Recently Defended Phd Thesis

LIST OF RECENT PH.D STUDENTS IN DEPARTMENT OF BOTANY

 

S/No

NAME

TITLE

NAME OF SUPERVISOR

YEAR OF COMPLETION

1

OLOWE Olumayowa Mary

Molecular Diversity Of Some Fusarium verticillioides (Sacc.) Strains of Zea mays L. Ear Rot, Pathogenicity and Interaction with Arbuscular Mycorrhizal Fungi

Prof. A.C. Odebode

2 March, 2016

2

OLURANTI Olayinka Oluyemi

Immunomodulatory and Antiplasmodial Potential of Selected Nigerian Higher Fungi

Prof. S.G. Jonathan

24 August, 2015

3

NDIMELE Chinatu Charity

Modelling of Heavy Metal Bioaccumulation of Eichhornia crassipes (Mart.) Solms and Pistia stratioles L. in Ologe Lagoon, Lagos, Nigeria.

Dr. K.S. Chukwuka

23 August, 2016

4

SHOKEFUN Emmanuel Oyeniyi

Taxonomic Studies on the Tribe Grewieae Endl. in Nigeria.

Prof. A.E. Ayodele

2 March, 2016

5

AYISIRE, Benjamin Erhinmeyoma

Germination, Seedling Growth and Propagation of Some Economic Tree Species Via Tissue Culture Techniques

Prof. O. Osonubi

12 November, 2015

6

AFOLAYAN, Ezekiel Taiwo

Evaluation of Mini-Tuber Production Techniques using Vine Cuttings and Soil Amendment on Tuber Yield of White Yam (Discorea Rotundata Poir.) Under Nutrient Depleted Siol.

Dr. O.J Oyetunji

15 November, 2015

7

OYETUNJI, Olumoye Ezekiel

Evaluation of Entomopathogenic Fungi {Beauvaria bassiana (Balsomo) Vuillemin and Metarhizium anisopliae (Mechnikoff) Sorokin} for The Control of African Rice Gall Midge (Orseolia oryzivora)

Prof. A.C Odebode

 

Dr. F.E. Nwilene

21 October, 2016

8

KOTUN, Bunmi Comfort

 Mycotoxin Production and Molecular Characterization of Penicillium Species Isolated from Millet (Pennisetum glaucum L.) R. Br. in Southwester Nigeria.

Prof. A.C Odebode

17 January, 2017

9

EKUN, Victor Segun

Cultivation and Molecular Characterization of Auricularia Species in Southwestern Nigeria.

Dr. Clementina O. Adenipekun

16 January, 2017

 

 

 


 

NAME:                         Olumayowa Mary OLOWE

MATRIC NO:              122280

TITLE:                         MOLECULAR DIVERSITY OF SOME Fusariumverticillioides (SACC.) STRAINS OF Zea mays L. EAR ROT, PATHOGENICITY AND INTERACTION WITH ARBUSCULAR MYCORRHIZAL FUNGI

 

ABSTRACT

 

Fusarium verticillioides of maize ear rot is a major constraint to maize production in Southwest Nigeria. The inaccurate morphological identification of F. verticillioides strains leads to ineffective disease control strategies. Therefore, characterization of this pathogen in maize using molecular techniques is needed for effective management of ear rot diseases. The objectives of this study were to carry out molecular characterization of F. verticillioides strains from infected ear of maize based on genetic relatedness, assess the pathogenic variability in symptoms of F. verticillioides strains and investigate the interactions of F. verticillioides and Arbuscular Mycorrhizal Fungi (AMF) on maize.

 

Five maize grains from infected cobs obtained from Derived Savanna (Iloora, Ijebu, Igboora and Eruwa), Rainforest (Ekiti, Akure, Ilesha and Ibadan) and Guinea Savanna (Saki, Igbooho) were cultured on Potato Dextrose Agar and incubated at 25oC for 5-7 days. Morphological and cultural characteristics were examined from isolates in the samples. The isolates (60)across the Agroecological Zones (AEZs) were further characterized using Amplified Fragment Length Polymorphism (AFLP) marker. The pathogenicity of thirty-two (32) characterized F. verticillioides strains based on virulence was examined on maize genotypes; T2L COMP.1.STR SYN-W-1, PVA SYN 8F2 and T2L COMP.4 obtained from IITA. The F. verticillioides was inoculated at 8 weeks after planting.The effect of AMF: Glomusclarum and G. deserticola on disease severity in maize infected with F. verticillioides was investigated. The treatments were evaluated for each of the AMF at four concentrations (0g, 10g, 20g and 30g). Data collected on growth and ear rot disease characters were subjected to analysis of variance (ANOVA) using SAS 9.1 statistical software.

