La fusariose de l’épi est une maladie fongique qui touche toutes les cultures de céréales à paille à travers le monde entrainant des baisses de rendements et de la qualité des grains. La fusariose pose également un problème pour la sécurité alimentaire lié à la contamination des grains infectés par des mycotoxines. Le développement de variétés résistantes est considéré comme la méthode la plus efficace et la plus durable pour réduire les dommages causés par la maladie et pour limiter la contamination par les mycotoxines. L’amélioration de la résistance à la fusariose chez le blé dur (Triticum durum Desf.) demeure un défi du fait de son extrême sensibilité à la maladie et de la faible variabilité génétique disponible pour ce caractère. L’objectif principal de cette thèse a été d’évaluer l’effet de Fhb1, le QTL majeur de résistance à la fusariose chez le blé tendre (Triticum aestivumL.), au sein de fonds génétiques de blé dur élite. Pour cela, trois populations de cartographie, comprenant chacune environ 100 F7-RIL (lignées pures recombinantes ou « recombinant inbred lines »), ont été développées à partir de croisements entre la lignée expérimentale de blé dur DBC-480, portant une introgression de Fhb1, et les cultivars de blé dur Karur, Durobonus et SZD1029K. Les lignées ont été évaluées au champ, sur trois saisons, pour leur résistance globale à la fusariose après inoculation en spray de Fusarium culmorum. Des notations morphologiques (date de floraison, hauteur des plantes) ont également été réalisées afin d'évaluer leur influence sur l'infestation. Les lignées ont été génotypées à l’aide de marqueurs SSR et de marqueurs GBS (génotypage par séquençage ou « genotyping-by-sequencing ») développés par DArTseq. L’analyse de liaison a permis d’identifier des QTL de résistance sur les bras des chromosomes 2BL, 3BS, 4AL, 4BS, 5AL et 6AS. DBC-480 contribuait à l’allèle de résistance à tous ces loci. Le QTL sur 3BS a été détecté au sein des trois populations centré sur l’intervalle de Fhb1, confirmant, pour la première fois, son introgression dans le blé dur. L’évaluation de la résistance à la propagation après inoculation ponctuelle, réalisé au sein d’une des trois populations, a également permis de valider l’effet de Fhb1 sur la résistance de type 2 chez le blé dur. La hauteur des plantes influe fortement sur la résistance globale à la fusariose et, en particulier, l’allèle de nanisme Rht-B1b est associé à une plus grande sensibilité à la maladie dans les trois populations. Cependant, l’effet négatif de Rht-B1b sur la résistance est largement compensé dans les lignées possédant Fhb1. Des lignées semi-naines avec un meilleur niveau de résistance ont été sélectionnées et favoriseront le développement de cultivars de blé dur résistants à la fusariose. / Fusarium head blight (FHB) is a devastating disease affecting small-grain cereals worldwide causing yield and quality losses. FHB affects food safety due to the contamination of infected grains by mycotoxins. Host plant resistance is considered the most efficient and sustainable approach to contain FHB and mycotoxin contaminations. In durum wheat (Triticum durum Desf.) breeding for FHB resistance remains a challenge due to its extreme susceptibility and to lack of genetic variation available in the primary durum wheat gene pool. The primary goal of this thesis was to evaluate the effect of Fhb1, the major common wheat (Triticum aestivum L.) FHB resistance QTL, in elite durum wheat background. Three F7-RIL (recombinant inbred lines) mapping populations of about 100 lines were developed from crosses between the durum wheat experimental line DBC-480, harboring Fhb1, and the durum wheat cultivars Karur, Durobonus and SZD1029K. The RILs were tested under field conditions by artificial spray inoculation with Fusarium culmorum in three seasons. Morphological traits (flowering date, height) were also recorded to assess their influence on FHB infestation. Genotyping of the lines was performed with SSR and genotyping-by-sequencing (GBS) DArTseq markers. QTL analysis identified genomic regions associated with FHB resistance on chromosome arms 2BL, 3BS, 4AL, 4BS, 5AL and 6AS. DBC-480 contributed the resistant allele at all loci. Fhb1 was detected in all three populations, demonstrating for the first time its successful deployment in durum wheat. The effect of Fhb1 on FHB resistance in durum wheat was further verified by evaluating type 2 resistance in one of the three populations. Plant height had a strong influence in modulating FHB severity. Although the semi-dwarf allele Rht-B1b was associated with increased FHB susceptibility, its negative effect was efficiently counterbalanced in lines carrying Fhb1. Semi-dwarf lines with enhanced levels of resistance were selected and will assist the development of FHB resistant cultivars.

