Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-03-01T14:00:04Z No. of bitstreams: 1 PGPV17MA223.pdf: 188914 bytes, checksum: 40f42384c685cd1e290ca430e4ced46a (MD5) / Made available in DSpace on 2018-03-01T14:00:04Z (GMT). No. of bitstreams: 1 PGPV17MA223.pdf: 188914 bytes, checksum: 40f42384c685cd1e290ca430e4ced46a (MD5) Previous issue date: 2017-02-17 / Capes / The foliar diseases of wheat reduce the area of the photosynthetic plant of the plant, compromising the yield of grains. The objective of this work was to obtain the intensity of foliar diseases, yield and hectoliter of grains in plants of the cultivars: i) TBIO Mestre sprayed with foliar fertilizers (FF) isolated and mixed with fungicides (harvest 2014); ii) TBIO Sinuelo sprayed with fungicides triazole, triazole + strobilurin and morpholine (harvest 2015); iii) the incidence and severity of the fungus Blumeria graminis f.sp tritici on plants sprayed with fungicides in the mode acton preventive and curative. Data were submitted to ANOVA and subsequent comparison of means by the Scott-Knott test or analysis of contrasts (p <0.05). Leaf rust and yellow spot were the predominant diseases in the cultivar TBIO Mestre. The mixture of FF and fungicides didn´t increase the control of rust and leaf spots, the yield and the hectoliter weight of the grains in relation to the isolated use of fungicides. Leaf rust and powdery mildew were the predominant diseases in the trial with the cultivar TBIO Sinuelo. The control of powdery mildew was verified in 40% with the morpholine spray, 41% with triazole and 56% with the triazole + strobilurin mixture. The rust control was 47% with triazoles, 93% with morpholine and 94% with the triazole + strobilurin mixtures. Powdery mildew was the predominant disease in the experiment with Marfim in Muitos Capões. Was detected 32% control of the mildew with the strobilurin + carboxamide mixture, 35% with dithiocarbamates, 68% with triazole + strobilurin and 74% with morpholine. The yellow spot was the predominant disease in the experiment conducted with wheat cultivar TBIO Toruk in Lages. The average control among the 13 fungicides with the greatest reduction of yellow spots AACPDS was 51%. In greenhouse, the pulverized fungicides presented average control of 68 % in preventive action and 56 % curative. It is suggested the control of powdery mildew with triazole + strobilurin, triazole + strobilurin + carboxamide or morpholine. The fungicides of the dithiocarbamate group and the strobilurin + carboxamide mixture don´t have effective control of powdery mildew. The spraying of fungicides resulted in higher grain yield in the four trials conducted in the 2014, 2015 and 2016 crops, with a mean of 669.75 kg ha-1 (18%), with a variation of 413 kg ha-1 (10%) in the cultivar TBIO Mestre in 2014, up to 1,027 kg ha-1 (31%) in the TBIO Sinuelo cultivar in 2015. The wheat grains harvested from the controls of the four field trials obtained 72 hectoliter compared to 76 in the pulverized fungicide / As doenças foliares do trigo reduzem a área foliar fotossintetizante da planta comprometendo o rendimento de grãos. Os objetivos deste trabalho foram obter a intensidade de doenças foliares, rendimento e peso hectolitro de grãos em plantas dos cultivares: i) TBIO Mestre pulverizadas com fertilizantes foliares (FF) isolados e em mistura com fungicidas (safra 2014); ii) TBIO Sinuelo pulverizadas com fungicidas triazol, triazol + estrobilurina e morfolina (safra 2015); iii) Marfim e TBIO Toruk pulverizadas com triazol + estrobilurina, triazol + estrobilurina + carboxamida, estrobilurina + carboxamida e ditiocarbamato (safra 2016) e iv) a incidência e severidade do fungo Blumeria graminis f.sp tritici em planats pulverizadas com fungicidas em modo de ação preventivo e curativo. Os dados foram submetidos à ANOVA e posterior comparação de médias pelo teste Scott-Knott ou análise de contrastes (p<0,05). A ferrugem da folha e mancha amarela foram as doenças predominantes no cultivar TBIO Mestre. A mistura de FF e fungicidas não aumentou o controle de ferrugem e manchas foliares, o rendimento e peso hectolitro de grãos em comparação ao uso isolado de fungicidas. A ferrugem da folha e oídio foram as doenças predominantes no ensaio com o cultivar TBIO Sinuelo. Foi verificado controle de oídio em 40 % com a pulverização de morfolina, 41 % com triazois e 56 % com a mistura de triazol + estrobilurina. O controle de ferrugem foi de 47 % com triazóis, 93 % com morfolina e 94 % com as misturas de triazol + estrobilurina. O oídio foi a doença predominante no experimento com o cultivar Marfim em Muitos Capões. Foi detectado 32 % de controle do oídio com a mistura de estrobilurina + carboxamida, 35 % com ditiocarbamatos, 68 % com a mistura de triazol + estrobilurina e 74 % com morfolina. A mancha amarela foi a doença predominante no experimento conduzido com o cultivar de trigo TBIO Toruk em Lages. A média de controle entre os 13 fungicidas de maior redução da AACPDS de mancha amarela foi de 51 %. Em casa de vegetação, os fungicidas pulverizados apresentaram controle médio de 68 em ação preventiva e 56 % curativa. Sugere-se para controle de oídio fungicidas formulados com triazol + estrobilurina, triazol + estrobilurina + carboxamida ou morfolina. Fungicidas do grupo dos ditiocarbamatos e a mistura de estrobilurina + carboxamida não tem controle eficiente de oídio. A pulverização de fungicidas resultou em maior rendimento de grãos nos quatro ensaios realizados nas safras 2014, 2015 e 2016, com média de 669,75 kg ha-1 (18 %), com variação de 413 kg ha-1 (10 %) no cultivar TBIO Mestre em 2014, até 1.027 kg ha-1 (31 %) no cultivar TBIO Sinuelo em 2015. Os grãos de trigos colhidos nas testemunhas dos quatro ensaios de campo obtiveram 72 de PH médio em comparação a 76 nas parcelas pulverizadas com fungicidas

