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1.
Nat Commun ; 11(1): 4954, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33009396

RESUMO

Genetic variation is of crucial importance for crop improvement. Landraces are valuable sources of diversity, but for quantitative traits efficient strategies for their targeted utilization are lacking. Here, we map haplotype-trait associations at high resolution in ~1000 doubled-haploid lines derived from three maize landraces to make their native diversity for early development traits accessible for elite germplasm improvement. A comparative genomic analysis of the discovered haplotypes in the landrace-derived lines and a panel of 65 breeding lines, both genotyped with 600k SNPs, points to untapped beneficial variation for target traits in the landraces. The superior phenotypic performance of lines carrying favorable landrace haplotypes as compared to breeding lines with alternative haplotypes confirms these findings. Stability of haplotype effects across populations and environments as well as their limited effects on undesired traits indicate that our strategy has high potential for harnessing beneficial haplotype variation for quantitative traits from genetic resources.


Assuntos
Haplótipos/genética , Característica Quantitativa Herdável , Zea mays/genética , Biblioteca Gênica , Variação Genética , Genoma de Planta , Estudo de Associação Genômica Ampla , Haploidia , Melhoramento Vegetal , Análise de Componente Principal , Zea mays/crescimento & desenvolvimento
2.
PLoS One ; 15(8): e0238042, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32841280

RESUMO

Long-term chemical fertilizer input causes soil organic matter losses, structural compaction, and changes in soil water and nutrient availability, which have been subdued in the most of dry farmland in China. The concept of "more efficiency with less fertilizer input" has been proposed and is urgently needed in current agriculture. Application of chemical fertilizer combined with organic manure (OM) could be a solution for soil protection and sustainable production of dry-land maize (Zea mays. L). Field research over three consecutive years on the Loess Plateau of China was conducted to evaluate the integrated effects of chemical fertilizer strategies and additional OM input on soil nutrients availability and water use in maize. The results showed that, after harvest, soil bulk density decreased significantly with OM application, concomitant with 11.9, 18.7 and 97.8% increases in topsoil total nitrogen, organic matter, and available phosphorus contents, respectively, compared with those under equal chemical NPK input. Water use in the 1.0-1.5 m soil profile was improved, therefore, the soil conditions were better for maize root growth, leaf area and shoot biomass of individual maize plants increased significantly with OM application. Optimized NPK strategies increased grain yield and water use efficiency by 18.5 and 20.6%, respectively, compared to only chemical NP input. Furthermore, additional OM input promoted yield and water use efficiency by 8.9 and 5.8%, respectively. Addition of OM promotes sustainable soil and maize grain productivity as well as friendly soil environmental management of dry land farming.


Assuntos
Esterco/análise , Nutrientes/metabolismo , Compostos Orgânicos/farmacologia , Solo/química , Água/análise , Zea mays/efeitos dos fármacos , Zea mays/crescimento & desenvolvimento , Biomassa , China , Fertilizantes/análise , Nitrogênio/metabolismo , Fósforo/metabolismo , Desenvolvimento Sustentável , Zea mays/metabolismo
3.
PLoS One ; 15(8): e0237715, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32822374

RESUMO

Transcriptomic responses of plants to weed presence gives insight on the physiological and molecular mechanisms involved in the stress response. This study evaluated transcriptomic and morphological responses of two teosinte (Zea mays ssp parviglumis) (an ancestor of domesticated maize) lines (Ames 21812 and Ames 21789) to weed presence and absence during two growing seasons. Responses were compared after 6 weeks of growth in Aurora, South Dakota, USA. Plant heights between treatments were similar in Ames 21812, whereas branch number decreased when weeds were present. Ames 21789 was 45% shorter in weedy vs weed-free plots, but branch numbers were similar between treatments. Season-long biomass was reduced in response to weed stress in both lines. Common down-regulated subnetworks in weed-stressed plants were related to light, photosynthesis, and carbon cycles. Several unique response networks (e.g. aging, response to chitin) and gene sets were present in each line. Comparing transcriptomic responses of maize (determined in an adjacent study) and teosinte lines indicated three common gene ontologies up-regulated when weed-stressed: jasmonic acid response/signaling, UDP-glucosyl and glucuronyltransferases, and quercetin glucosyltransferase (3-O and 7-O). Overall, morphologic and transcriptomic differences suggest a greater varietal (rather than a conserved) response to weed stress, and implies multiple responses are possible. These findings offer insights into opportunities to define and manipulate gene expression of several different pathways of modern maize varieties to improve performance under weedy conditions.


