Genetic diversity among early provitamin A quality protein maize inbred lines and the performance of derived hybrids under contrasting nitrogen environments

Open Access JournalInformation on population structure and genetic diversity of germplasm in a breeding programme is useful because it enhances judicious utilisation of genetic resources to achieve breeding objectives. Seventy early maturing provitamin A (PVA) quality protein maize (QPM) inbreds developed by the IITA- maize improvement programme were genotyped using 8171 DArTseq markers. Furthermore, 96 hybrids derived from 24 selected inbreds plus four checks were evaluated under low-N and optimal environments in Nigeria during 2016 and 2017. Genotypic and phenotypic data of inbreds and hybrids respectively, were analysed to (i) assess the level of genetic dissimilarities and population structure of the inbreds, and (ii) investigate the grain yield performance of derived hybrids under low-N, optimal and across environments

Gains in grain yield of extra-early maize during three breeding periods under drought and rain-fed conditions

Open Access Article; Published online: 30 Aug 2018Drought is a key maize (Zea mays L.) production constraint in sub-Saharan Africa. Fourteen, fifteen, and twenty-five extra-early maturing maize cultivars, with varying Striga resistance and drought and low soil N tolerance, were developed from 1995 to 2000 (Period 1), 2001 to 2006 (Period 2), and 2007 to 2012 (Period 3), respectively. The objectives of this study were to examine yield gains in the cultivars and to investigate inter-trait relationships and yield stability under six drought and 17 rainfed conditions in West Africa from 2013 to 2016. Annual rate of yield increase across cultivars was 0.034 (3.28%) and 0.068 Mg ha−1 (2.25%), whereas yield gains per period were 0.17 and 0.38 Mg ha−1 under drought and rainfed environments, respectively. Yield gains under drought and rainfed environments were related to prolonged flowering period, increased plant and ear heights, improved stalk lodging, and ear and plant aspects, whereas delayed leaf senescence and increased number of ears per plant accompanied yield improvement under drought only. Ear aspect and number of ears per plant were primary contributors to yield and could be used as selection criteria for yield enhancement under drought and rainfed conditions. High-yielding and stable cultivars across all environments based on additive main effects and multiplicative interaction (AMMI) biplot included ‘2004 TZEE-Y Pop STR C4’ and ‘TZEE-W Pop STR BC2 C0’ of Period 2 and ‘2009 TZEE-W STR’, ‘TZEE-Y STR 106’, ‘TZEE-W STR 107’, and ‘TZEE-W DT C0 STR C5’ of Period 3. These cultivars could be commercialized to improve food self-sufficiency in sub-Saharan Africa

Identification of early and extra-early maturing tropical maize inbred lines resistant to Exserohilum turcicum in sub-Saharan Africa

Open Access Article; Published online: 12 Sept 2020Northern corn leaf blight (NCLB) incited by the fungus Exserohilum turcicum is a foliar disease that significantly limits maize production and productivity in West and Central Africa (WCA), particularly in the mid-altitudes but during the last decade it has become a menace in lowland agro-ecologies. The most economical and environmentally friendly disease management strategy is the cultivation of maize varieties resistant or tolerant to NCLB. However, no early maturing (EM) and extra-early maturing (EEM) NCLB resistant varieties are commercially available in WCA. One hundred inbred lines each of EM and EEM derived from tropical maize germplasm were inoculated with a virulent isolate of E. turcicum at five locations in Nigeria during the 2017 and 2018 growing seasons. The objective of the study was to identify promising NCLB resistant lines and to investigate inter-relationships among the traits. Analysis of variance revealed highly significant genotype and genotype by environment (G × E) interactions for disease severity, grain yield (GYLD), and other agronomic traits. The average disease severity (TURC) values ranged from 1.9 to 5.8 and 2.9 to 5.7 for the EM and EEM inbred lines, respectively. The levels of reaction of the inbred lines to NCLB ranged from highly resistant to highly susceptible. Stepwise regression analysis showed that ears per plant, ear and plant aspects were significantly influenced by the disease scores. Ears per plant, ear and plant aspects, TURC and GYLD traits were employed to develop a base index (BI) for selecting NCLB resistant inbred lines for hybrid development. TZEI 135 and TZEEI 1 were outstanding in GYLD and also had the highest positive BI values in the EM and EEM inbred lines, respectively. The identification of NCLB resistant lines in this study has set the premise for development of NCLB resistant hybrids for WCA as well as the improvement of tropical maize breeding populations for NCLB resistance

Mineralogy, Physicochemical Characteristics and Industrial Potential of Some Residual Clay Deposits within Ekiti State, Southwestern Nigeria

