Letteratura scientifica selezionata sul tema "Raphanus raphanistrum L"

We evaluated the systematic relationship of the two sections of Raphanus (Brassicaceae) on the basis of morphological and ITS data. We obtained strong support that Raphanus is a polyphyletic group embedded in the Oleracea lineage of the tribe Brassiceae. Section Raphanis, which includes Raphanus raphanistrum, R. pugioniformis and R. sativus, is a strongly supported monophyletic lineage. Section Hesperidopsis is embedded in a different lineage together with Brassica deflexa and B. aucheri. We propose to reinstate the genus Quidproquo in place of Raphanus sect. Hesperidopsis as reflected by both morphological data and ITS phylogeny.

AbstractHarvest weed seed control (HWSC) is a weed management technique that intercepts and destroys weed seeds before they replenish the soil weed seedbank and can be used to control herbicide-resistant weeds in global cropping systems. Wild radish (Raphanus raphanistrum L.) is a problematic, globally distributed weed species that is considered highly susceptible to HWSC, as it retains much of its seed on the plant during grain harvest. However, previous studies have demonstrated that R. raphanistrum is capable of adapting its life cycle, in particular its flowering time, to allow individuals more time to mature and potentially shed seeds before harvest, thereby evading HWSC interception. This study compared the vegetative growth plus physiological and ecological fitness of an early-flowering R. raphanistrum biotype with an unselected genetically related biotype to determine whether physiological costs of early flowering exist when in competition with wheat (Triticum aestivum L.). Early flowering time adaptation in R. raphanistrum did not change the relative growth rate or competitive ability of R. raphanistrum. However, the height of first flower was reduced in the early flowering time–selected population, indicating that this population would retain more pods below the typical harvest cutting height (15 cm) used in HWSC. The presence of wheat competition (160 to 200 plants m−2) increased flowering height in the early flowering time–selected population, which would likely increase the susceptibility of early-flowering R. raphanistrum plants to HWSC. Overall, early-flowering adaption in R. raphanistrum is a possible strategy to escape being captured by the HWSC; however, increasing crop competition is likely to be an effective strategy to maintain the effectiveness of HWSC.

AbstractWild radish (Raphanus raphanistrum L.) is a problematic and economically damaging dicotyledonous weed infesting crops in many regions of the world. Resistance to the auxinic herbicides 2,4-D and dicamba is widespread in Western Australian R. raphanistrum populations, with the resistance mechanism appearing to involve alterations in the physiological response to synthetic auxins and in plant defense. This study aimed to determine whether these alterations cause inhibition in plant growth or reproduction that could potentially be exploited to manage 2,4-D–resistant populations in cropping areas. Therefore, the morphology and seed production of resistant and susceptible populations were compared in an outdoor pot study, with plants grown in the presence and absence of competition by wheat (Triticum aestivum L.). The susceptible and resistant R. raphanistrum populations were equally suppressed by wheat competition, with plant growth and seed production being decreased by approximately 50%. Although resistant populations produced less vegetative biomass than susceptible populations, there was no negative association between resistance and seed production. Therefore, it is unlikely that any nonherbicidal management practices will be more efficacious on 2,4-D–resistant than 2,4-D–susceptible R. raphanistrum populations.

Raphanus raphanistrum was grown in monoculture and as a range of cohorts of emergence in mixture with wheat. Growth and development were recorded at frequent intervals up to anthesis of the wheat.R. raphanistrum remained shorter than wheat, only over-topping the crop prior to anthesis for 2 of 7 sowing dates. When expressed in terms of photothermal time, growth in monocultures was similar for all sowing dates except those for wheat in mid-summer. Even a short delay in R. raphanistrumemergence in mixture decreased its growth considerably; R. raphanistrum emerging more than 4 weeks after the crop had no detectable effect on the wheat. However, even R. raphanistrum plants emerging 10 weeks after the crop produced some seeds. In mixture, R. raphanistrum had a higher specific leaf area (SLA), reduced leaf partitioning, and taller stems than in monoculture. A physiological growth model based on parameters from monocultures was unable to predict growth in mixtures; inclusion of changes in SLA and height in mixture improved predictions in some cases. It is concluded that competition models based on monoculture parameters, although previously successful for species with similar height and phasic development, are unlikely to work for species that differ in these attributes. Further work is required on the physiology of plants within mixtures.

