Orientador: Paulo Cezar Ceresini / Resumo: Fungos do gênero Pyricularia apresentam uma ampla gama de plantas hospedeiras, com capacidade de infectar mais de 50 espécies de gramíneas nas quais causam a doença brusone. Há relatos que a espécies forrageira braquiária (Urochloa brizantha) é hospedeira de muitas espécies deste fungo. Muito embora a brusone em braquiária não cause prejuízos à produção de pastagens, a distribuição generalizada desta forrageira no país a torna uma importante fonte de inóculo do patógeno para diversas outras culturas de importância agrícola severamente danificadas pela brusone, em especial o trigo. A brusone do trigo é causada principalmente por Pyricularia graminis-tritici (Pygt), pode ser também ser atribuída a duas outras espécies de Pyricularia, P. pennisetigena (Pp) e P. urashimae (Pu). Dessa forma o objetivo deste estudo foi determinar a suscetibilidade bem como a reação de nove espécies e/ou cultivares do gênero Urochloa aos patógenos Pygt, Pp, Pu e P. grisea (Pg), a única espécie, até então, relatada como patógeno de braquiária no Brasil. De Pygt, foi avaliado também a virulência de sete raças do patógeno em espécies/cultivares de braquiária. Houve variação significativa na patogenicidade e na virulência e agressividade de espécies Pyricularia à diferentes espécies de Urochloa. As cultivares Ipypoã, BRS Tupi e Xaraés foram as mais resistentes às diferentes espécies Pygt, Pg, Pp e Pu do patógenos da brusone. Quando avaliamos a reação de Urochloa às raças B, C e D de P. graminis-tritici ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Fungi of the genus Pyricularia have a wide range of host plants, and are capable of infecting more than 50 species of grasses in which they cause blast disease. There are reports that the signal grass forage species (Urochloa brizantha) is host to many species of this fungus. Although the blast disease in signal grass does not cause damage to pasture production, the widespread distribution of this forage in the country makes it an important source of pathogen inoculum for several other crops of agricultural importance severely damaged by blast, especially wheat. The wheat blast is caused mainly by Pyricularia graminis-tritici (Pygt), but it can also be associated with to two other species of Pyricularia, P. pennisetigena (Pp) and P. urashimae (Pu). Therefore, the objective of this study was to determine the susceptibility and the reaction of nine species and / or cultivars of the genus Urochloa to the pathogens Pygt, Pp, Pu and P. grisea (Pg), the only species hitherto reported as a pathogen of Urochloa in Brazil. For Pygt, the virulence of seven pathogen races or virulence groups to Urochloa species / cultivars was also evaluated. There was significant variation in the pathogenicity and virulence and aggressiveness of Pyricularia species to different Urochloa species. When we evaluated the reaction of Urochloa to P. graminis-tritici races B, C and D, the Urochloa species / cultivars tested showed susceptibility. However, resistance was detected for the other Pygt races. The ... (Complete abstract click electronic access below) / Mestre

Tesis por compendio / [ES] Se desarrolló un ensayo qPCR para la detección y cuantificación de inóculo aéreo de D. amygdali, incluyendo el diseño de un par de cebadores específicos para esta especie. Esta metodología se utilizó para estudiar la dinámica del inóculo de D. amygdali en trampas de esporas colocadas en dos huertos de almendros de diferentes ubicaciones, en dos temporadas de crecimiento. Con los datos climáticos registrados se construyó un modelo Hurdle de dos partes; la primera parte relacionó la presencia o ausencia de ADN de D. amygdali (Bernoulli o cualitativa) y la otra consideró la concentración promedio de ADN del hongo (Gamma o cuantitativa). El efecto de la temperatura estuvo relacionado con la amplitud térmica diaria; los rangos térmicos más amplios redujeron la concentración de ADN, mientras que los rangos térmicos más estrechos aumentaron la detección de ADN. Los días con un promedio de humedad relativa superior al 80% tuvieron un efecto negativo en la concentración de ADN de D. amygdali. Las precipitaciones tuvieron una influencia positiva en ambas partes del modelo, confirmando la contribución de la lluvia en la dispersión del inóculo. Finalmente, la variable velocidad del viento influyó positivamente en ambas partes del modelo, en ambas temporadas de crecimiento. En ensayos de laboratorio, se inocularon ramitas de 25 cultivares de almendro con cuatro aislados de D. amygdali, mientras que las inoculaciones de campo implicaron la inoculación