L’utilisation de molécules stimulatrices des défenses des plantes (SDP), également appelées inducteurs de résistance, constitue une alternative potentielle aux traitements fongicides conventionnels pour combattre les maladies dues à des champignons phytopathogènes. Trois SDPs, le tréhalose (TR), l’acide salicylique (SA) et l’heptanoyl d’acide salicylique (HSA), un dérivé fonctionnel du SA, protègent le blé (Triticum aestivum L.) contre l’oïdium (Blumeria graminis f.sp. tritici), lorsqu’ils sont utilisés de façon préventive. La protection obtenue n’est pas liée à un effet fongistatique direct sur la germination des spores du champignon, mais à l’induction chez le blé de défenses qui diminuent le développement de la maladie. Notre travail consistait à caractériser les mécanismes de défense mis en jeu après applications foliaires de TR, de HSA et de SA chez un cultivar de blé sensible à l’oïdium. Un suivi de l’expression de gènes marqueurs de défense, réalisé par RTqPCR, a été mené en cinétique,depuis le traitement par les SDPs jusqu'à 4 jours après infection. Les activités enzymatiques correspondantes ont été également mesurées, et l’influence indirecte des SPDs sur le processus infectieux a été observé en microscopie in planta. Ainsi, les réactions de défense déclenchées par le TR, le SA et le HSA ralentissent l’évolution de l’infection, jouant respectivement sur la germination des conidies, structures infectieuses de Bgt, sur la germination du tube germinatif appressorial (AGT) et sur la proportion d’AGTs qui parviennent à pénétrer dans les tissus foliaires. Le TR est à l’origine d’une augmentation de l’expression des gènes codant pour une lipoxygénase, une protéine de transfert des lipides et une phospholipase C, impliquées dans le métabolisme lipidique et la signalisation, et de gènes codant pour des protéines PR comme les chitinases et PR1, tous connus comme marqueurs de défense. Ainsi, les réactions déclenchées par le TR correspondent à un effet inducteur de défenseplutôt qu’à une réaction de stress osmotique. Le HSA modifie particulièrement le métabolisme lipidique, en induisant fortement et pendant toute la cinétique, l’expression du gène codant pour la LOX et l’activité correspondante, aussi bien hors contexte infectieux qu’en contexte infectieux. Cette augmentation de l’activité LOX n’est pas retrouvée chez des feuilles traitées au SA et caractérise donc le HSA. L’importance des réactions observées avec le TR, le SA et le HSA, hors contexte infectieux et en présence de Bgt amène à discuter les effets éliciteurs et potentialisateurs de ces 3 SDPs. / The use of plant elicitors, also known as resistance inducers, is an alternative to conventional fungicides to control diseases caused by phytopathogenic fungi. Three resistance inducers, trehalose (TR), salicylic acid (SA) and heptanoyl salicylic acid (HSA), a functional derivative of SA, protect wheat (Triticum aestivum L.) against powdery mildew (Blumeria graminis f . sp. tritici) when applied prior to infection. The protection obtained is not linked to any direct fungistatic effect on the fungal spore germination, but to the induction of wheat defences that impair the development of the disease. Our work aimed at characterizing the defence mechanisms triggered after foliar applications of TR, HSA and SA in a wheat cultivar susceptible to powdery mildew. Monitoring of defence markers genes expression by RTqPCR was conducted during a time-course experiment from the treatment time until 4 days after infection. Corresponding enzyme activities were also measured, and the indirect influence of elicitors on the infectious process was observed by microscopy in planta. Thus, defence responses triggered by TR, SA and HSA slow the progression of the infection, respectively altering the germination of infectious structures such as conidia, the differentiation of appressorial germ tube (AGT) and the proportion of AGTs that manage to penetrate the epidermis. TR causes an increase in the expression of genes encoding a lipoxygenase, a lipid transfer protein and a phospholipase C, which are involved in lipid metabolism and signaling, and genes encoding for PR-proteins such as chitinases and PR1, all known as markers of defence. Thus, the reactions triggered by TR match with the ones triggered during induced defence rather than during osmotic stress response. HSA specifically targeted lipid metabolism, inducing strongly and throughout the time-course, the expression ofthe gene encoding LOX and the corresponding enzyme activity, both in infectious and non-infectious contexts. This increase in LOX activity was not found in leaves treated with SA and thus characterizes HSA mode of action. The importance of the reactions observed with TR, SA and HSA, in non-infectious conditions and in the presence of Bgt have to be considered regarding either elicitation or potentiation.

