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Studying the genetic basis of drought tolerance in sorghum by managed stress trials and adjustments for phenological and plant height differences

Sabadin, P. K.; Malosetti, M.; Boer, M. P.; Tardin, F. D.; Santos, F. G.; Guimaraes, C. T.; Gomide, R. L.; Andrade, C. L. T.; Albuquerque, P. E. P.; Caniato, F. F.; Mollinari, M.; Margarido, G. R. A.; Oliveira, B. F.; Schaffert, R. E.; Garcia, A. A. F.; v
Fonte: SPRINGER; NEW YORK Publicador: SPRINGER; NEW YORK
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.47%
Managed environments in the form of well watered and water stressed trials were performed to study the genetic basis of grain yield and stay green in sorghum with the objective of validating previously detected QTL. As variations in phenology and plant height may influence QTL detection for the target traits, QTL for flowering time and plant height were introduced as cofactors in QTL analyses for yield and stay green. All but one of the flowering time QTL were detected near yield and stay green QTL. Similar co-localization was observed for two plant height QTL. QTL analysis for yield, using flowering time/plant height cofactors, led to yield QTL on chromosomes 2, 3, 6, 8 and 10. For stay green, QTL on chromosomes 3, 4, 8 and 10 were not related to differences in flowering time/plant height. The physical positions for markers in QTL regions projected on the sorghum genome suggest that the previously detected plant height QTL, Sb-HT9-1, and Dw2, in addition to the maturity gene, Ma5, had a major confounding impact on the expression of yield and stay green QTL. Co-localization between an apparently novel stay green QTL and a yield QTL on chromosome 3 suggests there is potential for indirect selection based on stay green to improve drought tolerance in sorghum. Our QTL study was carried out with a moderately sized population and spanned a limited geographic range...

Avaliação fisiológica e agronômica de soja geneticamente modificada para maior tolerância à seca; Physiologic and agronomic evaluation of genetically modified soybean to improve drought tolerance

Salinet, Luana Held
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 11/02/2009 PT
Relevância na Pesquisa
56.56%
A soja é uma das culturas com maior importância sócio-econômica no mundo, visto o complexo agro-industrial que movimenta. A ocorrência de períodos de seca durante a estação de desenvolvimento das lavouras de soja é muito freqüente, provocando reduções drásticas na produtividade. Sendo a seca um fator limitante de produção fora do controle direto do homem, e a necessidade de suprir a demanda mundial crescente de alimentos, fazem com que a estabilidade da produtividade seja a chave para este entrave. O objetivo deste trabalho foi avaliar as respostas fisiológicas e agronômicas de dois genótipos de soja, um geneticamente modificado contendo a construção rd29A:DREB1A, visando maior tolerância à seca, e sua isolínea convencional, comparando-as frente a diferentes condições de disponibilidade hídrica no solo. Para tal, plantas de soja foram transformadas com o cassete rd29A:DREB1A, ambos elementos de Arabidopsis thaliana, introduzido por biobalística. O efeito da super expressão do gene AtDREB sobre parâmetros fisiológicos e agronômicos foi avaliado em casa de vegetação em três cultivos. Os experimentos foram instalados em blocos casualizados em arranjo fatorial (2x2), com quatros blocos e três amostras por bloco...

Caracterização fisiológica e perfil de expressão gênica de cultivares de cana-de-açúcar (Saccharum spp) contrastantes para o deficit hídrico; Physiological characterization and gene expression profiling of sugarcane (Saccharum spp) genotypes contrasting for drought tolerance