Assuntos
Plantas Daninhas , Transcriptoma , Zea mays/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Luz , Fotossíntese , Plantas Daninhas/fisiologia , Estresse Fisiológico , Zea mays/genética , Zea mays/fisiologia
4.
PLoS One ; 15(8): e0237245, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32780782

RESUMO

Straw mulching has been widely adopted in dryland cropping but its effect on soil respiration and microbial communities under warming are not well understood. Soil samples were collected from a corn field with straw mulching (SM) for nine years and without straw mulching (CK), and incubated at 15°C, 25°C, and 35°C for 60 days. Soil respiration, C fractions and bacterial and fungal community structure were measured SM had greater soil organic carbon and potential C mineralization and a similar microbial biomass carbon throughout the incubation when compared with CK. Soil respiration increased with increasing temperature and its temperature sensitivity (Q10) was lower with SM than CK. Similar microbial community composition was found in the soils with SM and CK before incubation. However, SM had a greater bacterial richness and the relative abundances of Proteobacteria, Acidobacteria, Nitrospirae, Planctomycetes, Bacteroidetes, and Basidiomycota, but lower relative abundances of Actinobacteria, Chloroflexi, and Ascomycota than CK after incubation. Bacterial richness and diversity were greater at 15°C and 25°C than 35°C, but there was no difference in fungal richness and diversity among the incubation temperatures. As temperature increased, the relative abundances of Chloroflexi, Acidobacteria, and Bacteroidetes decreased, but Gemmatimonadetes and Ascomycota increased, and were significantly correlated with soil C fractions and respiration. These findings indicated that the effect of straw mulching on soil C cycling and microbial community structure can be highly modified by increasing temperature.


Assuntos
Produção Agrícola/métodos , Microbiologia do Solo , Solo/química , Bactérias/classificação , Bactérias/isolamento & purificação , Carbono/análise , Fungos/classificação , Fungos/isolamento & purificação , Microbiota , Micobioma , Temperatura , Zea mays/crescimento & desenvolvimento
5.
PLoS One ; 15(7): e0232811, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32614852

RESUMO

In the present work, the olive mill solid waste (OMSW)-derived biochar (BC) was produced at various pyrolytic temperatures (300-700°C) and characterized to investigate its potential negative versus positive application effects on pH, electrical conductivity (EC), and nutrients (P, K, Na, Ca, Mg, Fe, Mn, Zn, and Cu) availability in a calcareous loamy sand soil. Therefore, a greenhouse pot experiment with maize (Zea mays L.) was conducted using treatments consisting of a control (CK), inorganic fertilizer of NPK (INF), and 1% and 3% (w/w) of OMSW-derived BCs. The results showed that BC yield, volatile matter, functional groups, and zeta potential decreased with pyrolytic temperature, whereas BC pH, EC, and its contents of ash and fixed carbon increased with pyrolytic temperature. The changes in the BC properties with increasing pyrolytic temperatures reflected on soil pH, EC and the performance of soil nutrients availability. The BC application, especially with increasing pyrolytic temperature and/or application rate, significantly increased soil pH, EC, NH4OAc-extractable K, Na, Ca, and Mg, and ammonium bicarbonate-diethylenetriaminepentaacetic acid (AB-DTPA)-extractable Fe and Zn, while AB-DTPA-extractable Mn decreased. The application of 1% and 3% BC, respectively, increased the NH4OAc-extractable K by 2.5 and 5.2-fold for BC300, by 3.2 and 8.0-fold for BC500, and by 3.3 and 8.9-fold for BC700 compared with that of untreated soil. The results also showed significant increase in shoot content of K, Na, and Zn, while there was significant decrease in shoot content of P, Ca, Mg, and Mn. Furthermore, no significant effects were observed for maize growth as a result of BC addition. In conclusion, OMSW-derived BC can potentially have positive effects on the enhancement of soil K availability and its plant content but it reduced shoot nutrients, especially for P, Ca, Mg, and Mn; therefore, application of OMSW-derived BC to calcareous soil might be restricted.