de brotes en crecimiento de cultivares de almendro injertados en el portainjerto 'GF-677', durante cuatro años. En ambos tipos de experimentos, el inóculo consistió en discos de agar con micelio, que se insertaron debajo de la corteza y se midió la longitud de las lesiones causadas por el hongo. Todos los cultivares evaluados mostraron lesiones necróticas en respuesta a D. amygdali, confirmando su susceptibilidad. El análisis de conglomerados clasificó los cultivares como susceptibles o muy susceptibles. Las características agronómicas, como el tiempo de floración y maduración, se vincularon con la susceptibilidad de los cultivares. Los cultivares de floración tardía, muy tardía y de maduración temprana a media, mostraron una alta susceptibilidad. Se realizaron prospecciones entre 2018 y 2020 en seis provincias españolas, para recolectar e identificar oomicetos asociados con síntomas de pudrición de raíz y cuello en almendros. Se obtuvieron un total de 104 aislados de oomicetos procedentes de árboles enfermos, y la secuenciación de la región espaciadora transcrita interna (ITS) identificó especies de diferentes géneros. Phytopythium vexans y Ph. niederhauserii fueron las especies más frecuentes. Las pruebas de patogenicidad en plantas de almendro de un año de edad injertadas en el portainjerto 'Garnem' mostraron síntomas graves, como defoliación, marchitez y muerte regresiva, y algunas plantas murieron cuando se inocularon con Pp. vexans y Ph. niederhauserii. Algunos aislados de Ph. niederhauserii redujeron significativamente el peso seco de las raíces en comparación con el control, pero este efecto no se observó en plantas inoculadas con Pp. vexans. Se evaluó la patogenicidad de 12 especies de oomicetos presentes en el suelo en tres portainjertos híbridos de Prunus utilizados frecuentemente en la cuenca mediterránea. Se realizaron pruebas de patogenicidad con 15 aislados de oomicetos en plantas de portainjertos de 1 año de edad. Noventa días después de la inoculación se evaluaron los síntomas de la enfermedad con una escala de severidad y se calculó el AUDPC y la probabilidad de supervivencia de las plantas inoculadas. Todos los aislados fueron patógenos para las plántulas de los portainjertos y se volvieron a aislar de las lesiones de las raíces. Para cada portainjerto se detectaron grandes diferencias en virulencia entre las diferentes especies de oomicetos y aislados de Ph. niederhauserii. Phytophthora multivora y Pp. helicoides fueron generalmente los más virulentos. / [CA] Es va desenvolupar un assaig qPCR per a la detecció i quantificació d'inòcul aeri de D. amygdali, inclòs el disseny d'un parell d'encebadors específics per a aquesta espècie. Aquesta metodologia es va utilitzar per estudiar la dinàmica de l'inòcul de D. amygdali en trampes d'espores col·locades en dos horts d'ametllers de diferents indrets en dues temporades de creixement. Es va construir un model Hurdle de dues parts amb les dades climàtiques registrades; la primera part relacionava la presència o absència d'ADN de D. amygdali (Bernoulli o qualitatiu) i l'altra considerava la concentració mitjana d'ADN del fong (Gamma o quantitativa). L'efecte de la temperatura estava relacionat amb l'amplitud tèrmica diària; rangs tèrmics més amplis van reduir la concentració d'ADN, mentre que rangs tèrmics més estrets van augmentar la detecció d'ADN. Els dies amb una mitjana d'humitat relativa superior al 80% van tenir un efecte negatiu en la concentració d'ADN de D. amygdali. Les precipitacions van tenir una influència positiva en ambdues parts del model, confirmant la contribució de la pluja en la dispersió de l'inòcul. Finalment, la variable de velocitat del vent va influir positivament en ambdues parts del model, en ambdues temporades de creixement. En proves de laboratori, es van inocular branquetes de 25 cultivars d'ametller amb quatre aïllats de D. amygdali, mentre que les inoculacions de camp van implicar la inoculació de brots en creixement de cultivars d'ametller empeltats al portaempelt 'GF-677' durant quatre anys. En ambdós tipus d'experiments, l'inòcul consistia en discs d'agar amb miceli, que s'introduïen sota l'escorça i es mesuraven les longituds de les lesions provocades pel fong. Tots els cultivars avaluats van mostrar lesions necròtiques en resposta a D. amygdali, confirmant la seva susceptibilitat. L'anàlisi de conglomerats va categoritzar els cultivars com a susceptibles o molt susceptibles. Els trets agronòmics, com ara els temps de floració i maduració, estaven relacionats amb la susceptibilitat del conreu. Els cultivars de floració tardana, molt tardana i de maduració precoç