eduzhai > Life Sciences > Agricultural >

Agriculture: crop and livestock development systems

  • sky
  • (0) Download
  • 20211029
  • Save
https://www.eduzhai.net/ International Journal of Agriculture and Forestry 2016, 6(2): 74-79 DOI: 10.5923/j.ijaf.20160602.03 Agriculture: A Crop and Livestock Development System Benjamin E. Uchola Faculty of Agriculture, Federal University, Dutsin-ma, Nigeria Abstract Agriculture is generally defined as the cultivation of crops, rearing of livestock and efficient use of production inputs. But the study uses the domestication of plant and animal resources as an introduction to agriculture and its sub-sectors. One aspect of domestication involves the relocation of a resource or their parts to human-controlled environments. The other aspect entails selection of individuals that manifest superior performance in maturation time, yields and other production traits. Series of selection pressures progressively drive a plant resource into becoming a crop and an animal resource into a livestock. The complete transformation of a resource into a domesticate results in the development of different sub-sectors of agriculture such as aquaculture, horticulture and silviculture. Lack of due attention to agriculture as a “crop and livestock development system” is partly responsible for food insecurity in developing societies. Keywords Agriculture sub-sectors, Crop development, Resource domestication, Livestock development 1. Introduction The production of valuable products and its organisation has been changing since the onset of the “Neolithic Revolution”. This new form of production, which gradually replaced the exploitation of natural resources, may have been triggered by changes in climatic conditions, distribution pattern of food organisms and human population size [1, 2]. In the course of its gradual development, agriculture became a form of production that involves the establishment of human-controlled environments, invention of production units and practice of cultural methods. As a result, agriculture is associated solely with the cultivation of crops in fields or plantations, rearing of livestock in production pens or integration of different production units [3-6]. Agricultural production initially satisfied the food requirements of households but evolved into a form that meets the demand of communities and industries. As a form of production that depends on the use of inputs, the scope of agriculture may be expanded to include the efficient use of production inputs [7, 8]. The evolution of agriculture, from its simple to modern form, contributes to the development of human societies. Production of food products encouraged the ancients who were wanderers to embrace the sedentary lifestyle as well as facilitated the growth of trade through exchange of different farm products [2, 9]. Even more, the effect of surplus production in agrarian societies is novel as it freed some individuals to express other creative abilities such as writing * Corresponding author: buchola@fudutsinma.edu.ng (Benjamin E. Uchola) Published online at https://www.eduzhai.net Copyright © 2016 Scientific & Academic Publishing. All Rights Reserved and wood carving. Nevertheless, developing societies are often confronted with challenges in the process of organising agriculture into a form that can meet their growing requirement for food and raw materials. In most cases, there is a dearth of knowledge concerning the inherent nature of agriculture as a development system. This inadequacy finds expression in frequent changes in policy, frequent changes in institutional arrangements for agricultural research and instability in research governance [10-12]. There is, therefore, a need to understand the nature of agriculture as a development system. Domestication provides a means to a better understanding of agriculture since it is an attempt to secure the supply of plant and animal products [13, 14]. For this reason, the present study explores the transformation of a resource into a crop or livestock as an introduction to agriculture. 