491 research outputs found

    Seeding Date Effects on Camelina Seed Yield and Quality Traits

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    An alternative crop with potential for dryland crop production in the Great Plains is camelina (Camelina sativa L. Crantz). Time of planting is an important management consideration that can affect camelina production. A study was carried out in the spring of 2013, 2014, and 2015 to evaluate seeding date effects on spring camelina varieties grown under dryland conditions in western Kansas. Three spring varieties (Blaine Creek, Pronghorn, and Shoshone) were planted at three seeding dates: early (April 3, 2013; March 17, 2014; and March 18, 2015); mid (April 16, 2013; April 1, 2014; and April 1, 2015); and late (April 30, 2013; April 15, 2014; and April 15, 2015). Parameters collected included time of flowering and physiological maturity, stand count at maturity, seed yield, biomass yield, harvest index, oil and protein content. Our findings indicate that seeding date can affect the time of flowering and physiological maturity, stand count, seed yield, biomass yield, harvest index, and protein content, but it did not affect oil content. Harvest index and oil content was significantly different among varieties. In general, mid and late seeding dates produced the highest yield across the three years. There were yield differences among varieties; Blaine Creek produced the highest seed yield and was significantly different from Pronghorn and Shoshone. Seed yield ranged between 340 and 440 lb/a. Average oil and protein content was 26% and 30%, respectively. Based on environmental factors and agronomic characteristics, camelina varieties were more productive when planted between early and mid-April

    Nitrogen and Sulfur Fertilization Effects on Camelina Sativa in West Central Kansas

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    Camelina sativa is early maturing and possesses characteristics that make it a good fit as a rotation crop in dryland wheat cropping systems. Nitrogen (N) and sulfur (S) play very important roles in oilseed production, including camelina. This study was conducted over 3 years to determine N and S rates necessary for optimum camelina production in west central Kansas. The experiment was set up as randomized complete blocks with four replications in a split-plot arrangement. Treatments were two sulfur rates (0 and 18 lb/a) as the main plots, and four N rates (0, 20, 40, and 80 lb/a) as the sub-plot. Sulfur application did not affect stand count, biomass yield, harvest index, seed yield, oil and protein content. However, stand count, biomass yield, seed yield, and protein content were affected by N application (P \u3c 0.05). Average oil and protein content were 28.1% and 33.9% respectively. The optimum N rate for yield was 20 lb N/a, which produced around 680 lb/a seed yield. Based on soil test levels of 25 lb N/a, N requirement for camelina production is 45 lb N/a

    Modeling host-associating microbes under selection

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    The concept of fitness is often reduced to a single component, such as the replication rate in a given habitat. For species with multi-step life cycles, this can be an unjustified oversimplification, as every step of the life cycle can contribute to the overall reproductive success in a specific way. In particular, this applies to microbes that spend part of their life cycles associated to a host. In this case, there is a selection pressure not only on the replication rates, but also on the phenotypic traits associated to migrating from the external environment to the host and vice-versa (i.e., the migration rates). Here, we investigate a simple model of a microbial lineage living, replicating, migrating and competing in and between two compartments: a host and an environment. We perform a sensitivity analysis on the overall growth rate to determine the selection gradient experienced by the microbial lineage. We focus on the direction of selection at each point of the phenotypic space, defining an optimal way for the microbial lineage to increase its fitness. We show that microbes can adapt to the two-compartment life cycle through either changes in replication or migration rates, depending on the initial values of the traits, the initial distribution across the two compartments, the intensity of competition, and the time scales involved in the life cycle versus the time scale of adaptation (which determines the adequate probing time to measure fitness). Overall, our model provides a conceptual framework to study the selection on microbes experiencing a host-associated life cycle

    Econometrics of Domestication of the African Palm Weevil (<em>Rhynchophorus phoenicis</em> F.) Production as Small-Scale Business in Ghana

