Effects of Genetics and Environment on Fatty Acid Stability in Soybean Seed

Although seed oil production and composition are genetically controlled, changes of oil level and oil composition across genotypes and environments such as drought and temperature were observed. The mechanisms of how genotypes interact with environment, affecting oil production and composition, are still not well understood. The objective of this research was to investigate the effect of drought/water stress and temperature on soybean genotypes. Two soybean genotypes of maturity group (MG) II (PI 597411 B and PI 597408) and two of MG VI (Arksoy and PI 437726) were used. A repeated greenhouse experiment to study the effect of water stress and a repeated growth chamber experiment to study the effect of temperature were conducted. The results showed that both water stress and high temperature altered seed oil composition by increasing oleic acid and decreasing linoleic and linolenic acid concentrations. Severe water stress (soil water potential between -150 to -200 kPa) or high temperature (40/33℃, day/night) resulted in higher palmitic acid and lower stearic acid. Genotypes differed in their responses to water stress or temperature. Analyses of seed carbohydrates (glucose, fructose, sucrose, raffinose, and stachyose) showed a significant decline of glucose, fructose, and sucrose and a significant increase of stachyose concentration by water stress and high temperature. Analyses of natural abundance of δ15N and δ13C isotopes showed changes in sources of nitrogen and carbon fixation, possibly affecting nitrogen and carbon metabolism pathways. The research demonstrated that both water stress and high temperature altered oil production and composition, and this could be partially related to limited availability and movement of carbohydrates from leaves to seed. Further research to investigate the enzymes controlling fatty acids conversion and nitrogen and carbon metabolism is needed.

Relationships between Microsclerotia Content and Hyperspectral Reflectance Data in Soybean Tissue Infected by Macrophomina phaseolina

Alternative methods are needed to assess the severity of charcoal rot disease [Macrophomina phaseolina (Tassi) Goid] in soybean [Glycine max (L.)] plant tissue. The objective of this study was to define the relationship between light reflectance properties and microsclerotia content of soybean stem and root tissue. Understanding that relationship could lead to using spectral reflectance data as a tool to assess the severity of charcoal rot disease in soybean plants, thus reducing human bias associated with qualitative analysis of soybean plant tissue and cost and time issues connected with quantitative analysis. Hyperspectral reflectance measurements (400-2490 nm) were obtained with a non-imaging spectroradiometer of non-diseased and charcoal rot diseased ground stem and root tissue samples of six soybean genotypes (“Clark”, “LD00-3309”, “LG03- 4561-14”, “LG03-4561-19”, “Saline”, and “Y227-1”). Relationships between the reflectance measurements and tissue microsclerotia content were evaluated with Spearman correlation (rs) analysis (p < 0.05). Moderate (rs = ±0.40 to ±0.59), strong (rs = ±0.60 to ±0.79), and very strong (rs = ±0.80 to ±1.00) negative and positive statistically significant (p < 0.05) monotonic relationships were observed between tissue spectral reflectance values and tissue microsclerotia content. Near-infrared and shortwave-infrared wavelengths had the best relationships with microsclerotia content in the ground tissue samples, with consistent results obtained with near-infrared wavelengths in that decreases in near-infrared spectral reflectance values were associated with increases in microsclerotia content in the stem and root tissue of the soybean plants. The findings of this study provided evidence that relationships exist between tissue spectral reflectance and tissue microsclerotia content of soybean plants, supporting spectral reflectance data as a means for assessing variation of microsclerotia content in soybean plants. Future research should focus on the modelling capabilities of the selected wavelengths and on the feasibility of using these wavelengths in machine learning algorithms to differentiate non-diseased from charcoal rot diseased tissue.

