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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Host plant resistance as a management tool for Ditylenchus africanus (Nematoda: Tylenchidae) on groundnut (Arachis hypogaea) / Sonia Steenkamp

Steenkamp, Sonia January 2008 (has links)
HOST PLANT RESISTANCE AS A MANAGEMENT TOOL FOR DITYLENHUS AFRICANUS (MEMATODA: TYLENCHIDAE) ON GROUNDNUT {ARACHIS HYPOGAEA) Groundnut is an important cash crop both for commercial and smallscale farmers in South Africa. The effect of Ditylenchus africanus on groundnut is mainly qualitative, leading to downgrading of groundnut consignments. This nematode is difficult to control because of its high reproduction and damage potential. The objective of the study was to investigate the potential of host-plant resistance as an effective and economically-feasible alternative management tool for the control of D. africanus on groundnut. Selected groundnut genotypes were evaluated against D. africanus in microplot and field trials. PC254K1 and CG7 were identified as resistant to D. africanus. The resistance expressed by these two genotypes is sustainable under field conditions. The resistance expressed by PC254K1 is effective even at high population densities. This genotype consistently produced yields with a low UBS % at all nematode population levels. PC254K1 could therefore be used as a major source of resistance to D. africanus in the development of commercial cultivars. Although the breeding line PC287K5 also maintained low nematode numbers in some trials, its level of resistance does not seem to be as strong or as sustainable as that of PC254K1 or CG7. However, PC287K5 could still play an important role in the groundnut industry where lower D. africanus populations occur. The resistance expressed by PC254K1 is not transferred to leaf callus tissue of this genotype, confirming there is no short-cut for screening for resistance to D. africanus. The reproduction and damage potential of D. africanus populations from different geographically-isolated localities in the groundnut-production areas of South Africa was tested under controlled and semi-controlled conditions and were found to be similar to each other. Resistance of PC254K1 to all of the tested populations was confirmed. These results indicate that the presence of this resistant trait in a cultivar developed from PC254K1 should be sustainable over the whole groundnut-production area of South Africa. The absence of D. africanus from pod tissue of PC254K1 confirmed the genotype's resistance. The mechanism of resistance involved may be the inhibition of proper development of this nematode, preventing it to build up to damaging population levels. However, PC254K1 is not immune to this nematode since it does occur in small numbers on this genotype. The resistance trait in PC254K1 is seemingly governed by a number of genes, implying that it will be more durable under sustained pressure by D. africanus populations. Although markers associated with the resistance trait were mapped, they were not closely linked. Three putative qualitative trait loci (QTL's) were identified but markers associated with the resistance trait need to be refined and developed to be breeder-friendly in terms of marker-assisted selection. There are strong indications that CG7, which is a parent of PC254K1, may have more superior levels of resistance to D. africanus than PC254K1. The identification of markers closely associated with the resistance trait might, therefore, be more successful using CG7 in stead of PC254K1 / Thesis (Ph.D. (Zoology))--North-West University, Potchefstroom Campus, 2009.
22

Assessment of co-inoculation of Bradyrhizobium Japonicum and Bacillus subtilis on yield and metabolic profile of Bambara groundnut and cowpea under glasshouse conditions

