Theses and Dissertations

Permanent URI for this collection

https://ir.oauife.edu.ng/handle/123456789/233

Theses and Dissertations (Department of Plant and Science)

Browse

Now showing 1 - 16 of 16

Open Access
Assessment of Occupational Exposure Hazards on Farmers Due to Insecticide Control of Cacao Mirids (Insecta: Hemiptera) in Southwestern Nigeria
(2015-06-05) Sosan, Mosudi Babatunde
The study investigated the risks involved in applying selected insecticides to control mirids in cacao (Theobroma cacao L.) plantations in southwestern Nigeria. A field survey was conducted in 15 major cacao-producing villages from which 150 farmers were randomly selected for interview. Structured questionnaires were administered to the respondents while oral interviews were also conducted. Five exposure duration periods were identified based on number of years of involvement in insecticide application as < 5 years, 5-9years, 10-14 years, 15-19 years and > 20 years. The blood erythrocyte acetylcholinesterase enzyme (AChE) activities, haematological profile, and insecticide residue analyses were carried out to determine the possibility of insecticide poisoning, establish any relationships between haematological profile and exposure, and detect the presence of residues in the blood, and the farmers' sources of drinking water. The results showed that the cacao farmers used lindane formulated as Gamalin 20ECo; diazinon (Basudin 600 ECo); endosulfan (Sulfonex 35 ECo); and propoxur (Unden 20ECo) for mirid control. Sources of exposure identified included eating/chewing habits and drinking during application, non-adherence to the use of protective clothing, improper storage and disposal of used insecticide containers. Varying proportions of the farmers experienced the common symptoms that could be ascribed to insecticide exposure hazards. The results from the baseline AChE activity measurement of 76 cacao farmers revealed that eight of them had a relatively low AChE activity ranging from 33% to 50% N which is indicative of chronic poisoning. The baseline and post-insecticide application AChE activities determined among 40 of these farmers, showed that 90% of them experienced AChE activity inhibition ranging from < 20% to 50%. The duration of exposure had no significant effect on the PCV and WBC of the farmers but their WBC differential counts (eosinophil, neutrophil and lymphocyte) differed; farmers in the 15-19 and above 20 years exposure periods showed a marked prevalence of abnormal counts. The farmers also generally showed significant decreases in haemoglobin values between the pre-(13.9g/dl) and post-(12.9g/dl) insecticide application periods. The residue analyses revealed that 42 (53.3%) out of the 76 farmers had residues of diazinon, endosulfan, propoxur and lindane in their blood out of which 47.6% belonged in the >20 years exposure duration period. Nineteen percent of the farmers had diazinon in their blood, while 15% had endosulfan, 14% propoxur, and 8% lindane. Only 5% had no residues at all while 39% had unknown residues and possible metabolites of these insecticides in their blood. About 67% and 9% of the farmers that had diazinon and propoxur, respectively, in their blood exceeded the No Observable Effect Level (NOEL) of 0.02 ppm (diazinon) and 0.2 ppm (propoxur). The diazinon and propoxur detected in the farmers' sources of drinking water also exceeded the Acceptable Daily Intake (ADI) of 0.002 ppm and 0.02 ppm respectively. It was concluded from the study that cacao farmers had been occupationally exposed due to insecticide application for mirid control; and the exposure was sometimes of such magnitude as to be hazardous to the farmers and their respective communities.
