<p>Ambrosia artemisiifolia L., invazivna korovsko-ruderalna biljka, poslednjih<br />godina u na&scaron;oj zemlji predstavlja izuzetno veliki problem, ne samo za poljoprivredu<br />nego i za stanovni&scaron;tvo, izazivajući svojim polenom jake alergijske i druge zdravstvene<br />komplikacije. Shvatajući probleme koje ona izaziva, sve zemlje u kojima ambrozija<br />predstavlja veliki, pre svega zdravstveni problem, ulažu ogromne napore, izdvajaju<br />velika finansijska sredstva, organizuju stanovni&scaron;tvo, &scaron;kole, vojsku, javne službe,<br />sredstva informisanja, donose zakone, uredbe i deklaracije, da bi ograničili njeno<br />&scaron;irenje i osigurali njeno suzbijanje, dok se u na&scaron;oj zemlji jo&scaron; uvek nedovoljno ozbiljno<br />shvata ovaj problem.<br />Kako se radi o biljci koja se razmnožava samo generativno (semenom), istraživanja<br />&#39;&#39;banke semena&#39;&#39; pelenaste ambrozije u određenim zemlji&scaron;nim profilima omogućavaju<br />preciznu prognozu njene pojave na određenim stani&scaron;tima, &scaron;to kasnije znatno olak&scaron;ava<br />suzbijanje kako mehaničkim putem tako i primenom herbicida. Zemlji&scaron;ni uzorci za<br />analizu rezervi semena su uzeti, sa karakterističnih ruderalnih stani&scaron;ta, na području<br />Novi Sad, Zrenjanin i Ruma. Obzirom da se radi o ruderalnim stani&scaron;tima, na svim<br />istraživanim lokalitetima utvrđena je relativno visoka brojnost semena pelenaste<br />ambrozije. Prikazano istraživanje je prvo ovog tipa sprovedeno na teritoriji Republike<br />Srbije.<br />Ova proučavanja su od izuzetnog naučnog značaja budući da obuhvataju poznavanje<br />osnovnih biolo&scaron;kih osobina semena ambrozije, kao &scaron;to su morfolo&scaron;ke osobine,<br />karakteristike klijanja, nicanja i načina rasprostiranja.<br />Za potrebe ispitivanja klijavosti semena A. artemisifolia 2007. godine sa teritorije 15<br />gradskih i prigradskih naselja Grada Novog Sada prikupljeni su plodovi pelenaste<br />ambrozije. Od ukupne količine prikupljenog semena pelenaste ambrozije, polovina je<br />odložena u hladnu komoru sa temperaturom od +4&ordm;C a drugi deo materijala je odložen<br />u komoru sa temperaturom od - 8&ordm;C da bi se simulirali zimski uslovi, odnosno kako bi<br />seme bilo izloženo jarovizaciji. Naklijavanje izdvojenog semena vr&scaron;eno je u klimakomori,<br />pod uslovima povoljnim za nicanje semena. Nakon 9, 14, 21 i 28 dana<br />ocenjivana je klijavost semena. Utvrđena je dobra klijavost semena pelenaste<br />ambrozije, koja je bila značajno veća kod stratifikovanog semena.<br />Na osnovu rezultata dobijenih tokom ispitivanja rasprostranjenosti i suzbijanja<br />korovsko-ruderalne alergene biljke Ambrosia artemisifolia L. u regiji gradova Novi<br />Sad, Zrenjanin i Ruma, izvedeni su sledeći zaključci: Obavljena proučavanja<br />rasprostranjenosti i suzbijanja korovsko-ruderalne alergene biljke Ambrosia<br />artemisifolia L. u 15 zona grada Novog Sada, 10 zona u Zrenjaninu i 7 u Rumi,<br />ukazuju na izuzetnu zastupljenost ove biljke. Na osnovu proučavanja rasprostranjenosti i praćenja feno-faza razvoja pelenaste ambrozije obavljeno je<br />mehaničko ko&scaron;enje ručnim ili motornim kosilicama. Imajući u vidu stalne napore u<br />pogledu za&scaron;tite životne sredine koja podrazumeva na prvom mestu pozitivan uticaj na<br />zdravlje ljudi, na gradskim lokacijama tretman herbicidom glifosat nije primenjen, već<br />samo u nenastanjenim zonama i na zapu&scaron;tenim poljoprivrednim povr&scaron;inama i<br />utrinama. Prilikom suzbijanja pelenaste ambrozije mehaničkim putem, istaknuto je da<br />je ko&scaron;enje potrebno obaviti 3-4 puta tokom jedne vegetacione sezone, usled relativno<br />brze regeneracije poko&scaron;enih biljaka. Hemijsko suzbijanje ambrozije primenom<br />herbicida glifosat, pokazalo se kao znatno efikasnije jer je za njeno suzbijanje bio<br />dovoljan uglavnom jedan tretman.</p> / <p>Ambrosia artemisiifolia L., an invasive weed-ruderal plant in recent years in<br />our country is a very big problem, not only for agriculture but also for the human<br />population, causing her severe pollen allergy and other health complications.<br />Recognizing the problems that it causes, all countries where ragweed is a large,<br />primarily health problem, invest huge efforts, allocate significant financial resources,<br />organized residents, schools, the military, the media, legislate, to limit its spread and<br />ensure its suppression, while our country does not yet have a serious approach to this<br />problem.<br />Since this is a plant that reproduces a generative (seed), &#39;&#39;seed bank&#39;&#39; research in some<br />soil profiles allow to forecast its occurrence at some sites, which greatly facilitates<br />the later contol of both mechanically and by herbicides. Soil samples for analysis of<br />seed reserves were taken with typical ruderal habitats, in Novi Sad, Zrenjanin and<br />Ruma. Since these are ruderal habitats, at all study sites, a relatively high number of<br />ragweed seeds apears. Our study is the first of this type that was conducted in the<br />Republic of Serbia.