Search

Understanding the response of species to climate change and their ability to adapt is the key to describe the future development of plant communities. The aim of the study is to determinate intraspecific variability in germination of Festuca rubra from different original climates in response to novel climatic regimes. This study also observes if different climatic regimes lead to selection of different genotypes. Festuca rubra is a widespread clonal grass occurring in the Northern hemisphere. The plant material comes from 11 localities distributed along a climatic grid of factorially crossed temperature and precipitation situated in western Norway. The project was carried out in growth chambers, where the germination of seeds was monitored in two different temperature conditions and in two moisture treatments. Germinated seeds were planted into pots remaining in the same treatment where they germinated. Seedlings from one Petri dish grew together in one pot. One population, from the coldest and the driest original locality, growing in the warm-wet and cold-wet treatments was genetically analysed using microsatellites. Germination of the species was higher and faster in warm than in cold conditions, showing that germination of the species is enhanced by higher temperature. Germination was higher in...

Needed of wheat in Indonesia that increasing every year, indirectly forcing to improve development cultivation of wheat. By developing wheat crop that able to adapt in abiotic stresses such as high temperatures and dry land may be one of way out of from limited land. Purpose of study: determine dynamics of growth and yield of some wheat genotypes adapted to tropical lowlands, as well as selection of genotypes adapted to do that will be candidate varieties based on phenotypic appearance. Research done by planting ten genotypes of wheat which have been adapted year ago. Experiment was conducted in Telogoweru village, Guntur, Demak with altitude 20 meters above sea level in July until October 2013. Next research is selection process of genotypes based on best performance from planting F2 seed. Concluded: decrease in crops height in process of adaptation from elders, F1 and F2 and character of number of tillers seen an increase in adaptation process. Yield potential results also showed a decrease in 1000 grain weight and number of seeds per panicle in process of adaptation from elders, F1 and F2 but for yield per hectare, genotype LAJ3302, ALTAR, SELAYAR and OASIS able to show an increase. Selection process showed that genotype LAJ3302, ALTAR, SELAYAR, OASIS, and HP1744 BASRIBEY are genotype that can be used as candidate varieties that resistant high temperatures and drought stress

Selection of disease resistant genotypes is the main goal of wheat (Triticum aestivum L.) breeding programs. However, because of the lack of genotypes resistant to all diseases and the strong influence of the environment on the level of resistance of the genotypes, the use of fungicides is necessary in the cultivation of wheat. The objective of this study was to compare the gain in yield and the selection efficiency of wheat genotypes due to the fungicide application in trials carried out in different sites and years. This study used grain yield data from 816 wheat genotypes evaluated in 248 advanced trials at eight sites during the years from 2004 to 2012. The gain resulting from fungicide application for a given genotype was estimated by the difference between yield of plots on which fungicide was applied and control treatment. The greatest gains with fungicide application were observed in sites with lower average temperatures and higher rainfall indices, such as Campo Mourão, Castro, Não-Me-Toque and Guarapuava. On the other hand, the lowest gains with fungicide application occurred in Dourados and Palotina, environments where crops in general suffer water stress and present higher average temperatures. The year effect resulted in yield increases due to fungicide application ranging from 16.9 to 60.7%. The selection and evaluation of the response to the application of fungicide in wheat should be environment-specific to maximize the use of genotype x environment interaction. RESUMO A seleção de genótipos resistentes a doenças é uma meta prioritária dos programas de melhoramento genético de trigo (Triticum aestivum L.). Mas, devido não existir genótipos resistentes à todas as doenças e a forte influência do ambiente no nível de resistência dos genótipos, o uso de fungicidas é necessário no cultivo do trigo. O objetivo deste estudo foi comparar o ganho em produtividade e a eficiência da seleção de genótipos de trigo devido à aplicação de fungicida em ensaios realizados em diferentes locais e anos de cultivo. Foram utilizados dados de produtividade de grãos de 816 genótipos de trigo avaliados em 248 ensaios de competição, em oito locais, nas safras agrícolas de 2004 a 2012. O ganho com a aplicação de fungicida para um dado genótipo foi estimado pela diferença entre a produtividade das parcelas que receberam fungicida e o tratamento controle. Os maiores ganhos com a aplicação de fungicida foram observados em locais que apresentam menores temperaturas médias e maiores indíces pluviométricos, tais como Campo Mourão, Castro, Não-Me-Toque e Guarapuava. Já os menores ganhos com a aplicação de fungicidas ocorreram em Dourados e Palotina, ambientes que geralmente impõem estresses hídricos a cultura e que possuem temperaturas médias mais elevadas. O efeito de anos de cultivo resultou em incrementos de produtividade devido a aplicação de fungicida que variaram de 16,9 a 60,7%. A seleção e a avaliação da resposta à aplicação de fungicida em trigo deve ser ambiente-específica, buscando maximizar o aproveitamento da interação genótipo x ambiente.