Open Access
Distribution of Seeds of Mimosa Invisa Mart (Giant Sensitive Plant) in Soils and Factors Affecting Germination
(2015-04-20) Ekhator, Frank
This study was conducted to investigate the distribution of seeds of Mimosa invisa in the soil seed bank so as to develop effective control measures against this noxious weed. The specific objectives were to examine the distribution of seeds of M. invisa in 0-30 cm of soil depth; and, determine the effect of acid scarification, boiling water treatment, heat treatment, pH, planting depth and brine stress on germination and emergence of M. invisa seeds The experiments were laid out in a completely randomized design with four replications. Soil cores were collected from cultivated and fallow fields from the Nigerian Institute for Oil Palm Research (NIFOR) at three depths (0 – 7, 7 – 15 and 15 – 30 cm), processed and placed in germination trays 34 x 22 x 4 cm in the screenhouse for germination. Bulked seeds collected from oil palm plantation and fallow fields in NIFOR were used in investigating the effects of acid scarification, boiling water treatment, heat treatment, pH, planting depth and brine stress on germination and emergence of M. invisa. Data collected were subjected to analysis of variance and means compared using Least Significant Difference (LSD) at 5% level of probability, Shannon and Wiener index was used to estimate the weed species diversity. Results showed that there were no significant differences in the seed populations of M.invisa between depth of 7 to 15 cm and 15 to 30 cm in both cultivated and fallow fields. Although only significant (P<0.05,Fcal. = 196.16) on 0 to 7 cm depth in the fallow fields, the distribution of M .invisa seeds follow the same trend in soils of cultivated and fallow fields, decreasing down the depth (P<0.05, Fcal. = 196.16). However, seeds of M. invisa were significantly higher (P<0.05, Fcal. = 196.16) in fallow fields than in cultivated fields. Seeds of other weed species such as Panicum maximum Jacq., Chromolaena odorata (L.) R. M. King and Robinson, Cyperus species, Aspilia africana (Pers.) C.D. Adams and Boehavia coccinea Mill were found in the seed bank along with M. invisa. Shannon — Wiener diversity index showed that seeds of weed species were more diverse in the seed bank of cultivated than in the seed bank of the fallow fields. Percentage germination of M. invisa seeds treated with sulphuric acid were significantly higher (P<0.05, Fcal. = 1071.47) than those treated with hydrochloric and nitric acid at the different concentration rates of 0, 25, 50, 75 and 100%v/v of the acids used. Germination of M. invisa seeds was higher when seeds were immersed in boiling water for 2 minutes and no germination occurred when immersed in boiling water for 14 minutes. Germination of M. invisa increased with increase in temperature from 0°C (1.44%) up to 90°C (87%) and was totally inhibited at 110°C. M. invisa emerged better at soil depth of 0 cm (87%) and 5 cm (22.64%). M. invisa germinated over a wide range of pH (4 to 10), with the highest germination occurring at pH 6 (72.56%). While germination of M. invisa seeds was totally inhibited at 300 mM NaCl, over 80% germination occurred between 0 and 60 mM NaCl. In conclusion, seeds of M. invisa in the soil seed bank were found distributed through the 0 to 30 cm depths studied. Other weed species were found in association with M. invisa in the soil seed bank and the weed species diversity was greatest in the cultivated fields. Acid scarification, boiling water treatment and heat treatment were all effective in dormancy release of M. invisa seeds. Emergence of M. invisa was best at a planting depth of 0 cm. M. invisa germinated over a wide range of pH and NaCl solutions.
Open Access
Efficiency of Germination and Vigour Tests in Predicting Field Performance of Different Genotypes of Maize (Zea Mays L.)
(2015-05-11) Olosunde, Akinloye Adam
Eighteen varieties of maize (Zea mays L.) were used to evaluate the efficacy of germination and vigour tests in predicting maize emergence under field conditions as well as to investigate whether differential response to the tests exist among the maize varieties. The study was designed to establish which among the tests could be used to reliably predict field emergence of maize. The four tests used were the standard germination, accelerated ageing, tetrazolium staining and conductivity. Each test was evaluated with 4 replicates of 25 seeds per variety. The tests were conducted in the Seed Science Laboratory of the Department of Plant Science. In addition, the maize varieties were evaluated in a 4-replicate field trial, laid out as randomised complete-block design at the Teaching and Research Farm of the University during the 2004 late season. The results showed that eleven out of eighteen varieties evaluated had standard germination above 80%. The viability of seed as determined by tetrazolium staining was also above 80% for seventeen varieties. Germination for accelerated ageing test varied between 5% and 72% while conductivity test results ranged from 48.4 μs/cm/g to 146.6 μs/cm/g. Field emergence varied from 62% to 90%. There was variation in the results of relative ranking of each vigour test as well as the grand rank summation. Field emergence of varieties 18 (TZEEY — SR BC5) and 7 (TZE WPop X 1368 STR CI) could be reliably predicted by these vigour tests but predictions for varieties 9 (SIN 9432) and 12 (TZEE — SR Damascus) would be unreliable. Results of the relative ranking of the varieties within each test and the significant variety x test interactions observed in the study suggested that evaluation of seed vigour involving several maize varieties should be done under several seed quality tests in order to minimize the chances of taking wrong decisions. Furthermore the significant positive correlation coefficients of field emergence with tetrazolium (r = 0.62, P < 0.01) as well as accelerated ageing (r = 0.48, p < 0.05) indicated that these two tests could be used to predict maize emergence and seedling vigour in the field. The performance of the maize varieties in the field trial showed few significant con-elation coefficients between the laboratory tests and mature plant traits. Tetrazolium test had significant negative correlation with grain yield (r = -0.49, p < 0.05). For the standard germination test, there were significant negative correlations with days to 50% tasseling, pollen shed and Bilking (r = -0.64 to 0.62, p < 0.01) while accelerated ageing had significant correlation with days to 50% tasseling and pollen shed. Therefore, seedlots with high germination in the laboratory had a tendency to flower early. In conclusion, tetrazolium and accelerated ageing tests reliably predicted field emergence and flowering dates of the 18 maize varieties evaluated.