Oliveira, João Felipe Nebó Carlos de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 01/02/2013 PT
Relevância na Pesquisa
56.81%
A cana-de-açúcar (Saccharum spp.) é uma das culturas mais importantes para a economia brasileira, fonte de matéria-prima para produção de açúcar e álcool. O setor sucroalcoleiro tem expandido rapidamente devido à alta demanda por biocombustíveis. Para atender tal demanda e garantir a produção de açúcar, a área cultivada deverá ser expandida utilizando áreas de cerrado e pastagens degradadas no Sudeste e Centro-Oeste, caracterizadas por invernos secos com períodos de deficiência hídrica acentuada. Cultivares com tolerância a seca e alto potencial produtivo nessas regiões são desejadas para esta expansão, e a elucidação das bases moleculares e fisiológicas da tolerância é indispensável para o desenvolvimento de tais cultivares. Para investigar mecanismos fisiológicos e moleculares envolvidos na tolerância à seca metodologias baseadas em ensaios de campo e casa de vegetação foram avaliadas, com foco na fenotipagem e perfil de expressão gênica. O uso de polietilenoglicol (PEG) como agente estressor na solução de plantas hidropônicas foi avaliado para simulação da seca, bem como a avaliação do vazamento de eletrólitos após exposição ao Paraquat (methyl-viologen). Dois genótipos previamente selecionados com base no comportamento contrastante para resposta a seca foram utilizados para testar a hipótese dos mecanismos por trás da tolerância em cana...

Diversidade genética e mapeamento associativo de caracteres associados à tolerância do arroz ao déficit hídrico; Genetic diversity and association mapping for drought tolerance characters in rice

Savio, Filipe Luís
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 03/10/2014 PT
Relevância na Pesquisa
66.68%
A caracterização e o entendimento das variações genômicas e morfológicas, bem como a estrutura genética de variedades locais armazenadas em bancos de germoplasma é importante para sua efetiva utilização em programas de melhoramento visando tolerância a estresses. Neste trabalho um conjunto de 192 variedades oriundas de diferentes regiões geoclimáticas do Japão foram testadas quanto à suas características morfológicas e produtivas, utilizando ensaios de campo e metodogias de fenotipagem de alto desempenho. A fenotipagem por meio da metodologia de camadas de herbicida (Aminotriazol+Diuron+2,4D, 100mg/plant) alocado a 30 centímetros de profundidade foi possível detectar variação entre as variedades para comprimento de raiz e velocidade de emissão de raiz sendo possível a distinção de variedades com sistema radicular profundo e sistema radicular superficial baseando-se na sua pontuação no ensaio de herbicida, destacando-se 20 genótipos como possíveis doadores de genes para comprimento, densidade e velocidade de emissão de raízes. Ensaios a campo foram conduzidos em 4 localidades expondo as variedades as mais distintas condições climáticas, buscando analisar a diversidade fenotípica para caracteres agromorfológicos. Os dados fenotípicos obtidos pelos marcadores morfológicos geraram um total de 15 grupos de acessos quando utilizados os 13 caracteres avaliados. A média do índice de sensibilidade a seca foi de 0...

Caracterização fisiologica e molecular da tolerancia a seca e sua relação com o sistema radicular em especies de Coffea; Physiological and molecular characterization of drought tolerance and its relation with the root system in Coffea species

Adriana Brombini dos Santos
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 04/08/2009 PT
Relevância na Pesquisa
66.61%
Plantas das cultivares Catuaí Vermelho e Mundo Novo de Coffea arabica L. e da cultivar Apoatã de C. canephora Pierre ex Froehner, e plantas de Mundo Novo enxertadas sobre Apoatã foram avaliadas quanto a possíveis estratégias utilizadas para suportar a baixa disponibilidade de água no solo. Em paralelo, foi conduzido um ensaio com suspensões celulares de Catuaí Vermelho sob estresse osmótico induzido por PEG. Assim, este estudo teve por objetivo examinar alguns mecanismos de tolerância à seca em café através da avaliação de aspectos morfológicos (sistema radicular), fisiológicos (ajuste osmótico) e moleculares (expressão de deidrinas e aquaporinas) em plantas jovens e cultura de células. A análise de expressão do gene CaDh1 (deidrina) em suspensão celular de café tratada com PEG (15% m/v), por 8, 24 e 72 h, mostrou aumento na atividade sob estresse osmótico, o que poderia estar associado a um possível mecanismo de proteção de membranas e macromoléculas contra a dessecação. Não foi verificada alteração na resposta dos genes PIP1, PIP2 e TIP1(aquaporinas) sob condição de estresse nas células de café. Plantas de café cultivadas em vasos (4,0 L) foram submetidas a estresse hídrico moderado por suspensão da irrigação...