Aujourd'hui, alors que le nombre de marqueurs génétiques disponibles augmente rapidement, de nouvelles populations doivent être créées pour exploiter au mieux cette quantité d'informations dans le but de mieux comprendre l'architecture génétique de caractères complexes. Les populations de type MAGIC ont été créées pour rassembler les avantages des populations bi-parentales et des panels d'associations, la bonne puissance de détection et une localisation précise. L'objectif de cette thèse était d'étudier l'intérêt de la population MAGIC INRA pour l'analyse de l'architecture génétique de la précocité de floraison. Cette population a été créée à partir de 60 parents brassés durant 12 générations de panmixie grâce à l'introduction d'un gène de stérilité mâle (ms1b). Cette étude a été réalisée sur 56 parents toujours disponibles en banque de graines et 380 lignées dérivées de la population après les 12 générations de recombinaison. Cette population a été génotypée avec la puce 9K iSelect, représentant environ 5 000 SNPs localisés sur tout le génome, additionnée de 14 marqueurs localisés dans des gènes candidats. Ce jeu de données moléculaires a été complété par des données fines de phénotypage de la précocité de floraison. Suite aux 12 générations de panmixie, le DL de cette population a été très réduit, à longue comme à moyenne distance (<10cM). Ce faible DL nous a amené à développer un algorithme basé uniquement sur le DL qui ordonne les marqueurs de manière à avoir un DL décroissant monotone avec la distance. L'algorithme ordonne globalement de la même manière que la carte génétique les marqueurs à longue distance mais à courte distance le DL est moins lié à la distance génétique. La différence réside sur l'équilibre entre les effets de la recombinaison et de la dérive génétique sur le DL. L'intérêt de la population MAGIC INRA pour détecter des QTLs a ensuite été étudié avec deux approches : une approche évolutionniste et une approche de génétique d'association. La première approche détecte les loci soumis à sélection par comparaison des fréquences alléliques de la population initiale (G0) et de la population évoluée (G12) grâce à une nouvelle méthode. La population initiale est composée des parents pondérés par une contribution estimée avec une nouvelle méthode bayésienne. 26 régions génomiques soumises à sélection ont été détectées. Une analyse de génétique d'association avec les marqueurs détectés sous sélection a montré que respectivement cinq et trois zones étaient associées à la précocité avec un semis d'automne et au caractère printemps/hiver. Une analyse phénotypique a effectivement mis en évidence la précocification de la date de floraison et une augmentation de la proportion de plantes de type printemps. Une analyse de génétique d'association a ensuite été réalisée sur les lignées SSD sur 12 caractères x environnements i.e. la date d'épiaison et le temps de remplissage du grain mesurés dans six environnements. Les tests d'association ont aussi été réalisés avec des variables synthétisant l'information présente dans plusieurs traits phénotypiques soit avec une ACP, soit avec un modèle écophysiologique. Au total, toutes ces analyses ont détecté six QTLs dont trois correspondants à des gènes majeurs. Parmi ces six QTLs, deux sont spécifiques des caractères mesurés avec un semis d'automne et deux avec ceux mesurés avec un semis de printemps. / Nowadays, with the dramatically increase of available molecular markers, there is a deep need for new populations allowing to exploit all of this information to better understand the genetic architecture of complex traits. MAGIC populations as they are built to bring together bi-parental populations and association panel advantages, provide such powerful detection and fine mapping capacities. The aim of these PhD was to study the MAGIC INRA population usefulness for the study of genetic architecture of earliness. This population is derived from 12 cycles of random crosses between 60 founders, turning wheat from selfing to outcrossing thanks to the use of a nuclear male sterility gene (ms1b, Probus donor). This population is composed of 56 parents still available and 380 SSD lines. Parents and SSD lines were genotyped using the 9K iSelect SNPs array, providing around 5 000 SNPs on the whole genome, as well as 14 addition markers located in candidate genes. They were also finely phenotyped for earliness traits. With the 12 panmictic generations, the population LD decreased strongly, especially at long and medium distance (<10cM). This allowed us to develop an algorithm mapping markers on the sole pairwise LD information, ordering markers in a way to have the LD decreasing along the distance. When considering long distances, overall the results were consistent with the order found on genetic maps while at short distance LD was poorly linked to genetic distance. These differences between long and short distances were linked to the balance between recombination and drift effects on LD. The usefulness of the MAGIC INRA population for QTL detection was analyzed with two approaches: an evolutionary approach and an association genetics approach. The first one detects loci under selection by identifying high shift in allelic frequency with a new method. The initial population was composed of founders weighted by a contribution estimated with a new Bayesian method. 