Assuntos
Carvão Vegetal/farmacologia , Nutrientes/análise , Olea/química , Areia/química , Solo/química , Carvão Vegetal/química , Concentração de Íons de Hidrogênio , Minerais/metabolismo , Nutrientes/metabolismo , Fatores de Tempo , Zea mays/efeitos dos fármacos , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo
6.
PLoS Genet ; 16(7): e1008882, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32673315

RESUMO

Expansion of the maize growing area was central for food security in temperate regions. In addition to the suppression of the short-day requirement for floral induction, it required breeding for a large range of flowering time that compensates the effect of South-North gradients of temperatures. Here we show the role of a novel florigen gene, ZCN12, in the latter adaptation in cooperation with ZCN8. Strong eQTLs of ZCN8 and ZCN12, measured in 327 maize lines, accounted for most of the genetic variance of flowering time in platform and field experiments. ZCN12 had a strong effect on flowering time of transgenic Arabidopsis thaliana plants; a path analysis showed that it directly affected maize flowering time together with ZCN8. The allelic composition at ZCN QTLs showed clear signs of selection by breeders. This suggests that florigens played a central role in ensuring a large range of flowering time, necessary for adaptation to temperate areas.


Assuntos
Adaptação Fisiológica/genética , Florígeno/metabolismo , Proteínas de Plantas/genética , Zea mays/genética , Aclimatação/genética , Temperatura Baixa , Flores/genética , Flores/crescimento & desenvolvimento , Humanos , Fotoperíodo , Proteínas de Plantas/metabolismo , Locos de Características Quantitativas/genética , Zea mays/crescimento & desenvolvimento
7.
Gene ; 757: 144928, 2020 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-32622989

RESUMO

Tassel branch number (TBN) is the principal component of tassel inflorescence architecture in the maize plant. TBN is believed to be controlled by a set of quantitative trait loci (QTLs). However, it is necessary to identify and genetically evaluate these QTLs before the TBN can be improved upon using a molecular breeding approach. Therefore, in this study, we developed the chromosome segment introgression line (CSIL) TBN1 with the Zong31 (Z31) background and a higher TBN, and then we utilized the CSIL-TBN1-derived populations and identified a major QTL, qTBN6a, by linkage analysis. Fine mapping of the qTBN6a QTL was validated using a set of sub-CSILs and located in a 240-kb genomic region (Bin6.07) in B73RefGen_v4. One allele included in the introgression fragment had a positive effect, noticeably increasing the TBN and demonstrating the potential to improve the TBN of Z31. Afterward, in the qTBN6a interval, gene expression, sequence alignment, functional analysis, and the analysis of motifs in the 5' UTR suggested that candidate genes of qTBN6a are important functional genes at the early stage of immature infected tassel development. Among these candidate genes, a long W22::Mu-insertion/deletion in exon one and an 11-bp insertion/deletion in the promoter region may affect the variation of the qTBN6a QTL observed between Z31 and TBN1. In addition, the candidate genes of qTBN6a were found to encode a pentatricopeptide repeat (PPR)-containing protein and a histone deacetylase (HDA), which are known to be closely associated with RNA editing and stability and chromatin state activity for the transcription of gene expression, respectively. Finally, a model of qTBN6a based on the synergistic regulation of PPR and HDA for the maintenance of inflorescence meristem (IM) identity and its differentiation to the branch meristem (BM) in TBN1 was suggested. Collectively, our results provide an available locus for the molecular improvement of TBN and the isolation of functional genes underlying this QTL.


Assuntos
Meristema/genética , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Zea mays/genética , Genoma de Planta , Histona Desacetilases/genética , Meristema/crescimento & desenvolvimento , Proteínas de Plantas/genética , Zea mays/crescimento & desenvolvimento
8.
PLoS One ; 15(7): e0236571, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730284

RESUMO

The occurrence of genotype by environment interaction (G x E), which is defined as the differential response of genotypes to environmental variation, is frequently reported in maize cultures, making it challenging to recommend cultivars. Methods allowing to study the potential nonlinear pattern of genotype responses to environmental variation allied to prior beliefs on unknown parameters are interesting to evaluate the phenotypic adaptability and stability of genotypes. In this context, the present study aimed to assess the adaptability and stability of maize hybrids, by using the Bayesian segmented regression model, and evaluate the efficacy of using informative and minimally informative prior distributions for the selection of cultivars. Randomized complete-block design experiments were carried out to study the yield (kg/ha) of 25 maize hybrids, in 22 different environments, in Northeastern Brazil. The Bayesian segmented regression model fitted using informative prior distributions presented lower credibility intervals and Deviance Criterium of Information values, compared to those obtained by fitting using minimally informative distributions. Therefore, the model using informative prior distributions was considered for the adaptability and stability evaluation of maize genotypes. Once most northeastern farmers in Brazil have limited capital, the genotype P4285HX should be considered for planting, due to its high yield performance and adaptability to unfavorable environments.


