Public sector soybean (Glycine max) breeding: Advances in cultivar development in the African tropics     

Godfree Chigeza  Steve Boahen  Melaku Gedil  Eric Agoyi  Hapson Mushoriwa  Nicholas Denwar  Therese Gondwe  Abush Tesfaye  Alpha Kamara  Oladeji Emmanuel Alamu  David Chikoye 《Plant Breeding》2019,138(4):455-464

Formal public sector soybean breeding in Africa spans over four decades, and it was initiated by the International Institute of Tropical Agricultural (IITA). As the demand of soybean continues to outstrip production, strategic projects such the Tropical Legume (TL) were initiated, in which the main goal was to enhance the productivity of soybean in the farmers’ fields in Sub‐Saharan Africa. One of the strategies to enhance the productivity of soybean in the farmers’ fields is through developing and deploying improved soybean varieties in the target countries. Through the TL I and TL II projects, a number of varieties were released in the target countries, Kenya, Nigeria, Malawi and Mozambique by employing participatory variety selection (PVS). This review provides highlights of the achievements made by IITA breeding programme and insights of what needs to be done to enhance yield improvement for soybean in Africa using demand‐driven breeding approaches.  相似文献   

Sensitivity of Seeds to Chemical Mutagens,Detection of DNA Polymorphisms and Agro-Metrical Traits in M1 Generation of Coffee (Coffea arabica L.)     

Vargas-Segura  César  López-Gamboa  Emmanuel  Araya-Valverde  Emanuel  Valdez-Melara  Marta  Gatica-Arias  Andrés 《Journal of Crop Science and Biotechnology》2019,22(5):451-464

Journal of Crop Science and Biotechnology - Coffee (Coffea Arabica L.) is threatened by biotic and abiotic stresses. Nevertheless, the breeding of Arabica coffee is restricted due to its low...  相似文献   

Compost Amendment to Sandy Soil Affects Soil Properties and Greenhouse Tomato Productivity     

Emmanuel Arthur  Wim Cornelis  Fatemeh Razzaghi 《Compost science & utilization》2013,21(4):215-221

Sandy soils, with low productivity, could be improved by compost application to sustain crop production. This study aimed to examine the effect of three compost types (vegetable, fruit and yard waste compost, garden waste compost, and spent mushroom compost) on basic properties of a loamy sand and greenhouse tomato productivity. Disturbed and intact soil samples were taken from a decade-long compost field experiment on loamy sand with three compost types at application rate of 30 m³ ha^?1 yr^?1 (7.5 ton ha^?1 yr^?1). The soils were characterized for chemical and physical properties. Tomato was planted in a greenhouse using soil samples from the field and vegetative and yield parameters (plant height, stem diameter, leaf number, and fruit yield), water productivity, and harvest index were evaluated. All compost types significantly increased soil total carbon, total nitrogen, pH, electrical conductivity and significantly decreased bulk density, with no effect on plant available water compared to the control. Fresh and dry fruit weights were significantly increased after compost addition. Plant height, leaf number, stem diameter, and total biomass did not significantly improve after compost addition. Spent mushroom compost had greater effect in improving tomato productivity. A decade-long application of composts on loamy sand improved basic chemical and physical properties which were reflected in increased fruit yield in tomato. Since no negative effect of compost was observed, we suggest that sandy soils may serve as a safe end use option for these composts and potentially support crop growth.  相似文献   

Intra‐household constraints on educational attainment in rural households in Papua New Guinea          下载免费PDF全文

Sean Ryan  Gina Koczberski  George Nicolas Curry  Emmanuel Germis 《Asia Pacific viewpoint》2017,58(1):27-40

This paper examines intra‐household and socio‐cultural factors leading to differential outcomes in educational attainment by gender and birth order amongst smallholder oil palm households in Papua New Guinea. Not all children share equitably in the household resources allocated to education: females have lower average education levels than males, and high birth order children have higher education attainment than lower birth order siblings, indicating preferential parental investment in sons and early born children. The findings demonstrate that despite households having regular access to relatively high incomes from oil palm and residing in close proximity to schools, primary school net enrolment rates remain significantly lower than those for East Asia and the Pacific region, and the millennium development goal of universal primary education has not been met. This finding is likely to be the result of a combination of intra‐household factors including gender power imbalances, low parental education levels, the agency of youth in educational decision‐making and the weakening attraction of education as a means of improving income‐earning potential.  相似文献   

Clay content and mineralogy,organic carbon and cation exchange capacity affect water vapour sorption hysteresis of soil     

Emmanuel Arthur  Markus Tuller  Per Moldrup  Lis W. de Jonge 《European Journal of Soil Science》2020,71(2):204-214

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Soil organic carbon storage and quality are impacted by corn cob biochar application on a tropical sandy loam     

Amoakwah  Emmanuel  Arthur  Emmanuel  Frimpong  Kwame A.  Parikh  Sanjai J.  Islam  Rafiq 《Journal of Soils and Sediments》2020,20(4):1960-1969

Purpose

Humic substances, which are integral components of total organic carbon (TOC), influence soil quality. The study aimed to investigate whether humic and non-humic fractions exhibit early, consistent, and measurable changes and affect TOC sensitivity and storage in a tropical sandy loam soils amended with corn cob biochar.