Nelwamondo, Aluwani Mutanwa 01 1900 (has links)
Text in English with abstracts in isiVenda and Sepedi / Bambara groundnut and cowpea are essential legumes that are well adapted to unfavourable environmental conditions and have high dietary values for humans. However, they are under-researched and under-utilised. Thus, there are limited records on yields and metabolic profiling of these leguminous crops co-inoculated with B. japonicum and Bacillus subtilis. Generally, very few studies have reported on the effects of co-inoculation of other plant growth-promoting rhizobacteria and rhizobia strains on leguminous plants. This study therefore assessed the effects of B. subtilis (strain BD233) on germination of Bambara groundnut under different temperature regimes, and evaluated the effects of co-inoculation of B. japonicum and B. subtilis on yields of cowpea under glasshouse conditions. The study also assessed the metabolite profile of the crops using 1H nuclear magnetic resonance (NMR) spectroscopy. The data showed that inoculation of Bacillus subtilis on Bambara groundnut landraces under different temperatures enhanced germination (germination percentage, germination rate indices and plumule length). Furthermore, co-inoculation with B. japonicum and Bacillus subtilis (strain BD233) improved plant yield of cowpea plants. Partial least squares-discriminant analysis (PLS-DA) revealed distinct separations between treatments (co-inoculation of B. japonicum and Bacillus subtilis, inoculation of B. japonicum, uninoculated plus NO3 and zero inoculation) on Bambara groundnut and cowpea plants. The VIP score revealed that co-inoculation with B. japonicum and Bacillus subtilis (strain BD233) resulted in low concentrations of metabolites in Bambara groundnut plants and in contrast, high concentrations of metabolites in cowpea plants. Co-inoculation with B. japonicum and Bacillus subtilis (strain BD233) has a potential of improving yield of both Bambara groundnut and cowpea in sustainable agriculture. The metabolic profile of Bambara groundnut and cowpea subjected to co-inoculation has shown that both crops metabolic composition and profile are highly dependent on co-inoculation. / Phonda na ṋawa ndi mangaṋawa a ndeme ane a kona u tea zwavhuḓi kha nyimele dza vhupo vhune ha si vhe havhuḓi na ndeme ya nṱha ya pfushi kha vhathu. Naho zwo ralo, a hu athu u itwa ṱhoḓisiso dzo linganaho nga hadzo na u sa shumiswa Nga zwenezwo hu na rekhodo dzo pimiwaho nga ha khaṋo na u ela tshileme tsha molekulu ṱhukhu dza methaboḽiki dza zwiliṅwa izwi zwa mangaṋawa u khetha na B. japonicum na Bacillus subtilis. Nga u angaredza, ndi ngudo dzi si nngana dzo no vhigwaho nga ha masiandaitwa a khetha nyaluwo ya zwimela zwine zwa ṱuṱuwedza bakitheria dzine dza baḓekanywa na midzi na bakitheria dzine dza shandukisa naiṱirodzheni u vha amonia kha zwimela zwa mangaṋawa. Ngudo heyi nga zwenezwo yo asesa masiandaitwa a B. subtilis (tshiliṅwa tsha BD233) kha mumelo wa phonda nga fhasi ha ndaulo ya thempheretsha dzo fhambanaho, na u ela masiandaitwa a u khetha B. japonicum na B. subtilis kha khaṋo dza phonda na ṋawa nga fhasi ha nyimele ya fhethu hune ha ṱavhiwa zwimela nga fhasi ha tsireledzo kana ndangulo. Ngudo dzo dovha dza ela tshileme tsha molekulu ṱhukhu dza methaboḽiki dza zwiliṅwa hu tshi shumiswa 1H maanḓa a u tzwonzwiwa ha nyukiḽia nga eḽekiṱhironiki maginethe (NMR) nga u ṱanganelana ha radiesheni ya eḽekiṱhironiki maginethe. Data yo sumbedza u ḓivhadzwa ha Bacillus subtilis kha tshiliṅwa tshapo tsha phonda fhasi ha thempheretsha dzo fhambanaho u khwinisa mumelo (phesenthedzhi ya mumelo, zwisumbi zwa phimo ya