New techniques for breeding maize (Zea mays) varieties with fall armyworm resistance and market-preferred traits for sub-Saharan Africa

Deploying maize varieties with fall armyworm (Spodoptera frugiperda [J.E. Smith]; FAW) resistance, desirable product profiles (PPs) and climate resilience is fundamental for food and economic security in sub-Saharan Africa (SSA). This study reviewed and identified challenges and opportunities for effective and accelerated breeding of demand-led maize hybrids with FAW resistance and adaptation to the diverse agro-ecologies of SSA. Lessons were drawn on improving breeding efficiency through adequate genetic variation delivered via prebreeding programmes, speed breeding and a reduced breeding stage plan. Appropriate PPs aligned with demand-led breeding approaches were highlighted as foundations for variety design and commercialization. Challenges to accelerated FAW resistance breeding in maize included inadequate funds and modern tools; poor adaptation of some exotic donor parental lines; lack of information on FAW resistance among local varieties; lack of integration of molecular markers associated with FAW resistance and agronomic traits into selection plans; and limited infrastructure for FAW rearing and germplasm screening. Integration of modern breeding tools and scientific innovations were recommended for accelerated development and release of FAW resistant and market-preferred maize varieties.     

Characterisation of sweet stem sorghum genotypes for bio-ethanol production

In an effort to characterise and select promising sweet stem sorghum genotypes with enhanced biofuel productivity, the present study investigated phenotypic variability present among diverse sweet stem sorghum genotypes based on ethanol production and related agronomic traits. One hundred and ninety genotypes were evaluated. Data were subjected to variance, cluster, correlation, path coefficient and principal component analyses. Significant differences (P?<?0.01) were detected among tested genotypes for all measured traits. Days to flowering varied from 62 to 152 with a mean of 93. Plant height varied from 90 to 420?cm with a mean of 236?cm. Stem diameter ranged from 7 to 31?mm with a mean of 16?mm. Biomass yield varied from 6.668 to 111.2?t?ha^?1 with a mean of 30?t?ha^?1. Stalk dry matter content ranged from 17.2% to 44.2% with a mean of 29.8%, while fibre content varied from 8.92% to 34.8% with a mean of 17.2%. The stalk brix yield varied from 3.3% to 18.9% with a mean of 12.1%. Ethanol productivity ranged from 240.9 to 5500?l?ha^?1 with a mean of 1886?l?ha^?1. The best ethanol producing genotypes were AS203, AS391, AS205, AS251 and AS448. Days to flowering, plant height, stalk brix and stem diameter exerted the greatest indirect effects on ethanol production through higher biomass production. Biomass yield had the greatest direct effect on ethanol production. Therefore, the above traits should be considered during breeding sorghum for bio-ethanol production. Also, the traits had high heritability values, hence selection should provide for good genetic gains. Overall, the above sweet stem sorghum genotypes are useful genetic resources for breeding of sorghum with enhanced bio-ethanol production.     

Leaf gas exchange and water-use efficiency of dry-land wheat genotypes under water stressed and non-stressed conditions

The objective of this study was to determine drought tolerance characteristics of dryland wheat genotypes based on leaf gas exchange and water-use efficiency in order to identify promising genotypes for drought tolerance breeding. Physiological responses of ten genetically diverse wheat genotypes were studied under non-stressed (NS) and water stressed (WS) conditions using a 2?×?10 factorial experiment replicated 3 times. A highly significant water condition?×?genotype interaction (P?<?0.001) was observed for photosynthetic rate (A), ratio of photosynthetic rate and internal CO₂ concentration (A/C_i), ratio of internal and atmospheric CO₂ (C_i/C_a), intrinsic (WUE_i) and instantaneous (WUE_inst) water-use efficiencies suggesting genotypic variability among wheat genotypes under both test conditions. Principal component analysis (PCA) identified three principal components (PC’s) under both test conditions accounting for 84% and 89% of total variation, respectively. Bi-plot analysis identified G339 and G344 as drought tolerant genotypes with higher values of A, T, gs, A/C_i, WUE_i and WUE_inst under WS condition. The current study detected significant genetic variation for drought tolerance among the tested wheat genotypes using physiological parameters. Genotypes G339 and G344 were identified to be drought tolerant with efficient A, T, gs, A/Ci and water-use under water stressed condition.     