2. Resource Domestication: An Overview Some biotic components of the environment are of direct benefit to humans. The utility value of several plants and animals makes each one of them a resource [13, 14]. A plant resource is a potential candidate for domestication. Valued plants are often transferred from their natural habitat to artificial environments. Seeds of rubber tree (Hevea brasiliensis) were collected from the Amazonian forest, nursed into seedlings in a botanical garden before their transfer to Southeast (SE) Asia [15, 16]. In SE Asia, generations of garden-grown rubber seedlings flourished into extensive plantations across the region. Like the case of rubber, relocated seedlings oil palm (Elaeis guineensis) and their generations manifest faster growth rate in artificial environments due to favourable climatic conditions. In more International Journal of Agriculture and Forestry 2016, 6(2): 74-79 75 specific terms, individuals that were selected from field-grown dura populations produced higher yields when compared to previous generations and their semi-wild counterparts [17-20]. Even more, thick-shelled dura populations when crossed with the best of shell-less pisifera populations produced a thin-shelled fruit type also known as tenera [21]. The tenera yields more oil, given its reduced shell thickness and increased mesocarp size, making it the preferred planting materials in major oil palm projects. In this way, the transformation of the oil palm into a crop demonstrates the main aspects of Plant Resource Domestication (PRD), namely; relocation to human-controlled environments and selection of desired production traits. These main aspects of PRD are evident in all crops including rice (Oryza sativa) [22-24] and macadamia (Macadamia integrifoIia) [25, 26]. A valued animal is also a potential candidate for domestication. Common carp (Cyprinus carpio) was introduced into reservoirs from the Danube River and their successive generations flourished into present day cultured carp [27, 28]. Likewise, quails (Coturnix japanicus) were captured from the wild and transferred to confined conditions [29, 30]. Interestingly, selection for body weight and other production traits in captive populations produced better performances [31-33]. Domestication therefore facilitates better expression of production traits in a resource. The relocation of oil palm, to human-controlled environments and the improvements of its production traits, has reduced the age at maturity to about 2 years and increased yield to 24-32 tonnes per hectare in well managed plantations [20, 34]. Likewise, artificial selection in plantation-grown rubber tree increased latex yield from 400 pounds per acre in the earliest rubber plantings to over 3500 pounds per acre in modern selected clones [16, 35]. Similar improvements accompany the domestication of red jungle fowl (Gallus gallus) when its body weight (< 300g) is compared to those of improved meat breeds of domestic chicken (>1200g) within the same period [36, 37]. Selection for milk yield has improved the production of milk in cattle given the differences in performance between local breeds (< 900kg) and pure breeds (> 2000kg) within the same period [38, 39]. 3. Resource Domestication & the Sub-sectors of Agriculture The transformation of a resource into a crop or livestock initiates and expands a sector of agriculture. The development of aquaculture species is directly responsible for the advancement of aquaculture as a production unit in agriculture [27, 40, 41]. Horticulture, silviculture and other sections of agriculture owe their origin and expansion to the domestication of a resource [13, 14]. Several other plant resources have already been transformed into crops while relatively few animal resources are used as livestock (Table 1). Table 1. Selected resources and their crop or livestock equivalent Wild Plant Apple Potato Rice Rubber Wild Fish Carp Tilapia Wild Animal Auroch (Wild cattle) Bezoar (Wild goat) Mouflon (Wild sheep) Red Junge Fowl Genus Malus Solanum Oryza Hevea GENUS Cyprinus Oreochromis Genus Bos Capra Ovis Gallus PLANT RESOURCES [13] Species Estimate Wild Progenitor above 27 M. sieversii 206-232 Solanum brevicaule complex O. breviligulata 21 O.nivara/ O. rufipogon 9 H.brasiliensis FISH RESOURCES [27, 40, 41] Species Estimates Wild Progenitor 1 3 sub-species Cyprinus c. carpio 1 O. niloticus ANIMAL RESOURCES [14] Species Estimates Wild Progenitor 1 3 sub-species B.p. primigenius + B.p.opisthonomous B.p. nomadicus 