A review of biological information is provided for Raphanus raphanistrum L. Native to the Mediterranean region, the species is widely introduced and naturalized in temperate regions around the world. In Canada, it currently occurs in all provinces except Saskatchewan and Manitoba, has only a limited distribution in Alberta, and is also absent from the Yukon, the Northwest Territories and Nunavut. It is most abundant in the Atlantic and Pacific regions and is an important weed of field crops in the Maritime provinces and Quebec. A persistent seed bank, competitive annual growth habit and high fecundity all contribute to its weedy nature and ensure that it will be a continuing problem. It can easily hybridize with cultivated radish, R. sativus L., and commonly does so when they occur together. Limited hybridization with canola, Brassica napus L., has been reported from several experimental field and greenhouse trials. Selective herbicide control is most difficult in canola and other cruciferous crops. It is the most important dicot weed in the southwestern region of Australia, primarily due to the evolution of several different herbicide-resistant biotypes. These include biotypes resistant to the acetolactate synthase (ALS)-inhibitors (group 2 herbicides) and/or photosystem II-inhibitors (group 5), and a biotype with multiple resistance to ALS-inhibitors, photosystem II-inhibitors, an auxin (2,4-D amine), and a phytoene desaturase (PSDS)-inhibitor (diflufenican). A biotype resistant to the ALS-inhibiting herbicide chlorsulfuron has also been detected in South Africa. Key words: Wild radish, Raphanus raphanistrum, herbicide resistance, canola, hybridization, RAPRA

CLE-пептиды (CLAVATA3/ENOSPERM SURROUNDING REGION) - сигнальные молекулы-фитогормоны, которые играют центральную роль в контроле развития разных типов меристем, регулируя экспрессию генов WOX (WUSCHEL-RELATED HOMEOBOX). В частности, мишенями действия CLE-пептидов небольшой группы TDIF (Tracheary Element Differentiation Inhibitory Factor) является ген WOX4 - центральный регулятор развития камбия и проводящей системы. Мы изучали роль пептида группы TDIF CLE 41 в развитии запасающего корня на представителях рода Raphanus: культурном редисе (Raphanus sativus) - популярной корнеплодной культуре с запасающим корнем и его дикорастущем предке редьке полевой (Raphanus raphanistrum), у которой запасающая паренхима корня развита слабо. Было показано влияние сверхэкспрессии гена RsCLE 41 и обработки растений экзогенным пептидом CLE 41 на развитие камбия и ксилемы в корнях R. sativus и R. raphanistrum, а также на экспрессию генов разных групп. В целом можно сказать, что CLE 41 активирует экспрессию генов, гомологи которых у арабидопсиса играют центральную роль в поддержании камбия (RsWOX4, RsWOX14, RsHAM4, RsCYCD 3). В запасающем корне редиса пептид CLE 41 активирует пролиферацию клеток камбия, при этом снижая количество одного из элементов ксилемы - одревесневшей паренхимы. Полученные данные свидетельствуют о важной роли CLE 41 в развитии запасающего корня редиса.