Polymorphism of microsatellite loci in sugar beet’s selection lines

The genetic polymorphism of 12 microsatellite loci was revealed and unique DNA-profiles were obtained for initial lines of sugar beet. Two loci were monomorphic, other loci exhibited polymorphism. The genetic distances between the breeding materials were determined; the dendrogram of cluster analysis reflecting the probable divergence of samples was constructed. The data about the distance of the selection material will be used in the selection of pairs in heterotic breeding.     

Design and implementation of an electronic mobile poultry production documentation system

Documentation is a major component of any traceability system where traceability is defined in the ISO Regulation 8402:1994 as the ability to trace the history, application and location of what is under consideration. Traceability systems are record keeping systems designed to track the flow of product or product attributes through the production process or supply chain. All international supply chains are forced to comply with traceability requirements. In this paper, we develop and implement an end-to-end mobile application prototype that traces the poultry production. This application consists of front-end and back-end systems. At the front-end, the worker uses a GPRS enabled handheld device (cell phone, PDA, etc.) to capture information on poultry operations collected at a remote chicken farm and transmit it to a back-end server in the main office. Through customized application the back-end server analyses all information received from the front-end and based on a built-in business process and business rules, intelligently updates various stakeholders of any breach of bio-security measures that requires immediate attention. The proposed system administrators can also access this application via Internet for management decision making. The back-end system consists of web server, defined business application logic and database server.     

Effect of deficit irrigation on drip-irrigated wheat grown in semi-arid conditions of Upper Egypt

Shortage of water in arid and semi-arid regions increases the need of applying efficient drip irrigation system. A two-year field study in the semi-arid region of Upper Egypt was carried in randomized complete block design with four replicates. Wheat plants were irrigated by 100 or 75% of water requirements (I₁₀₀ = 5,370 and I₇₅ = 4,027 m³ ha^?1). Irrigation of wheat by I₁₀₀ increased growth and uptake of nitrogen, phosphorus, and potassium compared to low irrigation level. I₁₀₀ caused 14 and 5% increase in straw and biological yield, respectively, compared to I₇₅. Grain yield and water use efficiency (WUE) were higher by 20 and 59% in the case of I₇₅ compared to I₁₀₀. The use of deficit irrigation in drip-irrigated wheat under arid conditions is an effective tool to maximize efficiency of water use; moreover, 4,027 m³ ha^?1 is the optimum irrigation rate for maximum WUE and grain yield.     

Repeated oral administration of a cathepsin K inhibitor significantly suppresses bone resorption in exercising horses with evidence of increased bone formation and maintained bone turnover

Our investigations evaluated the effect of VEL‐0230, a highly specific irreversible inhibitor of cathepsin K (CatK). The objectives of our study were to determine whether repeated dosing of a CatK inhibitor (CatKI) produced a desired inhibition of the bone resorption biomarker (CTX‐1), and document the effect of repeated dosing on bone homeostasis, structure, and dynamics of bone resorption and formation in horses. Twelve young exercising horses were randomized in a prospective, controlled clinical trial and received 4 weekly doses of a CatKI or vehicle. Baseline and poststudy nuclear scintigraphy, blood sampling and analysis of plasma bone biomarkers (CTX‐1 and osteocalcin), poststudy bone fluorescent labeling, and bone biopsy were performed. Bone specimens were further processed for microcomputed tomography and bone histomorphometry. Each dose of this CatKI transiently inhibited plasma CTX‐1 (reflecting inhibition of bone collagen resorption) and increased bone plasma osteocalcin concentrations, with no detectable adverse effect on normal bone turnover in the face of exercise. Bone morphology, density, and formation rate were not different between control and treated group. Further investigation of CatK inhibition in abnormal bone turnover is required in animals with bone diseases.     