8-9 C.a. aegagrus 6 Ovis orientalis 4 Gallus gallus Cutivated Species M. domestica 7 species; S.tuberosum (globally) O. glaberrima O. sativa H.brasiliensis Cultured Species Cyprinus c. carpio O. niloticus Domestic Species Bos Taurus Bos indicus C. a. hircus Ovis aries G. domesticus 76 Benjamin E. Uchola: Agriculture: A Crop and Livestock Development System A wild plant or animal may be transferred from its natural habitat to human-controlled environments, for the purpose of domestication, whenever it is adjudged to be of immense value. Some of the on-going Resource Domestication programmes include those of the quinoa [42, 43], African bush mango [44,-47], African catfish [48, 49] and cane rat [50-53]. 3.1. Quinoa (Chenopodium quinoa) The quinoa is a native South American plant with a long history of cultivation. Grains of quinoa contain a bitter substance, saponin, believed to be one of the major factors that has restricted its spread to other continents. More recently, selection for certain traits allowed the development of new varieties of quinoa with higher yields and saponin-free grains [42, 43]. These improvements are changing the status of this native South American crop to a crop of global importance [54, 55]. 3.2. African Bush Mango (Irvingia gabonensis) The African bush mango is a tree found in the rainforest of Africa. It is one of the trees that were recently subjected to the process of domestication because of its utility value [13]. The tree, which can now be propagated through vegetative methods, has been transferred onto fields [44, 45]. Field-grown bush mango attains maturity in about half the period of its wild counterpart [46, 47]. Even more, the selection of superior genotypes within populations of field-grown bush mango is expected to complete the process of its domestication. 3.3. African Catfish (Clarias gariepinus) The African catfish is endemic to the rivers of Africa. Introduction of this catfish into controlled environments altered the seasonal pattern of its reproduction [48, 49, 56]. However, the chance of producing large quantities of fingerlings at any period of the year is low due to the production of few eggs. This challenge has been resolved through the administration of hormones (hypophysation) which aids the spawning of large quantity of eggs [48, 57]. In addition, pond-reared catfish accepts formulated diets, grows faster and attain maturity in about half the time taken by its wild counterpart [5, 49]. These positive signs encouraged initiatives that are aimed at transforming the African catfish into a complete aquatic livestock [58]. 3.4. Cane Rat (Thryonomys swinderianus) The cane rat is one of the animal resources in West and Central Africa. For this reason, the animal was transferred to human-controlled environments where it displayed faster growth rate and larger litter size [50, 51, 59]. There is a likelihood of transforming the cane rat into a livestock, through artificial selection, given the modest to high heritability values for growth and other production traits [50, 51]. Table 2. Selected crops, aquaculture species, livestock including varieties and breeds Crop Apple Potato Rice Rubber Cultured Species Carp Nile Tilapia Domestic Animal Cattle Goat Sheep Chicken CROP & SELECTED VARIETIES/ CULTIVAR/ CLONES Major varieties/ cultivars/ clones Malus domestica Brown, Circassian, Gala, Red, Paide's Winter, Wealthy [60]. Solanum tuberosum Atahualpa, Nicola, Russet Burbank, Tubira, Vitelotte [61] Oryza sativa Kimboka, Agora, Sookha Dhan 5, NSIC Rc 25, NSIC Rc 360 [62] Hevea brasiliensis GT l, Tjir, PB 86, PB 312, RRII 105 [35] AQUACULTURE SPECIES & SELECTED STRAINS Selected Strains Cyprinus carpio Germany mirror, Jian, Lotus, Songpu, Scattered mirror [52] Hybrids of female O.niloticus and O. aureus, O. macrochir, O. mossambicus, O. urolepis hornorum, O. spilurus niger [53] LIVESTOCK & SELECTED BREEDS Selected Trans-boundary Breeds Bos Taurus & Bos indicus Meat breeds: Aberdeen Angus, Braford, Braham, Dexter, Normande, Diary breeds: Ayrshire, Brown Swiss, Guernsey, Holstein, Jersey[63] C. a. hircus Anglo-Nubian, Boar, Bengal, Murciana, West African Dwarf [63] Meat Breed: Ovis aries Bornu, Dorper, Masai, Nguni Wool Breed: Ovis aries Australian merino, Corriedale, Devon longwool, Quessant, Romey [63] Egg