Salicylic acid and drought tolerance improvement in Eucalyptus; Ácido salícilico e o aumento da tolerância à seca em Eucalyptus

Jesus, Cláudia Marisa de
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
ENG
Relevância na Pesquisa
56.65%
Covering approximately 20 million ha, Eucalyptus genus is the most widely planted hardwood trees all over the world. In the Mediterranean region, the positive performance of Eucalyptus plantations is conditioned by low water availability that strongly limits forest productivity and alters plant growth and development. Plant drought tolerance can be managed by adopting strategies such as exogenous application of hormones. Salicylic acid (SA) is a plant endogenous regulator of growth (PGR) that has been reported as a compound playing a key role in plants responses to drought. In this study, we investigated if the exogenous application of SA improves drought tolerance on E. globulus and how this treatment regulates plant response to stress. SA was applied by foliar application of 0.75, 2.5 and 5 mM solution of sodium salicylate three consecutive days before water-stress (WS) induction (plants daily watered at 15% field capacity). Additionally a well-watered group (WW, daily watered at 70%) was analysed, with the same SA pre-treatments. Control plants (WW and WS) were not treated with SA. The assessed morpho-physiological and biochemical traits were: water potential, lipid peroxidation, pigments content, total soluble sugars, phenols, Fv/Fm...

Genome-Wide Analysis of ZmDREB Genes and Their Association with Natural Variation in Drought Tolerance at Seedling Stage of Zea mays L

Liu, Shengxue; Wang, Xianglan; Wang, Hongwei; Xin, Haibo; Yang, Xiaohong; Yan, Jianbing; Li, Jiansheng; Tran, Lam-Son Phan; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko; Qin, Feng
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.8%
The worldwide production of maize (Zea mays L.) is frequently impacted by water scarcity and as a result, increased drought tolerance is a priority target in maize breeding programs. While DREB transcription factors have been demonstrated to play a central role in desiccation tolerance, whether or not natural sequence variations in these genes are associated with the phenotypic variability of this trait is largely unknown. In the present study, eighteen ZmDREB genes present in the maize B73 genome were cloned and systematically analyzed to determine their phylogenetic relationship, synteny with rice, maize and sorghum genomes; pattern of drought-responsive gene expression, and protein transactivation activity. Importantly, the association between the nucleic acid variation of each ZmDREB gene with drought tolerance was evaluated using a diverse population of maize consisting of 368 varieties from tropical and temperate regions. A significant association between the genetic variation of ZmDREB2.7 and drought tolerance at seedling stage was identified. Further analysis found that the DNA polymorphisms in the promoter region of ZmDREB2.7, but not the protein coding region itself, was associated with different levels of drought tolerance among maize varieties...

Drought and low N status limiting maize production in Brazil.

SANTOS, M.X.; LOPES, M.A.; COELHO, A.M.; GUIMARAES, P.E.O.; PARENTONI, S.N.; GAMA, E.E.G.; FRANCA, G.E.
Fonte: In: SYMPOSIUM OF DEVELOPPING DROUGHT AND LOW N-TOLERANCE MAIZE, 1996, El Batan, Mexico. Proceedings... El Batan: CIMMYT, 1997. p. 20-23. . Publicador: In: SYMPOSIUM OF DEVELOPPING DROUGHT AND LOW N-TOLERANCE MAIZE, 1996, El Batan, Mexico. Proceedings... El Batan: CIMMYT, 1997. p. 20-23. .
Tipo: Artigo em anais de congresso (ALICE)
EN
Relevância na Pesquisa
56.45%
The Brazilian territory has an area of approximately 8,5 million km2, which is divided into five main regions with particular characteristics related to average climitaic conditions and natural soil fertility. Climatic variations may be very accentuated within each particular region, but a common feature is the irregular distribution of rains, which causes droughts of variable intensities. Maize is an important crop in most Brazilian regions, occupying approximately 13 million ha and producing annually 28-30 million tons of grain. It has been estimated that drought problems, depending on year intensity, reduce maize production by 14% to 28%. Another limiting factor for maize production in Brazil is the low natural fertility of the soils, especially in nutrients like phosphorus and nitrogen (N). It has been estimated that 80% of the soils in Brazil are deficient in N. Although fertilization is a common solution to this problem, its high costs make this option inaccessible to many farmers. The amount of supplemental N applied to maize in Brazil is low (36 kg N/ha), and of this only 50% to 60% is utilized by the crop. Considering that low N availability and drought are severe constraints to maize crop in Brazil, the National Maize and Sorghum Research Center (CNPMS/EMBRAPA) has initiated breeding programs aimed at the development of germplasm that performs more efficienctly under these two limiting conditions. Several genotypes have been developed on the basis of anthesis-silking interval selection (...); 1997