26 genomic areas under selection were detected. An association genetics analysis with the markers detected as under selection showed respectively five and three genomic regions associated with earliness and growth habit. Actually the G12 population was found phenotypically earlier than the G0 and with more spring individuals. A broader association genetics analysis was performed on G12 population, studying 12 traits x environments i.e. heading date and grain filling time, both observed in six environmental conditions. Two additional integrated traits from either PCA or ecophysiological model were also analyzed. In all, these different analyses detected six QTLs, three of them corresponding to candidate genes. Among these six QTLs, two were specific to autumn sowing and two specific to spring sowing.

A cultura de trigo (Triticum aestivum L.) é a segunda maior do mundo e o Brasil ocupa o segundo lugar de produção na América do sul. Entretanto, a produtividade desta cultura pode ser limitada devido à ocorrência de doenças como a brusone, causada pelo fungo Pyricularia grisea e a doença denominada giberela, causada pelo fungo Fusarium graminearum Populações bacterianas associadas à rizosfera de trigo podem apresentar potencial como agentes de controle biológico de diferentes fitopatógenos. Neste contexto, esta pesquisa foi direcionada ao estudo da composição da comunidade bacteriana rizosférica do trigo e a busca por micro-organismos com potencial para o controle biológico da brusone e da giberela. Assim, para melhor compreensão das comunidades associadas ao trigo, foram realizadas coletas em duas regiões diferentes no Brasil, sendo possível a obtenção de 606 estirpes entre bactérias e actinobactérias da rizosfera do trigo e de solo de cultivo da mesma cultura. Destas, 16 apresentaram, em testes in vitro, potencial antagonista diante dos fungos fitopatogênicos Pyricularia grisea e Fusarium graminearum com diferentes porcentagens de inibição. Dez dos isolados selecionados apresentaram similaridade com a família Streptomycetaceae, porém, quatro linhagens necessitam de estudos mais detalhados, pois a similaridade foi baixa, podendo indicar uma espécie ainda não descrita; quatro linhagens demonstraram similaridade com a família Bacillaceae e dois com a família Paenibacillaceae. Na avaliação de produção de metabólitos secundários com efeito inibitório, apenas dez apresentam potencial, porém estudos mais detalhados se fazem necessários para a confirmação deste mecanismo. A análise de diversidade bacteriana demonstrou uma maior abundância do filo Actinobacteria, seguido pelo filo Proteobacteria e Acidobacteria em ambas as áreas amostradas, entretanto, o filo Acidobacteria foi o que demonstrou a maior variação entre as classes presentes nas diferentes regiões estudadas, indicando uma seleção da comunidade de acordo com a variedade do cultivar e o estádio de desenvolvimento do vegetal. A comunidade bacteriana de trigo apresenta micro-organismos com potencial para a inibição dos fungos causadores da brusone e da giberela, porém o efeito destas linhagens deve ser melhor investigado em condições de campo. A compreensão das comunidades bacterianas associadas ao trigo pode se apresentar como uma importante ferramenta para direcionar a busca por antagonistas. / Wheat (Triticum aestivum) is the second largest crop in the world and Brazil is in the second position in the ranking of production in South America. However, its productivity can be limited due to the occurrence of diseases like wheat blast, caused by the fungus Pyricularia grisea and the disease called Fusarium head blight (FHB), caused by the fungus Fusarium graminearum. Bacterial populations associated to wheat rhizosphere may have potential to act as biological control agents of different plant pathogens. In this context, this research aimed to look at wheat rhizosphere bacterial community and the pursuit of microorganisms with potential for the biological control of wheat blast and FHB. Given this, in order to study wheat bacterial communities, data collection