a mitjana van mostrar una alta susceptibilitat. Entre el 2018 i el 2020 s'han realitzat prospeccions a 6 províncies d'Espanya per recollir i identificar oomicets associats a símptomes de podridura de l'arrel i del coll d'ametllers. Es van obtenir un total de 104 aïllats d'oomicets d'arbres malalts i la seqüenciació de la regió de l'espaiador transcrit intern (ITS) va identificar espècies de diferents gèneres. Phytopythium vexans i Ph. niederhauserii eren les espècies més comunes. Les proves de patogenicitat en plàntules d'ametller d'un any empeltades en el portaempelts 'Garnem' van revelar símptomes greus, com ara defoliació, marciment i mort, amb algunes plantes que van morir quan es van inocular amb Pp. vexans i Ph. niederhauserii. Alguns aïllats de Ph. niederhauserii van reduir significativament el pes sec de les arrels en comparació amb el control, però aquest efecte no es va observar en les plàntules inoculades amb Pp. vexans. Es va avaluar la patogenicitat de 12 espècies d'oomicets del sòl en tres portaempelts híbrids de Prunus d'ús habitual a la conca mediterrània. Es van realitzar proves de patogenicitat amb 15 aïllats d'oomicets en plàntules de portaempelt d'un any. Noranta dies després de la inoculació, es van avaluar els símptomes de la malaltia en una escala de gravetat i es va calcular AUDPC i la probabilitat de supervivència de les plàntules inoculades. Tots els aïllats van ser patògens per a les plàntules de portaempelt i es van tornar a aïllar de les lesions de les arrels. Per a cada portaempelt es van detectar grans diferències de virulència entre les diferents espècies d'oomicets i aïllats de Ph. niederhauserii. Phytophthora multivora i Pp. helicoides eren en general els més virulents. / [EN] A qPCR assay for the detection and quantification of aerial inoculum of D. amygdali, including the design of a pair of specific primers for this species, was developed. This methodology was used to study the dynamics of D. amygdali inoculum in spore traps placed at two almond orchards from different locations in two growing seasons. A two-part Hurdle model was built with the recorded climatic data; the first part related the presence or absence of D. amygdali DNA (Bernoulli or qualitative) and the other considered the average concentration of DNA of the fungus (Gamma or quantitative). The temperature effect was related to daily thermal amplitude; wider thermal ranges reduced DNA concentration, while narrower thermal ranges increased DNA detection. The days with average relative humidity higher than 80% had a negative effect on the concentration of D. amygdali DNA. Rainfall had a positive influence on both parts of the model, confirming the contribution of precipitation in the dispersal of inoculum. Finally, wind speed variable positively influenced both parts of the model, in both growing seasons. In laboratory tests, twigs from 25 almond cultivars were inoculated with four isolates of D. amygdali, while field inoculations involved the inoculation of growing shoots of almond cultivars grafted onto 'GF-677' rootstock over four years. In both type of experiments, inoculum consisted of agar plugs with mycelium, which were inserted underneath the bark and the lesion lengths caused by the fungus were measured. All evaluated cultivars showed necrotic lesions in response to D. amygdali, confirming their susceptibility. Cluster analysis categorized cultivars as susceptible or very susceptible. Agronomic traits, such as blooming and ripening times, were linked to cultivar susceptibility. Late blooming, very late blooming, and early to medium ripening cultivars exhibited high susceptibility. Surveys were carried out between 2018 and 2020 in 6 provinces of Spain to collect and identify oomycetes associated with root and crown rot symptoms on almond trees. A total of 104 oomycete isolates were obtained from diseased trees, and sequencing of the internal transcribed spacer (ITS) region identified species from different genera. Phytopythium vexans and Ph. niederhauserii were the most common species. Pathogenicity tests on one-year-old almond seedlings of 'Garnem' rootstock revealed severe symptoms, including defoliation, wilting, and dieback, with some plants dying when inoculated with Pp. vexans and Ph. niederhauserii. Some isolates of Ph. niederhauserii significantly reduced the dry weight of the roots compared with the control, but this effect was not observed in seedlings inoculated with Pp. vexans. Pathogenicity of 12 soil-borne oomycete species on three commonly used Prunus hybrid rootstocks in the Mediterranean Basin was evaluated. Pathogenicity tests with 15 