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Yield Advantage (yield + advantage)
Selected AbstractsElectrically Addressable Hybrid Architectures of Zinc Oxide Nanowires Grown on Aligned Carbon NanotubesADVANCED FUNCTIONAL MATERIALS, Issue 15 2010Jong G. Ok Abstract The fabrication and characterization of hybrid architectures of ZnO nanowires (ZNWs) grown on organized carbon nanotubes (CNTs), by a two-step chemical vapor deposition (CVD) process involving CNT growth from a hydrocarbon source followed by ZNW growth using a Zn metal source, is reported. The ZNWs grow uniformly and radially from individual CNTs and CNT bundles, and the aligned morphology of the CNTs is not disturbed by the ZNW growth process. The nucleation and growth of ZnO crystals on CNTs are analyzed in relation to the classical vapor,solid mechanism. Importantly, the CNTs make uniform and distributed electrical contact to the ZNWs, with up to a 1000-fold yield advantage over conventional ZNW growth on a flat substrate. Hybrid ZNW/CNT sheets are fabricated by scalable CVD, rolling, and printing methods; and their electrical properties, which are governed by transport through the anisotropic CNT network, are characterized. Functional interaction between the ZNWs and CNTs is demonstrated by photoconductive behavior and photocurrent generation of the hybrid material under UV illumination. There is significant future opportunity to extend these processing methods to fabricate other functional oxides on CNTs, and to build devices that harness the attractive properties of ZNWs and CNTs with high volumetric efficiency over large areas. [source] Evaluation of the effects of resistance to stem nematode (Ditylenchus dipsaci) in white clover (Trifolium repens L.) under sheep grazing and cuttingPLANT BREEDING, Issue 4 2007T. A. Williams Abstract Two field experiments were carried out to analyze the performance of white clover varieties differing in their resistance to stem nematode. Varieties were compared under grazing and cutting regimes in mixed swards with or without the addition of nematode and dry matter yields of white clover and perennial ryegrass recorded over a 3-year period. The resistant variety did not show a yield advantage in the absence of nematode but did so in the presence of nematode in the first year and for several of the sampling dates in the second year. White clover yields under grazing were significantly less than under cutting in both experiments. The hypothesis that the additional stress of grazing would increase the benefits of resistance relative to a cutting management was not supported. [source] Economic Returns to Feed Barley Yield-increasing and Disease Resistance Research at the Alberta Field Crop Development CentreCANADIAN JOURNAL OF AGRICULTURAL ECONOMICS, Issue 3 2003Joseph G. Nagy The Alberta Field Crop Development Centre (FCDC) at Lacombe has carried out an extensive research and development program on feed barley since 1973. Prior to 2002, FCDC released 11 hulled and six hull-less barley varieties that have been adopted by farmers. The primary objective of this study is to estimate an economic rate of return to the FCDC barley research and development program from 1973 to 2001. A secondary objective is to include benefits arising from research that improved feed barley disease resistance in new cultivars in addition to benefits from purely higher-yielding cultivar research. The analysis uses an ex post economic surplus methodology. Benefits are identified and empirically investigated for three separate FCDC feed barley research thrusts: , benefits arising from FCDC research that developed new, higher-yielding feed barley cultivars that give a yield advantage , benefits arising from FCDC research that improved feed barley disease resistance in new cultivars that result in yield loss avoidance from disease , benefits arising from FCDC research that developed new feed barley cultivars that yield higher silage production. Of the total benefits from research on feed grain varieties, 52% can be attributed to yield advantage research and 48% to yield loss avoidance research. The overall internal rate of return with base elasticity parameters is estimated at 27%, ranging between 23% and 31%, depending on the assumptions made about the yield advantage and base variety. The IRR was sensitive to changes in supply elasticities and ranges from 20% (,= 1.5) to 54% (,= 0.1). L'Alberta Field Crop Development Center (FCDC) de Lacombe poursuit un vaste programme de recherche et de dáveloppement sur l'orge fourragàre depuis 1973. Avant 2002, le FCDC a homologuá onze variátás d'orge ordinaire et six à grains nus que les agriculteurs ont par la suite adoptáes. La