 

Pinkish mycelia growth were found in all AEZs except in Iloora and Saki where some were whitish. A total of 164 polymorphic bands was detected and high genetic similarity (67%) was observed among strains 34, 36 (Ibadan), 39 (Igbooho), 46, 47 (Ekiti), 52 (Saki) and 57, 58, 59 and 60 (Igboora). Strains 19 and 20 (Ilesa) had the highest (97%) pair wise similarity coefficient. T2L COMP.4 genotype was the most susceptible to ear rot disease. Out of 32 strains of F. verticillioides studied, 9.4% were classified as highly virulent, 12.5% as virulent strains, 37.5% as moderately virulent, 21.9% as slightly virulent, and 18.8% as non-virulent. Glomus deserticola significantly increased the growth on the plant height 53.79% (100.96±27.66)cm, stem girth 51.05% (2.93±0.83)cm, number of leaves 52.66% (10.31±2.43) and leaf area 51.67% (234.56±73.70) cm2 after inoculation when compared to G. clarum and control (p≤0.05). There was significant reduction in disease severity by G. deserticola (1.22±1.32) and G. clarum (1.35±1.32) (p≤0.05). AMF concentration at 30g (0.97±1.32) had the lowest disease severity when compared with other concentrations and control.

 

An accurate identification usingAFLP marker ascertained genetic relatedness in F. verticillioides strains across the three AEZs. Therefore, effective control strategies using pathogenic variability and mycorrhizal interaction could be integrated into disease management.

 

  Key words:    Fusarium verticillioides, pathogenicity, maize, ear rot, AFLP, AMF

Word count: 466

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NAME:                                  Olayinka Oluyemi OLURANTI

MATRIC NO:                                  

TOPIC:                                  IMMUNOMODULATORY AND ANTIPLASMODIAL POTENTIAL OF SELECTED NIGERIAN HIGHER FUNGI

 

ABSTRACT

High mortality rate due to infections resulting from compromised immune system and malaria attack are current challenges in developing countries. The potential of higher fungi (mushrooms) as medicinal agents and immune boosters could be employed in overcoming these challenges. However, not much has been done to exploit the potentials of mushrooms in Nigeria. This study was designed to investigate the immunomodulatory and the antiplasmodial potentials of selected Nigeria mushrooms.

Sporophores of five higher fungi were purposively collected from decaying woods and were extracted with ethanol using soxhlet apparatus. The fungi extracts were screened in-vitro against six clinical bacterial isolates collected from Medical Microbiology and Parasitology Laboratory. University College Hospital, Ibadan for antibacterial activities, before immunomodulatory experiment. One thousand, one hundred and fifty two 8-12 weeks old Wistar rats (125-138g) were used and assigned into 36 groups of twelve rats each. Groups 1-6, 7-12, 13-18, 19-24, 25-30 and 31-36 were orally administered 1.0ml, each of Pleutrotus pulmonarius, Fomes lignosus, Lentinus subnudus, Termitomyces robustus, Pleurotus  tuber- regium and combined (1: 1:1:1:1) extracts (40mg/mL) of 101 cfu/ml each of Escherichia coll, Staphylococcus aureus, Salmonella typhi, Pseudomonas aeuginosa, Enterococcus faecalis and Bacillus cereus for pre- and post-infection treatments. In the antiplasmodial experiment, six hundred and twelve mice each. Groups 1-5, 6-10, 11-15, 16-20, 21-25, 26-30 were orally with 0.1mL each of the extracts (4, 0. 4, 0. 04, 0.004) and 0.0004mg/mL) for four days. They were infected with 0.2mL Plasmodium berghei berghei (5x106) parasitized erythrocytes. Chloroquine (20mg/ kg) served as controls. Livers and kidneys of the animals were histologically examined.

Survival rate, level of parasitemia, Parked Cell Volume (PCV) and weights of mice were determined using standard methods. Data were analyzed using descriptive statistics and ANOVA at p= 0.05.

 

All animals survived Escherichia coli  infection after pre-treatment with P.pulmonarius and combined extracts, Pleurotus tuber- regium and L. subnudus extracts were most effective against Staphylococcus aureus while T. robustus  extract was effective against Salmonella typhi. Pleurotus tuber-regium and P. pulmonarius produced highest survival rate of 100% and 75% against Pseudomonas aeruginosa for pre-infection and post- infection treatment respectively. All infected rats without extract died within five days, while all uninfected animals survived, Lentinus subnudus and F. lignoosus produced the highest antiplasmodial effect against Plasmodium berghei berghei with a decrease of 30% and 36% respectively in parasitemia. Tuber- regium extract produced least weight loss of 26.5% in pre-infection treated mice. All the extract (0.4 and 0.04mg/mL) produced similar effect as choloquine in antiplasmodial experiment. The pre- and posy in infection treatment effects of the extacts on parasitemia were significant. Combined extract had preventive and ameliorative effect on the organs of the animals.

