacy of plant-based pesticides for control of myco-induced storage rots of tubers and agricultural products in the tropics.
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Mycotoxins are toxic secondary metabolites from some species of Aspergillus , Fusarium Penicillium and their related fungi. Their contamination results generally in inferior quality of produce and produce end-products, food safety and ultimately barriers trans-border marketability of agro-produce. Though the presence of mycotoxigenic fungus on produce does not always translate to presence of mycotoxins; however, mycotoxins are silent killers and their effects could be submerged over a long period of time especially during intermittent exposures. These fungal toxins when ingested or inhaled participate in several metabolic dysfunctions in human and livestock systems such as immunological imbalance, cancers, allergies, abortions and in some cases death of the affected hosts. Conditions of high temperatures and relative humidity coupled with poor store standards and hygiene which characterized tropical subsistence farmsteads encourage mouldiness and mycotoxin contamination of agricultural products. The mycotoxins of most agricultural importance (aflatoxins, fumonisins, ochratoxins, trichothecenes) were enumerated in this review while their management strategies were also highlighted; with emphasis on plant-derived anti-mycotoxigenic interventions useable in low-input agricultural production systems of sub-Saharan Africa. Keywords: Mycotoxins, plant-derived fungicides, Aspergillus spp ., Fusarium spp ., Penicillium spp ., trichothecenes.
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Effects of leaf extracts of Ocimum gratissimum and Aframomum melegueta on spore germination and mycelial reduction of the most occurring fungal pathogen causing soft rot of yam tuber were investigated. Fungi isolated from rotted yams were Aspergillus niger, A. flavus, Fusarium oxsporium Rhizopus stolonifer, Botryodiplodia theobromae and Penicillium chrysogenum. The leaf extracts with ethanol extraction were most effective followed by cold-water and hot water extraction. The fungicidal activity with Ocimum gratissimum leaf extracts was more effective. In vitro inoculation of fresh yam with A. niger, A. flavus and F. oxsporum at room temperature for 3 months showed typical rot symptoms characteristic of the disease. The significance of these findings is discussed in relation to plant chemical or non-chemical means of disease control on yams in Africa.
Four fungi (Fusarium oxysporium, Aspergillus niger, Rhizopus stolonifer, Penicilium oxalicum) pathogens associated with dry rot of yam (Dioscorea rotundata) tubers were isolated. The efficacy of three plants extracts (Azadirachta indica, Nicotiana tabacum and Aloe barbadensis) were tested in vivo on the fungal pathogens. The 30 and 40% concentrations of cold and hot extracts of N. tabacum, completely prevented rot-depth caused by the four isolated pathogens (F. oxysporium, R. stolonifer,P. oxalicum and A. niger) in the yam tubers tested. Only the hot extract of A. barbadensis at 20, 30 and 40% concentrations completely prevented rot caused by F. oxysporium, R. stolonifer and P. oxalicum, while only the 40% concentration of its cold extract had similar effect on only the three pathogens like the hot extract. Also, only 30 and 40% concentrations of hot extract of A. indica prevented rot lesions caused by three of the pathogens (F. oxysporium, R. stolonifer and P. oxalicum), The hot extract of N. tabacum was most fungitoxic, followed by hot extracts of A. barbadensis and A. indica respectively.