was carried out in two different regions in Brazil, returning 606 bacterial and actinomycetes isolates from wheat rhizosphere and bulk soil. Among these,, 16 strains revealed antagonistic potential against both plant pathogens Pyricularia grisea and Fusarium graminearum, with different percentages of inhibition. Ten strains were selected out of the 16 and showed similarity with the family Streptomycetaceae, whereas four of them displayed a low similarity, requiring a deeper analysis and might indicate new species. Four isolates showed similarity with the family Bacillaceae and two with the family Paenibacillaceae. On the assessment of production of secondary metabolites with inhibitory effects, only ten strains were positive, but more detailed studies are necessary to confirm this mechanism. The analysis of bacterial diversity revealed a larger abundance of the phylum Actinobacteria, followed by the phylum Proteobacteria and Acidobacteria in both areas, however, the phylum Acidobacteria revealed more variation among its classes when both araes were compared, indicating a selection of the community according to the cultivar and the developmental stage. Wheat bacterial community presents microorganism with inhibition potential against fungi responsible for wheat blast and FHB, yet the effect of such strains should be investigated closely under field conditions. The understanding of bacterial communities associated to wheat may be seen as an important tool to help in the search for antagonists.

A cultura de trigo (Triticum aestivum L.) é a segunda maior do mundo e o Brasil ocupa o segundo lugar de produção na América do sul. Entretanto, a produtividade desta cultura pode ser limitada devido à ocorrência de doenças como a brusone, causada pelo fungo Pyricularia grisea e a doença denominada giberela, causada pelo fungo Fusarium graminearum Populações bacterianas associadas à rizosfera de trigo podem apresentar potencial como agentes de controle biológico de diferentes fitopatógenos. Neste contexto, esta pesquisa foi direcionada ao estudo da composição da comunidade bacteriana rizosférica do trigo e a busca por micro-organismos com potencial para o controle biológico da brusone e da giberela. Assim, para melhor compreensão das comunidades associadas ao trigo, foram realizadas coletas em duas regiões diferentes no Brasil, sendo possível a obtenção de 606 estirpes entre bactérias e actinobactérias da rizosfera do trigo e de solo de cultivo da mesma cultura. Destas, 16 apresentaram, em testes in vitro, potencial antagonista diante dos fungos fitopatogênicos Pyricularia grisea e Fusarium graminearum com diferentes porcentagens de inibição. Dez dos isolados selecionados apresentaram similaridade com a família Streptomycetaceae, porém, quatro linhagens necessitam de estudos mais detalhados, pois a similaridade foi baixa, podendo indicar uma espécie ainda não descrita; quatro linhagens demonstraram similaridade com a família Bacillaceae e dois com a família Paenibacillaceae. Na avaliação de produção de metabólitos secundários com efeito inibitório, apenas dez apresentam potencial, porém estudos mais detalhados se fazem necessários para a confirmação deste mecanismo. A análise de diversidade bacteriana demonstrou uma maior abundância do filo Actinobacteria, seguido pelo filo Proteobacteria e Acidobacteria em ambas as áreas amostradas, entretanto, o filo Acidobacteria foi o que demonstrou a maior variação entre as classes presentes nas diferentes regiões estudadas, indicando uma seleção da comunidade de acordo com a variedade do cultivar e o estádio de desenvolvimento do vegetal. A comunidade bacteriana de trigo apresenta micro-organismos com potencial para a inibição dos fungos causadores da brusone e da giberela, porém o efeito destas linhagens deve ser melhor investigado em condições de campo. A compreensão das comunidades bacterianas associadas ao trigo pode se apresentar como uma importante ferramenta para direcionar a busca por antagonistas. / Wheat (Triticum aestivum) is the second largest crop in the world and Brazil is in the second position in the ranking of production in South America. However, its productivity can be limited due to the occurrence of diseases like wheat blast, caused by the fungus Pyricularia grisea and the disease called Fusarium head blight (FHB), caused by the fungus Fusarium graminearum. Bacterial populations associated to wheat rhizosphere may have potential to act as biological control agents of different plant pathogens. In this context, this research aimed to look at wheat rhizosphere bacterial community and the pursuit of microorganisms with potential for the biological control of wheat blast and FHB. Given this, in order to study