 

Extracts of the higher fungi had immunomodulatory and antiplasmodial activities, and could be potential source of bioactive compounds.

 

Keywords:     Antimicrobial activities, immunomodulatory potentials, Antiplasmodial effects,

                        Nigerian higher fungi.

Word count:  454

 

 

 


NAME:                                  Chinatu Charity NDIMELE

Matric no:                             

TOPIC:                                  MODELLING OF HEAVY METAL BIOACCUMULATION OF EICHHORNIA CRASSIPES (MART.) SOLMS AND PISTIA STRATIOLES L. IN OLOGE LAGOON, LAGOS, NIGERIA.

 

ABSTRACT

Macrophytes such as Eichhornia ceassipes and Pista stratiotes are known bioaccumulators found in the Ologe Lagoon which receives effluents manly from Agbara Industrial Estate.  However, the mechanism of heavy metal bioaccumulation by these macrophytes has not been fully understood.  This study was designed to determine the mechanism of heavy metal bioaccumulators and model the phytoremediation capabilities of the macrophytes.

Five sampling stations: Owo (before the point of discharge of effluent as control), Agbara, otto Jetty, Morogbo and Etegbin (after the point of effluent discharge) were selected for the study.  Water samples, sediments,

E. crassipes and P. statiotes were collected uding standard [procedures in these stations from Jluy, 2013 to December, 2014 from the lagoon and analysed for heavy metals using standard methods. Temperature, pH, Conductivity, Total Suspended Solids (TSS), Total Dissolved Solids TDS) Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Dissolved Oxygen (DO) were determined according to APHA methods.   Selected heavy metals: Zn, Fe, Cu, Pb and Cd in water, sediments and the two macrophytes were determined in accordance with FAO/SIDA method.  Eichornia crassipes and P. stratiotes were grown in three different concentrations.  (10, 15 and 20 mg/L) of CuSO4.5H2O4;ZnSO4.7H2o and Pb(NO3)2 in three replicates for six weeks.  Thereafter, plant leaves, stems and roots were harvested and anlysed for metal bioaccumulation and translocation.  Time evolution of pollution was determined using first and second-order kinetic models.  Data were analysed using descriptive statistics, ANOVA and Fisher’s LSD test (a0.05).

Water temperature ranged from 28.7±0.37-29.4±0.690C, pH (6.7±0.1-6.9±0.1),  Conductively )1565±984.7-3088±1478.6 uS/cm), TSS (10.4±0.5-20.6±1.2 mg/L, TDS (89.2±1.8-1739±872.2 mg/L) COD (13.8±0.8-23.9±1.0 mg/L and DO (4.2±0.2-4,9±0.2 mg/L).

The concentration of Zn (30±2.0 ugL) in water sample was higher than the USEPA limit (6 µg/L at 45 hardness) for the protection of aquayic ecosystems.  The highest {Fe (2310±613 mg/kg) and Cu (38.20±10.21 mg/kg) }and lowest{Fe (13005±848 mg/kg) and Cu (2.92±0.37 m/kg)} concentrations in sediment were recorded in Agbara and Etegbin respectively.  The concentration (mg/kg)of heavy metals in E. crassipes and P. stratiotes from Agbara was significantly higher (fe=1369±236.12; Zn =42.60.±5.62) than values obtained from other sampling stations (Fe=470±55.96-642.58±303.26; Zn=11.14±1.83-20.41±4.332).  In the laboratory experiment, metals were accumulated through the roots to the shoot (phytoextraction) via a concentration gradient ( for E. crassipes pots spiked with 10, 15 and 20 mg?l of Zn, the average quantity of the metal absorbed were 5.56±0.09,  8.89±0.60 and 15.58±0.15 mg/L respectively.  The bioacculation factor in E. crassipes varied from 10 (Pb) to 9000 (Fe) while in P. stratiotes, it varied from 9 (Pb) to 85000 (Cu).  Translocation factors were higher in root/stem (7.06±1.09 for Pb) than stem/leaf (5.42±1.2 for Pb).  Iron accumulation in different parts of E crassipes {(mg/kg) was: (leaf  (0.45±0.6-15.58±0.15);  stem  (033±00.5-16.48±0.44);  root  (0.40±0.07-18.50±3.16) and P. stratiotes was:  {leaf (0.36±0.06-6.67±1.17) and root (0.45±0.08-7.49±1.78) }.  Pots seeded with Fe maintained green colouration for a longer time than thjose deeded with Cu, Zn and Pb.  The ti,e evolution of pollution was best described by first-order kinetic model.