prásente átude devait estimer la rentabilitá du programme entre 1973 et 2001. Un objectif secondaire consistait à inclure les retombáes rásultant des cultivars plus rásistants à la maladie à celles dérivant uniquement de l'amélioration du rendement. L'analyse reposait sur la méthode ex-post des excédents économiques. L'auteur a identifié les retombées et les a examinées en fonction de trois courants distincts de la recherche entreprise au FCDC: (1) les retombées issues des cultivars d'orge fourragère à rendement plus élevé; (2) celles venant des travaux sur la résistance des variétés qui ont abouti à un meilleur rendement grâce à de moins grandes pertes attribuables à la maladie; (3) celles résultant de la création de cultivars d'orge fourragère produisant plus d'ensilage. Sur les retombées totales de la recherche, 52 % résultaient de l'amélioration du rendement et 48 % de la réduction des pertes associées à la maladie. On situe le taux de rentabilité interne global à 27 % avec les élasticités de base, soit entre 23 et 31 % selon les hypothèses sur l'amélioration du rendement et la variété de départ. Le taux de rentabilité interne est sensible à la variation des élasticités de l'offre et fluctue de 20 ,= 1, 5) à 54% (,= 0,1). [source] The effect of pea cultivar and water stress on root and shoot competition between vegetative plants of maize and peaJOURNAL OF APPLIED ECOLOGY, Issue 1 2001Tzehaye Semere Summary 1Improvements in intercrop yields may be achieved through an understanding of yield advantages due to above-ground or below-ground interactions. 2Forage maize and two morphologically contrasting cultivars of pea (leafy cv. Bohatyr and semi-leafless cv. Grafila) were grown alone and in additive mixtures, under two contrasting levels of soil moisture (± water stress). 3The mechanism of competition between maize and pea was studied by separating the effects of root competition and shoot competition, using soil and aerial partitions. Plants were grown in rectangular tanks in a glasshouse. 4Leafy pea cv. Bohatyr was as competitive as maize, both below-ground and above-ground, whereas semi-leafless pea cv. Grafila was less competitive than maize or pea cv. Bohatyr. The greater competitive ability of the leafy pea, both above- and below-ground, was probably due to its greater growth rate, associated with its greater leaf area. 5The competitive ability of maize, relative to peas, was considerably reduced by water stress. Both the root and shoot competitive abilities of pea were greater under water stress, compared with those of maize. 6Relative yield total (RYT) values were significantly greater when maize and pea were subjected to shoot competition only (RYT = 1·76) than when subjected to root competition (RYT = 1·17) or when subjected to both shoot and root competition (RYT = 1·13). This reflects the fact that the effects of root competition were greater than those of shoot competition. 7Root competition decreased the shoot dry weights, plant height and leaf area of both maize and pea, whereas shoot competition had no significant effect on these attributes, indicating that soil resources, i.e. mineral nutrients and water, were more limiting than light. [source] Comparative evaluation of exotic and adapted germplasm of spring wheat for floral characteristics in the Indo-Gangetic Plains of northern IndiaPLANT BREEDING, Issue 6 2007S. K. Singh Abstract Four hundred spring wheat genotypes, comprising exotic and indigenous germplasm and adapted cultivars for commercial cultivation, were investigated during four crop seasons for six floral characteristics related to outcrossing behaviour. Genetic variability and heritability were investigated along with phenotypic correlation coefficients among these characteristics. A significant quantitative variation existed among the characteristics in all three groups. High heritability for stigma length, openness of florets, anther extrusion and duration of floral opening indicated that selection for these characteristics may be effective. The adapted cultivars were found more promising than the exotic and indigenous germplasm. Most of the characteristics showed significantly positive correlation with each other and high correlation was observed between anther and stigma length, and anther extrusion and duration of floral opening. Superiority of varietal mixtures and segregating generations (F3 and F4) of two crosses over parental lines suggested that heterozygosity and heterogeneity can provide yield advantages. Germplasm lines possessing superior expression of floral characteristics may be used to improve yielding ability through enhanced heterozygosity or the development of hybrids. [source] | ||||||||||