Prevalence of rotavirus A infection and the detection of type G3P[11] strain in ruminants in Yobe state,Nigeria

Rotaviruses have a worldwide distribution and the infection is associated with diarrhea in young of ruminants as well as children. However, limited data exist on its prevalence and types in Yobe state, Nigeria. Detection of rotavirus A and types in ruminant population in Yobe state was the aim of the study. A total of 470 diarrheic fecal samples were collected and tested for rotavirus and types using serology and molecular techniques respectively. A prevalence rate of 2.98% (14/470) was found in the three species with specific rates of 2.9% (6/202), 3.8% (6/158), and 1.8% (2/110) in goat, sheep, and cattle respectively. The prevalence rates of 3.6% (12/331), 1.2% (1/84), and 1.8% (1/55) were for those aged < 1–3, 4–6, and 7–9 months old, respectively, while 4.9% (9/185) and 1.7% (5/285) were in males and females respectively. Rotavirus genes VP7 and VP4 were detected in 2 (14.3%) out of the 14 ELISA-positive samples while deduced amino acid sequences of the major variable regions revealed the genes to belong to types G3P[11] strain. Significant association was found between the infection and sex (P < 0.05) unlike in the species and age groups of the ruminants. The circulation of rotavirus virus in ruminants and type G3P[11] in cattle has been confirmed in the study. Hence, there is a need for continuous surveillance, awareness campaign, and assessment of the economic losses and public health implications of rotavirus infection in Nigeria.

     

Suppression of the Plant-Parasitic Nematode Heterodera schachtii by the Fungus Dactylella oviparasitica

This study examined the role of the fungi Dactylella oviparasitica and Fusarium oxysporum in the beet-cyst nematode (Heterodera schachtii) suppressiveness exhibited by a southern Californian soil. In prior research, the abundance of D. oviparasitica rRNA genes positively correlated with high levels of suppressiveness, whereas the abundance of F. oxysporum rRNA genes positively correlated with minimal to moderate levels of suppressiveness. In this report, both fungi were added to fumigation-induced nonsuppressive soil, planted with Swiss chard, and infested with H. schachtii juveniles. After two nematode generations, D. oviparasitica strain 50 reduced the population densities of H. schachtii eggs and juveniles to those in the suppressive soil and H. schachtii cysts to levels lower than in the suppressive soil. F. oxysporum did not significantly reduce H. schachtii populations. These results suggest that D. oviparasitica strain 50 plays a major role in the suppression of H. schachtii population development in this southern Californian soil.     

Crop damage and yield loss caused by two species of rodents in irrigated fields in northern Nigeria

We investigated the damage and yield loss caused by two rodent species, Arvicanthis niloticus and Mastomys (Praomys) natalensis, in cereal crops in fields near Kano, northern Nigeria from August, 1990 to April, 1992. Using the random cluster technique, we selected 100 clusters of 30 hills in each rice and wheat field, and assessed damage fortnightly, using the Cut Tiller Count method. In premature crops, damage increased from tillering stages to the dough stages. Differences in the percentages of damage (yield loss) in mature rice (4.8% in 1990 and 12.6% in 1991) and in wheat (30.0% in 1991 and 21.7% in 1992) were statistically significant between years. Severe yield losses in wheat, compared to low and moderate levels in rice (grown for the most part during the rains), were probably a result of greater consumption of the wheat, grown entirely by irrigation during the dry season when other rodent food sources were less abundant. Results of ANOVA showed significant effects of developmental stage of the crop, year of cultivation, and their interactions on the magnitude of crop damage.     

Induction of Beet-Cyst Nematode Suppressiveness by the Fungi Dactylella oviparasitica and Fusarium oxysporum in Field Microplots

ABSTRACT The ability of Dactylella oviparasitica and Fusarium oxysporum to suppress Heterodera schachtii numbers was examined in field microplots. Fungi were individually added to fumigated field soil that was seeded with sugar beet. Four weeks later, soils were infested with H. schachtii second-stage juveniles (J2). At two harvests, 11 weeks and 19 weeks (1,469 and 2,547 degree days (base 8 degrees C), respectively) after nematode-infestation, H. schachtii cyst and egg numbers were assessed. At both time points, D. oviparasitica reduced H. schachtii population densities to those in the naturally suppressive soil, even when additional H. schachtii J2 were added to the microplots after the first harvest. Although F. oxy-sporum did not alter H. schachtii population densities after 11 weeks, significant reductions were detected after 19 weeks. The sustainability of the H. schachtii suppressiveness created by single applications of the fungi at the beginning of the microplot trials was further examined in a greenhouse study. Soil collected at the completion of the microplot trials was potted and seeded with sugar beet. Four weeks later, each pot was infested with H. schachtii J2. Approximately 16 weeks (1,389 degree days) after seeding, the D. oviparasitica-amended soil produced greater fresh root weights and considerably smaller nematode population densities than the nonamended control.     