wheat bacterial communities, data collection was carried out in two different regions in Brazil, returning 606 bacterial and actinomycetes isolates from wheat rhizosphere and bulk soil. Among these,, 16 strains revealed antagonistic potential against both plant pathogens Pyricularia grisea and Fusarium graminearum, with different percentages of inhibition. Ten strains were selected out of the 16 and showed similarity with the family Streptomycetaceae, whereas four of them displayed a low similarity, requiring a deeper analysis and might indicate new species. Four isolates showed similarity with the family Bacillaceae and two with the family Paenibacillaceae. On the assessment of production of secondary metabolites with inhibitory effects, only ten strains were positive, but more detailed studies are necessary to confirm this mechanism. The analysis of bacterial diversity revealed a larger abundance of the phylum Actinobacteria, followed by the phylum Proteobacteria and Acidobacteria in both areas, however, the phylum Acidobacteria revealed more variation among its classes when both araes were compared, indicating a selection of the community according to the cultivar and the developmental stage. Wheat bacterial community presents microorganism with inhibition potential against fungi responsible for wheat blast and FHB, yet the effect of such strains should be investigated closely under field conditions. The understanding of bacterial communities associated to wheat may be seen as an important tool to help in the search for antagonists.

Dans son environnement, la plante interagit sans cesse avec des microorganismes. Elle est confrontée à une variété de microorganismes bénéfiques, neutres ou pathogènes, qui sont fortement dépendants des ressources carbonées que la plante libère dans le sol, leur conférant ainsi un apport de nutriments et d’énergie nécessaire à leur développement. La mycorhize à arbuscules est une symbiose mutualiste formée par 80% des plantes terrestres datant de l’Ordovicien, i.e. environ 450 millions d’années avant notre ère. L’ensemble des travaux de recherche présenté au sein de ce manuscrit, s’inscrit dans le cadre de deux objectifs généraux : (i) acquérir une meilleure compréhension des mécanismes à l’origine des relations trophiques chez la plante mycorhizée, et (ii) étudier l’impact de la mycorhization sur la production végétale tant en terme de quantité que de qualité. Nous avons étudié la réponse à la mycorhization de variétés anciennes de blé afin d’appréhender s’il existait une différence dans un environnement semi-contrôlé (serres) ou dans un environnement non contrôlées (champ), et/ou en fonction de la communauté de champignons mycorhiziens à arbuscules présente. Nos résultats ont mis en évidence que la mycorhization et la nature des champignons mycorhiziens arbusculaires endogènes peuvent influer sur le rendement au stade tallage, même chez des variétés de blé ayant une faible capacité mycorhizogène. Nous avons aussi illustré l’importance de bien choisir les critères utilisés pour mesurer ce gain éventuel. Dans un deuxième axe de recherche nous nous sommes intéressés à l’impact de la mycorhize à arbuscules sur le développement de la tomate Micro-Tom, et les échanges trophiques au cours de l’interaction. Nous avons pu mettre en évidence, grâce à une analyse multivariée, à la fois des différences de comportement parmi les plantes particulièrement aux stades fruit vert mature et fruit rouge mature selon la nature des champignons mycorhiziens à arbuscules présents, et des potentiels phénomènes d’interaction entre deux souches de champignons mycorhiziens à arbuscules; nos résultats confirmant que les arbuscules ne sont pas les seules sites d’échanges dans la mycorhize à arbuscules. Le troisième axe de ce travail a porté sur l’impact potentiel des méthodes de production de semences de variétés anciennes de tomate en condition de sécheresse, à la fois sur la communauté endogène de champignons mycorhiziens au champ, sur la tolérance de la plante au stress hydrique et sur la production végétale en terme de rendement et de qualité des fruits. Le site d’expérimentation se situait au Potager de santé (ferme de production de semences gérée par Pascal Poot). Nos résultats ne montrent aucune différence, en conditions de stress hydrique au champ, entre des variétés cultivées régulièrement sur ce site et des variétés commerciales. Alors, on peut se demander si d’autres facteurs liés au site d’exploitation, tels que les microorganismes interagissant avec les racines de la plante pourraient être à l’origine de la tolérance accrue au stress hydrique. Des travaux sont en cours au laboratoire pour étudier cette hypothèse. L’ensemble de ces