oomycete isolates were conducted on 1-year-old rootstock seedlings. Ninety days after inoculation, disease symptoms were evaluated on a severity scale, and the AUDPC and the survival probability of the inoculated seedlings were calculated. All the isolates were pathogenic to the rootstock seedlings and were re-isolated from root lesions. For each rootstock large differences in virulence were detected among the different oomycete species and isolates of Ph. niederhauserii. Phytophthora multivora and Pp. helicoides were generally the most virulent. / Francisco Beluzán was supported by Agencia Nacional de Investigación y Desarrollo/Subdirección de Capital Humano/Doctorado Becas Chile en el Extranjero/72200145. / Beluzán Flores, FJ. (2024). Study of Diseases Caused by Diaporthe Amygdali and Oomycetes on Almond Crops [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/204445 / Compendio

Afin de caractériser les moûts de Melon B. et de Sauvignon Blanc en composition et de modéliser leur profil d'oxydation, diverses méthodologies analytiques quantitatives ont été développées et validées. La quantification par dilution isotopique des précurseurs de thiols a nécessité la synthèse de molécules marquées qui ont également servies de traceurs lors d'études de filiation dans des milieux complexes. Ainsi, au cours de la fermentation alcoolique, nous avons pu démontrer que le S-3-(hexan-1-ol)-glutathion (G3MH) et la S-4-(4-méthylpentan-2-one)-glutathion (G4MMP) sont métabolisés par la levure et libèrent le 3-mercaptohexan-1-ol (3MH) et la 4-méthyl-4-mercaptopentan-2-one (4MMP) avec des rendements de conversion molaires proches de 4,4 % et 0,3 % respectivement. La modélisation des phénomènes d'oxydation à l'échelle laboratoire a permis par ailleurs de vérifier, comme le laissaient supposer leurs structures chimiques, que les précurseurs de thiols ne sont pas dégradés par les mécanismes oxydatifs affectant les moûts. Au contraire, une formation de G3MH concomitante avec le pic de production du Grape Reaction Product (GRP) est observée. La validation de ces observations à l'échelle industrielle a été conduite par comparaison des pressurages traditionnel et inerté. L' élaboration d'un moût de Melon B. sous gaz inerte n'est pas favorable à la production de G3MH d'origine pré-fermentaire, et a pour conséquence une diminution des teneurs en 3MH dans les vins correspondants, sans pour autant, déprécier les qualités organoleptiques des vins jeunes. Pour le Sauvignon Blanc, le potentiel aromatique de type thiol n'est pas affecté par le type de pressurage, mais une diminution très significative en 3MH dans les vins issus des cuvées obtenues sous gaz inerte est observée. La voie du (E)-2-hexènal qui est certainement impliquée, pourrait expliquer cette perte aromatique. Ainsi, de manière globale, dans nos conditions expérimentales, une oxydation ménagée et raisonnée des moûts de Melon B., et dans une moindre mesure de Sauvignon Blanc, est favorable à la qualité aromatique des vins du Val de Loire. / In order to characterize Melon B. and Sauvignon Blanc musts in composition and to study their oxidation profiles, several analytical methodologies have been developed and validated. The quantification of thiols precursors by Stable Isotope Dilution Assay required the synthesis of labeled molecules, which have been used either as analytical standards or as tracers for relationship studies in complex matrices. Thus, we established that, during the alcoholic fermentation, the S-3-(hexan-1-ol)-glutathione (G3MH) and the S-4-(4-méthylpentan-2-one)-glutathione (G4MMP) are metabolized by the yeast to release the 3-mercaptohexan-1-ol (3MH) and the 4-méthyl-4-mercaptopentan-2-one (4MMP) with molar conversion yields close to 4.4 % and 0.3 % respectively. Oxidation mechanisms study at laboratory scale demonstrated that aromatic potential was not affected by oxidative reactions, as expected in regard to their chemical structures. On the contrary, the G3M H was produced in the same time as the Grape Reaction Product peak (GRP). The validation of these observations at industrial scale was conducted by comparing traditional and inerted pressing systems. The elaboration of a Melon B. must under inert gas was not in favor of a G3MH pre-fermentary production, which induced a decrease of 3MH concentration in wine without affecting the organoleptic qualities of young wines. For Sauvignon Blanc must, the aromatic potential was not affected by the kind of pressing systems but a significant decrease in 3MH was observed in the wines obtained with juices from the beginning of pressing. The E-(2)-hexenal pathway could certainly explain such aromatic losses. Thus, under our experimental conditions, a mild and controlled oxidation of Melon B. must and, in a certain extend of Sauvignon Blanc must, is in favor of the aromatic quality of wines from Loire Valley.