Inheritance of Resistance to Stenocarpella macrospora (Earle) Ear Rot of Maize in the Mid-altitude Zone of Nigeria

Inheritance of resistance to Stenocarpella macrospora (Earle) Sutton (syn. Diplodia macrospora Earle) ear rot of maize was studied among selected maize populations in the mid-altitude (1280m) agro-ecological zone of Nigeria. Diallel analysis among the populations showed significant values for general combining ability (GCA) and specific combining ability (SCA) effects at 5% and 1% levels respectively. Variance components of GCA and SCA on Stenocarpella ear rot were 0.019 and 0.627 respectively, indicating that non-additive genes play major roles in the inheritance of Stenocarpella ear rot resistance.The GCA and SCA effects were relatively dependent on the materials involved in the evaluations. Generation mean analysis was used on five selected parent inbreds (2 resistance and 3 susceptible crossed to give P₁, P₂, F₁, BC₁, BC₂ and F₂ generations). Estimates of the six parameters on ear rot indicate that dominance gene effects made the major contribution to variation in ear rot of maize in the crosses studied. The magnitude and significance of the estimates for digenic effects in the crosses suggest that epistatic gene effects are present and important in the basic mechanism of Stenocarpella ear rot inheritance in the populations studied. Additive effects have only minor importance in the total variation.     

Proximate and phytochemical screening of different parts of <Emphasis Type="Italic">Moringa oleifera</Emphasis>

Lack of proper nutrition is one of the most serious problem across the globe, affecting majorly African countries, where many children died not only due to inadequate food but also as a result of insufficient nutrient in their diet. This research was aimed to study the proximate composition and screening of chemical components in different part of Moringa oleifera Lam. Proximate analysis was adapted from the standard methods developed by Association of Official Analytical Chemists (AOAC). We have determined percentage of moisture content, ash content, crude protein, crude fibre, crude fat and carbohydrate which were ranges from 8.1–4%, 5.59–9.28%, 11.70–26.57%, 21.03–44.27, 11.82–20.19 and 8.16–31.12% respectively. Different bioactive compounds of polyphenol, flavonoids, tannins and saponin were determined. Different parts of plants accumulate different levels of polyphenol, flavonoids, tannins and saponin. Our study suggest that Moringa oleifera can served as a good supplement to our nutrition, due to high content of fibre, protein, fat. However intake of Moringa plant might reduce the risk of many oxidative related problems due to the present of some polyphenols and flavonoid in almost all part of the plant used.     

秸秆深埋还田开沟灭茬机设计与试验

秸秆还田是农作物秸秆综合利用最为直接的形式,深埋还田能打破犁底层、培肥地力,并提高土壤抗旱保墒能力。在秸秆深埋还田时,由于作物根茬未粉碎,深开沟的同时会出现大块土垡。秸秆深埋后还需对根茬和土垡进行二次粉碎,增加了作业成本。为满足秸秆深埋还田开沟灭茬碎土的需求,设计研制了一种集开深沟、碎土、灭茬等多道工序的用于秸秆深埋还田的开沟灭茬机。以导向铲入土深度、灭茬刀转速、灭茬深度为试验因素,机器的作业阻力和灭茬碎土率为试验指标,进行了三因素三水平正交试验。结果表明导向铲入土深度和灭茬深度对作业阻力有极显著影响,灭茬刀转速对灭茬碎土率有极显著影响。在开沟深度为35 cm时,导向铲入土深度、灭茬刀转速和灭茬深度分别为100 mm、340 r/min和60 mm时,开沟灭茬机的作业性能最好,作业阻力为21.6 k N、灭茬碎土率为96.3%、开沟深度稳定性为92.4%。试验表明该机具有很好的开沟、灭茬、碎土效果,该研究为秸秆深埋还田机具的研制和配备提供参考。