AbstractRaphanus raphanistrum (wild radish) is a highly competitive weed in winter crops. Integrated weed management practices and decision-making tools benefit from the ability to predict seed longevity and dormancy status in the soil seed bank, as well as time and density of emergence in the field. We wondered if unique values taken from databases could serve for modelling purposes, whatever the origins of the weed populations. We investigated dormancy and longevity of fruits buried in the soil over a four-year seed burial experiment of two highly contrasted populations that differ by their biogeographical origin (oceanic versus continental climate), their habitat (arable field versus undisturbed) and their fruit size (thick versus thin fruit wall). High viability persisted over two years, followed by a rapid reduction, especially for the ‘continental-undisturbed-thin’ population. Dormancy cycling, with dormancy at its lowest in October, was observed for the ‘oceanic-arable-thick’ population, whilst a slow decrease without clear seasonal pattern was found for the other population. These results indicate different ways of regulating seed persistence in the soil, which might be taken into account when building demographic models. These differences could be due to interactions between fruit wall thickness and the other factors; it is possible that a thicker fruit wall increases longevity by promoting dormancy by physical restriction, but depending on temperature. Thinner fruit walls would make plants display other adaptive strategies to maximize survival time in the soil seed bank. Studies involving more populations and isogenic material are needed to address this specific question.

AbstractWild radish (Raphanus raphanistrum L.) is a weed found globally in agricultural systems. The facultative winter annual nature of this plant and high genetic variability makes modeling its growth and phenology difficult. In the present study, R. raphanistrum natural seedbanks exhibited a biphasic pattern of emergence, with emergence peaks occurring in both fall and spring. Traditional sigmoidal models were inadequate to fit this pattern, regardless of the predictive environmental variable, and a corresponding biphasic model (sigmoidal + Weibull) was used to describe emergence based on the best parameters. Each best-fit chronological, thermal, and hydrothermal model accounted for at least 85% of the variation of the validation data. Observations on phenology progression from four cohorts were used to create a common model that described all cohorts adequately. Different phenological stages were described using chronological, thermal, hydrothermal, daylength-dependent thermal time, and daylength-dependent hydrothermal time. Integrating daylength and temperature into the models was important for predicting reproductive stages of R. raphanistrum.

The yield response of spring barley (Hordeum vulgare L. 'Morrison') to a range of densities of wild radish (Raphanus raphanistrum L.), wild oat (Avena fatua L.), hemp-nettle (Galeopsis tetrahit L.), and corn spurry (Spergula arvensis L.) was investigated in field experiments on Prince Edward Island from 1991 through 1994. Barley yield was modelled as a function of both barley and weed density. In the absence of weed competition, barley seed yield, number of main shoots, number of heads, and thousand-kernel weight varied significantly during the 4 yr of the study. Increasing densities of wild radish and wild oat reduced the number of barley heads primarily by interfering with tillering, but wild oat also reduced barley thousand-kernel weight. Hemp-nettle and corn-spurry at densities up to 200 plants m−2 had little effect on barley yield, except in a year of low barley yield potential. Estimated economic thresholds for wild radish, wild oat, hemp-nettle and corn spurry at a barley population of 250 plants m−2 were 37, 45, 122 and 297 plants m−2, respectively, assuming a weed-free yield of 4 t ha−1, a crop price of $100 t−1, and weed control costs of $30 ha−1. Key words: Avena fatua, Galeopsis tetrahit, Hordeum vulgare, Raphanus raphanistrum, Spergula arvensis, yield loss, weed interference, economic threshold

Raphanus raphanistrum L. (wild radish) is a widespread and economically problematic weed of winter crops including wheat (Triticum aestivum L.) in southern Australia. Management of the weed is achieved by a range of non-chemical and chemical techniques. Current management is failing to contain the weed, which is increasing in abundance and distribution. The characteristics of staggered recruitment, dormancy, rapid growth, competitive ability and high levels of seed production contribute to its persistence. The literature review concludes that weeds formed the basis for perpetuation of R. raphanistrum, a claim further investigated by simulation modeling. The effective management of R. raphanistrum should aim to achieve declining populations and this requires the integration of all factors that regulate seed production. Reducing seed production of R. raphanistrum in wheat can be achieved by applying herbicides at reproductive stages of development. This technique has been demonstrated to be an effective, safe and practical method of reducing seed production of R. raphanistrum in wheat. Reducing seed production of R. raphanistrum by herbicides applied at reproductive stages of development is a technique that can be incorporated into an integrated weed management program to improve control
Doctor of Philosophy (PhD)