muelo na vhulapfu ha pulumule). U isa phanḓa, u ḓivhadzwa hafhu ha B. japonicum na Bacillus subtilis (tshiliṅwa tsha BD233) khaṋo yo khwiniswaho ya tshiliṅwa kha zwimela zwa ṋawa. Musaukanyo wa u khethekanya zwitatisiṱika (Partial least squares-discriminant analysis) (PLS-DA) wo sumbedza khethekanyo dzo fhambanaho vhukati ha kushumisele (u ḓivhadzwa hafhu ha B.japonicum na Bacillus subtilis, u ḓivhadzwa ha B. japonicum, i songo ḓivhadzwaho hafhu na NO3 na ziro i songo ḓivhadzwa hafhu) kha phonda na zwiliṅwa zwa ṋawa. Tshikoro tsha VIP tsho wanulusa uri u ḓivhadzwa hafhu ha B. japonicum na Bacillus subtilis (kha tshiliṅwa tsha BD233) zwo bveledza mutzwonzwo wa fhasi wa methobolaithisi kha zwiliṅwa zwa phonda na phambano, ya mutzwonzwo wa nṱha wa methobolaithisi kha zwiliṅwa zwa ṋawa. U khetha ha B. japonicum na Bacillus subtilis (kha tshiliṅwa tsha BD233) zwo vha na ndeme ya u khwinisa khaṋo ya vhuvhili hazwo phonda na ṋawa kha vhulimi vhu sa nyeṱhi. U ela tshileme tsha molekulu ṱhukhu dza methaboḽiki dza phonda na ṋawa tenda u ḓivhadzwa hafhu ho sumbedza uri vhuvhili ha kubveledzele kwa methaboḽiki ya zwiliṅwa na muelo zwo ḓitika nga maanḓa nga u khetha. / Ditloo tša Bambara ke dipeu tše bohlokwa tšeo di kgonago go phela gabotse go maemo a tikologo yeo e sego ya loka e bile di na le boleng bja godimo bja dijo tšeo di lekanego go batho. Le ge go le bjalo, gona le dinyakišišo tša fase ka tšona le gore ga di šomišwe kudu. Ka gona, go na le direkhoto tše dinnyane ka ga pego ya mehola le tšhomišo ya yona ka ga dibjalo tše tša go dira dipeu tšeo di kopantšhwago le B. japonicum le Bacillus subtilis. Ka kakaretšo, dinyakišišo tše dinnyane kudu di begile ka ga dikhuetšo tša kopantšho ya mehlare e mengwe ya go huetša go gola ga pakteria ya medu (rhizobacteria) le dingangego tša pakteria ya ka gare ga medu (rhizobia) go dibjalo tša dipeu. Nyakišišo ye ka gona e lekotše dikhuetšo tša B. subtilis (strain BD233) go melo ya ditloo tša Bambara ka fase ga maemo a dithempereitšha tša go fapana, le go lekola dikhuetšo tša kopantšho ya B. japonicum le B. subtilis go mehola ya ditloo tša Bambara le dinawa ka fase ga maemo a ntlo ya digalase. Nyakišišo gape e lekotše pego ya tšhomišo ya dibjalo go šomišwa sedirišwa sa go laetša maatlakgogedi sa 1H (NMR). Tshedimošo e bontšhitše gore tsenyo ya Bacillus subtilis go ditloo tša Bambara tša tlwaelo ka fase ga dithempereitšha tša go fapana go kaonafaditše go mela (phesente ya go mela, lebelo la dikelo tša melo le botelele bja kutu ya sebjalo). Gape, kopantšho le B. japonicum le Bacillus subtilis (strain BD233) go kaonafaditše mehola ya dibjalo tša mehlare ya dinawa. Tshekatsheko ya go hwetša tswalano ya dithišu tše pedi (PLS-DS) e utollotše ditlogelano tša go fapana magareng ga mekgwa (kopantšho ya B. japonicum le Bacillus subtilis, tsenyo ya B. japonicum, yeo e sego ya tsenywa le NO3 le tsenyo ya lefeela) go ditloo tša Bambara le dibjalo tša dinawa. Dipoelo tša VIP di utollotše gore kopantšho ya B. japonicum le Bacillus subtilis (strain BD233) e tlišitše dipoelo tša fase tša ditšweletšwa tša dimolekule tša dibjalo tša ditloo tša Bambara e bile gape ge re dira phapanyo, bontšhi bjo bo lego godimo bja ditšweletšwa tša dimolekule ka go dibjalo tša dinawa. Kopantšho ya B. japonicum le Bacillus subtilis (strain BD233) e na le kgonagalo ya go kaonafatša mehola ya bobedi ditloo tša Bambara le dinawa ka go temo ya sa ruri. Seemo sa ditšweletšwa tša ditloo tša Bambara le dinawa tšeo di dirilwe kopantšho se bontšhitše gore bobedi tlhamotšweletšo le seemo sa dibjalo tše di ithekgile kudu mo go kopantšho. / Agriculture and  Animal Health / M. Sc. (Agriculture)
23