Open Access
Evaluation of Bacilus Thuringiensis Berliner and Baculovirus Heliothis as Microbial Control Agents of Heliothis Armigera (Hubner) and Spodoptera Littoralis (Boisduval) on Tomata.
(Obafemi Awolowo University, 1985) Lutwama, Julian Julius; Matanmi, B. A.
Field plantings of tomato grown during both the rainy and the dry seasons were subjected to foliar sprays of Bacillus thuringiensis Berliner (B.t.), Baculovirus heliothis (B.h.) and carbaryl, plus Tenac and Gustol adjuvants against larvae of Heliothis armigera (Hubner) and Spodoptera littoralis (Boisduval). In the laboratory, the dosage-mortality response of these larvae to B.t. and B.h., was also determined. This involved using the diet-surface treatment bioassay technique and obtaining the lethal concentrations (L.C.50) after probit analysis. H. armigera larvae were found to be highly susceptible to both B.t. and B.h. but S. littoralis larvae appeared highly susceptible to only B.t. The 0.5 Kg/ha and 1.0 Kg applications of B.t. gave good field control of the larvae, with the later giving control comparable to that of the 1.5 Kg/ha carbaryl application. B.t. and B.h. were shown to be compatible, though the combinations were not significantly more effective than either of the pathogens alone. Combinations of B.t. and B.h. with carbaryl were also not significantly different from either of the pathogens alone. The 0.5 Kg/ha application of B.t. with 0.5 Kg/ha carbaryl was as good as the 1.5 Kg/ha carbaryl application, thus indicating that B.t. could partially replace carbaryl in the spraying programme. The adjuvants GustolR and Tenac were compatible with B.t. and B.h. but they did not significantly increase the effectiveness of the pathogens.
Open Access
Evaluation of Local Packaging Materials for Efficient Handling of an Easily Bruisable Horticultural Produce (Tomato).
(Obafemi Awolowo University, 1987) Eniaiyeju, Damilola Emmanuel; Adegoroye, A. S.
Laboratory experiments were carried out to determine the tensile or compressive properties of cane and frond under various curing conditions. Three package shapes were constructed from both materials namely, U-, ellipsoid and trapezoid while the open U-shaped frond market type served as the control. Tomato fruits were used to evaluate the various package shapes. Cane, frond or composite packages so constructed were subjected to transportation hazard tests (compression or impact) at full or half loading. Contents and packages were evaluated for fruit defects and package deformation after test over 11 days at ambient storage. The effect of materials on physiological status of the fruits was also evaluated in lined or unlined fruit loaded packages. The results show that cane and frond behaved as-linear orthotropic viscoelastic materials in uniaxial tension. Although the tensile strength of fresh cane was much greater than that of fresh frond, cured frond samples had higher tensile strength than fresh cane samples and were as comparable in strength as cured cane samples. Curing brought about moisture reduction in both materials. In compression, significant differences were found for package type, compressive load and duration of bulk compression. The open U-shaped frond (control) was more prone to fruit damage due to instability of the package to compressive loading. Permissible produce damage/duration of bulk compression was three days. On impact-induced fruit loaded packages, significant differences were obtained for cultivar, loading, package material and package shape. Ife 2 was more susceptible to physical damage than Ife Plum. Cane inflicted more injury on fruits end resulted in greater fruit rot than control. Fruit damage of all categories except decay was less in-trapezoidal-shaped package compared with the control. Damage was also higher at half than full loading. In terms of package shape/material composition, the woven cane trapezoidal-shaped was better than the deformable U-shaped composite type. On the effects of lining and varietal differences, stress inducing factors, such as, impact and rot, increased the rate of ethylene production and physiological biodeterioration.