Flor Revisited(Again):eQTL and Mutational Analysis of NB-LRR Mediated Immunity to Powdery Mildew in Barley

Genes encoding early signaling events in pathogen defense often are identified only by their phenotype. Such genes involved in barley-powdery mildew interactions include Mla, specifying race-specific resistance; Rarl （Required for Mla12-specified resistance1）, and Roml （Restoration of Mla-specified resistancel）. The HSP90-SGT1-RAR1 complex appears to function as chaperone in MLA-specified resistance, however, much remains to be discovered regarding the precise signaling underlying plant immunity. Genetic analyses of fast-neutron mutants derived from CI 16151 （Mla6） uncovered a novel locus, designated Rar3 （R_equired for Mla6-specified resitance3）. Rar3 segregates independent of Mla6 and Rarl, and rar3 mutants are susceptible to Blumeria graminis f. sp. hordei （Bgh） isolate 5874 （A VRar）, whereas, wild-type progenitor plants are resistant. Comparative expression analyses of the rar3 mutant vs. its wild-type progenitor were conducted via Barleyl GeneChip and GAIIx paired-end RNA-Seq. Whereas Rarl affects transcription of relatively few genes; Rar3 appears to influence thousands, notably in genes controlling ATP binding, catalytic activity, transcription, and phosphorylation; possibly membrane bound or in the nucleus, eQTL analysis of a segregating doubled haploid population identified over two-thousand genes as being regulated by Mla （q value/FDR=0.00001）, a subset of which are significant in Rar3 interactions. The intersection of datasets derived from mla-loss-of-function mutants, Mla-associated eQTL, and rar3-mediated transcriptome reprogramming are narrowing the focus on essential genes required for Mla-specified immunity.

Tree ecophysiology in the context of climate change

Forest structure and function strongly depend on and concurrently influence environmental conditions.Tree performance is generally governed by its genetics and environment;thus,recent hotspots in this field include tree genotype×environment,phenotype×environment,and functional trait×environment interactions.The editorial,review,and 22 original research articles in this Special Issue,"Tree ecophysiology in the context of climate change",highlight ecophysiological phenomena(e.g.,climate hormesis,seed germination,tree mortality),processes(e.g.,tree metabolism,photosynthate allocation,nutrient uptake and transport),indicators(e.g.,carbon sequestration,pollutants),measurements(e.g.,thermal time methods,soil quality indices,vegetation spectral index,and near-infrared leaf reflectance),and modeling(e.g.,climate correlations with tree growth,photo synthetic phenology,hydraulic strategies,OliveCan model)in the context of global climate change.Understanding forest-environment interactions from an ecophysiological perspective as climate changes provides insights into species fitness in suboptimal environments,species competition for limited resources,and phylogenetic divergence or convergence of species,and predicting species distributions.

土壤镰孢菌Real-Time QPCR定量方法的建立及应用

基于镰孢菌ITS序列,设计一对应用于实时荧光定量PCR(Real-Time QPCR)反应的镰孢菌属特异性引物TS和TR,并建立了相应的Real-Time QPCR体系。应用该反应体系,绝对定量了无肥(NF)、化肥(NP)以及化肥配施有机肥(NPM)等3种施肥措施下大豆田土壤镰孢菌DNA含量。结果表明:引物TS和TR对镰孢菌属真菌有较好的特异性;Real-Time QPCR反应的扩增曲线中各梯度浓度标准品的循环阈值(Ct值)间隔均匀,熔点曲线无杂峰,标准曲线的相关系数R2=0.993,斜率为-0.2927;在大豆生育时期的苗期,NF、NP及NPM措施下土壤镰孢菌总DNA每克干土中含量分别为18.33、44.61和140.83 pg,且NPM措施含量极显著高于NF及NP措施(P<0.01)。

拮抗大豆根腐病细菌的Biolog鉴定

为明确2株生防细菌的分类地位,采用传统形态学方法结合Biolog微生物自动分析系统,鉴定了大豆根腐病的2株生防细菌。结果表明,菌株B021a与塔式弧菌相似度值为0.634,可能性是86%,遗传距离为4.00。菌株B04b与海藻巴斯德菌相似度值为0.610,可能性是75%,遗传距离为2.77。综合形态学和Biolog鉴定结果,认为菌株B021a是塔式弧菌,菌株B04b是海藻巴斯德菌。

粉红粘帚菌代谢物对南方根结线虫卵孵化及二龄幼虫的影响(英文)