Breed: Gallus domesticus Australorp, Legbar, Minorca, Dual-purpose Breed: Gallus domesticus Bresse, NewHampshire, Plymouth rock. Meat Breed: Gallus domesticus Fayoumi, Dokki, Jersey Giant [63] International Journal of Agriculture and Forestry 2016, 6(2): 74-79 77 The on-going domestication of bush mango gives an insight into the origin of other fruit trees and by extension horticulture. In the same way, the progress made in the process of domesticating the African catfish, makes present the history of aquaculture species and advances in aquaculture. Accordingly, there is an expectation that the cane rat, which is currently undergoing domestication, is on its way to becoming a livestock. This expectation includes a further selection of cane rat into breeds just as other livestock have breeds (Table 2). 4. Resource Domestication as a Development Principle in Agriculture Present domestication programmes and those of previous generations adopt similar procedures. Relocation of bush mango from the wild into field banks is similar to the introduction of oil palm into cultivated gardens [17, 19, 44, 46]. Likewise, the transfer of the African catfish from the rivers of Africa to artificial environments in Europe follows that same trend as the transportation of wild common carp from the Danube River into reservoirs [27, 28, 48, 49]. In the same way, the steps taken to improve production traits in cane rat is in line with those applied to other animal resources that were transformed into livestock [52, 53]. Relocation of a resource to human-controlled environments produces change in growth and production pattern. For instance, the bush mango grows for over a decade before the onset of maturity but its growth period is reduced to about 5 years when introduced into human-controlled environments [46, 47]. Like the bush mango, the growth period of a macadamia tree may extend up to two decades before maturity. However, nursery-grown seedlings take 4-6 years to mature after their transplantation onto cultivated fields [25, 26]. Similar effects of domestication on reproduction performance include those in African catfish and Japanese quail. Maturation of gonads in catfish is seasonal due to annual changes in water temperature, photoperiod and water levels. But the same gonads remain mature throughout the year in controlled environments where those factors are maintained at satisfactory levels [48, 49, 56]. Like in the African catfish, the laying of eggs by wild quails is a seasonal event but it is an almost daily exercise in human-controlled environments [30]. Generally, these achievements introduce the next phase of domestication, which is, artificial selection in established populations of a resource. Artificial selection often results in organisms with superior production performances. For instance, cultivated rice is susceptible to the rice grassy stunt virus (RGSV) which decreases rice yield significantly but becomes resistant to the disease through selective breeding programs [22, 23]. Given the differences in body weights of red jungle fowl ( < 300g) and that of improved meat breeds of chicken ( > 2000g) of the same age [36, 37], artificial selection for body weight improved meat yield 5 to 10 times. Selection also improves milk production given the differences in performance of local breeds of cattle (< 900kg) and those of improved breeds (> 2300kg) within the same period [38, 39]. The discussion reveals that both crops and livestock are products of the domestication process. From this perspective, domestication is a principle that controls the transition of a plant resource into a crop, in the same way, as it transforms an animal resource into a livestock [13, 14]. Put differently, domestication transforms primitive resources into highly productive crops and livestock. At the advanced level of plant and animal development, there is a function-based specialization in domesticates: rubber is grown exclusively for latex, certain birds are reared for eggs while some cattle are raised for milk (Table 2). This is the pattern of crop and livestock development in all the domestication centres from those in Southeast Asia to those in the Andean region of South America. 