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Grain amaranth (Amaranthus spp.) is an ancient crop that is now receiving fresh attention. This has led to a demand for crop management information, including that on N fertilization. This study evaluated the effect of N fertilizer on amaranth grain yield, yield components, and growth and development. The study was carried out in three Missouri environments with five levels of N fertilizer (NH4NO3 broadcast preplant at 0, 45, 90, 135, and 180 kg N ha−1) and three cultivars (Plainsman, D136, and K266). Averaged across cultivars and environments, N fertilizer at the top rate of 180 kg N ha−1 produced a yield increase of 42% relative to plots receiving no N fertilizer. Yields were consistently improved by additions of 45 and 90 kg N ha−1, but additional N fertilizer above the 90 kg N ha−1 rate increased yield in only one out of three environments. At the one site where yield components were evaluated, yield differences were due to increases in seed number per plant, since seed weight and plant population at maturity were unaffected by N fertilizer rate. Plots with high rates of N fertilizer had later maturity, as indicated by time of flowering and seed moisture. Average moisture of seeds harvested from plots receiving 180 kg N ha−1 was 320 g kg−1, while seeds from plots with no N fertilizer had 240 g kg−1 moisture. Comparing the same high‐N treatment to the control with no N showed height increases of 14, 24, and 44% in the three environments. Although amaranth yield is responsive to N fertilization, high rates of N fertilization can negatively affect grain harvest in terms of excessive plant height, increased lodging, and delayed crop maturity.
Intercropping is a common practice in developing countries because it may produce higher total yields than monocropping. The objective of this study was to apply intercropping principles to alternative and traditional crops in the USA under mechanized conditions. Although these crops have been examined in intercropping systems, in most cases studies were not conducted with improved varieties found in the USA or in strip widths that can accommodate machinery. A field study was conducted at two central Missouri locations in 1991 and 1992 to determine the effect of intercropping on grain yields of pearl millet [Pennisetum glaucum (L.) R. Br.], amaranth (Amaranthus hypochondriacus L. × A. hybridus L.), cowpea [Vigna unguiculata (L.) Walp.], guar [Cyamopsis tetragonoloba (L.) Taub.], and soybean [Glycine max (L.) Merrill]. Treatments were assigned in an incomplete factorial design and consisted of planting pattern (monocrops, narrow and wide row strips, and alternate row intercrops), N fertilizer (0, 56, or 112 kg N ha−1), and component crop combination. Each intercrop consisted of a legume (cowpea, soybean, or guar) and a nonlegume (pearl millet or amaranth). In the strip intercrops, only cowpea showed a consistent yield response to planting pattern, with the narrow strip arrangement with amaranth yielding 53 and 39% lower than its monocrop in two environments. Land equivalent ratios of amaranth and pearl millet grown in alternate rows with cowpea were not significantly different from their monocrops. At the Columbia site, yields of alternate row intercrops generally did not increase upon addition of N and in 1992, amaranth yield at 0 kg N ha−1 was 25% higher in the alternate row intercrop than it was at the same N rate in the monocrop. In general, grain yields were similar in the various intercrops compared with monocrops.