Raphanus raphanistrum L. (wild radish) is a widespread and economically problematic weed of winter crops including wheat (Triticum aestivum L.) in southern Australia. Management of the weed is achieved by a range of non-chemical and chemical techniques. Current management is failing to contain the weed, which is increasing in abundance and distribution. The characteristics of staggered recruitment, dormancy, rapid growth, competitive ability and high levels of seed production contribute to its persistence. The literature review concludes that weeds formed the basis for perpetuation of R. raphanistrum, a claim further investigated by simulation modeling. The effective management of R. raphanistrum should aim to achieve declining populations and this requires the integration of all factors that regulate seed production. Reducing seed production of R. raphanistrum in wheat can be achieved by applying herbicides at reproductive stages of development. This technique has been demonstrated to be an effective, safe and practical method of reducing seed production of R. raphanistrum in wheat. Reducing seed production of R. raphanistrum by herbicides applied at reproductive stages of development is a technique that can be incorporated into an integrated weed management program to improve control

Thesis (Ph.D.) -- University of Western Sydney, 2002.
"A thesis submitted for the degree of Doctor of Philosophy (Ph.D.) in the Centre for Landscape and Ecosystems Management, University of Western Sydney ... May 2002" Includes bibliography (leaves 159-177) and other bibliographical references.

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O presente trabalho teve como objetivo comparar dois tipos de cobertura vegetal de inverno, através de três sistemas de manejo do solo, avaliando seus efeitos no crescimento e desenvolvimento da cultura de milho. Os experimentos foram instalados e conduzidos na Fazenda Experimental Lageado, da Faculdade de Ciências Agronômicas da UNESP, Campus de Botucatu, no período compreendido entre fevereiro de 2005 e maio de 2006, em NITOSSOLO VERMELHO Distroférrico, cultivado há nove anos com os mesmos sistemas de manejo do solo. Os experimentos foram constituídos de seis tratamentos com quatro repetições utilizando o delineamento experimental de blocos ao acaso com parcelas subdivididas. As parcelas foram constituídas por três sistemas de manejo do solo (preparo convencional, constituído por uma gradagem pesada e duas gradagens leves; cultivo mínimo, escarificador equipado com disco de corte e rolo destorroador, trabalhando na profundidade entre 25 e 30 cm e plantio direto, com dessecação da vegetação de cobertura por meio de aplicação de herbicida) e as subparcelas foram compostas por duas culturas de inverno (nabo forrageiro, Raphanus sativus L. e nabiça, Raphanus raphanistrum L.), que conseqüentemente formaram os dois tipos de coberturas vegetais, sobre as quais foram realizados os sistemas de manejo do solo para a implantação da cultura de milho. Os dados obtidos foram submetidos à análise de variância com teste de Tukey a 5% de probabilidade para comparar as médias. As análises estatísticas demonstraram que o sistema de plantio direto apresentou maior densidade e resistência mecânica do solo à penetração, quando comparado ao preparo convencional e ao cultivo mínimo. O cultivo mínimo apresentou maiores valores de profundidade de trabalho, área de solo mobilizada e capacidade de campo efetiva e menores valores de tempo efetivo demandado, uso específico...
This paper aims to compare two types of winter vegetal covering, through three soil tillage systems, evaluating their effects in growth and development of corn crop. Experiments were installed and carried out at Lageado Experimental Farm at Agricultural Science University of UNESP, Botucatu Campus, from february 2005 to may 2006, in Distroferic Red Nitosoil, which has been cultivated for nine years under the same soil tillage systems. Experiments were carried out in six treatments with four repetitions, using randomized experimental blocks with subdivided parts. Parts were made up by three soil tillage systems (conventional tillage, made up by one heavy harrow and two leveling harrow; minimum tillage, with chisel plow with cut disk and roll, working at 25 to 30 cm deep and notillage, with herbicide drying coverage vegetation) and subparts were made up by two winter crops (Raphanus sativus L. and Raphanus raphanistrum L.) which made up the two vegetal coverings over which the soil tillage systems were carried out for corn cropping. Obtained data were analyzed by Turkey variance test at 5% of probability for comparing averages. Statistical analysis showed that no-tillage system had higher density as well as mechanical soil resistance to penetration, when compared to conventional and minimum tillages. Minimum tillage system showed higher values of work deepness, mobilized soil area as well as effective field capacity and lower values of demanded real time, specific energy use and fuel consumption. For Raphanus sativus L. and Raphanus raphanistrum L., sowing it was observed that no-tillage system showed lower traction force, steering bar power, demanded real time, specific energy use and fuel consumption. Raphanus raphanistrum L. showed higher length, volume and root dry matter compared to Raphanus sativus L., meantime not observed statistical differences between both. Raphanus raphanistrum...(Complete abstract click electronic access below)