Eichornia crassipes and Pstia stratiotes bioaccumulated heavy metals and the mechanism of bioacccummulation is a function of time and level of concentration of the heavy metals.

 

Keywords:  Bioconcentration factors, TYranscl;ocation factors, First-order kinetic model

 

Word count: 498

 


 

NAME:                      Emmanuel Oyeniyi SHOKEFUN

MATRIC.NO:           114311

TOPIC:                      TAXONOMIC STUDIES ON THE TRIBE GREWIEAE ENDL. IN NIGERIA

ABSTRACT

Grewieae is the largest tribe of the subfamily Grewioideae with about 491 species some of which are used for nutritive and medicinal purposes. Molecular phylogenetic studies indicated that the tribe is polyphyletic. However, there is no morphological basis for redefining the sub-clades and infra generic limits of the tribe due to incomplete taxon sampling particularly from West Africa. The aim of the study was to revise the Nigerian taxa and provide morphological support for the overall taxonomic relationship among the genera and species of the tribe Grewieae in Nigeria.

Specimens (260) comprising 120 field collections from 14 states covering all ecological zones in Nigeria and 140 representatives from Forest Herbarium Ibadan, University of Ibadan Herbarium and Lagos University Herbarium were studied. Vegetative and reproductive characters were assessed. Leaf epidermal morphology was studied using epidermal peels obtained from maceration of leaf fragments in concentrated Trioxonitrate (V) acid and stained in safranin o. Transverse sections of leaf blade and petiole were studied using sections obtained with the Reichert Sledge microtome, stained and counter stained with safranin and Alcian blue. Pollen morphological study was by acetolysis method of Erdtman. Phylogenetic analysis of the assessed morphological and anatomical characters with Triumfetta cordifolia as an out group was conducted using maximum parsimony. Robustness of tree topologies was estimated by bootstrapping with 10,000 replicates and full heuristic search. Principal Component Analysis (PCA) and Neighbour Joining (NJ) trees were constructed to elucidate taxonomic relationships among the taxa.

Twenty species and two new taxa Grewia sp A and sp B were documented. The leaf margins were mostly toothed except in Microcos which was entire. Flowers were yellow, orange, white, red, pinkish-white, purple and brown, borne on panicle or cyme inflorescence. Style apices were mostly broad with lobed stigma but narrow and unlobed in Microcos species. Fruits were indehiscent and mostly with wingless seeds, however seeds of Desplatsia and Duboscia species were winged. Trichomes were either glandular or non-glandular. Striations were present on the epidermis of most species. Pollen grains ranged from 19.7 to 61.2 μm in size and were mostly tricolporate except those of Grewia iii

 

venusta and Grewia sp B in which some tetracolporate grains were observed. The morphological and anatomical characters obtained were used in producing an indented dichotomous key. Anticlinal cell wall pattern, structure of stomata and number of stomata, number of palisade and spongy cells, presence and abundance of crystals were all of taxonomic significance in separating the tribe into two groups. Both groups correspond with the two clusters produced by the PCA and NJ analysis and the Microcos and Grewia clades obtained from the phylogenetic analysis. Section Pluriovulatae in the genus Grewia previously transferred to the genus Vincentia was re-introduced to accommodate Grewia flavescens and Grewia lasiodiscus while Grewia carpinifolia was re-assigned to section Oppositiflorae. The distinction between Microcos and Grewia hitherto lumped together in most flora is clearly separated based on morphological characters.

Grewieae species were revised with clear morphological characters that produced an indented dichotomous key for easy identification of the species.

 

Keywords: Grewieae taxonomy, Gross morphology, Leaf anatomy, Phylogenetic analysis.

Word count: 497


NAME:                                  Benjamin Erhinmeyoma AYISIRE

MATRIC NO:                       141122

TOPIC:                   GERMINATION, SEEDLING GROWTH AND PROPAGATION OF SOME  ECONOMIC TREE SPECIES VIA TISSUE CULTURE TECHNIQUES

ABSTRACT

Many West African tree species are threatened with extinction arising from their uncontrolled exploitation for several uses, therefore, reforestation is urgently needed. Many tropical tree species have seeds that are recalcitrant or hard-coated and consequently limit their seedling production. The study was therefore designed to provide baseline information on seed germination, seedling growth and to develop protocols for rapid propagation via tissue culture techniques of seven economic tropical tree species.