Miscanthus × giganteus yield and fertilizer N requirements have been well studied in Europe and parts of the United States, but few reports have investigated its production on eroded claypan soils economically marginal for grain crops. This study was conducted to evaluate yield potential and fertilizer N strategies for young and mature M. × giganteus on eroded soils. Constant (medium, high) and priming (low, medium, high) fertilizer N rates were applied during 2013 to 2015 at three locations in Missouri to young stands planted in 2012. Constant rates (low, medium, high) also were applied to one mature stand planted in 2007. Winter biomass yield (13.3-23.8 Mg ha-1) was comparable to more productive soils and increased with N fertilization at only two sites with young stands. At one location, yield increased by 44, 48, and 82% with fertilization in 2013, 2014, and 2015, respectively, while the other location increased by 43% only in 2015. At both locations, the medium constant rate (67 kg N ha-1 yr-1) was the lowest rate that maximized total yield across 3 yr. This rate was efficient as it did not increase N removal in harvested biomass. Fertilization always increased leaf chlorophyll concentration (LCC) and site-years with relative LCCM. × giganteus on eroded soils with low organic matter content, and relative LCC can accurately identify when fertilization is required. Disciplines
Herpes simplex virus type 1 (HSV-1) immediate-early (IE) proteins are required for the expression of viral early and late proteins. It has been hypothesized that host neuronal proteins regulate expression of HSV-1 IE genes that in turn control viral latency and reactivation. We investigated the ability of neuronal proteins in vivo to activate HSV-1 IE gene promoters (ICP0 and ICP27) and a late gene promoter (gC). Transgenic mice containing IE (ICP0 and ICP27) and late (gC) gene promoters of HSV-1 fused to the Escherichia coli -galactosidase coding sequence were generated. Expression of the ICP0 and ICP27 reporter transgenes was present in anatomically distinct subsets of neurons in the absence of viral proteins. The anatomic locations of -galactosidase-positive neurons in the brains of ICP0 and ICP27 reporter transgenic mice were similar and included cerebral cortex, lateral septal nucleus, cingulum, hippocampus, thalamus, amygdala, and vestibular nucleus. Trigeminal ganglion neurons were positive for -galactosidase in adult ICP0 and ICP27 reporter transgenic mice. The ICP0 reporter transgene was differentially regulated in trigeminal ganglion neurons depending upon age. -Galactosidase-labeled cells in trigeminal ganglia and cerebral cortex of ICP0 and ICP27 reporter transgenic mice were confirmed as neurons by double labeling with antineurofilament antibody. Nearly all nonneuronal cells in ICP0 and ICP27 reporter transgenic mice and all neuronal and nonneuronal cells in gC reporter transgenic mice were negative for -galactosidase labeling in the absence of HSV-1. We conclude that factors in neurons are able to differentially regulate the HSV-1 IE gene promoters (ICP0 and ICP27) in transgenic mice in the absence of viral proteins. These findings are important for understanding the regulation of the latent and reactivated stages of HSV-1 infection in neurons.Herpes simplex virus (HSV) causes significant disease in humans, including keratitis, conjunctivitis, encephalitis, and disseminated infections of the newborn (65). Lytic infection occurs initially at peripheral sites and is followed by axonal transport of HSV to sensory ganglion neurons. Neurons undergo either lytic or latent viral infection (59, 60). HSV type 1 (HSV-1) immediate-early (IE) genes are thought to be important in determining the outcome of infection (54). The level of IE gene expression may play a role in cell tropism, establishment of and reactivation from latency (19,21), and the extent of viral replication and disease. The HSV-1 IE ICP0 protein stimulates expression of early and late viral genes (6,16,17,18,22,23,39,48,67). ICP0 has been shown to initiate viral gene expression from a quiescent HSV-1 genome in cultured cells (25,26,29,66,68), and it appears to play a role in reactivation of the latent HSV-1 genome from sensory ganglion neurons in vivo (7,35).Many studies of the mechanism of IE gene regulation have been performed with cultured cells; however, little information exists about activation of the viral IE genes ICP0 and ICP27 ...
The percentage of soybean [Glycine max (L.) Merr.] reproductive structures that abscise is a potentially important yield factor. To better understand the involvement of light in the abscission of reproductive structures, a series of in vitro raceme‐culture and growthchamber experiments were conducted. In the in vitro raceme‐culture experiments, racemes with four to six flowers at or past anthesis were excised from the soybean plant (genotype 1X93‐100), embedded in a complete nutrient, solid agar medium, and subjected to various light treatments. A series of three experiments indicated that the racemes contain a photoreceptor, possibly phytochrome, capable of regulating sucrose accumulation. In each of the growth chamber studies, supplemental light was supplied directly to individual soybean flowers via fiber optic light guides. The light source (a tungsten filament bulb) increased the photon flux to the flowers by 10‐fold. The first growth chamber experiment showed that flowers receiving supplemental light were more intense sinks for 14C‐sucrose than were controls (intensity value of 1.0 vs. 0.4 ✕ 10−7, intensity = [dps of flower/dps of raceme]/[kg dry wt of flower]). In a second study, 42% of flowers treated with supplemental light set pods, while only 26% of control flowers set pods. A third experiment showed that red supplemental light produced 55% fruit set, compared to 41% set for far‐red light, and 35% for controls (far‐red not statistically different than control, but all other comparisons are significantly different). These experiments indicate that both photoassimilate accumulation and abscission in young soybean reproductive structures may be regulated by light quality.
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