Open Access
Genetic and Environmental Analysis of Vegetative and Yield Traits in the Oil Palm ( Elaeis Sp.).
(Obafemi Awolowo University, 1986) Opeke, Bolanle olufunmilayo; Fakorede, M. A. B
A total of 21 hybrids of oil palm consisting of four Elaeis,guineensis palms selected for shortness, three F1 interspecific hybrids (Elaeis oleifera x E. guineensis), 13 hybrids from the first backcross gene-ration (BC1) of the F1 interspecific hybrid crossed to E. guineensis and a standard cross used as check, were evaluated for yield and vegetative traits with a view to determining a suitable breeding method for short-stemmed palms. Associations among all traits were also investigated. Furthermore, the effects of climatic factors on vegetative and yield traits were investigated using correlations, stepwise multiple regression and path coefficient analyses. In addition, two environmental indices (biological and biophysical) were compared for yield stability using nine Dura (D) x Tenera (T) hybrids. Data for evaluation were collected from three field plantings made at the Nigerian Institute for Oil Palm Research near Benin City, between 1960 and 1969; and data collected covered the period 1963 to 1982.Generally, the backcross hybrids were superior in cumulative' trunk height and annual trunk increment compared to E. guineensis palms selected for shortness, the F1 interspecific hybrids and the check. However, average yield (as measured by fresh fruit bunch yield) of the backcross hybrids was 22.8-48.2% lower than the mean of the F1 interspecific hybrids. Number of bunches and mean bunch weight were associated with vigor characteristics (trunk height, crown diameter and number of leaves) in the backcross hybrids. Total sunshine hours and minimum relative humidity at about 18-21 months before harvest demonstrated the strongest associations with number of bunches and fresh fruit bunch yield. Generally, progenies maintained their relative ranking for environmental response regardless of the index used to quantify the environment.
Open Access
Genetic Variability and Predicted Responses to Four Types of Progeny Selection in a Nigeria Maize (Zeamays L.) population.
(Obafemi Awolowo University, 1986) Adeyemo, Moses Olusegun; Fakorede, M. A. B.
Genetic variability and predicted responses to full-sib (FS), half-sib (HS), Si and S1 testcross (TCH) selection methods were studied in the open-pollinating maize variety, TZSR-Y-1. Evaluation of progress after one cycle of selection was also done. Grain yield and seven agronomic traits were investigated. Mean grain yield ranged from 3.4 to 9.2 t/ha for FS, 2.9 to 7.5 t/ha for HS, 1.75 to 8.0 t/ha for S1 and 3.2 to 8.8 t/ha for TCH. Genetic variances ( 4;2) were largest for S1 families but there were no consistent trends for c2 among the other progeny types. Additive genetic variance constituted- the major portion of the total genetic variance for grain yield and the agronomic traits. Heritability estimates were moderate to high for nearly all agronomic traits of the four progeny types. Generally, only the correlations of yield with ear number per plot and ear length had coefficients appreciably larger than 0.50; these two traits were therefore the primary determinants of grain yield. Largest predicted direct gain per season of selection for grain yield was obtained for S1 families followed by TCH and FS which differed little. HS selection gave the smallest predicted gain. Predicted correlated responses in grain yield assuming selection was done for agronomic traits were generally smaller than predicted direct responses to selection for grain yield. After one cycle of selection, yield improvements of the derived populations relative to the source population were -2.5% for SI, 8.8% for HS, 13.5% for FS, and 14.6% for TCH selection methods. On the basis of operational efficiency and predicted versus realized gains from selection, FS family selection would be more effective than the other selection methods studied for improving the maize variety TZSR-Y-1.
Open Access
Genotype X Environment Component of Variance and its Implications in Maize (Zeamays L.) Yield Trials.
(Obafemi Awolowo University, 1985) Adisa, Aramide Omolara; Fakorede, M. A. B.