Efficiency of Subsurface Drip Irrigation for Potato Production Under Different Dry Stress Conditions

Efficient water delivery systems such as drip irrigation can contribute towards increasing crop yield potential, improving crop water and fertilizer use efficiency. However, critical management considerations such as subsurface drip irrigation are necessary to attain improved irrigation efficiencies and production benefits particularly under arid regions. The objective of this study was to determine the effect of two irrigation methods, surface and subsurface drip irrigation combined with four irrigation levels, 100, 80, 60 and 40% of crop evapotranspiration on yield and yield components of potato grown on sandy soil. The field experiments were conducted in the years 2008 and 2009. In terms of soil water availability to plants, subsurface drip provided more favorable growth conditions for plant growth and maintained higher soil water content at the root zone, which resulted in a significant higher potato yield compared to surface drip irrigation. The difference between the two irrigation methods on yield components was concentrated on the mean tuber weight per plant, while no significant difference was found on the tuber number per plant. Reducing the amounts of applied water significantly decreased total potato yield and its components. Under subsurface drip irrigation, reducing amounts of applied water to 80% ETc gave comparable yield and yield components to surface drip at full irrigation supply, indicating that 20% irrigation water can be saved without affecting the potato yield. At all irrigation levels, subsurface drip recorded higher water use efficiency (WUE) over surface drip. Maximum value was observed at 40% ETc. Fertilizer use efficiency (FUE) was also higher under subsurface drip and reduced significantly under both irrigation methods with increasing water deficit. These results suggested that subsurface drip offers the potential of better water management with respect to saving and distribution of water in the root zone and to obtain maximum yield accompanied by highest water and FUE.     

Yield response and <Emphasis Type="Italic">Stenocarpella</Emphasis> ear rot reaction among selected maize inbred lines and top cross hybrids

Stenocarpella ear rot of maize caused by Stenocarpella maydis (Berk.) Sutton is one of the most important ear rot diseases in South Africa. The objective of this study was to identify suitable maize inbred lines and top cross hybrids with Stenocarpella ear rot resistance and high grain yield. The study was conducted using 54 inbred lines and 54 top crosses with selected standard checks under natural and artificial disease inoculations. A split-plot design was used with three replications. There were considerable variations among tested inbred lines and top crosses for Stenocarpella ear rot resistance and grain yield. Two promising inbred lines GCI-35 and GCI-50 were selected possessing resistance to Stenocarpella ear rot and increased grain yield. Inbred line GCI-35 had a grain yield of 6.31 and 6.27 t/ha under natural and artificial inoculations, respectively. Line GCI-50 yielded 5.8 and 5.7 t/ha when tested under natural and artificial disease infestations, respectively. Two top cross hybrids GCT-14 and GCT-30 were selected with greater grain yield and high level of Stenocarpella ear rot resistance. Top cross entry GCT-14 yielded 7.5 and 9.33 t/ha, respectively, whereas GCT-30 had yield of 7.65 and 9.21 t/ha, respectively. The selected inbred lines and top cross hybrids will be useful in maize improvement for Stenocarpella ear rot resistance and increased grain yield in South Africa or other similar environments.     

Chemical Control of Weeds in Cotton in the Sudan Gezira

Abstract

Early work on chemical weed control in the fallow towards the end of the Second World War is reviewed briefly. Attempts to use contact residual herbicides as pre-emergence applications in the early 1950s are also described.

Pre-sowing applications of residual herbicides were found more phytotoxic to cotton than pre-emergence applications. The closer the time of pre-sowing application to cotton sowing, the more effective was suppression of weeds competing with cotton.

Mechanical cultivations and particularly disc ploughing and rotovation to a depth of more than 15 cm were found more effective in the control of Cynodon dactylon than pre-sowing herbicide applications.

Fluometuron, noruron and prometryne were found very effective as pre-emergence herbicides. Optimum rates of application were found to be only 25-50% of rates recommended for the USA and other countries. Resistant weeds included Cyperus rotundus, Cynodon dactylon, and Rhyncosia memnonia.

A large-scale trial with fluometuron, covering 125 feddans at Wad el Nairn showed that yields obtained were equal to those with normal weeding. Costs of herbicide treatments were also comparable to costs of hand-weeding in a year of exceptionally low hand-weeding costs.