Made available in DSpace on 2016-12-08T16:44:45Z (GMT). No. of bitstreams: 1 PGPV13MA124.pdf: 862800 bytes, checksum: 52145904b06c7b90decb7d1ef575d2ff (MD5) Previous issue date: 2013-04-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The fungicide application on the control of wheat foliar diseases increase the cost production and contribute to contaminate the environment, if unnecessary sprays would be made. The aim of this work was to analyse the available criteria to the technical assistance concerning to the decisive making about the moment of the fungicide application. The experiments were carried out at field, in the 2011 and 2012 growing seasons in Lages, Santa Catarina State, with the Mirante cultivar wheat. Were tested the following criteria: 1) witness (without fungicide spraying); 2) 1% of incidence of plants; 3) 10% of incidence of plants; 4) 5% of foliar severity; 5) main stem with from five to six tillers; 6) first visible node; 7) third visible node; 8) Economic Damage Threshold (EDT). The reapplications were made based on the period of fungicide mixture protection of azoxystrobin + cyproconazol (60g + 24g a.i. ha-1) + propiconazol (125g a.i. ha-1). The experimental unities were composed by 1.5 x 5 m plots arranged in a randomized blocks design with four replications. The applications were made with a coastal sprayer with pressure generated by CO2 gas delivering 200 L ha-1. In the economic analysis was taken in account the cost of applications, the number of applications, the price of wheat, the disease intensity (area under the disease progress curve AUDPC), control effectiveness based on the intensity disease and components of yield (productivity, mass of one thousand grains and weight of the hectoliter). The data were submitted to ANOVA with means compared by the Tukey`s test. In the two growing seasons, leaf rust, yellow spot and powdery mildew were the predominant diseases. The AUDPC values showed that the criteria 1% and 10% of incidence of plants and from five to six tillers presented lower intensities of disease, with higher control and higher yields, however, they received from three to four applications. The EDT criteria received two to three applications and obtained intermediate values, as well as, the criteria of first visible node that presented intermediate values for the means of incidence and severity and also for the productivity. The criteria of third visible node and 5% of foliar severity began the chemical control later, receiving from one to two applications and showed higher means of incidence and severity, lower control, as well as, a lower productivity of grains / A aplicação de fungicidas no controle de doenças foliares do trigo aumenta o custo de produção e pode contribuir para contaminar o meio ambiente caso sejam feitas aplicações desnecessárias. O objetivo deste trabalho foi analisar os critérios disponíveis para a assistência técnica sobre a tomada de decisão para o momento da aplicação de fungicida. Os experimentos foram conduzidos no campo nas safras agrícolas de 2011 e 2012, em Lages, Santa Catarina, com a cultivar de trigo Mirante. Foram testados os seguintes critérios: 1) Testemunha (sem aplicação de fungicida); 2) 1% de incidência de plantas; 3) 10% de incidência de plantas; 4) 5% de severidade foliar; 5) Colmo principal com cinco a seis afilhos; 6) Primeiro nó visível; 7) Terceiro nó visível; e 8) Limiar de Dano Econômico (LDE). As reaplicações foram feitas com base no período de proteção da mistura dos fungicidas azoxistrobina + ciproconazole (60g + 24g de i.a. ha-1) + propiconazole (125g de i.a. ha-1). As unidades experimentais constaram de parcelas de 1,5 x 5 m arranjadas em delineamento de blocos ao acaso com quatro repetições. As aplicações foram feitas com pulverizador costal com pressão gerada por gás CO2 para equivaler uma vazão de 200 L ha-1. Na análise econômica considerou-se o custo das aplicações, o número de aplicações, o preço do trigo, a intensidade de doenças (área abaixo da curva de progresso de doença - AACPD), a eficácia de controle com base na intensidade de doença e os componentes de rendimento (produtividade, massa de mil grãos e peso do hectolitro). Os dados foram submetidos à ANOVA e as médias comparadas pelo teste de Tukey. Nas duas safras as doenças predominantes foram ferrugem da folha, mancha amarela e oídio. Os valores da AACPD demonstraram que os critérios 1% e 10% de incidência em planta e cinco a seis afilhos apresentaram menores intensidades de doença, com maior controle e maiores produtividades, porém receberam de três a quatro aplicações. Os critérios do primeiro nó visível e LDE receberam de duas a três aplicações e apresentaram valores intermediários para incidência, 8 severidade e produtividade. Os critérios do terceiro nó visível e 5% de severidade foliar iniciaram o controle químico mais tardiamente, recebendo de uma a duas aplicações e demonstraram maiores médias de incidência e severidade, menor controle, bem como menor produtividade de grãos