 

Seeds were collected from Ile-Ife and Ilorin. The trees - Enterolobium cyclocarpum (Jacq.) Griseb (IFE-17447), Holarrhena floribunda (G. Don) Dur and Schinz (IFE-17448), Sterculia tragacantha Lindl (IFE-17446), Funtumia elastica (Preuss) Stupf (IFE-17450), Prosopis africana (Guill and Perr) Taub (IFE-17445), Blighia sapida Konig (IFE-17451) and Tetrapleura tetraptera (Schum. and Thonn.) Taub (IFE-17449) were identified and authenticated in IFE, Obafemi Awolowo University. Twenty seeds per species were sown in Petri dishes without pretreatment (control) and after physical scarification and pretreatment with concentrated H2SO4 varied at 5-30 minutes. Germination counts were made at 2-day intervals. Five seedlings per tree species were transferred to  humus soil in plastic bowls laid out in a randomised design with 5 replicates and their growth monitored for 14 weeks.  Leaf, stem (or hypocotyl), cotyledon and nodal explants obtained from 3-6 week-old seedlings of each species were cultured on Murashige and Skoog (MS) medium alone (control), and supplemented with various concentrations and combinations of hormones - Naphthaleneacetic acid (NAA), 2, 4-Dichlorophenoxyacetic acid (2,4-D), Benzyladenine (BA), and Kinetin for evaluation of callus formation and regeneration. Regenerated shoots were rooted on MS alone or supplemented with Indolebutyric

acid (IBA).  Each treatment had 20 replicates and the experiments were repeated 3 times. Data were subjected to descriptive statistics and ANOVA(at p≤ 0.05).

 

Pretreatment time (20-30 minutes) of seeds with concentrated H2SO4 gave percentage germination in E. cyclocarpum (96%), T. tetraptera (83%), P. africana (81%) and S. tragacantha (20%) while physical scarification gave in E. cyclocarpum (92%), B. sapida (91%), P. africana (87%), T. tetraptera (76%) and S. tragacantha (10%) which were significantly different from control (0%). Significant differences occurred in seedling growth among tree species between week 6 and 14, with E. cyclocarpum reaching highest shoot height (64.5±1.10 cm) and leaf area (375±4.05 cm2); S. tragacantha  had the least shoot height (10.9±0.20 cm) while F. elastica  had the lowest leaf area (168±1.17cm2). Nodal explants of E. cyclocarpum, H. floribunda, S.  tragacantha, and T. tetraptera and cotyledon explants of E. cyclocarpum and T. tetraptera produced multiple shoots on MS media supplemented with  NAA, 2,4-D, BA and Kinetin. Nodal explants of E. cyclocarpum and T. tetraptera cotyledon explants had highest number of shoot/explant of 4.1±0.23 and 2.8±0.13, respectively. These shoots rooted in control medium or MS supplemented with IBA and 80% of acclimatised plantlets survived in potted soils.

 

Germination and seedling growth of the tree species were determined and the in vitro generation of plantlets of E. cyclocarpum, H. floribunda, S. tragacantha and T. tetraptera obtained through nodal explants could facilitate rapid production of these economic trees for purposes of afforestation and conservation.

 

Keywords: Seed dormancy, Economic tree species, Forest afforestation, In vitro        propagation

 

Words Counts: 499

 


NAME:                       Ezekiel Taiwo AFOLAYAN

MATRIC. NO.:         78476

TITLE:                      EVALUATION OF MINI-TUBER PRODUCTION TECHNIQUES

                                    USING VINE CUTTINGS AND SOIL AMENDMENTS ON TUBER

                                    YIELD OF WHITE YAM (Dioscorea rotundata POIR) UNDER

                                    NUTRIENTS-DEPLATED SOIL

 

ABSTRACT

 

Vine cutting technology is an alternative approach to seed yam production. However, low survival rates, high cost of hormones and other technological requirement shave limited it adoption for the production of white yam, a major food crop in Africa. Also, application of some inorganic fertilizers in nutrient-depleted soils may not improve yield of white yam but Arbuscular Mycorrhizal Fungi (AMF) and soil amendments may yield results. This study therefore aimed at improving mini-tuber production from vine cutting and the white yam’s yield under nutrient-depleted soil using AMF and soil amendments.