<br />These studies are of great scientific importance as it includes knowing of basic<br />biological properties of ragweed seeds, such as morphological characteristics, the<br />characteristics of germination, emergence and control methods.<br />For the purposes of testing seed germination A. artemisifolia in year 2007. samples<br />of ambrosia seeds were collected from 15 different localities in the territory of the<br />city and suburbs of Novi Sad. Collected seeds were splited on two halfs: one part was<br />delayed in the cold chamber with a temperature of +4 &deg; C and the second part of the<br />material is disposed in the chamber with a temperature of - 8 &deg; C to simulate winter<br />conditions, in purpose to achieve seed vernalization. Seed germination was<br />performed in air chamber under optimal conditions for seed germination. After 9, 14,<br />21 and 28 days seed germination was evaluated. Germination of stratified seeds was<br />significantly higher than germination of not stratified seeds.<br />Based on the obtained results of distribution and controll of weed-ruderal allergenic<br />plant Ambrosia artemisiifolia L. in the cities Novi Sad, Zrenjanin and Ruma, the<br />following conclusions were made: Results mapping and control of Ambrosia<br />artemisiifolia L. in 15 zones in the city of Novi Sad, 10 zones in Zrenjanin, and 7 in<br />Ruma, indicating significant presence of this plant. Based on the study of the<br />distribution and monitoring of ragweed growth stages, mechanical controll mesures<br />were performed manually, by trimmers or by tractor. Because of ongoing efforts to<br />protect the environment, in the urban locations herbicide treatment was not applied.<br />Glyphosate treatment was applied only in uninhabited areas, agricultural land and<br />wasteland. If ragweed is controlled mechanically, the cutting should be done 3-4<br />times per year due to the relatively rapid regeneration of plants. Chemical control of<br />ragweed (herbicide glyphosate), has proven much more effective. One treatment per<br />year was sufficient.</p>

Ce travail a eu pour but premier d’étudier le risque d’évolution de la résistance aux herbicides inhibiteurs de l’acétolactate synthase (ALS) chez l’ambroisie à feuilles d’armoise (Ambrosia artemisiifolia L.) à travers quatre points : (i) la pression de sélection (étude de l’efficacité d’une gamme d'herbicides inhibiteurs de l’ALS), (ii) la capacité de réponse adaptative de l’adventice (détermination de la variation de la sensibilité aux inhibiteurs de l’ALS entre plantes et mise en place d’un programme de sélection récurrente), (iii) une étude de terrain (recherche de résistance aux inhibiteurs de l’ALS au champ en France), (iv) l’étude des mécanismes de résistance (liée à la cible – RLC – et non liée à la cible – RNLC – par une approche de transcriptomique). Le second objectif fut d’étudier la connectivité des populations d’A. artemisiifolia dans des paysages agricoles à l’aide de marqueurs microsatellites développés lors de ce travail afin de déterminer les facteurs qui pourraient faciliter la dispersion de cette espèce et de la résistance à l’échelle du paysage agricole.En ce qui concerne la résistance aux herbicides :-La réponse de d’A. artemisiifolia aux herbicides inhibiteurs de l’ALS est très variable entre substances.-Des plantes ayant survécu à la dose maximale autorisée et à des doses supérieures de metsulfuron ont été sélectionnées pour débuter un programme de sélection récurrente. Après deux cycles de sélection, on observe une intensification de la résistance au metsulfuron et une émergence de la résistance à l’imazamox et au tribénuron.-Trois cas de résistance à l’imazamox ont été identifiés au champ dont deux cas de pure RNLC et un cas de coexistence RLC – RNLC.-Un transcriptome d’A. artemisiifolia a été généré grâce à la technique de séquençage PacBio pour rechercher des gènes impliqués dans les mécanismes de RNLC (approche RNAseq). 62 gènes candidats ont été identifiés dont des transporteurs ABC, des cytochromes P450 ainsi que des glutathione-S-transférases connus pour être impliqués dans la dégradation des herbicides.Pour l’étude de la connectivité des populations agricoles :-26 marqueurs microsatellites ont été développés et ont révélé une forte variabilité génétique. La structuration génétique a été étudiée à grande échelle pour des populations d’A. artemisiifolia d’Europe (aire d’invasion) et d’Amérique du Nord (aire d’origine).