Given its high biomass and plasticity, Arundo donax L. is a promising ligno-cellulosic crop for cultivation in marginal lands in temperate climates. In order to test for adaptation to salinity, growth parameters of several A. donax clones were evaluated under two salt regimes in hydroponics. Mild NaCl stress (50 mM NaCl, 5.6 mS cm−1 EC, for 10 days) failed to discriminate between ecotypes, while a more severe NaCl treatment (150 mM, 18.8 mS cm−1 EC, for 21 days) enabled the identification of ecotypes maintaining plant growth under high salinity. Among several biometric parameters, 4th leaf width, and shoot and root DW consistently highlighted differences between ecotypes. Gas-exchange parameters also responded to severe NaCl treatment, while the photosystem efficiency was good, regardless of treatment. The results confirm that A. donax can be considered moderately tolerant to NaCl stress, with variation between ecotypes. Our screening protocol identified ecotypes with higher biomass production under severe NaCl treatment and can be useful for preliminary evaluation of NaCl tolerant clones for increasing productivity under salinity. The detected inter-ecotype variability could also be investigated to identify suitable clones for different environments.

Avaliou-se o grau de resistência de 36 clones de maracujazeiro obtidos por seleção massal de sete progênies de híbridos interespecíficos a três isolados de Xanthomonas axonopodis pv. passiflorae. As progênies foram obtidas por meio de cruzamentos entre a cultivar comercial Passiflora edulis "flavicarpa" com as espécies silvestres P. caerulea, P. edulis "roxo" e P. setacea. Os isolados da bactéria foram obtidos em Rio Claro-SP, Planaltina-DF e Limeira-SP. Clones individuais foram inoculados com solução bacteriana na concentração de 108ufc ml-1 aos 120 dias da semeadura. As avaliações ocorreram aos 5, 10 e 15 dias após a inoculação, medindo-se o diâmetro longitudinal e transversal das lesões. Em seguida, calculou-se a área abaixo da curva de progresso da lesão (AACPL). O delineamento experimental foi em blocos ao acaso com parcelas subdivididas, sendo os genótipos os tratamentos distribuídos em quatro blocos com parcelas de três plantas para cada genótipo. Em cada parcela, plantas individuais foram inoculadas com um dos isolados da bactéria, totalizando três plantas com isolados diferentes. Plantas das espécies genitoras P. caerulea (AACPL=0,17) e P. setacea (AACPL=14,50) apresentaram alto grau de resistência, quando comparadas às plantas da testemunha BRS Gigante Amarelo (AACPL=4089,25), enquanto genótipos híbridos apresentaram valores intermediários (AACPL de 15,67 a 768,42), indicando a importância desses materiais como fontes de resistência à bacteriose. The aim of this study was to evaluated the degree of resistance of 36 clones of passion obtained through mass selection progenies of seven interspecific hybrids, to three different isolates of X. axonopodis pv. passiflorae. The progenies were obtained by crossing among a commercial cultivate Passiflora edulis "yellow passion fruit" with wild species P. caerulea, P. edulis "purple passion fruit" and P. setacea. The bacterial isolates used were obtained in Rio Claro,SP, Planaltina,DF and Limeira,SP. Individual cloned were inoculated with bacterial solution in concentration with 108cfu ml-1 to 120 days of sowing. Symptoms were evaluated at 5, 10 and 15 days after inoculation, by measuring the longitudinal and transverse diameter of the lesion. Then, it was calculated the area under the lesion progress curve (AUPLC). A complete randomized block design with split plots was used, the treatments were the tested genotypes replicated in four blocks. All genotypes in each block had a three-plant plot. The bacterial isolates were inoculated in one plant of the plot, totaling three plants with different isolates. The plants of the genitors species P. caerulea (AUPLC=0.17) and P. setacea (AUPLC=14.50) presented high degree of resistance when compared to control plants BRS 'Gigante Amarelo' (AUPLC=4089.25), while hybrids genotypes presented intermediary values (AUPLC of 15.67 the 768.42), showing the importance of these wild Passiflora species as source of resistance to bacterial disease.