粉红粘帚菌(Gliocladium spp.)是一类对植物病原菌具有潜在生物控制作用的真菌,为了探讨粘帚菌对南方根结线虫(Meloidogyne incognita)的抑制作用,实验室条件下研究了粉红粘帚菌挥发性代谢产物和非挥发性代谢产物不同稀释度对南方根结线虫卵孵化及二龄幼虫活性的影响。结果显示非挥发性代谢产物在原液、5倍、10倍、20倍、50倍稀释浓度下,12 d后对南方根结线虫卵孵化的相对抑制率分别为80.4%、12.0%、10.5%、6.7%和5.2%,对二龄幼虫的矫正死亡率分别为32.0%、9.3%、2.0%、0.6%和0.1%,与对照组相比差异显著;挥发性代谢产物对南方根结线虫卵孵化的相对抑制率为22.5%,对二龄幼虫的相对死亡率为17.4%。因此,粉红粘帚菌的非挥发性和挥发性代谢产物对南方根结线虫卵孵化及二龄幼虫活性均有一定的抑制作用。

利用抗感品种混种防治大豆胞囊线虫效果的研究

在温室条件下以抗大豆胞囊线虫品种抗线4号和非抗大豆胞囊线虫品种黑农35为试材,探讨了品种混种对感病大豆生长发育的作用和抗线4号根系浸出物对黑农35生长发育的影响。结果表明,接种SCN后,大豆植株生长受抑制,其中抗线4株高减少幅度最高达到21.4%,主根长减少最高达到24.9%,侧根数减少幅度为7.8%～55.1%;黑农35清种时受大豆胞囊线虫危害,株高减少15.5%～30.8%,主根长减少17.2%～32.3%,侧根数减少最高达到71.9%。抗线和非抗线品种混种有利于大豆抵御大豆胞囊线虫的危害,促进植株的生长发育,与黑农35清种相比,品种混种作物群体的株高、植株鲜重、根鲜重和根长增加幅度分别高达16.9%、11.4%、17.9%和22.2%,与抗线4清种相比,品种混种主根长度增加最显著,达到9.3%。抗线4根系浸出物浇灌黑农35不接种SCN处理各测定指标的增幅达0.1%～8.4%,浇灌接种SCN的黑农35,各处理测定指标的增幅达9.7%～39.4%,说明抗性与非抗性品种混种后根系间相互作用可以促进非抗性品种生长发育,抵御大豆胞囊线虫的危害。

Identification of Quantitative Trait Loci (QTL) Underlying Protein, Oil, and Five Major Fatty Acids’ Contents in Soybean

Improved seed composition in soybean [Glycine max (L.) Merr.] for protein and oil quality is one of the major goals of soybean breeders. A group of genes that act as quantitative traits with their effects can alter protein, oil, palmitic, stearic, oleic, linoleic, and linolenic acids percentage in soybean seeds. The objective of this study was to identify Quantitative Trait Loci (QTL) controlling protein, oil, and fatty acids content in a set of F5:8 RILs derived from a cross between lines, ‘MD 96-5722’ and ‘Spencer’ using 5376 Single Nucleotide Polymorphism (SNP) markers from the Illumina Infinium SoySNP6K BeadChip array. QTL analysis used WinQTL Cart 2.5 software for composite interval mapping (CIM). Identified, were;one protein content QTL on linkage group (LG-) B2 or chromosome (Chr_) 14;11 QTL associated with oil content on six linkage groups LG-N (Chr_3), LG-A1 (Chr_5), LG-K (Chr_9), LG-F (Chr_13), LG-B2 (Chr_14), and LG-J (Chr_16);and sixteen QTL for five major fatty acids (palmitic, stearic, oleic, linoleic, and linolenic acids) on LG-N (Chr_3), LG-F (Chr_13), LG-B2 (Chr_14), LG-E (Chr_15), LG-J (Chr_16), and LG-G (Chr_18). The SNP markers closely linked to the QTL reported here will be useful for development of cultivars with altered oil and fatty acid compositions in soybean breeding programs.