Residual clay deposits overlying Precambrian Basement Complex situated at Orin, Igbara Odo, Ikere and Ado Ekiti were investigated using several analytical techniques. Field evidence supported by mineralogical and physicochemical analyses suggests that the kaolinitic clay deposits is a product of hydrothermal and in-situ weathering of aplite, and granite. Kaolinite is the predominant clay mineral of the studied clay deposits with subordinate quartz, potassium iron oxide and aluminium phosphatic minerals. There is localised occurrence of halloysite. The absence of vanadium in the EDS data of rolled into tubes kaolinite sheets of Ado Ekiti clay match up with XRF data. This result trend combined with field observation suggests that clay bodies formed from weathering of feldspar is deficient in vanadium. The study suggests that morphology of kaolinitic minerals is influenced by the kind of parent material (i.e. feldspars or micas) and degree of chemical weathering. The pH values of pore water from clay samples range from 7.14 - 9.08. The electrical conductivities (EC) of the clay/water slurries (S/L ratio) range from 0.004mS/cm – 3.02mS/cm.  The oxidation reduction potential (ORP) values range between -62.4 and – 6.8 for the solids or slurries prepared with water. The dissolved oxygen (DO) values range from 6.73ppm – 7.26ppm for solids or slurries prepared with water. The loss on ignition ranges from 2.24-13.39. The SiO2/Al2O3 molar ratio of 1.40 and 1.50 for Orin and Ikere clay bodies indicated that a 1:1 clay mineral was the dominant component. The high chemical index of alteration (CIA = 77.97~98.64) and chemical index of weathering (CIW = 97.21~99.93) values probably indicated the complete weathering of feldspars to kaolinite. The weathering index of Parker (WIP) values grouped the analysed clay samples into moderate to intense degree of weathering. This observation is confirmed by the absence of detrital feldspar in the XRD spectra peak. Factor analysis showed enrichment and depletion of major and trace elements which could be attributed to moderate to intense leaching conditions of the presumed parent material. The data shows explicit relationship between the clayeyness value (Al2O3/SiO2 ratio), the relative base loss (RBL) and the cation exchange capacity (CEC). Cluster analysis of major and trace elements showed two groups of chemical differences amongst the elements in the clays; moderate and intense degree of weathered clays. Nevertheless, the variations in the degree of weathering or leaching process have greater contribution to clay deposits differentiation. Assessment of the industrial potential of the studied clay bodies based on their physical and chemical characteristics revealed that they are suitable for the production of refractory bricks and ceramics. Suitable processing would be compulsory if they are to meet the requirements for other industrial applications, such as rubber, paper, paint, cosmetics, and fertilizer industries. Keywords: Clay; Mineralogy; Physicochemical characteristics; Weathering indices; Pore water; Multivariable analysis; Igbara Odo Ekiti; Ikere Ekiti; Ado Ekiti

A comparative study of albendazole and levamisole treatment of nematodes in cattle

The treatment of gastrointestinal nematodes using albendazole and levamisole was monitored in a herd of cattle following a poor state of health and maintenance of high faecal strongyle egg count after repeated therapeutic treatment with albendazole. Thirty-six animals were selected and randomly divided into three groups. Animals in groups A and B were treated orally with albendazole and levamisole respectively at a dose rate of 7.5 mg/kg body weight, while those in group C were left untreated. The faecal egg count reduction (FECR) test was used in assessing anthelmintic efficacy. Animals treated with albendazole had 67.38% reduction in faecal egg counts while those treated with levamisole had 96.10% reduction. Albendazole resistance was confirmed in this study. Haemonchus contortus larvae were cultured out of the post treatment faecal samples. Key words: Cattle, Albendazole, Levamisole, Nematodes. (Af J Livestock Extension: 2002: 47-49

A comparative study of alternative treatments of Peste des Petits Ruminants (PPR) in sheep and goat

A combination of husbandry and medical management was attempted in controlling an outbreak of Peste des Petits Ruminants (PPR) in sheep and goat. The animals were randomly grouped into four. Warmth at night and supplementary grain/concentrate feeding were provided for all the animals. Animals in group A, treated with Tylosin®, 1.5% Levamisole® and Vitamin B complex® had survival rate of 12.5% and 25% for goats and sheep respectively. Animals in group B, treated with Tridioxin®, 1.5% Levamisole® and Vitamin B complex® also had survival rate of 12.5 % and 25% for goats and sheep respectively. Animals in group C treated with Tylosin®, Tridioxin®, 1.5% Levamisole® and Vitamin B complex® had 25% and 66.7% survival rate for goats and sheep respectively. All untreated animals in group D died. The clinical response in this study is fair and may be applied in management when Tissue Culture Rinderpest Vaccine is not available. Key words: Sheep, Goat, PPR, Alternative treatment. (Af J of Livestock Extension: 1; 2002; pp.1-4

High (trans) scrotal orchidopexy for palpable undescended testes in children: Influence of age and testicular position