O meloeiro (Cucumis melo L.) é uma cultura de grande importância econômica para o comércio de exportação brasileiro e é cultivada principalmente na região Nordeste. A produção da cultura pode ser limitada por uma doença das partes aéreas, denominada oídio, sendo no Brasil, causada pelo fungo Podosphaera xanthii. Este patógeno apresenta diversas raças definidas com base na reação de um conjunto de cultivares diferenciadoras de meloeiro. Dentre estes genótipos, o acesso PI 414723 é resistente à maior parte das raças e a linhagem Védrantais é suscetível. O presente trabalho teve como objetivos: (i) estudar a herança da resistência às raças 1, 3 e 5 de P. xanthii em indivíduos da geração F2 do cruzamento PI 414723 x Védrantais e (ii) mapear os genes de resistência a estas raças com base em marcadores de polimorfismo de comprimento de fragmentos amplificados (AFLP), de repetições de sequências simples (SSR) e análogos de genes de resistência (RGA) também nesta população. A herança da resistência foi analisada em 87 indivíduos F2 cultivados em condições de casa-de-vegetação. As três raças foram inoculadas em seis regiões eqüidistantes da nervura central em quatro folhas de cada planta. Plantas foram classificadas como resistentes ou suscetíveis com base em avaliações visuais do desenvolvimento do fungo nas folhas. As plantas foram classificadas como suscetíveis quando houve reprodução abundante de conídios e resistentes quando a reprodução foi inexistente ou escassa. Frequências de indivíduos resistentes e suscetíveis indicaram que a resistência às três raças é controlada por um gene dominante de efeito maior. Um mapa genético foi construído compreendendo 1.469 cM, consistindo de 207 marcadores (139 AFLP, 47 SSR, 18 RGA e três fenotípicos) e com uma distância média de 7,4 cM entre marcadores distribuídos em 12 grupos de ligação. Análises de co-segregação com marcadores indicaram que os genes de resistência estão localizados no grupo de ligação II. Em adição a isto, as análises indicaram ligação completa entre os genes de resistência às raças 1 e 5, sendo este gene denominado Pm-x1.5. Já o gene de resistência à raça 3 (Pm-x3) foi localizado a 5,1 cM dos demais. Um marcador AFLP (H35M75_156) foi localizado entre os dois genes a 1,3 cM de Pm-x1.5 e 3,8 cM de Pm-x3. Este é o primeiro relato da localização genética de genes de resistência às raças 3 e 5 em PI 414723 e também o primeiro relato do mapeamento de marcadores RGA gerados pela técnica TRAP em meloeiro. / Melon (Cucumis melo L.) is a crop of great economic importance for the export trade in Brazil and is cultivated mainly in the Northeast. Crop yield can be affected by a disease of the aerial parts, called powdery mildew that in Brazil is caused by the fungus Podosphaera xanthii. This pathogen has several races characterized based on the reaction of a set of differential melon cultivars. Among these genotypes, the plant introgression PI 414723 is resistant to most races and the breeding line Védrantais is susceptible. This study aimed to: (i) study the inheritance of resistance to races 1, 3 and 5 of P. xanthii in the F2 generation from the cross PI 414723 x Védrantais, and (ii) map resistance genes to these races in this same population based on amplified fragment length polymorphism (AFLP), simple sequence repeat (SSR) and resistance gene analog (RGA) markers. The inheritance of resistance was analyzed on 87 F2 individuals grown under greenhouse conditions. The three races were inoculated simultaneously on four leaves of each plant. Plants were classified as resistant or susceptible based on visual assessments of fungal growth on the leaves. Plants were considered susceptible when there was abundant production of conidia and resistant when the production was scarce or non-existent. The frequencies of resistant and susceptible individuals indicated that resistance to all three races is controlled by a dominant major gene. A genetic map was constructed comprising 1469 cM, consisting of 207 markers (139 AFLP, 47 SSR, 18 RGA, and three phenotypic) with an average distance of 7.4 cM between markers distributed in 12 linkage groups. Co-segregation analysis with markers indicated that the resistance genes are located on linkage group II. Moreover, the analysis indicated complete linkage between resistance to races 1 and 5, and this gene was denominated Pm-x1.5. The gene for resistance to race 3 (Pm-x3) was located at 5.1 cM from Pmx1.5. An AFLP marker (H35M75_156) was located between the two genes at 1.3 cM from Pmx1.5 and 3.8 cM from Pm-x3. These is the first report on the location of resistance genes to races 3 and 5 in PI 414723, and also the first report of RGA markers mapping using the TRAP technique in melon.