[Truncated abstract] Wild radish (Raphanus raphanistrum L.), an outcrossing annual plant, is one of the most widespread and successful colonising weeds in the Australian wheat belt. It was introduced accidentally during the latter part of the 19th century, apparently independently through the major ports of southern Australia. The widespread success of wild radish, and therefore the likelihood of distinct populations, gives us the opportunity to study the colonizing process with adaptation in annual outbreeding species, and to explore their genetic diversity. The aims of this thesis were to study the genetic diversity of wild radish and to investigate which factors are important in its success. After an initial review of the literature (chapter 2), the thesis describes experiments where genetic variation between and within populations was compared at 55 sites in transects across the wheat belt and high rainfall zones of temperate Western Australia (chapter 3). In chapter 4, variation in life history traits was compared with variation in AFLP molecular markers. The role of seed dormancy in the survival of the species was examined in chapter 5, and variation in the oil content of seeds and their fatty acid composition was examined in chapter 6. Finally, the results were discussed in chapter 7 with special reference to the adaptive value of outcrossing in annual weeds. The results suggest that wild radish has evolved to fit the Australian environment. However, measurement of 14 morphological and phenological characters showed that in most cases within site variation was much greater than that between sites. Most of the variation between sites was associated with geoclusters, a name given to zones of similar environmental conditions in regard to rainfall and temperature. Thus plants from areas with high rainfall and low temperature produced longer, wider pods with more segments, heavier seeds and flowered later than plants from more arid areas.