Grain yield data obtained from yield trials conducted in 1981 and 1982 for five open-pollinating cultivars and eight varietal hybrids of maize (Zea mays L.) were used to investigate the effectiveness of 3 different yield trial methods. These included experiments A: 2 years, 2 locations, 1 planting date; experiment B: 1 year, 2 locations, 3 planting dates, and experiment C: 2 years, 1 location, 3 planting dates. Variance components were obtained for each method and optimum combinations of numbers of years, locations, planting dates and replications for varietal testing were determined by calculating theoretical standard error of the mean (SEM). Analysis of variance for the three methods showed highly significant location, year, planting date and genotype effects. SEM of 0.256 was obtained for 2 years, 2 locations, 1 planting date and 4 replications, and this was used as the standard for comparing the other two methods. When planting dates were substituted for years in experiment B, the SEM of 0.256 was obtained for combinations ranging from 1 year, 8 locations, 2 planting dates and 1 replication, to 1 year, 2 locations, 2 planting dates, and 4 replications. Substituting planting dates for location in experiment C however, resulted in the use of a larger number of planting dates than in experiment B, and not less than a 1-year period of testing to obtain the minimum SEM of 0.256. Planting dates can therefore be effectively substituted for years in order to reduce the time for conducting preliminary maize yield trials. Planting dates can also be substituted for locations where funds but not time, are limiting.
Open Access
Germination of Euphorbia Heterophylla L. and its Control in Cowpea (Vigna Unguiculata (L) walp).
(Obafemi Awolowo University, 1986) O'Makinwa, Rufus Oyeniyi; Akinyemiju, O. A.
In order to understand the influence of temperature and light duration on the germination of Euphorbia heterophylla L., freshly harvested and pre-chilled seeds of the weed were incubated in an illuminated cooled incubator for varying light and temperature regimes. Their germination was observed daily for 10 days. In another study aimed at identifying the most effective herbicides and herbicide combination and time of application for the control of E. heterophylla, separate screenhouse and field trials were conducted. In both the screenhouse, and field trials, two rates each of alachlor, cyanazine, acifluorfen and metobromuron + metolachlor were applied at different times after planting to control the weed in two cowpea (Vigna unguiculata (L.) Walp.) cultivars (Ife brown and TVx 3236) . Results of the germination study showed that the optimal conditions for germination of the freshly harvested seeds were 250C and 8 hours light duration. Prechilling was inhibitory to germination of heterophylla. In the screenhouse study, results showed that the pre-emergence application of various herbicides to suppress E. heterophylla was more effective than the post-emergence applications. Cyanazine and acifluorfen at both rates and at the various times of application were injurious to cowpea and E. heterophylla. Metobromuron + metolachlor at 2.5 kg a.i./ha was well tolerated by cowpea and suppressed the weed effectively when applied pre-emergence; its post-emergence application at 2.5 and 5.0 kg a.i./ha were lethal to cowpea, but suppressed E. heterophylla. Alachlor at 2.5 and 5 kg a.i. /ha applied pre and post-emergence were ineffective in the control of heterophylla. Results of the field experiment generally confirmed the screenhouse observation. In these series of studies it is clearly demonstrated that the control of E. heterophylla in cowpea in the field can be achieved by a pre-emergence application of 3 kg a.i./ha metobromuron + metolachlor.
Open Access
Growth and Yield of Cassava (Manihot Esculenta Crantz), Cowpea ( Vigna Unguiculata s.sp Unguiculata (L) Walp) and Maize (Zeamays L.) in Sole Cropping and Intercropping.
(Obafemi Awolowo University, 1986) Adekunle, Adolphus Adewale; Adetiloye, P. O.
Growth and yield of cowpea (Vigna unquiculata s.sp. unguiculata (L) Walp) maize (Zea mays L.) and cassava (Manihot._esculenta Crantz) were studied at two plant populations in sole crop and in a three crop association during the late season of 1983 and the early season of 1984 at the University of Ife Teaching and Research Farm. The eight mixture treatments were planted in a randomized complete block design with three replications. There were two sole crop plots for the two populations of each crop as checks. In the late season, maize and cassava populations significantly increased the plant height, but significantly decreased canopy diameter for all the associated crops and significantly decreased the dry matter yield for maize. Cowpea population significantly increased cowpea plant height and significantly decreased cow-pea canopy diameter. In the early season, cassava and maize significantly increased the plant height and significantly decreased the canopy diameter of all associated crops. Cowpea population significantly increased cowpea plant height and significantly decreased cowpea canopy diameter and dry matter yields. Cowpea population also significantly increased cowpea and maize grain yields. Maize population, however, significantly reduced the grain yields of cowpea and maize and the storage root yield of cassava. Cassava population significantly decreased cowpea and maize grain yields and significantly increased the storage root yield of cassava. The highest land equivalent ratio (LER) of 1.64, land equivalent coefficient (LEC) of 0.133 and monetary equivalent ratio (MER) of 1.22 were obtained from the treatment that contained cowpea at 36,600 plants, maize at 16,600 plants and cassava at 3,300 plants per hectare. LER of 1.64 and LEC of 0.133 shoved an agronomic advantage of 64% and 9.7%, respectively, in mixture while the MER of 1.22 showed an economic advantage of 22% of mixture over sole crop cassava.