Le cucurbitacee possono essere attaccate da più di 200 malattie, una corretta gestione è dunque fondamentale per ridurre il rischio di perdite di produzione, sia in termini di quantità sia in termini di qualità. Tra le malattie più importanti che attaccano le cucurbitacee ci sono l’oidio e la peronospora delle cucurbitacee. Podosphaera xanthii e Golovinomyces cichoracearum sono gli agenti causali dell’oidio. È stato studiato l’effetto della temperature sulla germinazione dei conidi in ambiente controllato a 6 temperature costanti (da 10 a 35°C, ad intervalli di 5C°) da 3 a 72 ore. La temperature ottimale per la germinazone, l’infezione e la sporulazione è risultata essere rispettivamente 24.4, 25.7 e 21.3°C per P. xanthii e 17.9, 17.3 e 16.2°C per G. cichoracearum. Un modello meccanicistico è stato sviluppato per il rischio che i due agenti patogeni causassero un attacco di oidio. Il modello simula la germinazione su foglie infettate sulla base delle condizioni ambientali di temperatura e umidità relativa. Le equazioni che calcolano la germinazione delle dei conidi di entrambi i funghi sono state sviluppate sulla base di dati presenti in bibliografia. Un secondo modello meccanicistico è stato sviluppato per Pseudoperonospora cubensis, agente causale della peronospora delle cucurbitacee. Il modello calcola la data di comparsa dei sintomi e la probabilità del superamento di determinate soglie di gravità della malattia, sulla base di sotto-processi dell’infezione. Il passaggio da uno stato dell’infezione al successivo è dipendente dalle condizioni ambientali. Entrambi i modelli sono stati validati confrontando i dati ottenuti dai modelli con dati indipendenti rilevati in coltivazioni del nord Italia. / Cucurbits are potentially affected by more than 200 diseases of diverse etiologies, so a good disease management is crucial to reduce the risk of high yield losses in terms of quantity and quality. Among the more important diseases there are powdery and downy mildew. Podosphaera xanthii and Golovinomyces cichoracearum are the causal agents of cucurbit powdery mildew. The effect of temperature on conidial germination was studied in controlled condition at 6 constant temperature (from 10 to 35°C, step 5°C) for 3 to 72 hours. Optima temperature for conidial germination, infection and sporulation were 24.4, 25.7 and 21.3°C respectively for P. xanthii and 17.9, 17.3 and 16.2°C for G. cichoracearum. A mechanistic model was developed for the risk posed by P. xanthii and G. cichoracearum to cause cucurbit powdery mildew. The model simulates germination on infected leaves on the base of environmental conditions of temperature and relative humidity. Equation regulating spore germination of both fungi were developed using published data. Another mechanistic model was develop also for Pseudoperonospora cubensis, causal agent of cucurbit downy mildew. The model calculates the symptoms appearance and the probability of overtaking severity threshold based on sub-processes of infection. Changes from one state of the infection to the following one depend on environmental conditions. Both models were validated by comparing model outputs with independent data sets collected in fields located in the north of Italy.

Comment concilier productivité et réduction de l'usage des pesticides ? Le développement de l'oïdium, maladie majeure en viticulture, peut être limité (service de régulation de l'oïdium) par un faible niveau de développement végétatif de la vigne associé à une forte porosité du couvert. Or, de telles caractéristiques limitent également la quantité de rayonnement intercepté par la vigne, et donc la production de biomasse par photosynthèse, et finalement le rendement (service d'approvisionnement). Peut-on augmenter la régulation de l'oïdium sans diminuer le rendement de la vigne ? Autrement dit, existe-t-il une relation de compromis entre ces deux services ? Pour répondre à cette question, deux expérimentations ont été mobilisées : une expérimentation au champ réalisée près de Montpellier de 2010 à 2012 (Syrah), et un réseau de témoins non traités suivis par l'IFV dans la région de Bordeaux de 2007 à 2013. L'analyse des données issues de ces expérimentations a permis de montrer (i) que l'effet des stress hydrique et azoté sur la formation des inflorescences dans les bourgeons latents à la floraison de l'année n-1 détermine 65 à 70 \% du rendement de la vigne lors de l'année n ; (ii) que l'effet du développement végétatif de la vigne sur le développement de l'oïdium n'est significatif que dans le cas d'épidémies de précocité moyenne, dont les premiers symptômes ont été détectés sur feuilles entre la floraison et la fermeture de la grappe. Le développement végétatif de la vigne à la floraison est donc un indicateur pertinent du service de régulation de l'oïdium. Ces résultats ont ensuite permis de confirmer expérimentalement l'hypothèse de l'existence d'un compromis entre rendement de la vigne et régulation de l'oïdium et d'identifier le stress hydrique à la floraison comme un déterminant partagé de ces deux services. Ce dernier point a alors été transcrit dans un modèle simple dans lequel le rendement de la vigne de l'année n dépend principalement de l'année n-1, et le développement végétatif dépend seulement de l'année n. L'analyse des propriétés mathématiques de ce modèle a permis de montrer que la réalisation de compromis favorables entre ces deux services (i.e. un fort niveau des deux services) est possible mais déterminée par l'occurrence de séquences climatiques particulières (une année humide suivie d'une année sèche). Ainsi, les compromis favorables ne peuvent être atteints deux années consécutives et ne sont donc pas stables dans le temps. Les règles de décisions d'application des traitements phytosanitaires pourraient ainsi être adaptées en fonction de la variabilité climatique inter-annuelle et de ses conséquences sur les compromis entre le rendement de la vigne et la régulation des maladies cryptogamiques. / How to combine crop productivity and reduction in pesticide use ? A reduction in plant growth and an increase in crop canopy porosity has been shown to limit the development of the grapevine powdery mildew (powdery mildew regulation service), which is a major disease in viticulture. However, this could also limit grapevine yield through a reduction in light interception and biomass production through photosynthesis. Can regulation of powdery mildew be increased without grapevine yield impairment ? In other words, do these two services trade off ? To address this question, two experiments were used. A field experiment was conducted in Montpellier from 2010 to 2012 on Shiraz, and a network of non-sprayed vineyard plots was monitored by the French Institute of Vine and wine in the Bordeaux region from 2007 to 2013. Data analyses showed that: (i) 65 to 70 \% of grapevine yield in year n were determined by the effect of water and nitrogen stresses on inflorescence formation in the latent buds at flowering in year n-1; (ii) the effect of grapevine vegetative development on powdery mildew depended on epidemic earliness and was significant only when first symptoms were detected on leaves between flowering and bunch closure. Grapevine vegetative development at flowering was therefore a relevant indicator of the powdery mildew regulation service. Based on these results, the hypothesis of a trade-off between grapevine yield and powdery mildew regulation was experimentally confirmed and water stress at flowering was identified as a shared driver of these two services. Then, a simple model was built that accounted for the effect of water stress at flowering on the two services, where grapevine yield depended mostly on year n-1 and grapevine vegetative development depended only on year n conditions. Analysis of the model's mathematical properties showed that "win-win" scenarios (high level of both services) did exist and were reached when specific climatic sequences occured (a wet year followed by a dry year). The "win-win" scenarios could not be reached two consecutive years and were therefore temporally unstable. Decision rules for pesticides application may be adapted in function of the inter-annual climatic variability and its effect on the trade-off between grapevine yield and regulation powdery mildew.