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Resumo: O presente trabalho teve como objetivo comparar dois tipos de cobertura vegetal de inverno, através de três sistemas de manejo do solo, avaliando seus efeitos no crescimento e desenvolvimento da cultura de milho. Os experimentos foram instalados e conduzidos na Fazenda Experimental Lageado, da Faculdade de Ciências Agronômicas da UNESP, Campus de Botucatu, no período compreendido entre fevereiro de 2005 e maio de 2006, em NITOSSOLO VERMELHO Distroférrico, cultivado há nove anos com os mesmos sistemas de manejo do solo. Os experimentos foram constituídos de seis tratamentos com quatro repetições utilizando o delineamento experimental de blocos ao acaso com parcelas subdivididas. As parcelas foram constituídas por três sistemas de manejo do solo (preparo convencional, constituído por uma gradagem pesada e duas gradagens leves; cultivo mínimo, escarificador equipado com disco de corte e rolo destorroador, trabalhando na profundidade entre 25 e 30 cm e plantio direto, com dessecação da vegetação de cobertura por meio de aplicação de herbicida) e as subparcelas foram compostas por duas culturas de inverno (nabo forrageiro, Raphanus sativus L. e nabiça, Raphanus raphanistrum L.), que conseqüentemente formaram os dois tipos de coberturas vegetais, sobre as quais foram realizados os sistemas de manejo do solo para a implantação da cultura de milho. Os dados obtidos foram submetidos à análise de variância com teste de Tukey a 5% de probabilidade para comparar as médias. As análises estatísticas demonstraram que o sistema de plantio direto apresentou maior densidade e resistência mecânica do solo à penetração, quando comparado ao preparo convencional e ao cultivo mínimo. O cultivo mínimo apresentou maiores valores de profundidade de trabalho, área de solo mobilizada e capacidade de campo efetiva e menores valores de tempo efetivo demandado, uso específico... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This paper aims to compare two types of winter vegetal covering, through three soil tillage systems, evaluating their effects in growth and development of corn crop. Experiments were installed and carried out at Lageado Experimental Farm at Agricultural Science University of UNESP, Botucatu Campus, from february 2005 to may 2006, in Distroferic Red Nitosoil, which has been cultivated for nine years under the same soil tillage systems. Experiments were carried out in six treatments with four repetitions, using randomized experimental blocks with subdivided parts. Parts were made up by three soil tillage systems (conventional tillage, made up by one heavy harrow and two leveling harrow; minimum tillage, with chisel plow with cut disk and roll, working at 25 to 30 cm deep and notillage, with herbicide drying coverage vegetation) and subparts were made up by two winter crops (Raphanus sativus L. and Raphanus raphanistrum L.) which made up the two vegetal coverings over which the soil tillage systems were carried out for corn cropping. Obtained data were analyzed by Turkey variance test at 5% of probability for comparing averages. Statistical analysis showed that no-tillage system had higher density as well as mechanical soil resistance to penetration, when compared to conventional and minimum tillages. Minimum tillage system showed higher values of work deepness, mobilized soil area as well as effective field capacity and lower values of demanded real time, specific energy use and fuel consumption. For Raphanus sativus L. and Raphanus raphanistrum L., sowing it was observed that no-tillage system showed lower traction force, steering bar power, demanded real time, specific energy use and fuel consumption. Raphanus raphanistrum L. showed higher length, volume and root dry matter compared to Raphanus sativus L., meantime not observed statistical differences between both. Raphanus raphanistrum...(Complete abstract click electronic access below)
Doutor

Les frequences d'hybridation interspecifique entre differentes lignees et hybrides male-steriles transgeniques de colza (brassica napus l, aacc 2n=38) avec des populations de ravenelle (raphanus raphanistrum l, rrrr 2n=18) ont ete evaluees en conditions naturelles. Les graines recoltees sur les genotypes de colza montrant un dimorphisme de taille, elles ont ete tamisees. Les grosses graines etaient toutes du colza. 72 a 100 pourcent des petites graines se sont averees etre des hybrides triploides acrr 2n=28, et 0 a 12 pourcent des amphidiploides aaccrrrr 2n=56. Des differences significatives de l'aptitude a la formation d'hybrides interspecifiques avec la ravenelle ont ete mises en evidence entre les genotypes de type hiver et ceux de type printemps. Un effet hybride a egalement ete observe, qui s'est revele fortement dependant des conditions environnementales. Les faibles fertilites male et femelle des hybrides triploides ont rendu la production d'une premiere generation de retrocroisement beaucoup plus difficile qu'au stade de la f1. Il n'a pas ete possible de distinguer les genotypes colza d'origine pour leur aptitude a la production de bc1. Les descendances obtenues ont montre des structures chromosomiques tres heterogenes: 50 pourcent etaient de la forme attendue acrrrr a 37 chromosomes, mais des formes acrr 2n=28, aaccrrrr 2n=56, ainsi que des structures intermediaires non multiples des genomes en presence, ont egalement ete mises en evidence. Des non reductions gametiques, des reductions partielles, des developpements apomictiques ou par endomitose apres fecondation, permettent d'expliquer cette variete des structures obtenues. L'observation de comportements meiotiques d'hybrides triploides ainsi que la constatation de remaniements chromosomiques ont montre que des echanges peuvent avoir lieu entre les genomes de colza et de ravenelle. Le suivi de marqueurs moleculaires specifiques du colza devrait permettre d'analyser chez les bc1 l'importance de ces echanges et les sites du genome concernes. D'autre part, la liaison de 4 marqueurs moleculaires au gene bar a partir de lignees haploides doublees de colza devrait permettre une analyse plus fine a un site d'insertion particulier, qui semble etre telomerique et donc potentiellement sujet a des recombinaisons