Assessing the climatic suitability of Bambara groundnut as an underutilised crop to future climate projections in Sikasso and Ségou, Mali

Ezekannagha, Ezinwanne 21 January 2021 (has links)
This study evaluates how future climatic projections will affect the suitability of bambara groundnut (Vigna subterranean(L) Verdc.), a type of underutilised crop in Sikasso and Ségou, southern Mali. This study was performed using a simulation approach, which considered the potential changes in suitability due to projected changes in two climate variables; temperature and precipitation. Monthly outputs of the two climate variables from 10 CORDEX bias-corrected regional projections under the Representative Concentration Pathway (RCP) 8.5 were applied. The suitability index range of bambara groundnut was projected, using the Ecocrop suitability model, considering three time periods: historical (1975-2005), near-term (2011-2040), and end of century (2070-2099). The results of this study showed that the model captured a long planting window for the crop in the regions across the time periods. With the projected increase in future climatic conditions, the suitability index range of bambara groundnut is projected to increase across the months suitable for planting the crop. Furthermore, Sikasso is projected to maintain a high suitability index in the near-term, and by the end of century, Ségou is expected to experience a potential increase in suitability index range and suitable areas, especially by the end of century. The results indicate that the CORDEX projections and suitability modelling technique applied in the study captured well the suitability of bambara groundnut in the regions which can help the farmers in making planting decisions. These results suggest an opportunity for optimal utilisation of the crop in the regions, as with a long planting window and expansion in suitable areas, farmers in the regions can plant multiple times and have more suitable areas to cultivate. This study contributes to improving the decision-making surrounding the promotion of underutilised crops as part of the strategy for climate-resilient agriculture and food security in Sikasso and Ségou.
24

Laboratory and field evaluations of Virginia-type peanut (Arachis hypogea L.) cultivars for resistance to Diabrotica undecimpunctata howardi Barber

Petka, William J. 02 May 2009 (has links)
The southern corn rootworm (Diabrotica undecimpunctata howardi Barber) is the primary soil insect pest to peanuts (A rachis hypogaea L.) in Virginia and North Carolina. The newer cultivars, which are planted on the majority of the acreage, have not been extensively screened for rootworm resistance. The objective of this study was to evaluate 5 new Virginia-type cultivars (NC-V 11, VA-C 92R, VA 93B, NC 10C, and AgraTech VC1) and 18 breeding lines (N90013E, VA 861101, VA 9211920, VA 9211289, VA 891438, VA 901072, VA 9010343, VA 8911115, VA 9109213, VA 9109235, VA 9109237, VA 9111309, N93007L, N92066L, N92074L, PI 121067, GP-NC 343, N92064L and N93003L) for resistance to southern corn rootworm in the laboratory and in the field. NC 7 and NC 9 were used as susceptible checks. NC 6 was used as a known resistant check. Rootworm mortality and feeding were measured from bioassays in the lab. Pod damage data were obtained from field plots. NC 6 caused some significant differences with more rootworm mortality at both the pupal and adult stages than NC 7, NC 9, NC 10C, NC-V11, N90013E, PI 121067, AgraTech VC-1, VA 93B, VA 861101, and VA 9211290 when feeding on peanut seedlings. In addition, NC 6 also caused significantly higher mortality at pupa and adult stages than NC 7, AgraTech VC-1, VA 861101, and VA 93B when larvae fed on the peg and immature pod tissue from field plantings. NC 6 also had less total pod damage than NC 7 in natural infestations of southern corn rootworm. Results from this study indicate that NC 61s are still the only cultivar that demonstrates resistance to rootworm. / Master of Science
25