Assuntos
Modelos Genéticos , Zea mays/genética , Adaptação Fisiológica/genética , Teorema de Bayes , Interação Gene-Ambiente , Genótipo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo
9.
Proc Natl Acad Sci U S A ; 117(31): 18385-18392, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32690686

RESUMO

Transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt) can suppress pests and reduce insecticide sprays, but their efficacy is reduced when pests evolve resistance. Although farmers plant refuges of non-Bt host plants to delay pest resistance, this tactic has not been sufficient against the western corn rootworm, Diabrotica virgifera virgifera In the United States, some populations of this devastating pest have rapidly evolved practical resistance to Cry3 toxins and Cry34/35Ab, the only Bt toxins in commercially available corn that kill rootworms. Here, we analyzed data from 2011 to 2016 on Bt corn fields producing Cry3Bb alone that were severely damaged by this pest in 25 crop-reporting districts of Illinois, Iowa, and Minnesota. The annual mean frequency of these problem fields was 29 fields (range 7 to 70) per million acres of Cry3Bb corn in 2011 to 2013, with a cost of $163 to $227 per damaged acre. The frequency of problem fields declined by 92% in 2014 to 2016 relative to 2011 to 2013 and was negatively associated with rotation of corn with soybean. The effectiveness of corn rotation for mitigating Bt resistance problems did not differ significantly between crop-reporting districts with versus without prevalent rotation-resistant rootworm populations. In some analyses, the frequency of problem fields was positively associated with planting of Cry3 corn and negatively associated with planting of Bt corn producing both a Cry3 toxin and Cry34/35Ab. The results highlight the central role of crop rotation for mitigating impacts of D. v. virgifera resistance to Bt corn.


Assuntos
Besouros/fisiologia , Produção Agrícola/métodos , Endotoxinas/farmacologia , Doenças das Plantas/parasitologia , Plantas Geneticamente Modificadas/imunologia , Zea mays/imunologia , Animais , Bacillus thuringiensis/genética , Bacillus thuringiensis/metabolismo , Besouros/efeitos dos fármacos , Produção Agrícola/economia , Endotoxinas/genética , Endotoxinas/metabolismo , Resistência a Inseticidas , Iowa , Controle Biológico de Vetores/economia , Doenças das Plantas/economia , Doenças das Plantas/imunologia , Doenças das Plantas/prevenção & controle , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/parasitologia , Soja/crescimento & desenvolvimento , Zea mays/genética , Zea mays/crescimento & desenvolvimento , Zea mays/parasitologia
10.
An Acad Bras Cienc ; 92 Suppl 1: e20181371, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32491139

RESUMO

The formononetin biostimulant may be an option for reducing P fertilization once it stimulates mycelial growth of arbuscular mycorrhizal fungi and increases plant ability to take up nutrients through the roots, especially phosphorus. The objective of this study was to evaluate the effect of formononetin associated with phosphorus fertilization in maize. Field experiments were conducted in a randomized block design with a 3 × 4 factorial arrangement (0, 50 or 70, and 140 kg ha-1 P2O5; and formononetin application rates: 0, 25, 50, and 100 g ha-1), with four replications. Formononetin (100 g ha-1) increased the mycorrhizal colonization rate up to 30% in maize in the first four weeks after emergence when no P fertilizer was applied, and to 17% when 50 or 70 kg ha-1 of P2O5 were applied. The application of 50 and 100 g ha-1 of formononetin significantly increased plant height, ear height, and grain yield (22% - 76%) when no P fertilizer was applied. The use of formononetin in the field stimulates mycorrhizal colonization, has a positive effect on maize yield, and reduces the need for P fertilizer application in maize. However, this effect was evident only at low P soil contents.


Assuntos
Fertilizantes , Isoflavonas/farmacologia , Fósforo/análise , Solo/química , Zea mays/crescimento & desenvolvimento , Micorrizas/fisiologia , Zea mays/efeitos dos fármacos
11.
An Acad Bras Cienc ; 92 Suppl 1: e20180874, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32491135

RESUMO

In plant breeding, the dialelic models univariate have aided the selection of parents for hybridization. Multivariate analyses allow combining and associating the multiple pieces of information of the genetic relationships between traits. Therefore, multivariate analyses might refine the discrimination and selection of the parents with greater potential to meet the goals of a plant breeding program. Here, we propose a method of multivariate analysis used for stablishing mega-traits (MTs) in diallel trials. The proposed model is applied in the evaluation of a multi-environment complete diallel trial with 90 F1's of simple maize hybrids. From a set of 14 traits, we demonstrated how establishing and interpreting MTs with agronomic implication. The diallel analyzes based on mega-traits present an important evolution in statistical procedures since the selection is based on several traits. We believe that the proposed method fills an important gap of plant breeding. In our example, three MTs were established. The first, formed by plant stature-related traits, the second by tassel size-related traits, and the third by grain yield-related traits. Individual and joint diallel analysis using the established MTs allowed identifying the best hybrid combinations for achieving F1's with lower plant stature, tassel size, and higher grain yield.