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A competição de azevém e nabo e a estimativa de dano econômico de nabo na cultura do trigo, além de práticas de manejo como a dessecação em pré-colheita com herbicidas e aplicação de trinexapac-ethyl e nitrogênio são fatores que merecem atenção pela pesquisa, visto que influenciam diretamente a produtividade e a qualidade fisiológica das sementes. O trabalho teve por objetivo avaliar a produtividade e a qualidade fisiológica de sementes de trigo produzidas em competição com azevém e/ou nabo (experimento 1); quantificar a produtividade, a qualidade fisiológica e o resíduo em sementes de trigo após a dessecação com herbicidas (experimento 2); avaliar a produtividade e a qualidade fisiológica de sementes de trigo em competição com nabo e sob a aplicação de trinexapac-ethyl e nitrogênio (experimento 3); e, estimar o nível de dano econômico de nabo em competição com as cultivares de trigo BRS 328, BRS 177 e BRS Umbu (experimento 4). Para as pesquisas realizadas o delineamento experimental adotado foi em blocos ao acaso, com quatro repetições, com exceção do ensaio 4 que utilizou uma repetição. O primeiro ensaio foi realizado com a cultivar BRS 177, o segundo com as cultivares BRS 177 e BRS Umbu, o terceiro com a cultivar BRS Guamirim e o quarto com as cultivares BRS 328, BRS 177 e BRS Umbu. As variáveis analisadas no experimento 1 foram número de antécios por espiga, número de sementes por espiga, peso hectolítrico, peso de mil sementes e produtividade. No experimento 2 avaliaram-se o peso de mil sementes, peso hectolítrico, número de antécios por espiga e a produtividade de sementes, além dos resíduos gerados nas sementes após a aplicação dos herbicidas em pré-colheita. No experimento 3 avaliaram-se o número de sementes por espiga e número de antécios, índice de colheita, produtividade biológica, produtividade de sementes, peso hectolítrico e peso de mil sementes e no experimento 4 avaliaram-se a população de plantas, massa seca da parte aérea, cobertura do solo, área foliar e produtividade. Ainda, nos três primeiros experimentos a qualidade fisiológica das sementes foram avaliadas por testes de vigor e germinação. Conclui-se que a competição de trigo na população de 5 plantas m-2 com azevém, nabo ou nabo + azevém reduz a produtividade da cultura, independentemente da época de emergência das plantas em relação as plantas daninhas, entretanto não prejudica a viabilidade e o vigor das sementes produzidas. A dessecação em pré-colheita com herbicida realizada em estádio posterior a maturidade fisiológica, de maneira geral, não influencia a qualidade fisiológica e a produtividade de sementes de trigo das cultivares BRS Umbu e BRS 177, entretanto apresentam resíduos nos grãos. A cultivar de trigo BRS Guamirim em competição com nabo submetido à adubação suplementar com nitrogênio, de maneira geral, apresenta aumento da produtividade de sementes até a dose de 100 kg ha-1, enquanto na ausência da competição o aumento ocorre até a dose de 150 kg ha-1, apesar da qualidade fisiológica das sementes serem reduzidas com o incremento das doses. A cultivar de trigo BRS 328, ciclo precoce, apresenta maior habilidade competitiva comparativamente a BRS 177, ciclo médio, e BRS Umbu, ciclo tardio. A planta daninha Raphanus raphanistrum mostra-se competitiva com a cultura trigo, sendo necessário no mínimo 1,6 plantas m-2 para que o controle se justifique.
The ryegrass and wild radish competition and the estimated wild radish economic threshold in wheat crop, besides management practices as herbicide pre-harvesting desiccation and application of trinexapac-ethyl and nitrogen are factors that deserve attention by the research, as they directly influence productivity and seed physiological quality. This study aimed to evaluate the productivity and physiological quality of wheat seeds produced in competition with ryegrass and/or wild radish (experiment 1); measure the yield, physiological quality and the residue in wheat seeds after herbicide desiccation (experiment 2); evaluate the productivity and physiological quality of wheat seeds in competition with wild radishes and under trinexapac-ethyl and nitrogen application (Experiment 3); and estimate the economic level of wild radish in competition with the wheat cultivars BRS 328, BRS 177 and BRS Umbu (experiment 4). To research performed the experimental design was a randomized block with four replications, except for the fourth experiment that used one replication. The first trial was conducted with BRS 177 cultivar, the second with the BRS 177 and BRS Umbu cultivars, the third with BRS Guamirim and the forth with the BRS 328, BRS 177 and BRS Umbu cultivars. The variables analyzed in experiment 1 were number of anthecium per spike, number of seeds per spike, test weight, thousand seed weight and productivity. In experiment 2 assessed the weight of a thousand seeds, test weight, number of anthecium per spike and seed yield, in addition to the residual generated in the seeds after herbicide application before the harvest. In Experiment 3 was evaluated the number of seeds per spike and number of anthecium, harvest index, biological yield, seed productivity, test weight and thousand seed weight and experiment 4 were evaluated plant population, dry mass of plant aerial part, soil cover, leaf area and productivity. Still, in the first three experiments the physiological seed quality was evaluated by germination and vigor tests. It was concluded that wheat competition in the population of 5 plants m-2 with ryegrass, wild radish or wild radish + ryegrass reduces crop yield, regardless of the time plant emergence over the weeds, however not affect the viability and vigor of produced seeds. The herbicide pre-hasvest desication held after physiological maturity stage, in general, does not affect the physiological quality of wheat seeds or it productivity in BRS Umbu and BRS 177 cultivars, however it shows residues present in grains. The wheat cultivar BRS Guamirim in competition with wild radish subjected nitrogen supplementar fertilization, in general, has increased seed yield until the dose of 100 kg ha-1, while in the absence of competition its increased until the dose of 150 kg ha-1, despite the physiological quality of seeds being reduced with increasing doses. The wheat cultivar BRS 328, early maturing, presents greater competitive ability compared to BRS 177, medium cycle, and BRS Umbu, late cycle. The weed Raphanus raphanistrum proves to be competitive with the wheat crop, requiring at least 1.6 plants m-2 so that the control is justified.