The use of various types of gel electrophoresis for characterization and identifying plant varieties is well estabilished. This diploma work deals with the possibility characterize potato cultivar (Solanum tuberosum L.) by the help of electrophoretic technique SDS {--} PAGE tuber protein profiles. Soluble potato tuber proteins can be classified according to their molecular weight (kDa) into three groups: First, the major tuber protein patatin (37 {--} 44 kDa); second, a group constituted of protease inhibitors (6 {--} 24 kDa); and third group containing all other proteins. First two group manifest genetic variability, which is necessary evalute for its potential using of potato cultivar characterization.

Agribusiness leaders in emerging economies require effective business model innovation strategies to succeed in closing innovation gaps and increasing market share in the growing smallholder farmers' market. Small agribusiness seed companies in Malawi, Zambia, and Zimbabwe in southern Africa often face the challenge of closing the innovation gap in the smallholders' market, resulting in small-scale seed companies missing 90% of the smallholder farmers' seed market segment. The purpose of this multiple case study was to explore strategies that small agribusiness seed company leaders used to close innovation gaps in smallholders' markets. The conceptual framework was based on the business model innovation(BMI). Ten agribusiness seed company executives selected for their innovations in smallholder markets shared their experiences with and insights into strategies that they successfully designed and implemented in closing innovation gaps in the smallholders' market. Data were collected using semistructured interviews. The data analysis process followed De Massis and Kotlar 5-phase analysis cycle: from interview responses analysis to member checking and a review of documents on seed businesses and BMI. Three themes emerged from the data analysis: seed production model, product and market differentiation, and value chain partnerships. The implications of this study for social change are that the results could improve food and nutrition security for more than 51 million impoverished smallholder farmers throughout Sub-Saharan Africa.

The justification for development of elite loblolly pine (Pinus taeda L.) genotypes includes potential increases in stand uniformity and reduction in planting densities and corresponding establishment costs. However, some genotypes produce less desirable characteristics than others. The ability to realize full potential genetic gains is dependent on selecting appropriate combinations of genetic material and silvicultural management. In 2008, a study was established in the upper coastal plain of Mississippi to examine the performance of two varietal loblolly pine genotypes, a “crop tree” ideotype (CROP) and a “competitor” ideotype (COMP), at two levels of management intensity and three different initial tree spacings. After nine growing seasons, differences in crown morphology, top dieback frequency, and growth and yield variables are apparent between genetics and silvicultural intensity. The COMP ideotype had, on average, greater crown volume, less acute branch angles, and LAI than the CROP ideotype. Increasing management intensity had greater impact on crown characteristics than genotype. Current annual increment growth of stem wood was statistically higher in the COMP ideotype under intensive management and lowest stocking level. The interaction of ideotype, management intensity and spacing level significantly impacted growth and yield. The COMP ideotype is projected to produce greater volume than the CROP ideotype on this site. There was no significant difference between ideotypes with respect to specific gravity for any combination of cultural treatments. Instances of top dieback were significantly higher in the CROP ideotype across management and spacing levels. Nutrient sufficiency levels for fast growing loblolly pine and foliar levels in the current study were statistically significant. Differences due to management intensity were related to reduced competition and lower incidence of damage. The results of this study provide a reference point for elite loblolly pine under different silvicultural regimes for landowners interested in performance potential in Mississippi’s upper coastal plain.