The financial feasibility of tree-planting under agroforestry: a case study from the Groundnut Basin of Senegal

Diallo, Alioune January 1992 (has links)
Agroforestry is a new term for an old practice of resource management which includes the planting of trees and agricultural crops on the same piece of land, either simultaneously or sequentially. In Senegal, this new approach has been praised, mainly because it came along at a time when private participation in reforestation was badly needed. Since the early 1980s, the Snegalese government has been devoting money and personnel to the implementation of agroforestry projects, particularly in the Groundnut Basin. In spite of these efforts, small private farmers response to the suggested agroforestry systems has been slow in most parts of the region. Assuming that financial return is the most viable mean for triggering large-scale adoption of agroforestry by private farmers, this study analyzes the financial attractiveness of the three agroforestry systems promoted in the Groundnut Basin, and compares them to the base case of growing groundnuts alone. The three agroforestry systems are: kad and millet, cashew and groundnuts, and a Eucalyptus block plantation. For each system, costs and benefits accruing to the farmer are identified and estimated. The financial attractiveness of each system is measured using two criteria: present net worth (PNW) and internal rate of return (IRR). Using the criterion that a system with a PNW greater than zero is acceptable, the results indicate that all three agroforestry systems are acceptable at 10 and 15 percent discount rates. The kad and millet system is acceptable at rates nearing 50 percent. This is due mainly to the valuation of the crop loss avoided in the presence of kad trees. When this component was not internalized, the IRR was found at only 15.8 percent. The cashew and groundnut system has the next highest IRR at 25.6 percent, followed by The Eucalyptus block plantation at 18.8 percent. The base case yields negative PNW at all three discount rates, and an IRR equal to 4. 7 percent. This low return from the groundnut enterprise may be due to the valuation of family labor which does not generally constitute an out-of-pocket cost. Some environmental benefits attributable to agroforestry systems and some socio-economic constraints that may be part of the farmers' reluctance to adopt the new systems are discussed. Finally, some recommendations are made to help improve the current approach to private involvement in reforestation. It is suggested that, in order to anticipate the loss in interest that follows most incentive programs once the incentives stop, the "cost sharing" program and other financial incentive programs should be limited to systems, which have strong favorable impacts on the environment but do not afford sufficient financial rewards by themselves for wide scale adoption. / M.S.
26

Morpho-physiological characterisation of bambara groundnut (Vigna subterranea L) landraces collected in Mpumalanga Province

Magongwa, Selwana Michael 09 1900 (has links)
MSCAGR (Plant Production) / Department of Plant Production / See the attached abstract below
27

Multi-Location Field Evaluation of Bambara Groundnut (Vigna Subterranean (L) Verdc) for Agronomic Performance and Seed Protein.