The agriculture sectors in Canada are highly vulnerable to a wide range of inter-related weather risks linked to seasonal climate variability (e.g., El Ni ̃no Southern Oscillation(ENSO)), short-term extreme weather events (e.g., heatwaves), and emergent disease(e.g., grape powdery mildew). All of these weather-related risks can cause severe crop losses to agricultural crop yield and crop quality as Canada grows a wide range of farm products, and the changing weather conditions mainly drive farming practices. This dissertation presents three machine learning-based statistical models to assess the weather risks on the Canadian agriculture regions and to provide reliable risk forecasting to improve the decision-making of Canadian agricultural producers in farming practices. The first study presents a multi-scale, cluster-based Principal Component Analysis(PCA) approach to assess the potential seasonal impacts of ENSO to spring wheat and barley on agricultural census regions across the Canada prairies areas. Model prediction skills for annual wheat and barley yield have examined in multi-scale from spatial cluster approaches. The ’best’ spatial models were used to define spatial patterns of ENSO forcing on wheat and barley yields. The model comparison of our spatial model to non-spatial models shows spatial clustering and ENSO forcing have increase model performance of prediction skills in forecasting future cereal crop production. The second study presents a copula-Bayesian network approach to assess the impact of extreme high-temperature events (heatwave events) on the developments of regional crops across the Canada agricultural regions at the eco-district-scale. Relevantweather variables and heatwave variables during heatwave periods have identified and used as input variables for model learning. Both a copula-Bayesian network and Gaussian-based network modeling approach is evaluated and inter-compared. The copula approach based on ’vine copulas’ generated the most accurate predictions of heatwave occurrence as a driver of crop heat stress. The last study presents a stochastic, hybrid-Bayesian machine-learning approach to explore the complex causal relationships between weather, pathogen, and host for grape powdery mildew in an experimental farm in Quebec, Canada. This study explores a high-performance network model for daily disease risk forecast by using estimated development factors of pathogen and host from recorded daily weather variables. A fungicide strategy for disease control has presented by using the model outputs and forecasted future weather variability. The dissertation findings are beneficial to Canada’s agricultural sector. The inter-related weather risks explored by the three separate studies in multi-scales provide a better understanding of the interactions between changing weather conditions, extreme weather, and crop production. The research showcases new insights, methods, and tools for minimizing risk in agricultural decision-making / Graduate / 2021-08-19

Plants can interact with many different organisms on many trophic levels in their life. In this thesis I investigated how three biotic inertactions, powdery mildew infection, caused by Podosphaera ferruginea, predispersal seed predation by Dusky Large Blue (Phengaris nausithous) and Scarce Large Blue (P. teleius) and deer grazing affect life cycle and population biology of the Great Burnet (Sanguisorba officinalis L.). I also analysed their preferences of environmental conditions. Most of studied plant populations growth rates (λ) were lower than 1 and population decreased, but quite surprisingly for more populations vegetative reproduction was more important than reproduction by seeds. All intraction mentioned above affects more generative reproduction, and thus their influence on Great Burnet population dynamics is low, even with modelled maximal possible effect. Environment conditions analysis showed that powdery mildew occurs on sites with more flowering individuals, where spreading is very easy, butterflies preferred high, well noticeable flower heads grown high above other vegetation and host ant presence. For host ants' presence model locality was only significant variable.