Migratory flight of insect pests within a year-round distribution: European corn borer as a case study

Insect migratory flight differs fundamentally from most other kinds of flight behavior, in that it is non-appetitive. The adult is not searching for anything, and migratory flight is not terminated by encounters with potential resources. Many insect pests of agricultural crops are long-distance migrants, moving from lower latitudes where they overwinter to higher latitudes in the spring to exploit superabundant, but seasonally ephemeral, host crops. The migratory nature of these pests is somewhat easy to recognize because of their sudden appearance in areas where they had been absent only a day or two earlier. Many other serious pests survive hostile winter conditions by diapausing, and therefore do not require migration to move between overwintering and breeding ranges. Yet there is evidence of migratory behavior engaged in by several pest species that inhabit high latitudes year-round. In these cases, the consequences of migratory flight are not immediately noticeable at the population level, because migration takes place for the most part within their larger year-round distribution. Nevertheless, the potential population-level consequences can be quite important in the contexts of pest management and insect resistance management. As a case study, I review the evidence for migratory flight behavior by individual European corn borer adults, and discuss the importance of understanding it. The kind of migratory behavior posited for pest species inhabiting a permanent distribution may be more common than we realize.

Soybean Seed Phenol, Lignin, and Isoflavones and Sugars Composition Altered by Foliar Boron Application in Soybean under Water Stress

Previous research showed that foliar boron (B) application at flowering or seed-fill growth stages altered seed protein, oil, and fatty acids. The objective of this research was to investigate the effects of foliar B fertilizer on seed phenolics (phenol, lignin, and isoflavones) and sugars concentrations. A repeated greenhouse experiment was conducted on soybean [(Glycine max(L.) Merr.)] under watered and water-stressed conditions. Soybean plants were divided into different sets, and each set was subjected to one of the following treatments: W = plants were watered with no foliar B;WB = plants were watered and received foliar B;WS = plants were water-stressed with no foliar B;WSB = plants were waterstressed and received foliar B. Foliar B was applied at rate of 0.45 kg/ha twice at flowering and twice at seed-fill stages. The results showed that total phenol and lignin concentrations were higher in seed collected from water-stressed plants compared with those collected from watered plants whether B was applied or not. The higher total phenol and lignin concentration in seed collected of water-stressed plants may be due to B-deficiency in plant tissues. Application of B resulted in higher concentrations of total seed B and isoflavones under watered and water-stressed plants. Higher cell wall B was higher in water-stressed plants than in watered plants, having an opposite trend to total B. Application of B resulted in higher seed sucrose in watered and water-stressed plants, but raffinose and stachyose were significantly higher under water-stressed plants. The research demonstrated that foliar B fertilizer altered seed phenol, lignin, isoflavones, and sugars, suggesting that B involved in phenolics and sugar metabolism. The higher cell wall B in waterstressed plants than in watered plants supports previous research that B has mainly a structural role. The higher sucrose resulting from foliar B in watered plants is desirable as sucrose contributes to seed quality. The increase of raffinose and stachyose concentrations in seed of water-stressed plants is undesirable as raffinose, and especially stachyose may be involved in water stress/drought tolerance. The current knowledge would help soybean breeders select for higher phenolic compounds and desirable sugars for higher seed qualities under drought conditions.

Characterization of Gh SERK2 and its expression associated with somatic embryogenesis and hormones level in Upland cotton

Somatic embryogenesis （SE） is one of the most important steps during regeneration of cotton, but the molecular mechanism of SE remains unclear. SOMATIC EMBRYOGENSIS RECEPTOR KINASE （SERK） gene is known to function in SE. A homolog GhSERK2 （accession number： JF430801） was cloned from Upland cotton and characterized for its functions in SE. GhSERK2 expressed in different tissues and showed higher expression level in floral organs than vegetative ones with the highest levels in ovule and anther. GhSERK2 expressed during SE with a high level at globular embryos stage. Upon treatment with indole-3-butytic acid （IBA）, the transcription level of GhSERK2 was induced and promoted SE subsequently. A 2-day treatment of 2,4-dichlorophenoxyacetic acid （2,4-D） induced the expression of GhSERK2, but treatments of 2,4-D for longer periods sharply inhibited the GhSERK2 transcription level of embryogenic callus （EC）. The levels of hormones, including 3-indoleacetic acid （IAA）, abscisic acid （ABA）, and brassinosteroid （BR）, were increased in the initial calli induced from the over-expression of GhSERK2 cotton. Our results indicated that GhSERK2 expression was associated with induction of SE and closely related to hormone levels during tissue culture in Upland cotton, and the gene might play an important role in regeneration of cotton.