Bread wheat (Triticum aestivum L.) is one of the most important cereals worldwide and is being grown in many areas of the world. However, there is a lack of information about using the proper stress index to determine the tolerance of wheat cultivars to water stress. A two-year field study was conducted with the objective of determining the effect of different rates of nitrogen (N) (control, 80 kg N/ha, and 160 kg N/ha) and two irrigation treatments (non stressed and post anthesis water stressed) on three bread wheat cultivars. Water deficit markedly affected grain yield, straw yield, and harvest index. Under water deficit grain yield was reduced by 58%, showing that wheat cultivars were sensitive to drought stress. Tolerance (TOL) index was lower under water deficit than well watered (WW) conditions in both years. Stress Tolerance Index (STI), Mean Productivity (MP), and TOL indices were efficient in evaluating the sensitivity to drought stress. Grain yield under stress condition showed positive correlation with STI, MP and TOL indices. Water use efficiency and irrigation water use efficiency increased with increasing the N rates in WW treatment but decreased in WD treatment. In general, for the most efficient use on both N and water, the supply of one should be adjusted to that of the other. If irrigation is for maximum yields, fertilization should be too; but if irrigation is limited, the fertilizer supply should be adjusted accordingly to prevent N loss and pollution of the environment

Very little is known about JCV infection and genotype distribution with respect to the different demographic and clinical characteristics of the Italian population. A cross-sectional study was carried out on the prevalence of JCV genotypes in 323 Caucasian subjects (mean age: 37.5 years, range: 2-70 years). Urine samples from 200 immunocompromised patients, including patients affected by Multiple Sclerosis (MS), Human Immunodeficiency Virus (HIV), colon cancer, inflammatory diseases and Progressive Multifocal Leukoencephalopathy (PML), and 123 immunocompetent individuals were tested by quantitative real time PCR. Sequencing of the JCV viral protein 1 (VP1) and transcriptional control region (TCR) was performed. In this series, the overall prevalence of JCV excretion was 32.8% without significant differences between males and females. JCV was detected in 39.5% of patients and in 22% of healthy individuals (P = 0.004). The most prevalent JCV genotype excreted was genotype 1 (69.8%), followed by genotype 2 (22.6%) and genotype 4 (7.5%). Distribution of genotypes between patients and healthy subjects showed a statistically significant difference for the type 1 compared to the other variants (P