Assuntos
Hibridização Genética/genética , Melhoramento Vegetal/métodos , Zea mays/genética , Análise Fatorial , Genótipo , Análise Multivariada , Fenótipo , Zea mays/crescimento & desenvolvimento
12.
PLoS One ; 15(6): e0233723, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32484821

RESUMO

Farmland management and irrigation scheduling are vital to a productive agricultural economy. A multistage stochastic programming model is proposed to maximize farmers' annual profit under uncertainty. The uncertainties considered include crop prices, irrigation water availability, and precipitation. During the first stage, pre-season decisions including seed type and plant density are made, while determinations of when to irrigate and how much water to be used for each irrigation are made in the later stages. The presented case study, based on a farm in Nebraska, U.S.A., showed that a 10% profit increase could be achieved by taking the corn price and irrigation water availability uncertainties into consideration using two-stage stochastic programming. An additional 13% profit increase could be achieved by taking precipitation uncertainty into consideration using multistage stochastic programming. The stochastic model outperforms the deterministic model, especially when there are limited water supplies. These results indicate that multistage stochastic programming is a promising method for farm-scale irrigation management and can increase farm profitability.


Assuntos
Irrigação Agrícola/métodos , Modelos Teóricos , Irrigação Agrícola/estatística & dados numéricos , Clima , Produção Agrícola/métodos , Produção Agrícola/estatística & dados numéricos , Nebraska , Processos Estocásticos , Incerteza , Zea mays/crescimento & desenvolvimento
13.
PLoS One ; 15(6): e0232633, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32555651

RESUMO

Maize, a main crop worldwide, establishes a mutualistic symbiosis with arbuscular mycorrhizal (AM) fungi providing nutrients to the roots from soil volumes which are normally not in reach of the non-colonized root. The mycorrhizal phosphate uptake pathway (MPU) spans from extraradical hyphae to root cortex cells housing fungal arbuscules and promotes the supply of phosphate to the mycorrhizal host in exchange for photosynthetic carbon. This symbiotic association with the mycobiont has been shown to affect plant host nutritional status and growth performance. However, whether and how the MPU affects the root microbial community associated with mycorrhizal hosts in association with neighboring plants, remains to be demonstrated. Here the maize germinal Mu transposon insertion mutant pht1;6, defective in mycorrhiza-specific Pi transporter PHT1;6 gene, and wild type B73 (wt) plants were grown in mono- and mixed culture and examined under greenhouse and field conditions. Disruption of the MPU in pht1;6 resulted in strongly diminished growth performance, in reduced P allocation to photosynthetic source leaves, and in imbalances in leaf elemental composition beyond P. At the microbial community level a loss of MPU activity had a minor effect on the root-associated fungal microbiome which was almost fully restricted to AM fungi of the Glomeromycotina. Moreover, while wt grew better in presence of pht1;6, pht1;6 accumulated little biomass irrespective of whether it was grown in mono- or mixed culture and despite of an enhanced fungal colonization of its roots in co-culture with wt. This suggested that a functional MPU is prerequisite to maintain maize growth and that neighboring plants competed for AM fungal Pi in low P soil. Thus future strategies towards improving yield in maize populations on soils with low inputs of P fertilizer could be realized by enhancing MPU at the individual plant level while leaving the root-associated fungal community largely unaffected.


Assuntos
Micorrizas/metabolismo , Fosfatos/metabolismo , Zea mays/microbiologia , Zea mays/fisiologia , Biomassa , Mutação com Perda de Função , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Plantas Geneticamente Modificadas , Solo/química , Simbiose/fisiologia , Zea mays/genética , Zea mays/crescimento & desenvolvimento
14.
Ecotoxicol Environ Saf ; 201: 110803, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32505761