This study was undertaken to determine the sensitivity of grape downy mildew (DM, Plasmopara viticola) and powdery mildew (PM, Erysiphe necator) to commonly used single-site fungicides in Virginia and nearby states. DM and PM isolates were collected from 2005 to 2007. In grape leaf disc bioassays, 92% of the DM isolates were QoI (azoxystrobin)-resistant, but none were resistant to mefenoxam. Eighty-two percent of the PM isolates were QoI-resistant, but none were resistant to boscalid and quinoxyfen. The frequency of the G143A point mutation, which confers high levels of QoI resistance, was quantified in DM and PM isolates by real-time PCR. Most of the QoI-resistant DM and PM isolates contained >95% of the 143A allele. QoI-sensitive DM isolates contained less than 1% of 143A. One out of 145 and 14 out of 154 QoI-resistant DM and PM isolates (able to grow on azoxystrobin concentration ï ³ 1 µg/ml), respectively, contained less than 1% 143A. Most PM isolates exhibited reduced sensitivity to five DMI fungicides when compared to a sensitive subgroup (n=9) and compared to published reports for unexposed populations; the resistance factor (median EC50 of the entire isolate collection divided by median EC50 of sensitive subgroup) was highest for tebuconazole (360) and myclobutanil (350), followed by triflumizole (79), triadimefon (61), and fenarimol (53). Sensitivities to all five DMI fungicides, but also azoxystrobin, were moderately to strongly correlated (pairwise r-values ranging from 0.60 to 0.88). / Master of Science in Life Sciences

Development of fungicide resistance in fungal and oomycete pathogens is a serious problem in grape production. Quinoxyfen is a fungicide widely used against grape powdery mildew (Erysiphe necator). In 2013, E. necator isolates with reduced quinoxyfen sensitivity (designated as quinoxyfen lab resistance or QLR) were detected in Virginia. Field trials were conducted in 2014, 2015, and 2016 at the affected vineyard to determine to what extent quinoxyfen might still contribute to disease control. Powdery mildew control by quinoxyfen was good, similar to, or only slightly less, than that provided by myclobutanil and boscalid in all three years. The frequency of QLR in vines not treated with quinoxyfen declined only slowly over the three years, from 65% to 46%. Information about the mode of action of quinoxyfen is limited; previous research suggests that quinoxyfen interferes with the signal transduction process. We profiled the transcriptomes of QLR and sensitive isolates in response to quinoxyfen treatment, providing support for this hypothesis. Additional transcriptional targets of quinoxyfen were revealed to be involved in the positive regulation of the MAPK signaling cascade, pathogenesis, and sporulation activity. Grape downy mildew (Plasmopara viticola), another important grape pathogen, is commonly controlled by phosphite fungicides. A field trial and laboratory bioassays were conducted to determine whether P. viticola isolates from vineyards with suspected control failures showed reduced sensitivity against phosphite fungicides. Prophyt applied at 14-day intervals under high disease pressure provided poor downy mildew control in the field. Next-generation sequencing technologies were utilized to identify 391,930 single nucleotide polymorphisms (SNPs) and generated a draft P. viticola genome assembly at ~130 megabase (Mb). Finally, field isolates of P. viticola collected from a Virginia vineyard with suspected mandipropamid control failure were bioassayed. The EC50 values of the isolates were >240 μg.ml-1 for mandipropamid, well above the field rate. The PvCesA3 gene of two resistant isolates was sequenced revealing that these isolates had a GGC-to-AGC substitution at codon 1105, the same mutation that has been found associated with CAA resistance elsewhere. / PHD / Powdery and downy mildew are two diseases of grapes that can cause large yield losses, and are usually controlled by regular fungicide applications. Development of fungicide resistance has been a growing challenge. Quinoxyfen is a protectant fungicide commonly used against powdery mildews. Unusual grape powdery mildew isolates that grew well on quinoxyfen-treated plants in the laboratory (designated as quinoxyfen lab resistance or QLR) were detected in a Virginia vineyard. In 2014, the first year of this study, 65% of powdery mildew isolates from parts of this vineyard that received no further quinoxyfen treatments had the QLR type of resistance, and this declined only slowly to 46% by the third year. Field trials were conducted in 2014, 2015, and 2016 to determine the efficacy of quinoxyfen in the presence of QLR. Powdery mildew control by quinoxyfen on both grape clusters and leaves was similar to, or only slightly less, than that provided by the standard anti-powdery mildew fungicides myclobutanil and boscalid in all three years. In order to gain a better understanding of the mode(s) of action and resistance mechanism(s) of quinoxyfen, gene expression of QLR and sensitive isolates, both in the presence and absence of quinoxyfen, was analyzed by nucleic acid sequencing. This study confirms previous research suggesting that quinoxyfen interferes with the important biological process signal transduction, and revealed additional gene targets of quinoxyfen. The phosphites are a group of fungicides commonly used to control grape downy mildew. Control failures after phosphite application have occasionally been suspected, and downy mildew isolates from vineyards with and without suspected control failures were tested in laboratory bioassays to determine if any level of resistance could be demonstrated. There was a limited range of sensitivity, and none of the isolates showed a notable loss of sensitivity. A field trial was conducted to determine the efficacy of one phosphite fungicide, Prophyt, applied at 14-day intervals under conditions favorable for disease development. Prophyt provided poor downy mildew control, suggesting that it has to be applied more frequently. Next-generation sequencing technologies were utilized to identify genetic markers for clade identification and generated a draft genome assembly of grape downy mildew, which improves the understanding of grape downy mildew genome. Grape downy mildew isolates collected from a vineyard in Virginia where mandipropamid provided poor control of downy mildew were bioassayed. The isolates tolerated mandipropamid rates well above the field rate, showing that they were indeed resistant. The mutation that confers mandipropamid resistance on other continents was found in the PvCesA3 gene of two resistant isolates.