The objective of this work was to assess, during six years, the temporal stability of natural rubber yield of 25 superior Hevea brasiliensis genotypes, using the Wricke, Eberhart & Russell, Lin & Binns, additive main effect and multiplicative interaction (AMMI) analysis, and harmonic mean of the relative performance of the genetic values (HMRPGV) methods. The IAC 40 and IAC 300 genotypes were identified as stable and high yielding by the Eberhart & Russell, Lin & Binns, HMRPGV, and AMMI Biplot methods. The ranking of the other more stable genotypes identified by these analyses was altered. The observed results in the AMMI Biplot agreed with those observed in the Wricke method for identifying stable, but lower yielding genotypes. The simultaneous use of different methods allows a more accurate indication of stable genotypes. Stability analyses based on different principles show agreement in indicating stable genotypes. O objetivo deste trabalho foi avaliar, durante seis anos, a estabilidade temporal da produção de borracha natural de 25 genótipos superiores de Hevea brasiliensis, utilizando os métodos de Wricke, Eberhart & Russell, Lin & Binns, análise dos efeitos aditivos principais e interação multiplicativa (AMMI) e média harmônica da performance relativa dos valores genéticos (MHPRV). Os genótipos IAC 40 e IAC 300 foram identificados como estáveis e produtivos, pelos métodos de Eberhart & Russell, Lin & Binns, MHPRV e Biplot AMMI. Houve alteração no ordenamento dos demais genótipos mais estáveis identificados a partir dessas análises. Os resultados observados no Biplot AMMI mostraram concordância com os observados no método de Wricke para a identificação de genótipos estáveis, mas menos produtivos. A utilização simultânea de diferentes métodos permite a indicação mais precisa de genótipos estáveis. Análises de estabilidade baseadas em diferentes princípios mostram concordância na indicação de genótipos estáveis.

Na agricultura atual, o método mais utilizado para o controle de plantas daninhas é o químico, em razão da facilidade de uso, elevada eficiência e baixa necessidade de mão de obra. No entanto, a utilização inadequada desses produtos provoca problemas ao ambiente e à saúde humana. Cresce, portanto, a busca por métodos alternativos de controle de plantas daninhas, menos demandadores de energia e menos tóxicos e agressivos ao ambiente. Este trabalho objetivou avaliar o efeito alelopático da cultura do girassol (Helianthus annuus) sobre diferentes espécies de plantas daninhas e cultivadas, em dois experimentos realizados em delineamento experimental completamente casualizado, utilizando o método da semeadura em substituição. O primeiro experimento foi realizado com quatro repetições, em esquema bifatorial. O primeiro fator foi constituído por seis espécies indicadoras: picão-preto (Bidens pilosa), corda-de-viola (Ipomoea grandifolia), caruru (Amaranthus hybridus), alface (Lactuca sativa, cultivar Aurélia), tomate (Lycopersicon esculentum, cultivar Santa Cruz), trigo (Triticum aestivum, cultivar BRS 208); e o segundo, pela presença ou não de plântulas de girassol. O segundo experimento foi composto por 24 tratamentos, representados por 23 genótipos de girassol e por uma testemunha sem girassol, utilizando-se quatro repetições. A espécie indicadora foi apenas o picão-preto. Em ambos os experimentos, no final do período de sete dias de convívio, foram avaliados o número de sementes germinadas e o comprimento radicular e da parte aérea das espécies indicadoras. Não foram observadas diferenças entre as porcentagens de germinação de quaisquer das espécies indicadoras avaliadas, em função da presença ou não das plântulas de girassol. A presença de plântulas de girassol estimulou o crescimento radicular das plântulas de tomate e trigo e inibiu o crescimento da parte aérea de picão-preto, trigo e corda-de-viola. Houve grande variabilidade de potencial alelopático entre genótipos de girassol sobre a germinação e o crescimento radicular e da parte aérea de Bidens pilosa. Os resultados demonstram que a técnica da semeadura em substituição é adequada para detectar efeitos estimulativos ou inibitórios de girassol sobre espécies indicadoras e para discriminar genótipos de girassol quanto à habilidade em inibir ou estimular plântulas de Bidens pilosa. In modern agriculture, the chemical method is the most used for weed control because it is highly efficient, easy to apply, and demands limited labor. However, the inadequate use of chemical products can lead to environmental and human health problems. Thus, there is a growing need to search for alternative weed control methods using substances which are less energy-demanding, less toxic and less aggressive to the environment. This work aimed to evaluate the allelopathic potential of sunflower (Helianthus annuus) culture on different weed and cultivated species, in two experiments conducted in a completely randomized design, using the relay seeding technique. The first experiment was carried out with four repetitions, in a bi-factorial scheme. The first factor was constituted by six indicative target species: beggarticks (Bidens spp.), common morninglory (Ipomoea grandifolia), pigweed (Amaranthus hybridus), lettuce (Lactuca sativa, cv. Aurélia), tomato (Solanum lycopersicum, cv. Santa Cruz), and wheat (Triticum aestivum, cv. BRS 208).The second factor was constituted by the presence or absence of sunflower seedlings. The relay seeding technique was applied. The second experiment was composed by 24 treatments including 23 sunflower genotypes and a control without sunflower, with four repetitions. The indicative species was only the beggarticks. In both experiments, at the end of seven coexistence days, number of germinated seeds, and root and aerial part length of the target species were evaluated. No difference was observed among the germination percentages of the indicative species evaluated in the presence or absence of the sunflower plants. The presence of the sunflower plants stimulated tomato and wheat root growth and inhibited the growth of the beggartick, wheat and common morninglory aerial parts. There was great variability of the potential allelopathic effect of the sunflower genotypes on germination and root and aerial part length of Bidens pilosa. The results show that the relay seeding technique is adapted to discriminate stimulating and inhibiting effects of sunflower among indicative species and to discriminate sunflower genotypes in their ability to inhibit or stimulate Bidens pilosa plants.