5. Conclusions In developing societies, the practice of agriculture is based mainly on the cultivation of crops and rearing of livestock. This narrow version neglects the role of agriculture as a crop and livestock development system. Not surprising, this narrow version of agriculture eventual proves to be ineffective in addressing the food and raw material needs of those societies for the following reasons: First, there is an under-utilization of available lands since most crops do not thrive in drought-prone areas and soils with high salt content. Next, yield is often low as the productivity of existing crops and livestock remains constant and may decline in extreme climatic conditions. Furthermore, crops and livestock are often prone to new diseases such as the rice grassy stunt virus (RGSV) and dermatophilosis in cattle, both of which negatively affect production output. Finally, the narrow version of agriculture lacks the capacity to diversify its crop and livestock base. To overcome these limitations, agriculture may have to be organised in such a way that it includes the development of new crops and livestock as well as the improvement of existing ones into novel varieties and breeds. For instance, the development of salt-tolerant varieties of rice expands land area that may be used for rice cultivation, the artificial selection of high-yielding rice varieties increases the yield of rice per hectare while RGSV-resistant varieties prevents the loss of rice yield in a large scale. From this position, a society’s quest for security in food and raw materials would be achieved when agriculture is also viewed as a Crop and Livestock Development System. REFERENCES [1] Diamond, J. 2002 Evolution, consequences and future of plant and animal domestication. Nature 418: 700–707. 78 Benjamin E. Uchola: Agriculture: A Crop and Livestock Development System [2] Blumler M.A.1992. Independent inventionism and recent genetic evidence on plant domestication. Economic Botany 46:98-111. [3] Oikeh S.O., Nwilene F.E., Agunbiade T.A., Oladimeji O., Ajayi O., Semon M., Tsunematsu H. and H. Samejima Growing upland rice: a production handbook. Africa Rice Center (WARDA). 40p+. [4] Sonaiya EB and Swan SEJ 2004. Small-scale poultry production, technical guide. Animal Production and Health Manual. FAO Rome. [5] Viveen W.J.A.R, Richter C.J.J, Van Oordt P.G.W.J, Janssen J.A.L, Huisman E.A. 1985. Practical manual for the culture of the African catfish (Clarias gariepinus). The Netherlands Ministry for Development Cooperation, The Hague, Netherlands. 128 pp. [6] FAO/ICLARM/IRRI 2001. Integrated agriculture-aquacultur e: a primer. FAO Fisheries Technical Paper No. 407. Rome. 149p. [7] Ajibefun A.I., Battese G.E. and Daramola A.G. 2002. Determinants of Technical Efficiency in Small Holder Food Crop Farming: Application of Stochastic Frontier Production Function. Quaterly Journal of International Agriculture 41: 225-240. [8] Heady E.O. and Russell S. 1954. Resource Returns and Productivity Coefficients in Selected Farming Areas. Journal of Farm Economics, 36(2): 243-257. [9] Diamond J. and Bellwood P. 2003. Farmers and their languages: the first expansions. Science 300:597–603. [10] Idachaba F.S.1980. Agricultural research policy in Nigeria. International Food Policy Institute Research Report 17, Washington D.C. [11] Idachaba F.S. 1981. Agricultural research staff instability. The Nigerian experience. Nigeria Journal of Agricultural Science 3 1: 71-82. [12] Idachaba F.S. 1997. Instability of National Agricultural Research Systems in Sub-Saharan Africa: Lessons from Nigeria. ISNAR Research Report No. 13. The Hague: International Service for National Agricultural Research. [13] Uchola B.E. 2015a. Agriculture: From a development perspective to Plant Resource Domestication. American Journal of Agriculture and Forestry 3(4):127-134. [14] Uchola B.E. 2015b. Agriculture: From a development perspective to Animal Resource Domestication. Journal of Research in Agriculture and Animal Science 3(2):05-12. [15] Schultes R.E. 1984. The tree that changed the world in one century. Arnoldia 14(2): 2-16. [16] Schultes R.E. 1993. The Domestication of the Rubber Tree: Economic and Sociological Implications. The American Journal of Economics and Sociology, 52 (4): 479-485. [17] Zeven AC. The semi-wild oil palm and its industry in Africa. Agricultural Research Report, No. 