RESUMO

Water stress and nutrient supply are two of the most ubiquitous global changes that surely drive substantial variations not only in agricultural productivity but also extend to alert soil living organisms. The present study aims to understand the intrinsic changes in the composition of soil populations and their functions due to the interaction between long-term fertilization and rainfall fluctuations, seeing whether fertilization history would render the soil microbial communities and their activities more resistant to water stress or not. The experiment was established in 1988 on a typical meadow soil (Vertisols) as a rainfed maize monoculture receiving six elevated rates of NPK annually. The 30-year average annual precipitation of the growing season in this region is 345.1 mm. However, in 2010 rainfall was 106.1% greater than the average, while in 2011 it was 26.5% lower. The results show that long-term NPK fertilization has made the soil microbes more tolerant to changes in soil moisture content resulting from rainfall fluctuations. Soil microbes and their activities, however, did not follow a dose-response relationship of NPK as soil moisture content was the main driving factor. Numbers of total fungi, cellulose decomposing bacteria, and nitrifying bacteria increased as rainfall in 2010 increased. Moreover, microbial biomass carbon in 2010 was almost 2-fold higher than in 2009. Soil respiration in 2010 was 11 and 35% higher than in 2009 and 2011, respectively. Otherwise, high rainfall in 2010 significantly diminished soil NO3- content and nitrification rate. Soil enzyme activity showed a higher response to soil moisture than the rate of NPK. The highest activity of phosphatase, dehydrogenase, and saccharase was measured in the driest year (2011), while urease displayed its highest activity in 2010. High rates of NPK significantly reduced soil dehydrogenase activity. These results illustrate how important it is for fertilizer programs to be flexible to match expected climate change in order to improve productivity and reduce environmental pollution.


Assuntos
Desidratação , Fertilizantes/análise , Microbiota/efeitos dos fármacos , Chuva , Microbiologia do Solo , Solo/química , Biomassa , Fertilizantes/efeitos adversos , Hungria , Nitratos/análise , Nitrificação , Urease/análise , Zea mays/crescimento & desenvolvimento
15.
Ecotoxicol Environ Saf ; 202: 110865, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32570103

RESUMO

Crop production in acid soils is facing enormous challenges due to low soil quality associated with an increase in the acidification rate and aluminum toxicity. Despite comprehensive prior work with biochar application on nutrient availability and crop productivity in acid soils, little information is available about the recommendation or standardization of biochar application rates that are more suitable for soil fertility improvement under different soil environments (physico-chemical properties) for maximizing the benefits of biochar applications and minimizing the potential environmental risk. Thus, the objective of this study was to investigate the effectiveness of poultry litter (PL) and poultry litter biochar (PLB) in ameliorating the fertility of acid soils through incubation and pot experiments. The soil was amended with different materials as follows; lime (1 g kg-1), PL (5, 10 and 15 g kg-1) and PLB (5, 10 and 15 g kg-1) along with control (non-amended). A pot experiment was also conducted using similar treatments to observe the responses of maize crop to the different amendments. The results indicated an increase in the pH and a decrease in exchangeable acidity in lime, PL and PLB amended soils. Lower soil pH, base cations and soil available phosphorus (P), and higher exchangeable acidity were found in control than the amended soils. Compared to PL and lime, PLB achieved greater increase rate in soil pH and reduction rate in soil exchangeable acidity with increased soil exchangeable base cations. An increase in soil available calcium (Ca) was observed in the lime treatment, while in PL and PLB treatments, there was an increase in soil available Ca, magnesium (Mg), potassium (K) and P. Application of the amendments increased availability of nitrogen (N), P, K, Ca and Mg relative to the control for maize in the pot experiment. When PL and PLB amendments were compared, it was found that the PLB was the best choice for the amelioration of acid soils as well as nutrient uptake by maize plants. It is suggested that application of PLB at the rate of 15 g kg-1 is suitable for maize growth in acid soils.


Assuntos
Carvão Vegetal , Recuperação e Remediação Ambiental/métodos , Zea mays/fisiologia , Ácidos , Animais , Cálcio , Compostos de Cálcio , Magnésio , Nitrogênio , Óxidos , Fósforo , Potássio , Aves Domésticas , Solo/química , Poluentes do Solo/análise , Zea mays/crescimento & desenvolvimento
16.
Proc Natl Acad Sci U S A ; 117(22): 12464-12471, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32424100

RESUMO

Plant cuticles are composed of wax and cutin and evolved in the land plants as a hydrophobic boundary that reduces water loss from the plant epidermis. The expanding maize adult leaf displays a dynamic, proximodistal gradient of cuticle development, from the leaf base to the tip. Laser microdissection RNA Sequencing (LM-RNAseq) was performed along this proximodistal gradient, and complementary network analyses identified potential regulators of cuticle biosynthesis and deposition. A weighted gene coexpression network (WGCN) analysis suggested a previously undescribed function for PHYTOCHROME-mediated light signaling during the regulation of cuticular wax deposition. Genetic analyses reveal that phyB1 phyB2 double mutants of maize exhibit abnormal cuticle composition, supporting the predictions of our coexpression analysis. Reverse genetic analyses also show that phy mutants of the moss Physcomitrella patens exhibit abnormal cuticle composition, suggesting an ancestral role for PHYTOCHROME-mediated, light-stimulated regulation of cuticle development during plant evolution.