Objectives: To assess the influence of increasing age of subjects and testicular position on the outcome of single incision orchidopexy.Subjects and methods: A prospective randomized study of children aged ≤ 15 years with palpable undescended testes. The study was conducted between July 2015 and December 2016 in a Nigerian tertiary hospital. Patients were randomized into two groups: single incision orchidopexy and conventional orchidopexy group by simple balloting. The parameters studied were the patients’ bio-data, most caudal position of the testes, duration of surgery, wound complications such as wound infection, scrotal edema and haematoma. Others included testicular position at 6 months post-operatively, testicular hypotrophy and cosmetic appearance of scar. A p-value <0.05 was deemed significant.Results: There were 52 patients with 59 testes. Their ages ranged from 1 year to 13 years with a mean of 6.5 ± 3.5 years. The age groups and testicular positions were well matched, p > 0.05. There was no conversion from high scrotal to conventional orchidopexy irrespective of the age and testicular position during surgery. The operative time was shorter in the high scrotal group compared to conventional group, p < 0.05. The rate of testicular reascent between both groups did not attain statistical significance, p > 0.05. Within the high scrotal group, increasing age and testicular location had no influence on the operative time, p > 0.05. There was no statistical significant difference in the rate of testicular retraction between the young and relatively older children among the high scrotal group, p > 0.05. All wounds healed without wound infection, scrotal edema and haematoma.Conclusion: Increasing age of patients and location of testes had no effect on the outcome of high scrotal orchidopexy in terms of successful placement of testes in the scrotum and rate of testicular retraction  when compared to the conventional orchidopexy. However, the operative time was shorter and the cosmetic appearance of scar was better in the high scrotal group compared to the conventional orchidopexy.Keywords: High scrotal; Single; Orchidopexy; Outcome; Testicular retraction; Operative tim

Sexual behavioural pattern of orchidectomised and hormone replaced weaner pigs

The persistence or cessation of sexual behaviour after abrupt testosterone withdrawal i.e. castration depends among other things on the age of the animal at castration. The aim of this work is to ascertain the effect of early orchidectomy and subsequent hormone replacement to 24 weeks of age on restoration of sexual behaviour in pigs. Five weeks olds male weaner pigs, 24 in number, randomly grouped into two, twelve in each group were used for this study. The first group was not orchidectomised and not given any form of hormone injection (control). The second group was orchidectomised and given Testosterone enanthate and Oestradiol benzoate hormone replacement respectively (CHR). Orchidectomy was carried out at 5 weeks of age using standard procedure. There was no significant difference in the numbers of subjects mounting in both cases. Whereas only 17% had intromission in the control while 33% had this in the CHR. The control had 0 % ejaculation while 33% ejaculated in the CHR. Sexual behaviour index differs significantly between the two groups with the higher value in the CHR, 2.18±0.10 and 1.56±0.05 in the control. There were no significant difference in the strutting and restless/slashing in the CHR in the control , Violent/biting behaviour was in the control involving all the subjects, 100%, while 83% displayed this in the CHR. Aggressive index is higher in the control than in the CHR, 2.70+0.100 and 2.55+0.05 respectively. The study showed than the CHR (castrated with hormone replacement) group displayed improved  sexual behaviour the than control group, although, the latter group was more aggressive.Keywords: Hormonal replacement, Orchidectomy, Weaner pigs, Sexual behaviou

Improvement in grain yield and low-nitrogen tolerance in maize cultivars of there eras

Maize (Zea mays L.) is the most important staple crop in West and Central Africa (WCA), but its production is severely constrained by low soil nitrogen (low N). Fifty-six extra-early open-pollinated maize cultivars developed during three breeding eras, 1995–2000, 2001–2006 and 2007–2012, were evaluated under low N and high soil nitrogen (high N) at two locations in Nigeria in 2013 and 2014, to investigate the genetic gains in grain yield and identify outstanding cultivars. During the first breeding era, the emphasis of the programme was on breeding for resistance to the maize streak virus (MSV) and high yield potential, while the major breeding emphasis during the second era was on recurrent selection for improved grain yield and Striga resistance in two extra-early-maturing source populations, TZEE-W Pop STR (white) and TZEE-Y Pop STR (yellow). Starting from the third era, the source populations were subjected to improvement for tolerance to drought, low N and resistance to Striga. A randomized incomplete block design with two replications was used for the field evaluations. Results revealed genetic gains in grain yield of 0.314 Mg ha−1 (13.29%) and 0.493 Mg ha−1 (16.84%) per era under low N and high N, respectively. The annual genetic gains in grain yield was 0.054 Mg ha–1 (2.14%) under low N and 0.081 Mg ha–1 (2.56%) under high N environments. The cultivar 2009 TZEE-OR2 STR of era 3 was the most stable, with competitive yield across environments, while 2004 TZEE-W Pop STR C4 from era 2, and TZEE-W STR 104, TZEE-W STR 108 and 2012 TZEE-W DT STR C5 from era 3 were high yielding but less stable. These cultivars should be further tested on-farm and commercialized in WCA. Substantial progress has been made in breeding for high grain yield and low-N tolerance in the sub-region