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    A reconnaissance survey of the domestication of the African palm weevil (APW) (Rhynchophorus phoenicis), which produces the edible larvae that are cherished as a delicacy among many tribes in Ghana, was conducted. Out of a total number of 560 semi-trained farmers, 271 (48.39%) were actively engaged in R. phoenicis farming near their homes or gardens, while 289 (51.61%) were non-active. Economic viability analyses showed that the active farmers would break even and repay their loans of GH¢1000 when they produce 3020 larvae at unit selling price of GH¢0.33, within a period of 4 months and 7 days (17 weeks). In a year, a farmer would have three production cycles and generate a total revenue of GH¢3018.79, at average monthly production of 755 edible larvae, net cash availability of GH¢1448.79, and projected net profit of GH¢448.79 in the first year of production. The farmer would make more profit and become wealthy in business in subsequent years. The pilot scheme of palm weevil farming was viable and ameliorated poverty and malnutrition of rural farmers in Ghana

    Evaluation of Maize Top Cross Hybrids for Grain Yield and Associated Traits in Three Agro-Ecological Zones in Ghana

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    Maize (Zea mays L.) is an important food crop in Ghana, but its productivity in farmers‟ fields throughout the country is generally low. The low grain yields can be attributed partly to the use of traditional low-yielding open-pollinated varieties. In an attempt to increase maize productivity, 39 top cross hybrids were developed using 21 inbred lines and 3 open-pollinated varieties. The trial was set up in a randomized complete block design with two replications in three locations in southern Ghana. The overall objective of the study was to investigate traits which influence yields in top cross hybrids and to ascertain the yield potential of the hybrids in three agro-ecological zones in Ghana. The Genotypes were evaluated to determine agronomic performances and correlations between yield and yield component traits were calculated to assess the degrees of associations. Highly significant variations (

    Progress on implementation of an accelerated sweetpotato breeding scheme in Ghana.

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    The sweetpotato support platform for West Africa was established at the CSIR-Crops Research Institute in Kumasi, Ghana in early 2010 with the objective of supporting cultivar development in Ghana and elsewhere in West Africa through the development of adapted less sweet germplasm, and through a participatory approach. The accelerated sweetpotato breeding approach in Ghana uses multi-locational clonal evaluation of seedling families to identify promising families and genotypes, followed by 2 years of additional multi-locational evaluation in target environments. Superior early selections may be used as parents in population improvement in order to speed genetic gain for various attributes. In 2010, roughly 250 genotypes from 34 families, from Ghana, Uganda and Kenya were evaluated at 3 locations, and high yielding, virus resistant genotypes were selected, some at 2 or more locations. In 2011 selected genotypes and introduced clones from diverse sources (330 genotypes) were evaluated in replicated trials at 5 locations covering major production zones and agroecologies. At harvest, farmers were involved in assessment of performance and taste, and selections were evaluated for sugars, minerals and carotenoids using near infrared reflectance spectroscopy. Sixteen genotypes are in advanced trials in 2012.

    Multi-locational assessment of some physicochemical attributes and amylase activity of sweetpotato varieties and elite materials in Ghana.

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    As part of the breeding objectives to select sweetpotato materials with acceptable quality attributes for adaptation and subsequent utilisation in Ghana, the total amylase activity and physicochemical attributes (flesh colour, Beta-carotene, dry matter, starch and sugars) of 13 sweetpotato genotypes across five locations were evaluated. Near Infrared Reflectance Spectrometry (NIRS), was mainly employed in the study. The flesh colour of the materials ranged from white to deep orange while thedry matter content ranged from 20% to 44%. Starch, fructose, glucose and sucrose contents were 46– 74, 0.3 - 5, 2 – 8 and 9 – 22% respectively. Apomuden, a deep orange type, recorded the highesttotal sugar content of 36% and the lowest dry matter and starch content of 20% and 46% respectively. Hi-starch variety had the highest dry matter (45%), starch (74%) and the lowest sugar (11%). Dry matter content correlated positively with starch content whilst orange colour intensity was inversely proportional to dry matter content. The outcome of the study supports the fact that sweet potato contains high extractable amylases. Amylase activity of the materials was fairly stable across locations. Okomkum, Faara, Santom Pona, Kemb, and Cemsa 74-228 recorded the highest activity while Hi-starch, Apomuden, Mohc, and 199062.1 were low. There was no correlation between raw sugars and amylase activity. The potential of individual cultivars for food industry will be discussed in relation to starch content and extractable amylases

    Isothermal Recombinase Polymerase amplification (RPA) of Schistosoma haematobium DNA and oligochromatographic lateral flow detection

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    © 2015 Rosser et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. The attached file is the published version of the article
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