A pesar de los beneficios a corto plazo que se obtienen al utilizar insecticidas sintéticos convencionales para el control de plagas agrícolas, su uso continuo puede generar varios problemas a largo plazo (contaminación ambiental, eliminación de entomofauna benéfica, selección de individuos resistentes y daños a la salud humana). Esta situación lleva a una búsqueda permanente de métodos alternativos de control. En la presente Tesis se analizó la resistencia de cultivares de Medicago sativa L., la actividad insecticida, el efecto sobre la reproducción y la actividad repelente de los aceites esenciales de Eucalyptus globulus Labill. y de Mentha x piperita L. en adultos de Acyrthosiphon pisum H., Aphis craccivora K. y Therioaphis trifolii M. (Hemiptera: Aphididae). En 23 cultivares de M. sativa se evaluaron la resistencia por antixenosis y por antibiosis y la tolerancia. Los cultivares ACA 605, Brava y CW 194 resultaron antixénoticos. Los cultivares CW 194, CW 1010, EBC 90, Pampa Flor, Sirosal y Venus, poseen resistencia por antibiosis. Finalmente, Carmina, CW 194, CW 830 y SPS 6550 fueron altamente tolerantes al ataque de estos áfidos. La actividad insecticida de los aceites esenciales de E. globulus y de M. x piperita se evaluó a través de ensayos de inmersión propuestos por la FAO y por exposición a hojas tratadas. Los aceites esenciales de E. globulus y de M. x piperita producen toxicidad por inmersión y por contacto. El efecto subletal de los aceites esenciales fue evaluado utilizando el método de inmersión de hoja. Ambos aceites disminuyeron la progenie en las tres especies de áfidos evaluadas. Por otra parte, el efecto repelente se analizó mediante una prueba de elección foliar. Ambos aceites produjeron un efecto repelente en adultos de A. pisum, A. craccivora y T. trifolii. En consecuencia, los cultivares resistentes y los aceites esenciales de E. globulus y de M. x piperita tienen una potencial aplicación como herramientas dentro del manejo integrado de plagas. / Although the use of synthetic insecticides is really advantageous for the control of agricultural pests at short periods, their continuous use can generate several longterm problems (environmental contamination, elimination of beneficial entomofauna, generation of resistance and damage to human health). This situation leads to a permanent search for alternative methods of control. In this thesis were assessed the resistance of cultivars of Medicago sativa L., the insecticidal activity, the effect on the reproduction and the repellent activity of essential oils of Eucalyptus globulus Labill. and Mentha x piperita L. on adults of Acyrthosiphon pisum H., Aphis craccivora K. and Therioaphis trifolii M. (Hemiptera: Aphididae). Twenty-three cultivars of M. sativa were evaluated for their antixenosis and antibiosis resistance and tolerance. Cultivars ACA 605, Brava and CW 194 were antixenotic. Cultivars CW 194, CW 1010, EBC 90, Pampa Flor, Sirosal and Venus, had resistance by antibiosis. Finally, Carmina, CW 194, CW 830 and SPS 6550 were highly tolerant to the attack of these aphids. The insecticidal activity of both essential oils was evaluated through two methods: toxicity by inmersion using the FAO dip test protocol and exposition to a pretreated leaf. Essential oils of E. globulus and M. x piperita produced toxicity by inmersion and by contact. The sublethal effect of essential oils on reproduction was evaluated using the leaf-dipping method. Both essential oils decreased progeny production of all the three aphid species evaluated. On the other hand, the repellent effect was analyzed by foliar choice test. Both oils produced a repellent effect on adults of A. pisum, A. craccivora and T. trifolii. Therefore, M. sativa resistance cultivars and essential oils of E. globulus and M. x piperita have potential applications for integrated management of this pest.