White yam vines (250) were collected from the Teaching and Teaserch Farm, University of Ibadan and treated with Indole-3-Butyric Acid (IBA), Naphthalene Actic (NAA), Ash and Charcoal experimental bags with 30kg soil at 5 vines per bag in a screen-house. Also, 175 vines were collected and planted in Improvised Screen-house (ISH) using transparent nylon cover, Permanent Shade (PSH) under tree canopy and combination of both (ISH+PSH) on the field without rooting hormone. Seed yam (110) obtained from Bodija market and mini-tubers from the vine cuttings were planted on heaps. Both the screen house and field experiments were laid out in a completely randomized design with five replicates. Survived vines in both experiments and sprouted seed yam/mini-tubers were treated with (AMF, Glomus mosseae), Green manure (GM), Poultry Manure (PM), NPK fertilizer, superphosphate and urea fertilizer. Percentage survival, chlorophyll and Relative Water Contents (RWC, shoot weight, number of roots, root weights, tuber weights and length were determined using standard methods.  Data were analysed using descriptive statistics, correlation and ANOVA at   

In the screen-house, percentage survival of vines ranged from 51.2±3.0 (ASH) to 73.1±2.5  (IBA+NAA). Vines treated with IBA alone had the highest shoot weight (12.9±0.46g), chlorophyll  content (82.8±1.3 µmol/m2), RWC (85.5±1.3%) and root number (7.7±0.3). vines treated with IBA + charcoal had the highest root weight (2.1±0.1g) In the field experiments, vine treated with  ISH  + PSH had the highest percentage survival (91.9±2.1%) and chlorophyll contents (59.5±0.9 µmol/m2). Vines treated with AMF+GM had the highest mini-tuber weight (28.5±96.2g) mini-tuber length (19.7±4.3cm) and mini-tuber width (8.7±0.9cm). Correlation between the mini-tuber weights and chlorophyll contents was positively significant (r=0.658). In the seed yam experiments, AMF+PM enhanced tuber weight (4.9±0.2kg) and tuber length (45.3±1.9cm), while tuber weight of 5.4±0.2kg was obtained in AMF+GM treated plants from the mini-tuber experiments. The GM applied singly enhance higher chlorophyll production (73.6±2.0 µmol/m2) in the mini-tuber experiments. There was no significant difference in the tuber weights, tuber lengths, chlorophyll contents and RWC between the plants from the seed yams and mini-tubers’ experiments.  Vine cutting survival was improved under the improvised screen-house and permanent shade without rooting hormones. This treatment can be employed by farmers in obtaining planting materials. Mycorrhiza (Glomus mosseae) and green manure were good for yam productivity in nutrient-depleted soils.

 

Keywords: Rooting hormone, Arbuscular mycorrhizal fungi, Improvised screen-house, Vine

       Cuttings, White yam, Soil amendments

 

Word count: 488


NAME:                       Olumoye Ezekiel OYETUNJI

MATRIC. NO.:          141132

TITLE:                      EVELUATION OF ENTOMOPATHOGENIC FUNGI [Beauveria

                                    bassiana (BALSAMO) VUILLEMIN AND Metarhizum anisopllae

                                    (METCHNIKOFF) SOROKIN[ FOR CONTROL OF AFICAN RICE

                                    GALL MIDGE (Orseolia oryzivora)

 

ABSTRACT

 

Rice (Oryza sp) cultivation has tremendous economic benefit, however its production is limited by infestation of African Rice Gall Midge (AfRGM), Orseolia oryzivora resulting in low yield. Approaches to manage AfRGM such as the use of chemical pesticides like carbofuran has negativeimpact on human health. Entomopathogenic fungi [(EPF) (Beaveria bassiana and Metarhizium anisopliae)] have been extensively used for biological control of insect pests, however there is no documented information on their use for control of AfRGM. Therefore, this work aimed at managing AfRGM using B. bassiana and M. anisopliae and isolating entomopathogenic fungi from local rice paddy soil. Culture and isolation of fungi from infested paddy soil, rice panicles and gall midge purposively collected from ten rice fields in Ibadan and Edozhigi were carried out using Potato Dextrose Agar, Sabouraud Dextrose Agar, Czapek Dox Agar and Oat Meal Agar. There strains each of B. bassiana  (Bba362, Bba5653, Bba5654) and M. anisopliae (Meta31, IC30, Ic20) obtained from IITA culture collection were used for AfRGM control. Insect pathogenic activity (IPA) of EPF was determined on different stages of pest development (adult, egg, pupae) on infested rice plants and monitored using completely randomized design with three republications. Evaluation of EPF effect was done on ten rice genotypes infested with AfRGM using augmented design with six strains of EPF, one synthetic chemical and untreated control. Level of genotype resistance was determined using standard method. Data on tiller infestation, chlorophyll content, plant height, panicle number and grain number were collected weekly using standard method an analaysed with descriptive statistics,  linear correlation and ANOVA at 0.05.