Materials and methods

There were four treatments with four replicates established in a randomized complete block design. Composite soil samples were taken from plots without biochar (CT), from plots incorporated with 15 t biochar ha^?1 (BC-15), and 30 t biochar ha^?1 without or with phosphate fertilizer (BC-30 and BC-30+P). The TOC, and humin, humic acid (HA), and fulvic acid (HA) fractions of soil organic carbon were determined for each treatment. The optical densities (400–700 nm) were measured on the soil-free extracts by spectrophotometry; the densities measured at 465 and 665 nm were used to calculate the E₄₆₅/E₆₆₅ ratios.

Results and discussion

The BC-30 and BC-30+P plots recorded the highest TOC, humin, humic acid (HA), and fulvic acid (FA) contents with respect to the lowest in the CT. The total exchangeable carbon stratification was significantly higher in all the biochar-treated plots relative to the CT. Spectral analysis showed higher values of E₄₆₅/E₆₆₅ (5.02 and 5.15) in the CT and BC-15-treated soils, respectively, compared with the BC-30 and BC-30+P-amended soils with E₄₆₅/E₆₆₅ ratios of 2.76 and 2.98, respectively.

Conclusions

Corn cob biochar applied to a tropical sandy loam:

? increased the concentrations of HA and FA and led to increased stratification of TOC, with a stronger effect on HA compared with FA;

? significantly lowered E₄₆₅/E₆₆₅ at the high biochar application rate of 30 t ha^?1, implying the dominance of high molecular weight humic acid-like substances, and increased degree of aromaticity of the TOC.

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Genetic analysis of the maximum germination distance of Striga under Fusarium oxysporum f. sp. strigae biocontrol in sorghum     

Emmanuel Mrema  Hussein Shimelis  Mark Laing  Learnmore Mwadzingeni 《农业科学学报》2018,17(7):1585-1593

Maximum germination distance(MGD) is an important component of Striga resistance in sorghum. The objective of this study was to determine gene action influencing MGD of Striga hermonthica and Striga asiatica among selected sorghum lines treated with a biocontrol agent, Fusarium oxysporum f. sp. strigae(FOS) for effective breeding with Striga resistance, and FOS compatibility. Twelve sorghum genotypes were selected based on their Striga resistance, FOS compatibility, and superior agronomic performance. Selected genotypes were crossed using a bi-parental mating design to generate six families for genetic analysis. Agar-gel assays were used to determine low haustorium initiation factor(LHF) using the 12 parental lines, their F_1 progenies, backcross derivatives, and F_2 segregants in two sets. One set had S. hermonthica seed and the other one had S. asiatica seed. Both were treated with and without FOS. Genotypes were evaluated using a split-plot design with three replications and MGD data were recorded followed by generation mean analysis. FOS reduced MGD by 1cm under both S. hermonthica and S. asiatica infestations. Additive, dominance, and epistatic gene actions were involved in the control of MGD of the two Striga species in the evaluated populations. On average, the relative contribution of additive, additive×additive and dominance×dominance genetic effects on the MGD of S. hermonthica and S. asiatica, with FOS, were 20, 33, and 36%; and 21, 32, and 35%, respectively. Breeding methods exploiting these genetic effects may provide enhanced response to selection for Striga resistance and FOS compatibility in integrated Striga management(ISM) programmes.  相似文献   

Morphological development and allometric growth of yellowtail kingfish Seriola lalandi V. larvae under culture conditions          下载免费PDF全文

Emmanuel Martínez‐Montaño  Karina González‐Álvarez  Juan Pablo Lazo  Juan Manuel Audelo‐Naranjo  Antonio Vélez‐Medel 《Aquaculture Research》2016,47(4):1277-1287

Morphological development and allometric growth patterns of Seriola lalandi larvae were assessed to characterize normal growth patterns under culture conditions. Early ontogenetic stages of yellowtail kingfish exhibited an exponential growth in terms of standard length as a function of age. Five development stages were characterized from hatching to the juvenile stage: larval stage I (0–2 days post hatch, dph) with endogenous feeding, characterized by a small yolk sac, unpigmented eyes, primordial finfold surrounding the body and a closed mouth; larval stage II (2–15 dph) characterized by mouth opening, complete pigmentation of eyes and the beginning of the exogenous feeding; subsequently, in the larval stage III (15–25 dph) the posterior tip of notochord of the larvae bended upward and the first rays appeared in fins, concomitant with a change in swimming behaviour; thereafter, larval stage IV (post‐flexion stage; 25–30 dph) began when larvae resembled in morphology to a juvenile organism; however, caudal and dorsal fins were not completely development. Lastly, the juvenile stage was reached 30 dph characterized by a morphology and fin structures similar to those of the adults. Growth and development of structures and organs associated with vital functions such as feeding, sensorial and breathing systems seemed to be more critical previous to 23 dph, which was reflected with a positive allometric growth of head and eyes during this period. The results from this study can be used as a tool‐guide to assess normal development in larval research with S. lalandi to improve existing rearing protocols in hatchery production.  相似文献   

A split‐body,randomized, blinded study to evaluate the efficacy of a topical spray composed of essential oils and essential fatty acids from plant extracts with antimicrobial properties          下载免费PDF全文

Emmanuel Bensignor  Lionel Fabriès  Lucie Bailleux 《Veterinary dermatology》2016,27(6):464-e123

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The effect of male proximity on vaginal patency,estrous cycle length and feed intake of female grasscutters     

John Kormla Nyameasem  Emmanuel Kwadwo Adu  Kwame Owusu Amoah  Bernard Ato Hagan 《Tropical animal health and production》2016,48(2):445-449

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