687,178p. 1967. [18] Zeven, A.C.1972. The partial and complete domestication of oil palm (Elaeis guineensis)”. Economic Botany 26:274– 279. [19] Corley, R.H.V; Gary, B.S and Ng, S.K.1971a. Productivity of the oil palm (Elaeis guineensis Jacq.) in Malaysia. Experimental Agriculture 7:129-136. [20] Corley, R.H.V; Hardon J.J and Tan, G.Y. 1971b. Analysis of growth of the oil palm (Elaeis guineesis Jacq) I. Estimation of growth parameters and applicaton in breeding. Euphytica 20: 304-315. [21] Hardon J.J, Corley R.H.V. and Lee C.H.1987. Breeding and selecting the oil palm”, in Improving vegetatively propagated crops. A.J. Abott and R.K. Atkin Eds, Academic Press, London. Pp. 63-68. [22] Brar D.S., Dalmacio R., Elloran R., Aggarwal R., Angeles R., Khush G.S.1996. Gene transfer and molecular characterization of introgression from wild Oryza species into rice. In Rice Genetics Ill, International Rice Research Institute, Manila-Philippines. Pp. 477-486. [23] Brar D.S., Khush G.S.1997. Alien introgression in rice. Plant Molecular Biology 35: 35-47. [24] Khush G.S. 1997 Origin, dispersal, cultivation and variation of rice. Plant Molecular Biology 35: 25–34. [25] Hardner C.M., Peace C., Lowe A.J., Neal J., Pisanu P., Powell M., Schmidt A., Spain C. and Williams K. 2009. Genetic Resource and Domestication of Macadamia. Horticulture Review 35:1–125. [26] Neal, J.M., Hardner C. M., and Gross C. L. 2010. Population demography and fecundity do not decline with habitat fragmentation in the rainforest tree Macadamia integrifolia (Proteaceae). Biological Conservation, 143:2591–2600. [27] Balon E.K. 1995. Origin and domestication of the wild carp, Cyprinus carpio: from Roman gourmets to the swimming flowers. Aquaculture 129: 3–48. [28] Balon E.K. 2004. About the oldest domesticates among fishes. The Fisheries Society of the British Isles. Journal of Fish Biology 65(SupplementA), 1–27. [29] Kerr H.W. Quailology: The domestication, propagation, care and treatment of wild quail in confinement. Little Sioux, Iowa, U. S. A: The Taxiderm Company. 1903. [30] Chang G.B., Liu X.P., Chang H., Chen G.H., Zhao W.M., Ji D.J., Chen R., Qin Y.R., Shi X.K. and Hu G.S. 2009. Behavior differentiation between wild japanese quail and domestic quail. Poultry Science 88: 1137–1142. [31] Nestor K.E., Bacon W.L. and Lambio A.L. 1982, Divergent selection for body weight and yolk precursor in Coturnix coturnix japonica. 1. Selection response. Poultry Science 61: 12-17. [32] Marks H. L. 1996. Long-term selection for body weight in japanese quail under different environments. Poultry Science 75. 1198-1203. [33] Khaldari M, Pakdel A, Mehrabani Yegane H, Nejati Javaremi A and Berg P. 2010. Response to selection and genetic parameters of body and carcass weight in Japanese quail selected for 4-week body weight. Poultry Science 89: 1834–1841. [34] Ataga C.D., Van Der Vossen H.A.M. (2007) Elaeis guineensis Jacq. In: Van Der Vossen, HAM & Mkamilo GS (eds). PROTA 14: Vegetable oils/Oléagineux. [CD-Rom]. Wageningen, Netherlands. [35] Rubber Board 2002. Rubber clones. http://rubberboard.org. International Journal of Agriculture and Forestry 2016, 6(2): 74-79 79 [36] Zulkifli I, Iman Rahayi H.S, Alimon A.R, Vidyadaran M.K and Babjee S.A. 2001. Responses of choice-fed red jungle fowl and commercial broiler chickens offered a completed diet, corn and soybean. Asian-Australasian Journal of Animal Science 14(12):1758-17562. [37] Oluyemi J.A, Adene D.F and laboye G.O 1979. Comparison of Nigeria indigenous fowl with White Rock under conditions of disease and nutritional stress. Tropical Animal Health and Production, 11: 199-202. [38] Buvanendran V, Olayiwole M.B, Protrowskiu K.I and Oyejola B.A. 1981. A comparison of milk production traits in Friesian x White Fulani crossbred cattle. Animal production 32: 165-170. [39] Ogundipe R.I. and Adeoye A.A. 2013. Evaluation of the dairy potential of Friesian, Wadara and their crossbreds in Bauchi State. Scholarly Journal of Agricultural Science 3(6): 223-225. [40] Jeney Z. and Jian Z. 2009. Use and exchange of aquatic resources relevant for food and aquaculture: common carp (Cyprinus carpio L.) Reviews in Aquaculture 1:163–173. [41] Eknath A.E. and Hulata G. 2009. Use and exchange of genetic resources of Nile tilapia (Oreochromis niloticus) Reviews in Aquaculture 1:197–213. [42] Limburg H. and Mastebroek H. D. 1996. Breeding high yielding lines of Chenopodium quinoa Willd. with saponin free seed. Proceedings of COST-Workshop., 22–24/2 1996, European Commission EUR 17473/KVL, Copenhagen Copenhagen: KVL, pp. 103–114. [43] Mastebroek H.D, Van Loo E.N. and Dolstra O. 2002 Combining ability for seed yield traits of Chenopodium quinoa breeding lines”. Euphytica 125(3): 427-432. [44] Shiembo P.N, Newton A.C. and Leakey, R.R.B. 1996. Vegetative propagation of Irvingia gabonensis, a West African fruit tree. Forest Ecology and Management. 