International audience; The Cydia pomonella granulovirus (CpGV) has been used for many years as biological agent for codling moth control in apple orchards. Resistance to the Mexican strain of CpGV was detected in orchards in Germany, France and Italy. A laboratory insect colony was started from insects collected in a French resistant orchard. It was named RGV. Various virus isolates were identified as active against this resistant insect colony. Field tests were carried out in 2007 to test if the two virus isolates CpGV-I12 and NPP-R1 were effective in the field. Although these virus isolates were not able to reduce insect caused fruit damages, they significantly reduced the overwintering insect populations. NPP-R1 was subjected to eight passages on RGV larvae (NPP-R1.8) that improved its biological activity on RGV larvae. 2008 field trials were set up to test this improved virus strain, compared to CpGV-I12 and Madex plus active on RGV. These tests confirmed the ability to control both in susceptible and resistant insect populations.

High land productivity is a must for any commercial cultivation including Hevea brasiliensis (rubber). Also, the high demand for natural rubber has placed great pressure on expanding rubber cultivation to new and non-traditional areas. Understanding the ecophysiological principles behind the measures of productivity improvements is vital for wide application of these measures and to assess their sustainability. This review discusses the ecophysiological principles and tools used, along with the measures taken, to address productivity needs in terms of: genotype selection, determination of optimum planting density, and establishment of intercropping systems. Breeding for high yields and selection of suitable genotypes for different growing conditions are a top priority throughout the research history of rubber, however, early selection tools are necessary to reduce the time required for this process. As for any crop, photosynthesis drives the productivity of the rubber crop and, therefore, factors that govern and/or parameters that indicate the efficiency of photosynthetic productivity under field conditions could be used as tools in the selection of Hevea genotypes. Particularly for the early selection of genotypes in breeding programmes, mature crop characteristics which determine crop photosynthesis and productivity, should be linked to juvenile plant characteristics. The spatial and temporal efficiency by which plants acquire growth resources determines the overall productivity of the rubber crop, hence the optimum planting density and suitable crop combinations in intercropping systems. Changes in crop microclimate influence the efficiency of resource capture and thereby can be important for determining planting density and intercrops. Research needs regarding all the above aspects are also discussed. Para qualquer cultivo comercial, incluindo Hevea brasiliensis (seringueira), alta produtividade é um mister a ser perseguido Ademais, alta demanda por borracha natural tem exercido grande pressão para a expansão do cultivo de seringa para novas áreas não-tradicionais. Nesta revisão, são discutidos os princípios ecofisiológicos e ferramentas usadas, bem como as medidas a serem tomadas, para direcionar o aumento da produtividade, em termos de seleção de genótipos, determinação da densidade ótima de plantio e estabelecimento de sistemas de consorciação. Melhoramento para altos rendimentos e seleção de genótipos adequados para diferentes condições de cultivo tem sido uma prioridade constante ao longo da historia de pesquisas sobre seringueira; todavia, ferramentas para a seleção precoce são necessárias são para reduzir-se o tempo requerido para esse processo. Como em qualquer cultura, a fotossíntese governa a produtividade da seringueira e, portanto, fatores ou parâmetros associados, ou que indicam, a eficiência da produtividade fotossintética sob condições de campo podem ser usados como ferramentas na seleção de genótipos de Hevea. Particularmente, para a seleção precoce de genótipos em programas de melhoramento, as características da planta adulta, que determinam a fotossíntese e a produtividade da cultura, devem ser associadas com as características da planta na fase juvenil. A eficiência temporal e espacial pelas quais as plantas adquirem recursos necessários ao crescimento determina a produtividade global da cultura da seringueira e, portanto, a densidade de plantio ótima e as combinações adequadas de culturas em sistemas de consorciação. Alterações no microclima da cultura influenciam a eficiência de captura de recursos e, assim, podem ser importantes para determinar a densidade de plantio e as espécies envolvidas na consorciação. Necessidades de pesquisa no que tange aos aspectos supramencionados são também discutidos.