Drought tolerance and antioxidant enzymatic activity in transgenic ?Swingle? citrumelo plants over-accumulating proline.

CAMPOS, M. K. F. de; CARVALHO, K. de; SOUZA, F. S. de; MARUR, C. J.; PEREIRA, L. F. P.; BESPALHOK FILHO, J. C.; VIEIRA, L. G. E.
Fonte: Environmental and Experimental Botany, v.72, n. 2, p. 242-250, 2011. Publicador: Environmental and Experimental Botany, v.72, n. 2, p. 242-250, 2011.
Tipo: Artigo em periódico indexado (ALICE)
EN
Relevância na Pesquisa
56.41%
In this study we investigated the effects of the high endogenous proline level on water relations, gas exchange and antioxidant enzymatic activity in leaves of transgenic ?Swingle? citrumelo rootstocks transformed with the P5CSF129A gene coding for the key-enzyme for proline synthesis, under water deficit. Leaf total water, osmotic and pressure potentials, stomatal conductance, photosynthetic rates and xylem sapflowwere evaluated in non-transformed control and transgenic plants during water deficit treatment. Malondialdehyde (MDA) content, catalase (CAT; EC 1.11.1.6), superoxide dismutase (SOD; EC 1.15.1.1) and ascorbate peroxidase (APX; EC 1.11.1.11) activities were quantified in leaves collected based on their total water potential, representing the following conditions: irrigated (w =−1.3 MPa), moderate stress (w =−2.3 to −2.5 MPa), severe stress (w =−3.8 to −3.9 MPa) and recovery (24 h after re-irrigation: w =−1.3 to −1.9 MPa). Osmotic adjustment was observed in transgenic plants until 11 days after withholding water, while pressure potential in non-transformed controls was close to zero after nine days of water deprivation. This superior maintenance of turgor pressure in leaves of transgenic plants led to higher stomatal conductance...

Drought tolerance phenotyping in crops under contrasting target environments: procedures and practices.

GOMIDE, R. L.; DURAES, F. O. M.; GUIMARÃES, C. M.; ANDRADE, C. de L. T.; ALBUQUERQUE, P. E. P.; BASTOS, E. A.; VIANA, J. H. M.; STONE, L. F.; MORAIS, O. P.; DEL PELOSO, M. J.; MAGALHAES, P. C.; MORGADO, L. B.; OLIVEIRA, A. C.
Fonte: In: MONNEVEUX, P.; RIBAUT, J.-M. (Ed.). Drought phenotyping in crops: from theory to practice. Mexico, DF: CGIAR: CIMMYT, 2011. Publicador: In: MONNEVEUX, P.; RIBAUT, J.-M. (Ed.). Drought phenotyping in crops: from theory to practice. Mexico, DF: CGIAR: CIMMYT, 2011.
Tipo: Capítulo em livro técnico-científico (ALICE) Formato: p. 51-91.
EN
Relevância na Pesquisa
56.69%
Introduction. Comparing target environment characteristics for drought tolerance phenotyping. Site selection criteria. Soil characteristics for establishment of a specific site area. Main steps for a specific site selection and establishment in the field. A specific site selection and establishment case study: Sete Lagoas (Minas Gerais), Janaúba (Minas Gerais) and Teresina (Piauí), Brazil. Procedures for monitoring and controlling water stress for drought tolerance phenotyping. Irrigation scheme selection. Conventional sprinkler system. Localised irrigation system. Linear moving system. Field calibration procedures for water application and distribution. Container setupe for conventional sprinkler and linear moving irrigation systems. Calculation of the uniformity of water distribution. Procedures for the evaluation of applied water depth and distribution. Irrigation water management. Soil moisture measurements on drought tolerance field trials. Crop water requirements in localised systems. Irrigation depth. Measurement of crop water stress. Pehnotyping cereals and legumes for drought tolerance. Structure, maintenance and management of a database and modelling for drought tolerance phenothyping.; 2011

Overexpression of the ABA-dependent AREB1 transcription Factor from Arabidopsis thaliana improves soybean tolerance to water deficit.