Open Access
Heterotic Patterns of Early Maturing Inbred Lines of Maize (Zea mays L.) in Striga–Infested And Striga–Free Environments
(2015-03-27) Agbaje, Samuel Ademola
The study was designed to separate early maturing yellow- and white-endosperm inbred lines of maize (Zea mays L.) into heterotic groups; evaluate the effects of tester, location and infestation of Striga hermonthica (Del.) Benth on the heterotic groups; and rank the heterotic patterns of the inbreds in Striga-free and Striga-infested environments. Seventy yellow and 84 white endosperm testcrosses were generated by crossing 35 yellow and 42 white endosperm inbred lines to two testers each under irrigation in the dry season of 2004. The testers for the yellow inbred lines were 4001 and KU 14 l4 while those for the white inbred lines were 1368 and 907L The testcrosses plus 7 checks for the yellow and 4 for the white lines, were evaluated under Striga-free environments at Obafemi Awolowo University Teaching and Research Farm as well as under ,Striga-free and Striga-infected environments at IITA's experimental outstations in Abuja and Mokwa in 2005. Each trial was laid out as 11 x 7 and 11 x 8 randomised incomplete block design for the yellow and white testcrosses, respectively. Data were collected on flowering traits, root and stalk lodging, plant and ear heights, incidence of diseases (ratings), grain yield and yield components. Additional data were collected at 8 and 10 weeks after planting (WAP) on Striga damage rating on a 1 to 9 scale and Striga emergence count in the Striga-infested environments. Analysis of variance was performed for each set of testcrosses in each location as well as combined across the three locations. Line x tester analysis was performed from which values for general (GCA) and specific (SCA) combining ability effects were obtained. Correlation of GCA effects among the traits was computed also. The results revealed that, mean squares for location and line GCA effects were significant for grain yield and several other agronomic traits in both evaluation environments. In Striga-free environments, SCA effects were significant (f = 1.54, P<0.05) for blight and days to 50% anthesis among yellow testcrosses while for white testcrosses ear aspect and grain yield had significant SCA effects. Under Striga-infested conditions, SCA was significant only for Striga damage rating at 10 WAY among the white testcross hybrids. About 62% of the white and 77% of the yellow lines had large GCA effects for grain yield in the two evaluation environments. Only 13 of the 42 white inbred lines could be classified into heterotic groups based on the SCA effects and testcross mean grain yield in Striga-free environments. Three of these white inbreds maintained their heterotic group under the two evaluation environments. None of the yellow inbred lines could be classified into heterotic groups under any of the evaluation environments. It was concluded that the testers used in this study were not sufficiently effective in classifying the yellow inbred lines and most of the white lines into heterotic groups.
Open Access
Inheritance of Resistance to Cowpea Aphid-Borne Mosaic Virus and Southern Bean Mosaic Virus in Cowpea. Vigna Unguiculata S. SP. Unguiculata (L) Walp.
(Obafemi Awolowo University, 1986) Arowolo, James Ajayi; Obisesan, I. O.
Abstract: The mode of inheritance of resistance to cowpea aphid-borne mosaic virus (CAMV) and southern bean mosaic virus (SBMV) was determined in the following cowpea (Vigna unguiculata s.sp. unguiculata (L) Walp) varieties: A44/2, TVu 222, TVu 612 all resistant to CAMV and TVu 1948, which is resistant to both CAMV and SBMV. Crosses were made between each of the resistant varieties and C20-55, a cowpea variety susceptible to CAMV and SBMV. The parents, FI, F2, B1 and B2 progenies of each cross were raised in the greenhouse and inoculated with the appropriate virus. The results showed that two recessive genes control resistance to CAMV in A44/2, a single dominant gene controls resistance to the same virus in TVu 222, while a single recessive gene was responsible for resistance in each of the varieties TVu 612 and TVu 1948. Results of allelic tests among the F1 and F2 progenies of crosses among A44/2, TVu 612, and TVu 222 indicated that each of them possesses different genes for resistance to CAMV. Resistance to SBMV was under the control of a single dominant gene in TVu 1948.