Twelve fungi species were isolated from rice panicles, insect pest and soil but none was entomopathogenic, Rice plants infested with adult AfRGM and treated with IC30 had 90.6% of  non-infested tillers, while those treated with IC20 78.9%. The IPA of EPF on plants infested with AfRGM eggs showed that plants treated with Meta31 had highest percentage (84.1%) of non- infested tillers followed by plants with Ic 30, Bba5654 and Bba326 with 78.2%, 76.7% and 76.5%, respectively. Effects of EPF on plants infested with AfRGM pupae showed that plants treated with IC30 had 98.2% of non-infested tiller followed by plant treated with Bba5653 (89.8%). Chlorophyll content of plants treated with Bba5654 was 35.5±1.5 nmol/cm2 followed by plants treated with IC30 (34.9±2.3 nmol/cm2). Plants treated with IC20 had highest plant height (97.3±2.7 cm) among all treatments. Highest number of panicles (5.1±0.8) and grains (354±5.6) were produced by plants treated with Bba5653. Genotype TOG7106 was highly resistant to AfRGM with no infestation, while genotypes TOG7206 and TOS14510 were resistant  3.1% and 4.6% tiller infestation respectively. All other genotypes were susceptible. Genotype TOS14519 had 4.6% tiller infestation without EPF, while it had 1.2% and 2.4% when treated with Bba5653 and IC30, respectively. Tiller infestation was negatively correlated with chlorophyll content (r=0.72), plant height (r=0.61), panicles number (r=0.52) and grain number (r=0.56). Metarhizium anisopliae IC30, Metarhizium anisopliae Meta31 and Beauveria bassiana Bba5653 effectively controlled African rice gall midge with increased rice yield.

 

Keywords: Non-infested tiller, rice genotypes, Beauveria bassiana, Metarhizium anisopliae          

Word count: 499


NAME:                      Bunmi Comfort KOTUN

MATRIC. NO.:         135952

TITLE:                      MYCOTOXIN PRODUCTION AND MOLECULAR CHARACTERISATION OF Penicillum SPECIES ISOLATED FROM MILLET (Pennisetum glaucum) (L.) R. Br IN SOUTHWESTERN NIGERIA

ABSTRACT

Millet, a widely consumed food crop, is subject to fungal contamination during storage. These fungi produce mycotoxins in stored food products. Mycotoxins such as citrinin and ochratoxin produced by Penicillium species have been reported to be injurious to consumers. Knowledge of the fungi involved in the production of these mycotoxins will help in the control of its spread in food products. However, there is dearth of information on the mycotoxins produced by Penicillium on millet grain and the species characterisation with molecular technique in Nigeria. Hence, this study was designed to investigate the distribution of Penicillium species and determine the presence of mycotoxins in the millet grains with molecular techniques.

Samples of millet grains were purchased from three randomly selected markets each in Lagos, Ogun, Ondo, Oyo and Ekiti states all in southwestern Nigeria. One hundred grains from each of the millet samples were employed for isolation of fungi using Dichloran rose bengal chloramphenicol agar.  Morphological identification of the fungal isolates was done using Pitt`s manual. The DNA of the Penicillium species were isolated using standard procedures. Similarities between species were determined by amplifying their internal transcribed spacer (ITS1, ITS4) region and partial beta tubulin gene (Bt2a, Bt2b). Physiological assessment of the Penicillium isolates which includes optimum pH, carbon and nitrogen sources, temperature and incubation time for mycelial growth were carried out using standard methods. Toxigenic screenings of the isolates were carried out by amplifying the genes pksCT, ctnA, orf3 and otanps responsible for citrinin and ochratoxin production. The effects of pH and temperature on mycotoxin production were determined and quantified using Enzyme linked immunosorbent assay. Data were analysed using descriptive statistics.    

Thirty-four isolates were obtained, out of which twenty-three were identified as Penicillium citrinum (17), P. capsulatum (1), P. simplicissimum (1), P. oxalicum (1), P. steckii (2) and P. chrysogenum (1). Distributions among the states were Ondo: Penicillium citrinum, P. simplicissimum and P. oxalicum, Ogun: Penicillium citrinum and P. chrysogenum while only Penicillium citrinum was obtained from Lagos, Oyo and Ekiti states. Twenty-one isolates showed amplification to the beta tubulin gene with a uniform amplicon size of 500 base pair, while P. simplicissimum  and P. oxalicum exhibited variation in amplicon fragement sizes (450 and 550 base pair), respectively. Physiological assessment of the isolates showed optimum growth at pH 8  having 2.51 g Mycelia Weight (MW) and starch as carbon source  having (2.14 g MW), (NH4)2SO4 as nitrogen source having (0.86 g MW), optimum temperature was at 30 °C  having (0.96 g MW) and 14 days as best incubation time with 0.94 g as dry MW. Toxigenic genes ctnA (678-679 base pair), orf3 (428-447 base pair) and otanps (788 base pair) was detected in six Penicillium (26%) isolates. Ochratoxin production was highest at pH 8 with 7.0 ppb, and at 25 °C with 5.0 ppb.