BARBOSA, E. G. G.; LEITE, J. P.; MARIN, S. R. R.; MARINHO, J. P.; CARVALHO, J. de F. C.; FUGANTI-PAGLIARINI, R.; FARIAS, J. R. B.; NEUMAIER, N.; MARCELINO-GUIMARÃES, F. C.; OLIVEIRA, M. C. N. de; YAMAGUCHI-SHINOZAKI, K.; NAKASHIMA, K.; MARUYAMA, K.; KANA
Fonte: Plant Molecular Biology Reporter, 2012. Publicador: Plant Molecular Biology Reporter, 2012.
Tipo: Artigo em periódico indexado (ALICE) Formato: 12 p.
EN
Relevância na Pesquisa
56.61%
Among current strategies for the development of drought-tolerant plants, engineering transcription factors that regulate the expression of genes related to abiotic stress is promising. Soybean plants overexpressing the transcription factor AtAREB1, which is involved in abscisic acid (ABA)-dependent stress responses, were generated using biolistics. Embryos of cultivar BR16, which is considered drought sensitive, were co-transformed with two plant expression vectors, 35S::AtAREB1 and 35S::ahas. Among the lines obtained, the drought tolerance of A24.10 and A2889.12 was assessed because these lines overexpressed the AtAREB1 gene and had a low copy number of the transgene. Another line, A2057.03, was also selected because it had a high copy number of the transgene (more than 100 copies) and low levels of transgene expression. Among the two low-copy lines, the A24.10 plants exhibited a slightly lower number of leaves and a shortening of the internode length; however, no growth retardation was observed for the line A2057.03. Water stress tolerance was particularly improved in the low-copy lines A24.10 and A2889.12. Plants of these lines were able to survive a water stress period of 5 days and exhibited no leaf damage, i.e., dried areas in the leaves 3 days after rewatering. Furthermore...

Evaluation of physiological traits and identification of QTLs for drought tolerance in hexaploid wheat (Triticum aestivum L.).

Izanloo, Ali
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2008
Relevância na Pesquisa
56.76%
This study comprised three major parts: a comparative physiological study of drought responses under controlled conditions; a genetic study to construct the skeleton map of a doubled haploid (DH) population; and a quantitative trait loci (QTL) analysis to identify QTLs associated with drought tolerance traits in the field. In the first part (Chapter 3), three cultivars of wheat (Triticum aestivum L.) adapted to South Australian conditions were tested for drought tolerance under cyclic drought in growth rooms and glasshouse. Extensive physiological traits, including stomatal conductance, chlorophyll content and fluorescence, ABA content, water status traits (e.g. osmotic adjustment, RWC and leaf water potential), water soluble carbohydrates (WSC) and carbon isotope discrimination (Δ¹ ³C) were measured during experiments. Through these experiments, the drought responses of the three cultivars were physiologically dissected and the likely processes contributing most to drought tolerance were identified. In the South Australian wheatbelt, cyclic drought is a frequent event, represented by intermittent periods of rainfall which can occur around anthesis and post-anthesis in wheat. Three South Australian bread wheat cultivars, Excalibur...