RESUMO Entre as espécies indicadas para a restauração da vegetação arbórea em sítios degradados no sul de Minas Gerais, destaca-se a candeia (Eremanthus erythropappus (DC.) MacLeish), que ocorre naturalmente em solos pobres e pedregosos, além de possuir atributos relativos à durabilidade natural da madeira e à qualidade de óleo essencial para uso na farmacologia. O sucesso da recuperação dessas áreas está relacionado com a rapidez com que a vegetação é restabelecida. Assim, a busca de genótipos superiores e adaptados, que possam rapidamente recolonizar a área, é de grande importância econômica e ambiental. Neste estudo, foram coletadas sementes de polinização livre de 27 matrizes em duas populações de candeia distintas, São Tomé das Letras e Carrancas, localizadas no Estado de Minas Gerais. Após a germinação, as mudas foram repicadas para tubetes e arranjadas em blocos casualizados completos, com três repetições. Três meses após a repicagem, foi avaliada a variação entre e dentro das populações. Verificou-se, pela análise de variância, que existem diferenças significativas entre e dentro de populações para o caráter diâmetro do caule. As variações entre as progênies foram significativas dentro da população de São Tomé das Letras para o diâmetro, e, dentro da população de Carrancas, para o caráter altura total das mudas. Porém, para a seleção de genótipos, é necessário maior tempo de avaliação, visto que grande parte da variação apresentada na fase de mudas pode ser decorrente do efeito materno, o qual não é transmitido para a geração seguinte. ABSTRACT Among the suitable species for restoration of arboreal vegetation in degraded lands in the south of Minas Gerais, candeia trees (Eremanthus erythropappus (DC.) MacLeish) stand out because they occur and regenerate naturally in stony and poor sites. Besides, they have good attributes related to the natural durability of wood and the quality of essential oil for use in pharmacology. The success of restoration is related to the speed with which the vegetation is reestablished. Hence, the search for superior and adapted genotypes, which are able to colonize the area quickly, is of great economical and environmental importance. Open-pollinated seeds were collected from 27 mother trees in two distinct populations: São Tomé das Letras and Carrancas, Minas Gerais state, Brazil. The germinated plantlets were arranged in a randomized block design with three replications containing seedling from the 27 open-pollinated progenies. After three months of seedling grown in containers, the genetic variation among and within seed populations was evaluated. The analyses of variance showed that there were significant differences among and within populations in stem diameter. Within São Tomé das Letras population, the variation among progenies was significant in diameter and, within Carrancas population, only in seedling height the variation was significant. However, a longer term of evaluation is required for the sake of genotype selection of candeia, since a large extent of the manifested variation in seedlings stage might be due to inheritance of maternal influences that will not be transmitted for the following generations.