Open Access
Inheritance of Yield and Agronomic Traits in a Maize (Zeamays L.) Population at Two Levels of Inbreeding.
(Obafemi Awolowo University, 1986) Ajala, Samson Oyewole; Fakorede, M. A. B.
Hybrids resulting from diallel crosses of ten radom lines at the second (S2) and fifth (S5) generations of inbreeding in the TZSR-W population of maize (Zea mays L.) were studied. Eight of the lines were common to both generations. At both generations, general combining ability (gca) was more important than specific combining ability (sca) for most traits. For grain yield however, gca and sca were nearly equal. Therefore, recurrent selection methods that utilize both additive and non-additive gene actions should be used to improve the population. Generally, lines with positive gca effects at the S2 generation also had positive gca at the S5 generation with line 013 being the best at both generations. However, the relative performance of crosses (sca) differed between the two generations. Appreciable inbreeding depression had occurred at the S2 generation with little further depression at the S5 generation. The preponderance and relative stability of gca effects, and the magnitude of inbreeding depression at the S2 generation suggest that good inbred lines can be selected as from the S2 generation. However, the inconsistent ranking of hybrids for sca effects at both generations implies that the yielding ability of such selected lines must be specifically tested to identify the best hybrid combinations. Correlation, stepwise multiple regression and path-coefficient analyses indicated that vigorous lines that mature early, with long rather than wide ears will be high-yielding in hybrid combinations. These analyses also showed that shelling percentage, emergence percentage and numbers of days to silking of S2 X S2 hybrids positively influenced grain yield in the S5 X S5 hybrids. Therefore, these traits could be used as indirect selection criteria for high-yielding hybrids.
Open Access
Seed Setting under Controlled Natural Cross Pollination in Three Populations of Coconut (Cocas Nucifera L.)
(2015-04-20) Enaberue, Louis
The purpose of this study was for high rate production of coconut natural hybrids resulting from controlled natural pollination. The primary objective of this study was to evaluate the seed setting percentage resulting from controlled natural pollination in various cross combinations of coconut (Cocos nucifera L.). A secondary objective was to estimate the effect of climatic factors on number of bunches, number of buttons and number of nuts produced by the cross combinations. Four coconut types: West African Tall (WAT), Malayan Green Dwarf (MGD), Malayan Yellow Dwarf (MYD) and Malayan Red Dwarf (MRD) were planted in 1987 in an isolated coconut seed garden in Field 42 of the main station of the Nigerian Institute for Oil Palm Research (NIFOR) near Benin-City. The goal was to produce different types of Dwarf (D) x Tall (T) hybrids through open pollination. The male flowers of the selected dwarf mother palms were emasculated, while the male flowers of the tall mother palms were not, allowing the tall palms to cross pollinate the emasculated dwarf palms. Controlled natural pollination of these selected dwarf mother palms was carried out for four years (1997-2000) and seed setting percentage (S%) was recorded during the period. The various cross combinations (populations) studied were MGD x WAT (population 1), MYD x WAT (population 2), and MRD x WAT (population 3). Data collected included number of bunches (NOB), number of buttons (NOBT) and number of nuts (NON). The relationship between climatic factors and NOB, NOBT, NON and S% in the various populations was evaluated using correlation and regression techniques. The climatic Factors included, temperature, rainfall. relative humidity, solar- radiation and sunshine hours. Data were subjected to the analysis of variance (ANOVA) for a complete randomized design. The Least Significant Difference (LSD) was used for separation of means of traits that had significant F-test. Data on S% were subjected to aresine transformation before analysis. Analysis of variance showed significant mean squares for palms and years for NOB. NOBT, NON and S%(p< 0.01).The mean S% for the four years of investigation was 51.4%, with a range of 48.2-54.3%. Maximum S% was 54.3% in population 3, 51.7% in population 1 and 48.2% in population 2. Broadsense heritability for the four traits ranged from a low value of 3.020/o for NON in population I to a fairly moderate value of 56.22% for NOB in population 2. Statistically significant positive correlation coefficients of 0.85, 0.80, 0.72, 0.71, 0.06 and 0.04 occurred between NOB vs NOBT, NOBT vs NON, NOB vs NON, NON vs S%, NOB vs S% and NOBT vs S% at 0.05 and 0.01 level of probability respectively. The climatic factors were correlated with NOB, NOBT. NON and S%. Amongst the live climatic factors, only rainfall and sunshine hours were significantly correlated (-0.96 and -0.96) with seed setting percentage. Coefficients of determination (R2) of rainfall, temperature, relative humidity, sunshine hours and solar radiation investigated on the seed setting percentage across populations were 54%, 44%, 5 8 % , 64% and 74%, respectively. In conclusion, controlled natural cross- pollination method was effective in the production of high D x T hybrid seed setting in coconut palms.