The potential contribution of wild barley (Hordeum vulgare ssp spontaneum) germplasm to drought tolerance of cultivated barley (H. vulgare ssp. vulgare)

Lakew, B.; Eglinton, J.; Henry, R.; Baum, M.; Grando, S.; Ceccarelli, S.
Fonte: Elsevier Science BV Publicador: Elsevier Science BV
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
Relevância na Pesquisa
56.63%
Improving drought tolerance has always been an important objective in many crop improvement programs and is becoming more important as one way of adapting crops to climate changes. However, due to its complexity, the genetic mechanisms underlying the expression of drought tolerance in plants are poorly understood and this trait is difficult to characterize and quantify. This study assessed the importance of the wild progenitor of cultivated barley, Hordeum spontaneum C. Koch, in contributing developmental and yield-related traits associated with drought tolerance and therefore its usefulness in breeding for improved adaptation to drought stress conditions. Fifty-seven fixed barley lines derived from crosses with two H. spontaneum lines (41-1 and 41-5) were evaluated in Mediterranean low rainfall environments with 10 improved varieties and three landraces for grain yield, developmental and agronomic traits. The study was conducted for three years (2004–2006) in a total of nine environments (location–year combinations), eight in Syria and one in Jordan, which were eventually reduced to seven due to a large error variance in two of them. There was significant genetic variation among the genotypes for most of the traits measured, as well as differential responses of genotypes across environments. Traits such as peduncle length...

SSR analysis of introgression of drought tolerance from the genome of Hordeum spontaneum into cultivated barley (Hordeum vulgare ssp vulgare)

Lakew, B.; Henry, R.; Eglinton, J.; Baum, M.; Ceccarelli, S.; Grando, S.
Fonte: Kluwer Academic Publ Publicador: Kluwer Academic Publ
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
Relevância na Pesquisa
56.53%
Wild barley (Hordeum vulgare ssp. spontaneum) and landraces are important sources of resistance to biotic and abiotic stresses since they possess wide genetic diversity that may be missing in current elite varieties. In this study, we evaluated a set of 57 barley introgression lines divided in groups depending on the expected levels of introgression (50, 25, and 12.5 %) from one Hordeum spontaneum accessions (Hsp 41-1) and on those (50 and 25 %) from a second (Hsp 41-5); in both cases the 25 % level was represented by two groups depending on the other parent. The two H. spontaneum accessions have been used as the best sources of drought tolerance in the ICARDA barley-breeding program. Graphical genotyping and genetic diversity analysis were used to examine the relative contribution of H. spontaneum and the extent of genetic differences among the 57 lines using 74 microsatellite markers that cover 941 cM of the barley genome. The average proportion of the genome containing H. spontaneum alleles in each group was of 44.5 %, group 1; 24.6 %, group 2; 21.6 %, group 3; 45.4 %, group 4; 19 %, group 5; 15.5 %, group 6 and 11.4 %, group 7. Introgression lines in group 1 and 4, with the highest observed introgression with Hsp 41-1 and Hsp 41-5...

Genetic analysis and phenotypic associations for drought tolerance in Hordeum spontaneum introgression lines using SSR and SNP markers

Lakew, B.; Henry, R.; Ceccarelli, S.; Grando, S.; Eglinton, J.; Baum, M.
Fonte: Kluwer Academic Publ Publicador: Kluwer Academic Publ
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
Relevância na Pesquisa
56.55%
Associations between markers and drought related traits were investigated on a set of 57 advanced barley breeding lines, carrying various levels of introgression from Hordeum spontaneum lines 41-1 and 41-5, the best sources of drought tolerance in the ICARDA barley breeding program, using 74 simple sequences repeats (SSR) and 20 single nucleotide polymorphism markers. The 57 lines were evaluated for grain yield and drought related traits for three years (2003/04, 2004/05, 2005/06) in nine Mediterranean low rainfall environments. A high level of polymorphism was found with SSR markers, and the mean polymorphism information content and gene diversity values were 0.67 and 0.71, respectively. The number of alleles per locus varied from 2 to 11, with an average of 5.8 alleles per marker. Considering all the 57 lines, the linkage disequilibrium (LD) analysis was significant at a comparison-wise P < 0.01 level in nearly 9 % of the SSR marker pairs used and a decay of LD was observed to a value of r 2 < 0.2 at a genetic distance of 40 cM. The association analysis revealed a total of 147 significant marker–trait associations for grain yield and drought related traits. A total of 72 (49 %) marker–trait associations showed favorable effects of the exotic germplasm where the H. spontaneum lines contributed to an improvement of the trait under drought stress conditions. The number of significant marker–trait associations per trait were: 12 for growth habit; 2 for growth vigor; 11 for peduncle extrusion; 5 for number of grains per spike; 20 for peduncle length; 16 for days to heading; 20 for plant height; 8 for spike length; 17 for thousand kernel weight; 30 for grain yield; 4 for harvest index and 2 for biological yield. The phenotypic variation explained by individual marker–trait associations ranged from 7.6 % to 36.2 %. The identification of genomic regions associated with grain yield and drought related traits is useful for the genetic improvement of cultivars better adapted to drought stress environments. Thus...