Effect of a near-zero magnetic field on development and flight of oriental armyworm(Mythimna separata)

The geomagnetic field affects all living organisms on the Earth.In this study we investigated the developmental and behavioral effects of rearing Mythimna separata in a near-zero magnetic field(<500 n T)compared to the local geomagnetic field(approximately 50μT).The near-zero magnetic field produced by a Helmholtz coil system significantly lengthened larval and pupal development durations,increased male longevity,and reduced pupal weight,female reproduction,and the relative expression level of the vitellogenin(Vg)gene in newly emerged females.Moreover,the near-zero magnetic field had a considerable negative effect on the mating ratio of M.separata adults.In addition,the moths in the near-zero magnetic field displayed less flight activity late in the night than those in the Earth's normal geomagnetic field,indicating that the flight rhythm of M.separata may be affected by the near-zero magnetic field.Reduction in magnetic field intensity may have negative effects on the development and flight of oriental armyworm,with consequent additional effects on its migration.

Effects of chelating agents on protein, oil, fatty acids, and minerals in soybean seed

Soybean seed is a major source of protein and oil for human diet. Since not much information is available on the effects of chelating agents on soybean seed composition constituents, the current study aimed to investigate the effects of various chelating agents on soybean [(Glycine max (L.) Merr.)] seed protein, oil, fatty acids, and mineral concentrations. Three chelating agent [citric acid (CA), disodium EDTA (DA), and Salicylic acid (SA)] were applied separately or combined with ferrous (Fe2+) ion (CA + Fe, EDTA + Fe, and SA + Fe) to three-week-old soybean plants. After application, the plants were allowed to grow until harvest maturity under greenhouse conditions. The results showed that CA, DA, SA, and Fe resulted in an increase of oleic acid from 13.0% to 33.5%. However, these treatments resulted in a decrease of linolenic acid from 17.8 to 31.0%. The treatments with CA and SA applications increased protein from 2.9% to 3.4%. The treatments DA + Fe and SA + Fe resulted in an increase in oil from 6.8% to 7.9%. Seed macro- and micro-elements were also altered. The results indicated that the CA, SA, DA, and Fe treatments can alter seed protein, oil, fatty acids, and mineral concentrations. Further studies are needed for conclusive results.

Cottonseed Protein, Oil, and Mineral Nutrition in Near-Isogenic <i>Gossypium hirsutum</i>Cotton Lines Expressing Leaf Color Phenotypes under Field Conditions

Information about the effects of phenotype traits on cottonseed protein, oil, and nutrients is scarce. The objective of this research was to investigate the effects of leaf color trait on seed nutrition in near-isogenic Gossypium hirsutum cotton expressing green (G) and yellow (Y) leaf color phenotypes. Our hypothesis was that leaf color can influence the accumulation of nutrients in seeds. Sets of isogenic lines were: DES 119 (G) and DES 119 (Y);DP 5690 (G) and DP 5690 (Y);MD 51ne (G) and MD 51ne (Y);SG 747 (G) and SG 747 (Y). Each NIL set is 98.44 % identical. Parent line SA 30 (P) was used as the control. The experiment was repeated for two years (2014 and 2015). The results showed that, in 2014, seed oil in DES 119 (G) and SG 747 (G) were significantly higher than their equivalent yellow lines. Green lines showed higher content of phosphorus compared with yellow lines. Higher levels of Cu, Fe, Mn, Ni, and Zn were recorded in DES 119 (G) and MD 51ne (G). In 2015, seed protein, oil, C, N, P, B, Cu, and Fe were higher in green lines than in yellow lines. There was a significant correlation between protein and nutrients, and between oil and nutrients in 2015, but not in 2014 as the temperature was warmer in 2015 than in 2014. This research demonstrated that leaf color can alter seed composition and mineral nutrition under certain environmental growing conditions such as temperature.