Assuntos
Folhas de Planta/crescimento & desenvolvimento , Transcriptoma , Zea mays/genética , Bryopsida/genética , Bryopsida/metabolismo , Bryopsida/efeitos da radiação , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Luz , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Transcriptoma/efeitos da radiação , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo , Zea mays/efeitos da radiação
17.
PLoS One ; 15(5): e0232269, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32357181

RESUMO

Susceptibility of plants to abiotic stresses, including extreme temperatures, salinity and drought, poses an increasing threat to crop productivity worldwide. Here the drought-induced response of maize was modulated by applications of methyl jasmonate (MeJA) and salicylic acid (SA) to seeds prior to sowing and to leaves prior to stress treatment. Pot experiments were conducted to ascertain the effects of exogenous applications of these hormones on maize growth, physiology and biochemistry under drought stress and well-watered (control) conditions. Maize plants were subjected to single as well as combined pre-treatments of MeJA and SA. Drought stress severely affected maize morphology and reduced relative water content, above and below-ground biomass, rates of photosynthesis, and protein content. The prolonged water deficit also led to increased relative membrane permeability and oxidative stress induced by the production of malondialdehyde (from lipid peroxidation), lipoxygenase activity (LOX) and the production of H2O2. The single applications of MeJA and SA were not found to be effective in maize for drought tolerance while the combined pre-treatments with exogenous MeJA+SA mitigated the adverse effects of drought-induced oxidative stress, as reflected in lower levels of lipid peroxidation, LOX activity and H2O2. The same pre-treatment also maintained adequate water status of the plants under drought stress by increasing osmolytes including proline, total carbohydrate content and total soluble sugars. Furthermore, exogenous applications of MeJA+SA approximately doubled the activities of the antioxidant enzymes catalase, peroxidase and superoxide dismutase. Pre-treatment with MeJA alone gave the highest increase in drought-induced production of endogenous abscisic acid (ABA). Pre-treatment with MeJA+SA partially prevented drought-induced oxidative stress by modulating levels of osmolytes and endogenous ABA, as well as the activities of antioxidant enzymes. Taken together, the results show that seed and foliar pre-treatments with exogenous MeJA and/or SA can have positive effects on the responses of maize seedlings to drought.


Assuntos
Acetatos/farmacologia , Ciclopentanos/farmacologia , Secas , Oxilipinas/farmacologia , Reguladores de Crescimento de Planta/farmacologia , Ácido Salicílico/farmacologia , Estresse Fisiológico/efeitos dos fármacos , Zea mays/efeitos dos fármacos , Antioxidantes/metabolismo , Carotenoides/metabolismo , Clorofila/metabolismo , Concentração Osmolar , Estresse Oxidativo/efeitos dos fármacos , Proteínas de Plantas/metabolismo , Análise de Componente Principal , Sementes/efeitos dos fármacos , Solo , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo
18.
PLoS One ; 15(5): e0233674, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32469984

RESUMO

Timing and rate of nitrogen (N) fertilizer application can influence maize (Zea mays L.) grain yield, N uptake, and nitrogen use efficiency (NUE) parameters, but results have been inconsistent across the upper Midwest. This study compared single (fall and preplant) and split applications of differing N rates for maize under irrigated conditions on loamy sand at Becker, MN and under rainfed conditions on loam and clay loam soils at Lamberton, MN and Waseca, MN, respectively, in 2014 to 2016. Fall and preplant applications of N were applied at recommended and 125% of recommended rates (RN) according to University of Minnesota guidelines. Split-application treatments included a two-way (Sp, applied at 75% and 100% of RN) and a three-way split (TSp applied at 50%, 75%, and 100% of RN), with the total N rate equally split among application times. At Becker, maize grain yield with TSp was 12.6 to 15.7 Mg ha-1 among years and significantly greater than that with fall or preplant treatments. The TSp treatment also improved agronomic efficiency (AE) and recovery efficiency (RE) by an average of 30% over fall or preplant treatments. At Lamberton, maize grain yield, AE and RE did not differ among treatments. However, TSp75 improved AE by 8.3 kg kg-1 while producing comparable yields to fall and preplant treatments. At Waseca, Sp or TSp improved grain yield and AE compared with fall treatments. These results suggest that split applications of N can increase maize grain yield, AE, and RE on irrigated coarse-textured soils and applying N fertilizer near planting or as a split application can improve N management on non-irrigated clay loam soils.