Varietal forestry may increase the productivity of loblolly pine (Pinus taeda L.) in the Southern United Sates. However, the effects of these genetic x environment interactions are still poorly understood. In this study we examined the responses in growth, stand uniformity and leaf level physiology of loblolly pine clonal varieties and families to silvicultural intensity and site effects. We also looked for patterns in observed traits that were consistent between crown ideotypes. Two varieties of each crown ideotype (narrow vs broad crowns) and two families (controlled mass pollinated (CMP) and open pollinated (OP) family) were tested on the Virginia Piedmont (VA) and the North Carolina Coastal Plain (NC) under different silvicultural intensities (operational vs intensive), and planting density (617, 1235 and 1852 trees per hectare). Data were collected during the first four growing season after establishment. At NC, intensive silviculture increased crown-width, height and dbh by 33%, 14%, and 23%, respectively. At VA, intensive silviculture increased crown-width, height and dbh by 41%, 10%, and 23%, respectively. Intensive silviculture also increased slightly but significantly the stand uniformity of stem growth. However, the differences in productivity between silvicultural treatments were not explained by differences in leaf-level physiology. Across all treatments and sites the varieties generally grew faster than the OP family, but the differences were higher at VA. Varieties did not differ in stem growth, but the broadest crown variety had greater stand uniformity, photosynthetic rate (Asat), carbon isotope discrimination (∆¹³) and lower fascicle size than the OP family. None of the traits assessed inthis study was consistent within the ideotypes. Varieties classified in the same crown-ideotypes may respond differently to the environmental effects of site and silviculture, which reinforces the need of matching varietal forestry with precision silviculture to achieve gains in productivity. / Ph. D.

La diversité des espèces cultivées résulte d’une série d’évènements de domestication, de flux de gènes entre compartiments sauvages et cultivés, d’effets de la sélection adaptative naturelle et aussi de la sélection humaine et des dynamiques de diffusion à de larges échelles, souvent sur de longues périodes. L’impact de ces processus sur la diversité dépend non seulement de la biologie de l’espèce, mais elle est aussi fortement liée au contexte social et aux pratiques humaines. Cette thèse contribue à la compréhension de l’influence de l’Homme sur la dynamique de la diversité de l’amandier in situ. La démarche suivie fait appel à la génétique des populations et à l’anthropologie pour étudier la structuration de la diversité génétique de cette espèce fruitière pérenne allogame, cultivée au Liban. Cette étude comprend trois parties:Dans la première partie, nous avons cherché à comprendre les processus de diversification continue de l’amandier cultivée en se basant sur des évidences tirées de l'archéologie, de l'histoire et de la biologie évolutive de l’amandier dans le Bassin Méditerranéen. Nous avons utilisé une approche de génétique des populations avec de nombreux individus représentant chaque cultivar collecté auLiban. L'échantillonnage intensif de cultivars libanais a été comparé à un grand nombre d’arbres cultivés in situ provenant de différentes régions méditerranéennes. Les résultats nous ont permis de distinguer l’impact des différents périodes de diffusion sur la structure de la diversité génétique.La deuxième partie, a permis d’évaluer l’importance culturelle de l’amandier cultivé au Liban, et d’identifier sa diversité intra-spécifique telle qu’elle est perçue par les informateurs. Nos résultats montrent une hétérogénéité des connaissances des informateurs qui a mené à une taxonomie locale flexible. La flexibilité de la taxonomie locale est révélée par la présence de catégories englobantes et par la complexité du système de nomenclature.Dans la troisième partie, nous avons évalué l’effet du changement de pratiques de propagation sur la structuration et dynamique de la diversité génétique entre les variétés et à l’intérieur de chacune des deux variétés étudiées. Nos résultats montrent que le cultivar traditionnel, multiplié par semis, est structuré géographiquement. L’introduction du mode de propagation clonal par greffage a été adoptée graduellement. Au début, les agriculteurs ont maintenu une certaine diversité génétique par la multiplication sexuée occasionnelle du cultivar introduit. Par contre, l’introduction après l’adoption du greffage a réduit la diversité génétique intra-variétale dans les vergers récents.Cette thèse montre comment