Soybean Seed Phenolics, Sugars, and Minerals Are Altered by Charcoal Rot Infection in MG III Soybean Cultivars

Soybean seed is a major source of phytochemical compounds that impact human health nutrition and livestock meal. Charcoal rot is a disease caused by the fungus Macrophomina phaseolina (Tassi) Goid, and thought to infect the plants through roots by a toxin-mediated mechanism, resulting in yield loss and poor seed quality, especially under drought conditions. Limited information is available on the effect of charcoal rot on seed phytochemical compounds and mineral nutrition in soybean. Therefore, the objective of this research was to investigate the effect of charcoal rot infection on seed phenol, seed coat lignin, isoflavones, and minerals using susceptible (S) (DK 3964) and moderately resistant (MR) (AG 3905) maturity group (MG)III soybean cultivars to charcoal rot. A two-year field experiment was conducted, and infested soil with charcoal rot (infested soil conditions, INF) or control (non-infested soil conditions, NINF) was used. The results showed that the moderately resistant genotype had higher concentrations of seed phenolics, total isoflavones, and seed coat lignin under infested and non-infested conditions and under irrigated or non-irrigated conditions compared with the susceptible genotype. The same general trend was found for seed K, Ca, P, Mn, Zn, B, and Cu concentrations in the moderately resistant genotype compared with the susceptible genotype. Our research demonstrated that these seed phytochemical constituents may explain the differences between susceptible and moderately resistant cultivars and may play an important role in the resistance to charcoal rot.

Employing Canopy Hyperspectral Narrowband Data and Random Forest Algorithm to Differentiate Palmer Amaranth from Colored Cotton

Palmer amaranth (Amaranthus palmeri S. Wats.) invasion negatively impacts cotton (Gossypium hirsutum L.) production systems throughout the United States. The objective of this study was to evaluate canopy hyperspectral narrowband data as input into the random forest machine learning algorithm to distinguish Palmer amaranth from cotton. The study focused on differentiating the Palmer amaranth from cotton near-isogenic lines with bronze, green, and yellow leaves. A spectroradiometer was used to acquire hyperspectral reflectance measurements of Palmer amaranth and cotton canopies for two separate dates, December 12, 2016, and May 14, 2017. Data were collected from plants that were grown in a greenhouse. The spectral data were aggregated to twenty-four hyperspectral narrowbands proposed for study of vegetation and agriculture crops. Those bands were tested by the conditional inference version of random forest (cforest) to differentiate the Palmer amaranth from cotton. Classifications were binary: Palmer amaranth and cotton bronze, Palmer amaranth and cotton green, and Palmer amaranth and cotton yellow. Classification accuracies were verified with overall, user’s, and producer’s accuracy. For the two dates combined, overall accuracy ranged from 77.8% to 88.9%. The highest overall accuracies were observed for the Palmer amaranth versus the cotton yellow classification (88.9%, December 12, 2016;83.3%, May 14, 2017). Producer’s and user’s accuracies range was 66.7% to 94.4%. Errors were predominately attributed to cotton being misclassified as Palmer amaranth. The overall results indicated that cforest has moderate to strong potential for differentiating Palmer amaranth from cotton when it used hyperspectral narrowbands known to be useful for vegetation and agricultural surveys as input variables. This research further supports using hyperspectral narrowband data and cforest as decision support tools in cotton production systems.

Spectral Discrimination of Two Pigweeds from Cotton with Different Leaf Colors

To implement strategies to control Palmer amaranth (Amaranthus palmeri S. Wats.) and redroot pigweed (Amaranthus retroflexus L.) infestations in cotton (Gossypium hirsutum L.) production systems, managers need effective techniques to identify the weeds. Leaf light reflectance measurements have shown promise as a tool to distinguish crops from weeds. Studies have targeted plants with green leaves. This study focused on using leaf hyperspectral reflectance data to develop spectral profiles of Palmer amaranth, redroot pigweed, and cotton and to determine regions of the light spectrum most sensitive for pigweed and cotton discrimination. The study focused on cotton near-isogenic lines created to have bronze, green, or yellow colored leaves. Reflectance measurements within the 400 to 2500 nm spectral range were obtained from cotton and weed plants grown in a greenhouse in 2015 and 2016. Two scenarios were evaluated for the comparison: (1) Palmer amaranth versus cotton lines and (2) redroot pigweed versus cotton lines. Statistical significance (p ≤ 0.05) was determined with analysis of variance (ANOVA) and Dunnett’s test. Sensitivity measurements were tabulated to determine the optimal region of the light spectrum for weed and cotton line discrimination. Optimal bands for weed and cotton separation were 600 to 700 nm (both weeds versus cotton bronze and cotton yellow), 710 nm (Palmer amaranth versus cotton green), and 1460 nm (redroot pigweed versus cotton green). Spectral bands were identified for separating Palmer amaranth and redroot pigweed from cotton lines with bronze, green, and yellow leaves. Ground-based and airborne sensors can be tuned into the regions of spectrum identified, facilitating using remote sensing technology for Palmer amaranth and redroot pigweed identification in cotton production systems.