Auxinic herbicide-resistant (i.e., resistant to 2,4-D and MCPA) wild radish (Raphanus raphanistrum L.) was discovered in the Western Australian wheatbelt, providing an opportunity to integrate auxinic herbicide resistance into cultivated radish (R. sativus L.) using conventional breeding methods. It was hypothesized that the inheritance of auxinic herbicide resistance in wild radish is conferred by a single, dominant nuclear gene and, therefore, will be relatively easy to introgress from wild radish to cultivated radish; and the mechanism of auxinic herbicide resistance in wild radish is through an altered target-site. Visual injury data of the F2 progeny suggested that resistance was conferred by a quantitative trait with the susceptible allele(s) exhibiting dominance with minor cytoplasmically inherited genes masking the susceptible trait. In conclusion, the resistance allele(s) were quantitative and, thus, make selection for resistance difficult. Therefore, the introgression of the resistance allele(s) was not successfully completed. To determine the mechanism of resistance, the wild radish plants resistant WARR6-26 (R) and susceptible WARR7-5 (S) were treated with radiolabeled MCPA. There was no difference in metabolism of [14C]MCPA between R and S plants. Based upon the decline in the total 14C recovered over 72 h in R and S it was clear that both were “losing” [14C]MCPA; however, R plants were losing MCPA more rapidly. It was hypothesized that because R plants exude 14C more rapidly from their roots than S plants, this accounted for the resistance of R plants.