les connaissances et les décisions de l’Homme à différents échelles spatiales et temporelles influencent la structure et la dynamique de la diversité de cette espèce. / The diversity of cultivated species results from a series of domestication events, gene flow between wild and cultivated compartments, effects of natural adaptive selection and also on human selection and diffusion dynamics at large scales, often over long periods. The impact of these processes on diversity depends not only on the biology of the species but is also strongly related to social context and human practices. This thesis contributes to the understanding of the influence of human on the dynamics of almond diversity in situ. The approach followed uses population genetics and anthropology to study the structuring of the genetic diversity of this allogamous perennial fruit species, grown in Lebanon. This study consists of three parts:In the first part, we sought to understand the processes of continuous diversification of cultivated almond trees based on evidence from archeology, history and evolutionary biology of almond trees in the Mediterranean Basin. We used a population genetics approach with many individuals representing each cultivar collected in Lebanon. Intensive sampling of Lebanese cultivars was compared to a large number of in situ grown trees from different Mediterranean regions. The results allowed us to distinguish the impact of different diffusion periods on the structure of genetic diversity.The second part assessed the cultural importance of the almond tree grown in Lebanon and identified its intraspecific diversity as perceived by the informants. Our results show heterogeneity of informants' knowledge that led to a flexible local taxonomy. The flexibility of local taxonomy is revealed by the presence of inclusive categories and the complexity of the nomenclature system.In the third part, we assessed the effect of the change in propagation practices on the structuration and dynamics of genetic diversity between two varieties and within each of the varieties studied.Our results show that the traditional cultivar, sexually propagated, is geographically structured. The introduction of clonal propagation mode by grafting was gradually adopted. At first, farmers maintained some genetic diversity through occasional sexual multiplication of the introduced cultivar. In contrast, introduction after grafting has reduced intra-varietal genetic diversity in recent orchards.This thesis shows how human knowledge and decisions at different spatial and temporal scales influence the structure and dynamics of the diversity of this species.

La mise au point d’une méthode d’analyse par UPLC-MS/MS et dilution isotopique nous a permis d’identifier pour la première fois dans un moût le S-3-(hexan-1-ol)-<gamma>-glutamyl-cystéine (<gamma>GluCys-3MH). Suite à cette découverte, l’étude des interconversions entre les glutathionylés, dipeptides et cystéinylés S-conjugués au 3-mercaptohexan-1-ol (3MH) ou à la 4-mercapto-4-méthyl-pentan-2-one (4MMP), a permis de mettre en évidence deux nouvelles formes de précurseurs. Le suivi de l’évolution de ces différents composés au cours de fermentations alcooliques à l’échelle laboratoire a permis de clarifier leur rôle de précurseurs et d’établir les éventuels mécanismes d’interconversion. Par ailleurs, à travers plusieurs expérimentations viticoles et œnologiques conduites à l’échelle pilote en Languedoc et Val de Loire pendant trois années consécutives, des éléments nouveaux ont pu être apportés quant à l’impact de la maturation du raisin et son hétérogénéité, ainsi qu’à l’importance des opérations pré-fermentaires comme la macération pelliculaire ou la stabulation sur bourbes. / The development of a method using UPLC-MS/MS and stable isotope dilution assay allowed us to identify for the first time the S-3-(hexan-1-ol)-<gamma>-glutamyl-cysteine (<gamma>GluCys-3MH) in musts. Following this discovery, the study of interconversions between glutathione, dipeptides and cysteine S-conjugates to 3-mercaptohexan-1-ol (3MH) or 4-mercapto-4-methyl-pentan-2-one (4MMP) highlighted two new forms of precursors. The evolution monitoring of these compounds during alcoholic fermentations at laboratory scale allowed us to clarify their role as precursors and to establish the possible interconversion mechanisms. In addition, through several viticultural and oenological experiments carried out at pilot scale in Languedoc and Val de Loire during three consecutive years, new elements could be … about the impact of grape ripening and its heterogeneity, as well as the importance of prefermentative processes, such as skin maceration and must conservation on lees.