Evaluation of juvenile drought stress tolerance and genotyping by sequencing with wild barley introgression lines

Honsdorf, N.; March, T.J.; Hecht, A.; Eglinton, J.; Pillen, K.
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
Publicado em //2014 EN
Relevância na Pesquisa
56.71%
Drought is a major stress which can seriously limit yield in many crops including barley. Wild barley introgression lines (ILs) like the S42IL library may enhance drought stress tolerance of barley cultivars through the introduction of exotic alleles. The S42IL library was already characterized with 636 Illumina SNPs. New approaches like genotyping by sequencing (GBS) are available for barley to enhance the characterization of ILs. We generated an improved genetic map of the S42IL library, consisting of 4,201 SNPs by adding GBS data. The new map with a total length of 989.2 cM confirmed the extent of wild barley introgressions. Adding GBS data increased the resolution of the S42IL map tenfold from 0.4 to 4.2 markers/cM. This may assist to select possible candidate genes that improve drought tolerance. In four greenhouse experiments, juvenile drought stress response of 52 barley S42ILs was tested to identify quantitative trait loci (QTL). Thirteen S42ILs showed effects for plant biomass and leaf senescence. Subsequently, two verification experiments were conducted with these S42ILs. Nine out of eleven QTL were verified, and 22 additional QTL were detected. For 21 QTL, the Hsp allele increased trait performance, indicating the value of wild barley introgressions. For example...

The TaDREB3 transgene transferred by conventional crossings to different genetic backgrounds of bread wheat improves drought tolerance

Shavrukov, Y.; Baho, M.; Lopato, S.; Langridge, P.
Fonte: Wiley Publicador: Wiley
Tipo: Artigo de Revista Científica
Publicado em //2015 EN
Relevância na Pesquisa
56.61%
Drought tolerance of the wheat cultivar Bobwhite was previously enhanced by transformation with a construct containing the wheat DREB3 gene driven by the stress-inducible maize Rab17 promoter. Progeny of a single T2 transgenic line were used as pollinators in crosses with four elite bread wheat cultivars from Western Australia: Bonnie Rock, IGW-2971, Magenta and Wyalkatchem, with the aim of evaluating transgene performance in different genetic backgrounds. The selected pollinator line, BW8-9-10-3, contained multiple transgene copies, had significantly improved drought tolerance compared with wild-type plants and showed no growth and development penalties or abnormalities. A single hybrid plant was selected from each cross-combination for three rounds of backcrossing with the corresponding maternal wheat cultivar. The transgene was detected in all four F1 BC3 combinations, but stress-inducible transgene expression was found in only three of the four combinations. Under well-watered conditions, the phenotypes and grain yield components of the F2 BC3 transgene-expressing lines were similar to those of corresponding recurrent parents and null-segregants. Under severe drought conditions, the backcross lines demonstrated 12-18% higher survival rates than the corresponding control plants. Two from four F3 BC3 transgenic lines showed significantly higher yield (18.9% and 21.5%) than control plants under limited water conditions. There was no induction of transgene expression under cold stress...

Técnicas de interés en la mejora de cebadas tolerantes a la sequía y temperaturas elevadas. I. Estabilidad de las membranas celulares; Interesting techniques in barley breeding for drought and high temperature tolerance. I. Cell membranes stability.