Distribution of Penicillium on millet grain across the study area was determined, the isolates were characterised and mycotoxin from Penicillium citrinum was found to be above the standard permissible limit of ochratoxin.

  

  Keywords: Millet grain, Mycotoxigenic Penicillium species, Ochratoxin and citrinin genes

  Word count: 497

 

 

NAME:                      Victor Segun EKUN

MATRIC. NO.:         52996

TITLE:                      CULTIVATION AND MOLECULAR CHARACTERISATION OF

                                    Auricularia SPECIES IN SOUTHWESTERN NIGERIA

 

ABSTRACT

 

Mushrooms such as Pleurotus, Vovariella and Auricularia species are cultivated for food medicinal purpose in the world. However, cultivation of Auricularia in Nigeria is limited due to inadequate designed to characterize Auricularia species in Southwestern Nigeria and determine suitable for their cultivation.

Fifty-four samples of Auricularia species were randomly collected based on availability from secondary forests in Osun, Oyo, Ondo, Ekiti, Ogun and Lagos states Pieces of tissue from each samples were cultured on Potato Dextrose Agar (PDA). Samples with mycelial growth were later cultured on sterised sorghum grains to produce spawns. Six substrates comprising Mansonia altisima (A.Chev) A Chev sawdust, cotton waste-Gossypium hirsutum Linn, rice straw Oryza sativa Linn, each in polythylene bags and drilled logs of Mangifera indica Linn, Gliricidia sepium (Jacq) Walp, and Cedrela odorata Linn, were purposively selected for spawn inoculation to produce mushrooms. Morphological    identification (colour, shape and texture) of Auricularia species, the growth parameters (days of spawn run, days pf pin head formation), and yield (fresh weight) of the mushrooms were determined using standard procedures. Nutrient contents (nitrogen, phosphorus, and potassium) and proximate analysis (Protein, Fat and Carbohydrate) were carried out using AOAC methods. Fifteen Random Amplified samples Polymorphic DNA (RAPD) primers were used for PCR amplification of the DNA of Auricularia to determine the degree of genetic diversity. Phylogenetic relation were determined by cluster analysis, Polymorphic Information Content (PIC) and genetic diversity determined using standard procedures. Data were analyzed using descriptive statistics, clustering and Principal Component Analyses (PCA).

Morphologically, 31 samples of A.auricular, (yellow brown, auriform, leathery texture) and 12 samples of A. polytricha dark brown, discoid, gelatinous) were identified while 5 samples were unidentified and samples did not grow. Auricularia species samples cultivated on M.altissima sawdust, cotton waste, rice staw in bags produced mycelial growth but did not frucify while samples on drilled logs had myclelial growth and fructified. Mangifera indica had highest days of spawn run (24.3±0.7), pin head formation (28.7±0.6) and highest yield (10.0±0.4g). The highest nitrogen content (13.6±mg/kg) was in A. polythrica, phosphorus (39.3±7.6mg/kg) in A. auricular and calcium (61.9±3.6mg/kg) in A. auricular. The highest protein (7.0±0.8%) and crude fibre (25.1±2.5%) were obtained in A. polythrica. Fat content (7.0±0.1mg/kg) was highest in A. auricular. Clustering analysis and morphological traits produced  distinct groups while the PCA produced eigen  values of 23.0%, 16.0%, 14.0% 11.0%, 10.0% and 9.0 % on six corresponding axes. The RAPD primers grouped the Auricularia species into 6 distinct clusters based on morphological traits. The PLC ranged from 0.5594 (OPH-15) to).7819 (OPB-12) and gene   diversity from 0.5930 (OPH-15) to 0.7077 (OPB-12). Primer OPB-12 was the most informative for genetic diversity of Auicularia species. Auricularia species exhibited genetic variation and Mangifera indica enhanced their growth. Auricularia  polytricha was the most nutrient species.

              

keywords: Mushroom cultivation, Mangifera indica susctrate, Polymorphic information content

  Word count: 454