Mogale, Tlou Elizabeth 18 May 2018 (has links)
MSCAGR (Plant Production) / Department of Plant Production / Bambara groundnut (Vigna subterranea) is one of the most important legumes cultivated primarily for food by smallholder farmers in Africa. It is an affordable source of protein and contributes to income generation as well as soil fertility. Despite its importance, it is cultivated largely for subsistence purposes in South Africa. Growers use landraces. The agronomic performance of the traditional varieties depends on environmental factors prevailing in a particular area. In Limpopo and Mpumalanga Provinces, there is no adequate information regarding the performance of bambara groundnut germplasm. The objectives of the study were to (i) determine the agronomic performance of Bambara groundnut across three contrasting locations in Limpopo and Mpumalanga provinces over two cropping seasons (ii) determine the genotypic variation in the seed protein level among 42 bambara groundnut genotypes. Forty-two bambara groundnut genotypes were evaluated under three different environmental conditions (Syferkuil, Thohoyandou and Nelspruit) over two (2013/2014, 2014/2015) seasons in a 7 × 6 rectangular lattice design replicated three times. Eight agronomic traits including dry shoot weight (DSW), number of pods per plant (NPP), pod length (PL), number of seed per pod (NSP), pod weight per plant (PWT), seed weight per plant (SWT), 100 seed weight (100-SWT) and seed yield (SYLD) were measured. The results showed that there were significant genotype x location interactions which demonstrated that the prevailing agro-ecological conditions at the test locations were distinct from each other. Five genotypes (‘BGN-19‘, ‘BGN-11‘, ‘BGN-12‘, ‘BGN-4‘and ‘BGN-34‘) attained >25.0% seed yield advantage over the local check ‘BGN-39‘. The results also showed that light brown coloured genotypes attained relatively higher seed yield compared to the other seed colours types. The cultivar superiority index (CSI) showed that three genotypes (‘BGN-12‘, ‘BGN-19’ and ‘BGN-34’) were the most stable across the test locations and attained >900.0 kg/ha on average. There were significantly high positive correlations between PWT and each of the three other attributes (SWT, 100 SWT and SYLD). In terms of seed protein, the results showed a poor relationship between seed yield and protein levels. ‘BGN-12’ which produced the highest seed yield, attained the lowest percent seed protein while genotype. On average, the genotypes contained 21.72% protein. The highest and lowest seed protein quantities were attained by the genotypes ‘BGN-42’ (25.17%) and ‘BGN-12’ (19.89%) respectively. / NRF
28

A study of the systematics and implications of the presence of the testa nematode, Aphelenchoides arachidis Bos, 1977 in South Africa / Madimane Moses Lesufi

Lesufi, Madimane Moses January 2007 (has links)
An introduction to nematode systematics is provided which deals broadly with the history of the classification of nematodes, the controversial usage of the Phylum names Nemata Cobb, 1919 and Nematoda (Rudolphi, 1808) Lankester, 1877 and the reason why the name Nematoda was used in the present study. The classification, diagnosis and bionomics of the genus Aphelenchoides Fischer, 1894, the genus to which A. arachidis Bos, 1977 belongs is discussed. The section on bionomics is included to capture the astounding ability of this group of organisms to adapt to different trophic levels, a concept that is used to attempt an explanation for the ability of a supposedly African nematode, A. arachidis, to infest an alien crop species (groundnut). The ability of Aphelenchoides spp. to adapt to different host plant species is discussed, as well as the ability of the groundnut plant to mature its pods underground, a characteristic that predisposes these plants to a host of pathogens. The damage caused by two of the most important endoparasitic nematode species on groundnut, A. arachidis and Ditylenchus africanus Wendt, Swart, Vrain & Webster, 1995 were compared with each other. The South African population of A. arachidis was found predominantly in the shells of groundnut, whereas they were found in the shells, roots, hypocotyls and testas of the groundnut plants in Nigeria. The present study showed that A. arachidis and D. africanus occur together in groundnut in South Africa with D. africanus usually being the dominant species. In only one instance, at Bullhill (Vaalharts Irrigation Scheme, Northern Cape), the groundnut shells and testas were infested by A. arachidis alone. The importance of plant quarantine in South Africa is dealt with and the aims and principles of quarantine, as well as the different guidelines that have to be adhered to when deciding on the quarantine status of an organism are explained. Descriptions are provided of the methods used to prepare specimens for viewing with the light microscope (LM) and the scanning electron microscope (SEM), as well as the procedures of the molecular study. A morphological and morphometrical description of A. arachidis specimens from South Africa, as well as a comparison with specimens from Nigeria was done. Differences between the South African and Nigerian populations included, respectively, a lower b-value (7 - 11 vs 10 - 18), more lateral lines (2 - 4 vs 2), a slightly shorter stylet (8-10 m vs 10 - 12 m) and a longer length of the post-uterine sac as a percentage of the distance from vulva to anus (41 - 96 % vs ± 50 %). Scanning electron micrographs of this species are presented for the first time and shows the morphology of the lip region and lateral lines. Since both A. arachidis and A. blastophthorus were detected in the pods, a study was done to evaluate a PCR-based diagnostic method for the identification of these species and to compare the results with those reported in literature. Restriction fragment length polymorphisms (RFLPs) in the rDNA fragment were used to compare and differentiate between nematode species. The differences encountered within the South African population (morphological, morphometrical and molecular) warrant a study of more specimens from more localities. Through this it could be ascertained whether the South African population is a subspecies of A. arachidis or if this species just differs widely between localities. Future research should focus on a survey of the groundnut producing areas in South Africa to determine the distribution and economic impact of A. arachidis. The incidence of A. arachidis on other agricultural crops, especially those used in rotation with groundnut, also needs to be determined. The next issue to address is what enables a supposedly endemic species to Africa, A. arachidis, to parasitize an alien plant species (groundnut) from South America. Screening of the endemic bean family (Fabaceae) in Africa for the presence of A. arachidis, could hold the answer to this question. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2008.
29