González, Águeda
Fonte: Servicio de Publicaciones - Universidad de Murcia Publicador: Servicio de Publicaciones - Universidad de Murcia
Tipo: Artigo de Revista Científica Formato: application/pdf
SPA
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La sequía al final del ciclo del cultivo de la cebada es frecuente en la mayoría de las regiones españolas por lo que conseguir variedades mejor adaptadas a la disponibilidad de agua del cultivo es importante, tanto en programas de mejora tradicional como en sistema de cultivo ecológico. La estabilidad de las membranas celulares es uno de los índices de selección de tolerancia a la sequía más importante utilizados en cereales. Para ver la variabilidad de este carácter se utilizaron catorce genotipos de cebada cultivados en el campo, sometiendo las muestras de hoja a distintos tratamientos de temperatura y distintas concentraciones de PEG. Se ha observado que la diferencia entre genotipos es muy significativa (p<0,001) y que la temperatura de 51ºC y concentraciones de PEG del 40% (p/v) son las más adecuadas para los materiales estudiados. Con estos tratamientos se obtienen la mejor separación entre genotipos con menor porcentaje de daño causado a los tejidos.; Abstract: In most areas of Spain, drought at the end of the barley growth cycle is common. The production of varieties better adapted to the reduced amount of water available at this time is therefore important; this is true for both traditional and ecological agricultural systems. The stability of the cell membrane is one of the most important selection indices for drought tolerance in cereals. The variability in this trait was examined in 14 barley genotypes...

Análise do papel do microtranscritoma na tolerância à seca em cana-de-açúcar : Analysis of sugarcane microtranscritome in drought tolerance; Analysis of sugarcane microtranscritome in drought tolerance

Lara Isys Dias
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 22/06/2015 PT
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A cana-de-açúcar (Saccharum spp.) é a cultura mais promissora para a obtenção de energia renovável, tendo sua produção movida pelo setor sucroenergético. O Brasil é o maior produtor mundial e os cultivares atualmente utilizados são híbridos interespecíficos aneuplóides, resultado do melhoramento genético clássico. As espécies selvagens que deram origem a esses cultivares, Saccharum officinarum e Saccharum spontaneum, possuem características importantes para a produção como alto teor de sacarose e resistência à doenças e estresse abióticos, respectivamente. Contudo, as perdas de produtividade são frequentes nas regiões produtoras. A regulação gênica mediada por microRNAs pode estar relacionada a mecanismos de tolerância a estresses abióticos. Os microRNAs são sequências de RNA de 19-24 nucleotídeos. Esses pequenos RNAs (sRNAs) atuam no silenciamento gênico através da clivagem ou repressão da tradução de genes alvos, por similaridade quase perfeita de suas sequências. Neste trabalho foi realizada a análise do microtranscritoma de plantas de cana-de-açúcar com 11 meses, cultivadas em campo sob regimes de irrigação (controle) ou sequeiro (estressado). Amostras de sRNAs folhas de quatro cultivares foram sequenciadas (RB867515...

Barley populations for drought tolerance

Lasa Dolhagaray, José Manuel; Pavón Freire, Alberto; Medina del Río, Blanca
Fonte: CSIC - Estación Experimental de Aula Dei (EEAD) Publicador: CSIC - Estación Experimental de Aula Dei (EEAD)
Tipo: Artículo Formato: 304150 bytes; application/pdf
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[EN] After evaluation under drought conditions of S1 progenies from four different Composite Crosses, CC XXXIX developed in US for one irrigation culture regime, and CRC-1 developed in Spain for drought tolerance, were selected to be used as a bridge for the introduction and recombination of local adapted old cultivars, and to undergo recurrent selection processes. Both populations showed acceptable drought tolerance, and high within population variability for most of the traits studied. Visual scores on tillering at stem elongation, and biomass at spike emergence offer good opportunities as indirect indicators of yield.; [ES} Tras la evaluación en condiciones de sequía de familias S1 procedentes de cuatro Cruzamientos Compuestos de cebada, las poblaciones CC XXXIX desarrollada en USA para condiciones de un único aporte de agua, y CRC-1 desarrollada en España para tolerancia a sequía, han sido seleccionadas para su utilización como puente en la introducción y recombinación de antiguos cultivares locales, y su posterior manejo mediante selección recurrente. Ambas poblaciones muestran un aceptable nivel de tolerancia a sequía y elevada variabilidad intrapoblacional para la mayor parte de los caracteres estudiados. Las estimaciones visuales de ahijamiento en fase de elongación...