Seed protein, oil, fatty acids, and minerals concentration as affected by foliar K-glyphosate applications in soybean cultivars

Previous studies showed that glyphosate (Gly) may chelate cation nutrients, including potassium (K), which might affect the nutritional status of soybean seed. The objective of this study was to evaluate seed composition (protein, oil, fatty acids, and minerals) as influenced by foliar applications of K + Gly. A greenhouse experiment was conducted at Mississippi Valley State University, using two glyphosate-resistant soybean cultivars DK 4968 and Pioneer 95Y70 grown in a randomized complete block design. The treatments were foliar applications of K alone, Gly alone, K + Gly combined, and nontreated control (C). A single application of potassium (1.75% as K2SO4) was applied, and Gly was applied at a rate of 0.75 ae/ha at V5 stage. Leaf samples were harvested one week after treatment (1WAT) and 3WAT. Mature seeds were collected at harvest maturity (R8). The results showed that K, nitrogen (N), and phosphorus (P) concentrations increased in leaves in K alone and K + Gly treatments at 1WAT, but significantly increased at 3WAT in all treatments. The concentration of iron (Fe) and zinc (Zn) showed a decrease in leaf concentration in Gly and K + Gly treatments compared to C. Boron (B) concentration increased in Gly treatment. Seed protein percentage was higher in all treatments in cultivar DK 4968, and the increase was about 4.0% in K treatment, 6.9% in Gly treatment, and 3.5% in K + Gly treatment compared to C. The opposite trend was observed in oil concentration, especially in Gly treatment where the percentage decrease was 11.2% compared to C. Stearic fatty acid was significantly higher in K + Gly treatment compared to K treatment for DK 4968. A higher percentage increase in linolenic acid was observed in DK 4968 in K treatment (an increase of 24.5%) and in K + Gly treatment (an increase of 29.5%) compared to C. In Pioneer 95Y70, the decrease in oil was 2.7% in K treatment and 2.3% in K + Gly treatment compared to C. Stearic acid in Pioneer 95Y70 was significantly higher in Gly treatment, an increase of 8.3%, compared to C. Our research demonstrated that foliar application of K and Gly altered mineral concentration in leaves and shifted seed composition towards protein and stearic concentration. Further research under field conditions is needed before final conclusions are made.

Phosphorus Fertilization Differentially Influences Fatty Acids, Protein, and Oil in Soybean

Information is limited about phosphorus (P) fertilization effects on soybean seed composition. A field experiment was conducted to investigate the effects of P application rates on the concentrations of various fatty acids, protein, and oil in soybean under no-tillage on low and high testing P soils at Jackson and Milan, Tennessee from 2008 through 2011. Five P rates 0, 10, 20, 30, and 40 kg·P·ha-1 plus the recommended P fertilizer rate based on soil P testing results were arranged in a randomized complete block design with four replicates. Protein, oil, and fatty acid concentrations in seed responded differently to P fertilization. In general, protein concentrations were enhanced but oil levels decreased with increased P application rate. Palmitic and oleic concentrations responded positively to P application rate up to a certain level. However, the response of linolenic acid concentration was inconsistent (negative or positive). Stearic concentration was not influenced by P fertilization. Application of 10 kg·P·ha-1 resulted in higher production of protein and palmitic, oleic, and linolenic acids than zero P and the higher P application rates as well on the P deficient soil. Excessive P application rates could lower seed yield and the quality of some attributes in seed. In conclusion, linoleic acid concentration, a key quality attribute in soybean seed for human and animal consumption, can sometimes be enhanced by P fertilization;the indigenous soil P level and P application rate should be taken into account in breeding soybean cultivars with low linolenic acid level.