[ES] Las cucurbitáceas son la segunda familia de hortícolas más importante a nivel mundial, solo por detrás de las solanáceas. Tradicionalmente su cultivo se ha llevado a cabo en las zonas templadas del planeta. Sin embargo, las condiciones de cambio climático, el comercio internacional y los modelos de agricultura intensiva favorecen la aparición de nuevas virosis y enfermedades fúngicas en zonas donde antes no estaban presentes. En este sentido, resulta esencial el monitoreo periódico de las principales zonas productoras, para así poder detectar los virus y hongos emergentes en cada territorio y adaptar los programas de mejora a los objetivos específicos de cada zona. En el caso concreto del melón (Cucumis melo) existe una gran variabilidad intraespecífica que puede servir como fuente de alelos de resistencia frente a estos patógenos. Sin embargo, las fuentes de resistencia suelen encontrarse dentro del germoplasma silvestre, normalmente originario de África o Asia, y en el que el nivel de domesticación es reducido. Para un mejor aprovechamiento de las accesiones resistentes, resulta necesario un estudio del control genético de los caracteres de interés, que permita localizar las regiones asociadas a la resistencia y diseñar marcadores moleculares asociadas a las mismas. Esto facilita los programas de mejora orientados a la introgresión de las resistencias manteniendo el fondo genético de las variedades de interés En la presente tesis doctoral, durante las campañas de verano de 2019 y 2020, se ha llevado a cabo un estudio de la incidencia y diversidad genética de 9 especies virales potencialmente limitantes para el cultivo de cucurbitáceas en el sur este español. Se ha podido observar que los virus transmitidos por pulgones son prevalentes frente a los transmitidos por mosca blanca. Dentro del primer grupo destacó la presencia de watermelon mosaic virus (WMV), cucurbits aphid borne yellows virus (CABYV) y cucumber mosaic virus (CMV), ya que fueron detectados en todas las zonas y cultivos estudiados, apareciendo frecuentemente en infecciones mixtas. Moroccan watermelon mosaic virus (MWMV) y tomato leaf curl New Delhi virus (ToLCNDV) también fueron detectados en algunas zonas, pero con porcentajes de infección más bajos y normalmente en infecciones mixtas con WMV. Los análisis filogenéticos de los distintos aislados encontrados ha permitido la identificación de 7 nuevos perfiles moleculares de WMV y de aislados recombinantes de CMV, lo que es consistente con los resultados obtenidos en otros países y pone de manifiesto la gran variabilidad de estos patógenos. Las accesiones silvestres de melón recogidas en distintos bancos de germoplasma son un valioso recurso para los programas de mejora genética frente a estreses bióticos. La accesión africana TGR-1551 ha sido descrita previamente como resistente a WMV, CYSDV (cucurbit yellow stunting disorder virus), CABYV y el hongo Podosphaera xanthii (Px, razas 1, 2 y 5) agente causal del oídio en melón. Además, es tolerante a la mosca blanca (Bemisia tabaci) y portadora del gen Vat (virus aphid transmission), el cual limita la transmisión de virus por pulgón. Por lo tanto, esta accesión constituye una buena fuente de alelos de resistencia y, al poder utilizar un único parental donante, su uso acortaría los programas de mejora. En el marco de la presente tesis doctoral, mediante el desarrollo de poblaciones segregantes de mapeo y el aprovechamiento de las tecnologías de genotipado masivo se han podido cartografiar los QTLs asociados a la resistencia a CYSDV derivados de esta entrada. En el caso de la resistencia a CYSDV, se han detectado dos QTL en el cromosoma 5. El primero de ellos es de efecto mayor y herencia dominante, estando asociado al desarrollo de síntomas. El segundo QTL, de efecto menor y también de herencia dominante, no confiere resistencia por sí mismo y está asociado a la carga viral durante la infección. Siguiendo una estrategia similar se han podido cartografiar y estrecha / [CA] Les cucurbitàcies són la segona família d'hortícoles més important a nivell mundial, només per darrere de les solanàcies. Tradicionalment el seu cultiu s'ha dut a terme a les zones temperades del planeta. No obstant això, les condicions de canvi climàtic, el comerç internacional i els models d'agricultura intensiva afavoreixen l'aparició de noves virosis i malalties fúngiques en zones on abans no estaven presents. En aquest sentit, resulta essencial el monitoratge periòdic de les principals zones productores, per a d'aquesta manera, poder detectar els virus i fongs emergents en cada territori i adaptar els programes de millora als objectius específics de cada zona. En el cas concret del meló (Cucumis melo) existeix una gran variabilitat intraespecífica que pot servir com a font d'al·lels de resistència enfront d'aquests patògens. No obstant això, les fonts de resistència solen trobar-se dins del germoplasma silvestre, normalment originari d'Àfrica o Àsia, i en el qual el nivell de domesticació és reduït. Per a un millor aprofitament de les accessions resistents, resulta necessari un estudi del control genètic dels caràcters d'interés, que permeta localitzar les regions associades a la resistència i dissenyar marcadors moleculars associats a aquestes. Això facilita els programes de millora orientats a la introgressió de les resistències mantenint el fons genètic de les varietats d'interés. En la present tesi doctoral, durant les campanyes d'estiu de 2019 i 2020, s'ha dut a terme un estudi de la incidència i diversitat genètica de nou espècies virals potencialment limitants per al cultiu de cucurbitàcies en el sud-est espanyol. S'ha pogut observar que els virus transmesos per pugons són prevalents enfront dels transmesos per mosca blanca. Dins del primer grup va destacar la presència de watermelon mosaic virus (WMV), cucurbits aphid born yellows virus (CABYV) i cucumber mosaic virus (CMV), ja que van ser detectats en totes les zones i cultius estudiats, apareixent sovint en infeccions mixtes. Moroccan watermelon mosaic virus (MWMV) i tomatoleaf curl New Delhi virus (ToLCNDV) també van ser detectats en algunes zones, però amb percentatges d'infecció més baixos i normalment en infeccions mixtes amb WMV. Les anàlisis filogenètiques dels diferents aïllats trobats ha permés la identificació de set nous perfils