Open Access
Studies on Cowpea Varietal Resistance to the Cowpea Flower and Pod Borer, Maruca Testulalis (Geyer) (Lepidoptera Pyralidae).
(Obafemi Awolowo University, 1985) Echendu, Thank-God Nnamdi; Akingbohungbe, A.E.
Several varieties of cowpea, Vigna unguiculata s.sp. unguiculata (L,) Walp., were screened for resistance to the cowpea flower and pod borer, Maruca testulalis (Geyer) using free-choice field trials, cohort tests in large screened cages and no-choice tests in the screenhouse and the laboratory. The damage potential of M. testulalis on Ife Brown cowpea was also studied using controlled infestations in order to establish a baseline infestation level that could be used to differentiate resistance effectively in no choice tests. The study on the damage potential showed that successful establishment of the first in star larvae could only be obtained and sustained throughout the crop growth at the flower bud stage. At this stage, infested plants showed significantly reduced numbers of flowers and pods as well as seed yield. Two first in star larvae per plant was the lowest infestation that produced such significant differences between infested plants and the control. Thus, it is suggested as an adequate level for differentiating susceptible and resistant varieties in no choice tests employing Ife Brown as a standard. The free choice field trials showed significant differences in the degree of susceptibility of the varieties screened. Using overall susceptibility indices that considered some parameters associated with pest attack and which could affect flowering, podding and seed yield, TVu 1896 A/G, Sese, EW/1 and H64-3 were found to be moderately resistant to flower damage; while 2Ak and TVu 1896 A/G were shown to be moderately resistant to pod and seed damage. The field resistance was confirmed by the cohort and no-choice tests. TVu 1896 A/G and H51-1 were found to be resistant to pod and seed damage while TVu 946 and 2Ak were moderately resistant. Non-preference for oviposition and larval feeding appeared responsible for the resistance observed. Antibiosis manifested in form of reduced weight and size, and lengthened pupal period was also observed.
Open Access
A Taxonomic Study of the Acridoidea (Orthoptera) of Southwestern Nigeria.
(Obafemi Awolowo University, 1987) Nzekwu, Anthony Nwora; Akingbohungbe, A. E.
The Acridoidea of southwestern Nigeria was studied. Collection of species of Acridoidea was made from different parts of southwestern Nigeria between 1982 and 1986. The collected specimens were identified and a checklist of the species was prepared. Detailed description of each species was carried out. Keys for the separation of these species were prepared based on the external morphological features. The genitalia were examined and four different vies illustrated for each species. Photographs of all the species are presented in this thesis. A total of 58 species were studied belonging to the families’ pyrgomorphidae and Acrididae. Most of the phallic structures were in agreement with previous studies. However, the phallic structures of the sub-family Oedipodinae contrary to the views of some acridologists showed some affinities especially in the epiphallus. Some affinities were also observed in the phallic structures of Coryphosima producta (Walker), C. stenoptera (Schaum), Holoperono gestaeckeri I. Bolivar, Zacompsa festa Karsch, Gymnobothrus flaviventris Urarov and Chrisra compta (Walker). The families Pyrgomorphidae are made up of species that are generally less active than those of Acrididae. The similarities in the habitat preferences and colour patterns or Oxya hyla Serville and Spathostrenum pygmaeum Karsch were not matched by morpholozical affinities.

Browse

Browsing Theses and Dissertations by Title

Results Per Page

Sort Options