Protoplast isolation and plant regeneration in Bambara groundnut : a platform for transient gene expression

Ayeleso, Taiwo Betty January 2016 (has links)
Thesis (MTech (Agriculture))--Cape Peninsula University Of Technology, 2016. / Bambara groundnut (Vigna subterranea), a dicotyledonous plant is a legume which has a potential to contribute to food security and nutrition. Protoplasts are naked plant cells lacking cell walls. Viable protoplasts are potentially totipotent. Therefore, when given the correct stimuli, each protoplast is capable, theoretically, of regenerating a new wall and undergoing repeated mitotic division to produce daughter cells from which fertile plants may be regenerated through the tissue culture process. Protoplast systems are valuable and versatile cell based systems that are useful in observing cellular processes and activities. In this study, the isolation of protoplast from the leaves of Bambara groundnut plant was extensively optimised. The factors affecting protoplast isolation considered in this study were ages of plant material, mannitol concentration, combinations and concentrations of enzymes and duration of incubation. Effects of ages of Bambara groundnut plant (4, 6, 8, 10 weeks), molarities of mannitol (0.4 M, 0.5 M. 0.6 M and 0.7 M), concentration and combination of enzymes (1%, 2% and 4% cellulase, 0.5% and 1% macerozyme and, 0.5% and 1% pectinase) at different incubation duration (4, 18, 24, 42 hours) were investigated. Overall, it can be deduced from this study that the optimal protoplast yield (4.6 ± 0.14×105ml-1/gFW) and viability (86.5 ± 2.12%) were achieved by digesting the leaves of four week old Bambara groundnut plant with 2% cellulase and 0.5 % macerozyme with 0.5M mannitol for 18 hours. Freshly isolated protoplasts were then cultured at different densities of 1 × 104 - 2 ×106 protoplasts/ml using MS in three different culture (Liquid, agar and agarose bead) methods. First cell division was observed only in liquid medium. With several attempts, no division was achieved in the agar and agarose bead methods, division also did not progress in the liquid medium and hence, plant regeneration from Bambara groundnut protoplasts could not be achieved in this study. Consequently, a further study is underway to compare the proteomic profiles of freshly isolated protoplasts and cultured protoplasts in order to gain insights into the expression of proteins that could perhaps be contributing to the difficulty in regenerating Bambara groundnut plant through protoplast technology. The present study is novel because it is the first study to optimise the various factors that could affect protoplast isolation from the leaves of Bambara groundnut and thus developed an efficient protocol for protoplasts isolation from leaves of Bambara groundnut for cell manipulation studies.
30

Assessing the morphological variation and characterising the proteins of bambara groundnut (Vigna Subterranea L. Verdc)