moleculars de WMV i d'aïllats recombinants de CMV, la qual cosa és consistent amb els resultats obtinguts en altres països i posa de manifest la gran variabilitat d'aquests patògens. Les accessions silvestres de meló recollides en diferents bancs de germoplasma són un valuós recurs per als programes de millora genètica enfront d'estressos biòtics. L'accessió africana *TGR-1551 ha sigut descrita prèviament com a resistent a WMV, CYSDV (cucurbit yellow stunting disorder virus), CABYV i el fong Podosphaera xanthii (Px, races 1, 2 i 5) agent causal de l'oïdi en meló. A més, és tolerant a la mosca blanca (Bemisia tabaci) i portadora del gen Vat (virus aphid transmission), el qual limita la transmissió de virus per pugó. Per tant, aquesta accessió constitueix una bona font d'al·lels de resistència i, en poder utilitzar un únic parental donant, el seu ús acurtaria els programes de millora. En el marc de la present tesi doctoral, mitjançant el desenvolupament de poblacions segregants de mapatge i l'aprofitament de les tecnologies de genotipat massiu s'ha pogut cartografiar els QTLs associats a la resistència a CYSDV derivats d'aquesta entrada. En el cas de la resistència a CYSDV, s'han detectat dues QTL en el cromosoma cinc. El primer d'ells és d'efecte major i herència dominant, estant associat al desenvolupament de símptomes. El segon QTL, d'efecte menor i també d'herència dominant, no confereix resistència per si mateix i està associat a la càrrega viral durant la infecció. Seguint una estratègia similar s'han pogut cartografiar i estrényer els *QTLs de resistència enfront de Px. En aquest cas es tracta d'una epistàsia dominant-re / [EN] Cucurbits represent the second most important horticultural family worldwide, second only the Solanaceae family. Traditionally, their cultivation has been concentrated in temperate regions across the globe. However, climate change conditions, international trade, and intensive agricultural practices are contributing to the emergence of new viral and fungal diseases in regions where they were previously absent. In this regard, it is crucial to regularly monitor major production areas to detect emerging viruses and fungi specific to each region. This monitoring allows for the adaptation of breeding programs to the unique goals of each area. In the case of melon (Cucumis melo), it exists significant intraspecific variability that can serve as a source of resistance alleles against these pathogens. However, sources of resistance are often found within wild germplasm, typically originating from Africa or Asia, and characterized by limited domestication. To better utilize these resistant accessions, a study of the genetic control of desirable traits is necessary. This study aims to locate regions associated with resistance and design molecular markers linked to these regions. Such an approach streamlines breeding programs focused on introgressing resistance traits while preserving the genetic background of the desired varieties. During the summer campaigns of 2019 and 2020, this doctoral thesis conducted a study on the incidence and genetic diversity of nine viral species potentially affecting cucurbit cultivation in southeastern Spain. It was observed that viruses transmitted by aphids were more prevalent than those transmitted by whiteflies. Within the first group, the presence of watermelon mosaic virus (WMV), cucurbits aphid borne yellows virus (CABYV), and cucumber mosaic virus (CMV) stood out, as they were detected in all the studied areas and crops, often in mixed infections. Moroccan watermelon mosaic virus (MWMV) and tomato leaf curl New Delhi virus (ToLCNDV) were also detected in some areas but with lower infection percentages, typically in mixed infections with WMV. Phylogenetic analyses of the found isolates have identified seven new molecular profiles of WMV and recombinant CMV isolates, which is consistent with results from other countries, highlighting the extensive variability of these pathogens. Wild melon accessions preserved in various germplasm banks represent a valuable resource for breeding programs against biotic stresses. The African accession TGR-1551 has been previously described as resistant to WMV, CYSDV (cucurbit yellow stunting disorder virus), CABYV, and the fungus Podosphaera xanthii (Px, races 1, 2, and 5), which causes powdery mildew in melons. Additionally, it is tolerant to whiteflies (Bemisia tabaci) and carries the Vat gene (Virus Aphid Transmission), limiting virus transmission by aphids. Therefore, this accession constitutes as an excellent source of resistance alleles, and its use, as a single donor parent, can expedite breeding programs. Within the scope of this doctoral thesis, through the development of segregating mapping populations and the utilization of high-throughput genotyping technologies, the QTLs associated with CYSDV resistance from this accession have been mapped. In the case of CYSDV resistance, two QTLs have been detected on chromosome 5. The first of these, with major effects and dominant inheritance, is associated with symptom development. The second QTL, with minor effects and also dominant inheritance, does not confer resistance by itself and is linked to viral load during infection. A similar strategy was employed to map and narrow down the QTLs for resistance against Px. In this case, it involves a dominant-recessive epistasis, with the recessive gene located on chromosome 12 and the dominant gene on chromosome 5, specifically in the same region where the major CYSDV resistance QTL is located. Regarding resistance against WMV, previous studies conducted by the research / This research was funded by the Spanish Ministerio de Ciencia e Innovación (MCIN/AEI/10.13039/501100011033), grant number PID2020-116055RB (C21 and C22), and by the Conselleria d’Educació, Investigació, Cultura i Esports de la Generalitat Valenciana, grant number PROMETEO/2021/072 (to promote excellence groups, cofinanced with FEDER funds). M.L. is a recipient of a predoctoral fellowship (PRE2018-083466) of the Spanish Ministerio de Ciencia, Innovación y Universidades co-financed with FSE funds. / López Martín, M. (2023). Breeding Melons for Resistance to Viral and Fungal Diseases. Exploiting the Multi-Resistant Accession TGR-1551 [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/202060