87:185-192. [45] Tchoundjeu Z., Duguma B., Fondoun J-M, Kengue J. 1998. Strategy for the domestication of indigenous fruit trees of West Africa: case of Irvingia gabonensis in southern Cameroon. Cameroon Journal of Biology and Biochemical Science 4:21-28. [46] Ladipo D.O., Fondoun J.M. and Ganga N. 1996. Domestication of the bush mango (Irvingia spp.): some exploitable intraspecific variations in west and central Africa”, in Domestication and commercialization of non-timber tree products for Agro-forestry. FAO Tech Paper, No. 9. FAO, Rome. Pp. 193–205. [47] Atangana A.R., Tchoundjeu Z., Fondoun J-M., Asaah E, Ndoumbe M and Leakey R.R.B. 2001. Domestication of Irvingia gabonensis: I. Phenotypic variation in fruit and kernel traits in two populations from the humid lowlands of Cameroon. Agroforestry Systems 53:55-64. field experiments. Aquaculture 17 (4): 323-333. [49] Huisman E.A. and Richter C.J.J. 1987. Reproduction, Growth, Health Control and Aquaculture Potential of the African Catfish, Clarias gariepinus (Burchell 1822). Aquaculture 63: 1-14. [50] Ajayi S.S. and Tewe O.O. 1980. Food preference and carcass composition of the grasscutter (Thryonomys swinderianus) in captivity. African Journal of Ecology 18 (2-3):133–140. [51] Onadeko S.A. and Amubode F.O. 2002. Reproductive indices and performance of captive reared grasscutters (Thryonomys swinderianus Temminck) Nigerian Journal of Animal Production 29(1) 142-149. [52] Annor S.Y, Ahunu B.K., Aboagye G.S., Boa-Amponsem K., Cassady J.P. 2012a. Phenotypic and genetic estimates of grasscutter production traits. 1. (Co) variance components and heritability. Global Advance Research Journal of Agricultural Science 1(6):148-155. [53] Annor S.Y, Ahunu B.K., Aboagye G.S., Boa-Amponsem K., Cassady J.P. 2012b. Phenotypic and genetic estimates of grasscutter production traits.2. Genetic and phenotypic correlations. Global Advance Research Journal of Agricultural Science 1(6):156-162. [54] Jacobsen S.E. and Stølen, O. 1993. Quinoa—morphology and phenology and prospects for its production as a new crop in Europe. European Journal of Agronomy. 2:19–29. [55] Jacobsen S.E. 2003. The worldwide potential for quinoa (Chenopodium quinoa Willd.). Food Reviews International, 19, 1&2:167–177. [56] Owiti D.O. and Dadzie S. 1989. Maturity, fecundity and the effect of reduced rainfall on the spawning rhythm of a siluroidcatfish, Clarias mossambicus (Peters). Aquaculture and Fisheries Management 20: 355-368. [57] Hogendoorn H and Vismans M.M. 1980. Controlled propagation of the African catfish, Clarias lazera (C&V). II. Artificial reproduction. Aquaculture, 21: 39-53. [58] Ponzoni R.W. and Nguyen N.H. (eds). Proceedings of a Workshop on the Development of a Genetic Improvement Program for African catfish Clarias gariepinus. Conference Proceedings Number 1889. The WorldFish Center, Penang, Malaysia. 130 p. 2008. [59] Steir C.H., Mensah G.A. and Gall C.F. 1991. Breeding of cane rats (Thrynomys swinderianus) for the production of meat. World Animal Review 69. 44-49. [60] Germplasm Resources Information Network, United States Department of Agriculture. http://www.ars-grin.gov Retrieved 2015-11-01. [61] FAO International Year of Potato, 2008. Potato varieties. http://www.fao.org/potato-2008/en/potato/varieties.html. [62] IRRI Rice varieties. Global release: 2014. irri.org. [48] Hogendoorn H. 1979. Controlled propagation of the African [63] FAO Domestic Animal Diversity Information System. catfish, Clarias lazera (C&V). I. Reproductive biology and dad.fao.org Retrieved 2016-01-28.

... pages left unread,continue reading

Document pages: 6 pages

Please select stars to rate!

         

0 comments Sign in to leave a comment.

    Data loading, please wait...
×