-À une échelle plus fine (paysage agricole), la structure génétique des populations reste influencée par les événements de colonisation. Les événements de migration qui ont été identifiés entre zones de présence de l’ambroisie suggèrent des flux de gènes (pollen/semences) et une connectivité modérés à l’échelle d’un territoire agricole. Dans les environnements agricoles, la dispersion des allèles de résistance aux herbicides pourrait se faire facilement de proche en proche via les flux de pollen, et également à plus longue distance via des dispersions de graines. Les activités anthropiques jouent un rôle majeur dans la dispersion des semences (machineries agricoles, lots de semences contaminés…).-L’analyse du système de reproduction a confirmé que cette espèce est allogame ce qui entraîne des flux de gènes intra- et inter-populations importants.Les connaissances acquises au cours de ce travail pourront aider à développer des stratégies de contrôle mieux adaptées, pour lutter efficacement contre A. artemisiifolia afin de limiter son expansion, telles que :-Des stratégies de désherbage diversifiées : combinaison de lutte mécanique (dont faux semis) et chimique (diversification des modes d’action herbicides).-Un allongement et une diversification des rotations de cultures en favorisant des cultures d’hiver et/ou des cultures couvrantes et compétitrices.Ces connaissances pourront aussi être utilisées dans la lutte contre une autre espèce adventice du genre Ambrosia, Ambrosia trifida.Mots-clés (6) : Ambrosia artemisiifolia L., ambroisies, résistance aux herbicides, / The first aim of this work was to investigate the risk for the evolution of resistance to acetolactate synthase inhibitor (ALS) herbicides in the common ragweed (Ambrosia artemisiifolia L.) through four points: (i) the selection pressure (effectiveness of a range of ALS inhibitor herbicides), (ii) the adaptive response of Ambrosia artemisiifolia (recurrent selection experiment), (iii) a resistance monitoring in fields in France, and (iv) the investigation of the mechanisms underlying herbicide resistance (target-site (TSR) and non-target-site resistance (NTSR) using transcriptomic analyses). The second aim was to study the connectivity of A. artemisiifolia populations in agricultural landscapes using microsatellite markers developed during this work, to determine factors that could facilitate the spread of this invasive weed species and the spread of herbicide resistance.In regards to herbicide resistance:-The sensitivity of A. artemisiifolia to ALS-inhibiting herbicides is variable between active ingredients.-Plants that survived the French maximum authorized field rate and higher rates of metsulfuron were selected to implement a recurrent breeding program. After two selection cycles, the resistance level to metsulfuron increased and resistance to imazamox and tribenuron emerged.-Three cases of imazamox resistance were identified in the field, including two cases of pure NTSR and one case of TSR - NTSR coexistence.-A transcriptome for A. artemisiifolia, AMBELbase, was generated using the PacBio sequencing technology to search for genes involved in NTSR mechanisms (RNAseq approach). 62 candidate contigs were identified including ABC transporters, cytochromes P450 and glutathione S-transferases known to be involved in the degradation of herbicides.In regards to population connectivity:-26 microsatellite markers were developed and revealed high genetic variability. Genetic structuring has been studied on a large scale for populations of A. artemisiifolia from Europe (invasion range) and North America (native range).-On a finer scale (agricultural landscape), the genetic structure of populations was influenced by colonization events. Migration events detected among the areas colonized by A. artemisiifolia suggested moderate pollen/seed flows and connectivity at the farmland scale. In agricultural environments, herbicide resistant alleles could be easily spread among neighbouring populations via pollen flow, and also at longer distances via seed dispersal. Human-related activities play a major role in the dispersal of seeds (agricultural machinery, contaminated seed lots, etc.).-The mating system analysis confirmed that A. artemisiifolia is an obligate outcrossing species which leads to important intra- and inter-population gene flow.The knowledge acquired during this work may help to foster the development of better management strategies to effectively control A. artemisiifolia to limit its spread, such as:-Diversified weed control strategies: combination of mechanical (including false-seed) and chemical weeding (diversification of herbicide modes of action).-Longer diversified crop rotations including more winter crops and/or cover and competitive crops to break the life cycle of A. artemisiifolia.These knowledge may also be used to better control of another weed species of the genus Ambrosia, Ambrosia trifida L.