Assuntos
Produção Agrícola/métodos , Fertilizantes , Nitrogênio , Zea mays/crescimento & desenvolvimento , Irrigação Agrícola , Fertilizantes/análise , Nitrogênio/análise , Nitrogênio/metabolismo , Chuva , Solo/química , Zea mays/metabolismo
19.
Nature ; 581(7807): 190-193, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32404996

RESUMO

The onset of plant cultivation is one of the most important cultural transitions in human history1-4. Southwestern Amazonia has previously been proposed as an early centre of plant domestication, on the basis of molecular markers that show genetic similarities between domesticated plants and wild relatives4-6. However, the nature of the early human occupation of southwestern Amazonia, and the history of plant cultivation in this region, are poorly understood. Here we document the cultivation of squash (Cucurbita sp.) at about 10,250 calibrated years before present (cal. yr BP), manioc (Manihot sp.) at about 10,350 cal. yr BP and maize (Zea mays) at about 6,850 cal. yr BP, in the Llanos de Moxos (Bolivia). We show that, starting at around 10,850 cal. yr BP, inhabitants of this region began to create a landscape that ultimately comprised approximately 4,700 artificial forest islands within a treeless, seasonally flooded savannah. Our results confirm that the Llanos de Moxos is a hotspot for early plant cultivation and demonstrate that-ever since their arrival in Amazonia-humans have markedly altered the landscape, with lasting repercussions for habitat heterogeneity and species conservation.


Assuntos
Produção Agrícola/história , Produtos Agrícolas/história , Florestas , Pradaria , Atividades Humanas , Biodiversidade , Bolívia , Conservação dos Recursos Naturais , Cucurbita/crescimento & desenvolvimento , Mapeamento Geográfico , História Antiga , Manihot/crescimento & desenvolvimento , Manihot/história , Amido , Zea mays/crescimento & desenvolvimento
20.
PLoS One ; 15(4): e0232164, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32330189

RESUMO

Maize (Zea mays L) is one of main nutrients sources for humans and animals worldwide. In Africa, storage of maize ensures food resources availability throughout the year. However, it often suffers losses exceeding 20% due to insects such as the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera; Bostrichidae), major pest of stored maize in the tropical countries. This study aims to select resistant varieties to reduce maize storage losses and explain the physicochemical parameters role in grains susceptibility. In the first study, maize grains were artificially infested under no-choice method with insects. Susceptibility parameters such as weight loss, grain damage, number of emerged insects, median development time and susceptibility index varied significantly through maize varieties. Dobie susceptibility index (SI) was assessed as a major indicator of resistance. The most resistant varieties were Early-Thaï, DMR-ES and Tzee-Yellow. Conversely, Synth-9243, Obatampa and Synth-C varieties were susceptible. SWAN, Across-Pool and Tzee-White were classified as moderately resistant varieties. The insect reproductive potential was significantly different in the nine maize varieties and Early-Thaï, DMR-ES and Tzee-Yellow varieties were the least favourable host. To assess the relationship between grains physicochemical characteristics and varietal susceptibility, moisture, total phenolics, palmitic acid, proteins, amylose, density and grain hardness were evaluated according to standardized methods. Palmitic acid, SI, insects emerged and grain damage were significantly and positively correlated with each other, and negatively correlated with grains hardness, phenolics and amylose contents. Maize susceptibility index was significantly and negatively correlated to amylose, and phenolics contents and positively correlated to palmitic acid content. This study identified three resistant maize varieties to P. tuncatus and revealed that the major factors involved in this resistance were hardness, phenolic and amylose contents of grains.


Assuntos
Besouros/patogenicidade , Zea mays/crescimento & desenvolvimento , Zea mays/parasitologia , África , Amilose/metabolismo , Animais , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Ácido Palmítico/metabolismo , Fenol/metabolismo , Estruturas Vegetais/crescimento & desenvolvimento , Estruturas Vegetais/metabolismo , Estruturas Vegetais/parasitologia , Zea mays/metabolismo
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