Evangeline, Unigwe Amara 12 1900 (has links)
M. Tech. (Department of Biotechnology, Faculty of Applied and Computer Sciences), Vaal University of Technology / Bambara groundnut (Vigna subterranea L. Verdc) is an underutilized crop in the African continent. It is a drought tolerant crop and fixes atmospheric nitrogen. Bambara groundnut is primarily grown for the protein content of its seeds and is mainly produced by small scale farmers at the subsistence level. However, despite its importance as a subsistence crop in many African countries, only local landraces of bambara groundnut are still cultivated. Mass selection of a few local varieties for the main agronomic characteristics has been carried out. All the bambara groundnut germplasm in South Africa has not been morphologically characterized. Although the protein of bambara groundnut is of good quality and is rich in lysine, there is no information on the characterisation of these proteins. The presence of antinutritional factors in the crop has also received little attention. This study focused on three major objectives including: (I) to assess the extent of morphological variations among thirty selected landraces of bambara groundnut, (II) to characterize the major seed proteins in these accessions using one dimensional gel electrophoresis, and (III) to determine the presence of any anti-nutritional factors in the seeds of the selected bambara groundnut landraces. 30 accessions of bambara groundnut were evaluated for their variability in agronomic and morphological traits. The field experiment was conducted at ARC-VOPI in Roodeplaat research farm during the 2014/2015 summer cropping season. The field trial was arranged as a complete randomized block design with 3 replications. 18 quantitative traits were recorded to estimate the level of genetic variability among accessions. 4 different methods were employed to extract seed proteins from 30 bambara groundnut accessions in order to ascertain the best method for protein extraction. These methods included: 10%-80% isopropanol, 10% trichloroacetic acid (TCA) in acetone solution, sonication and 2x Lammeli buffer extraction methods. The quick start Qubit® fluorometer protein kit was used to determine the protein concentration in each sample. The samples were then subjected to one dimensional gel electrophoresis. For antinutritional analysis, 5 factors (condensed tannins, free and phytic acid phosphate, polyphenol and trypsin contents) were used to determine the amount of antinutrient in 30 bambara seeds that were ground to a fine powdery flour. 3 replicates of all the samples were ground for each assay evaluated. The flour was then immediately extracted and used for the different assays. The analysis of variance revealed significant differences only in 10 of the 18 phenotypic traits that were evaluated. The UPGMA cluster analysis based on the quantitative traits produced vii four distinct groups of genotypes and a singleton. Genotypes SB11-1A, SB19-1A, SB12-3B and Bambara-12 were found to possess good vegetative characters and are recommended for use as suitable parents when breeding cultivars for fodder production. Desirable yield and yield-related traits were identified in B7-1, SB4-4C, SB19-1A, Bambara-12 and SB16-5A and are recommended as suitable parental lines for bambara groundnut grain production improvement. The quantitative characters therefore provided a useful measure of genetic variability among bambara genotypes and will enable the identification of potential parental materials for future breeding programmes in South Africa. Out of the 4 different seed protein extraction methods exploited for this study, the 2x Laemmli buffer extraction method produced the best result with clear protein bands. A unique feature from all extraction methods was the presence of a common protein band at ̴ 75 kDa. All extraction methods except 10 % TCA-Acetone resolved common banding patterns in all the bambara groundnut samples. This data suggests that there is very little or no intraspecific genetic diversity among the seed proteins of bambara groundnut accessions studied. There was wide variation in the content of the five antinutritional compounds among the thirty bambara groundnut accessions. The mean values for condensed tannin content ranged between 0.20 - 6.20 mg/g. Free phosphate recorded an overall mean of 1.71 mg/g while a range of 1.35 - 4.93 mg/g was observed by phytic acid phosphate (PAP). The polyphenol content had an overall mean of 0.39 mg/g and trypsin inhibitor (TIA) was quite variable among the bambara groundnut accessions ranging from 5.30 - 73.40 TIA/mg. Generally, higher levels of antinutrients were observed in this study compared to the other studies. The results obtained in this study led to a conclusion that although variations exits among the accessions studied, further research is required to verify the extent of morphological variations, the efficiency of protein extractions methods evaluated and the effects of these antinutrients in human and animal feeds.

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