travaux ouvrent la voie à de nouvelles recherches visant à élucider les mécanismes moléculaires impliqués dans la régulation des échanges trophiques au cours de la mycorhize à arbuscules et à la valorisation des services écosystémiques rendus par la mycorhize à arbuscules au champ. / In its environment, the plant interacts constantly with microorganisms. It is confronted with a variety of beneficial, neutral or pathogenic microorganisms, which are highly dependent on the carbon resources that the plant releases into the soil, giving them a supply of nutrients and energy necessary for their development. The arbuscular mycorrhiza is a mutualistic symbiosis formed by 80% of terrestrial plants from the Ordovician period, i.e. about 450 million years ago. The research presented in this manuscript was focused on two main goals: (i) to gain a better understanding of the mechanisms underlying trophic relationships in the mycorrhizal plant, and (ii) to study the impact of mycorhization on plant production, both in terms of quantity and quality. We investigated the mycorrhizal response of wheat landraces in order to understand if there were differences in a semi-controlled environment (greenhouses) or in an uncontrolled environment (field), and / or depending on the community of mycorrhizal fungi. Our results showed that mycorrhization and the nature of endogenous arbuscular mycorrhizal fungi can affect yield, even in wheat varieties with low mycorrhizal ability. We also highlighted the importance of choosing the criteria used to measure this potential gain. In a second line of research, we were interested in the impact of arbuscular mycorrhiza on the development of Micro-Tom tomato, and the trophic exchanges during the interaction. Multivariate analysis revealed behavioral differences between plants at mature green fruit and red ripening stages depending on arbuscular mycorrhizal fungal strain, as well as potential interaction event between two arbuscular mycorrhiza fungus trains. Our results confirm that the arbuscules are not the only sites of exchange in arbuscular mycorrhiza. The third axis of this work focused on the potential impact of seed production methods of ancient tomato varieties in drought condition, both on the endogenous community of arbuscular mycorrhizal fungi in the field, on the tolerance of the plant to water stress and on crop production in terms of fruit yield and quality. The experimental site was located in the Potager de santé (seed farm managed by Pascal Poot). Our results show no difference, under conditions of water stress in the field, between varieties regularly cultivated on this site and commercial varieties. Then, one may wonder if other factors related to the exploitation site, such as the beneficial microorganisms interacting with the roots of the plants could be at the origin of the increased tolerance to water stress. Work is underway in the laboratory to study this hypothesis. All of this work paves the way for new research aimed at elucidating the molecular mechanisms involved in the regulation of trophic exchanges during arbuscular mycorrhizae and the valuation of the ecosystem services rendered by arbuscular mycorrhizae in the field.

Made available in DSpace on 2017-07-25T19:30:00Z (GMT). No. of bitstreams: 1 Wilson Nardi Filho.pdf: 1510441 bytes, checksum: 3a6bcb2f67eddeab1b172c8fd648b505 (MD5) Previous issue date: 2013-11-28 / The inclusion of RR soybean resistant to glyphosate caused changes in weed control, since glyphosate has been used more frequently, resulting in the occurrence of resistant weeds. Therefore, management techniques that reduce the number of glyphosate applications in the production system and the possibility of using alternative herbicides are necessary. Accordingly, three independent experiments were conducted on the Farm School of the State University of Ponta Grossa, Ponta Grossa, PR. The first experiment ( E1 ) aimed to evaluate the selectivity of glyphosate used on its own or in combination with bentazon, clethodim, chlorimuron ethyl, fenoxaprope-p-ethyl, fenoxaprope-p-ethyl + clethodim, fomesafen, glufosinate ammonium salt, imazethapyr and sethoxydim at commercial doses in soybean cultivars of Coodetec 202RR, 206RR, 248 and 250, Brasmax Potência and Apolo and Nidera 5909, 7321 and 6411. In the experiment 2 (E2), the objective was to assess the desiccation effects of wheat pre-harvest and the effects of this desiccation in the culture as well as in the occurrence of weeds in soybean sown in succession. In this experiment the wheat cultivar used was Quartzo, desiccated in the pre-harvest with diquate at doses of 300, 400 and 500 g.ha-1 and glufosinate ammonium salt at doses of 300 and 400 g.ha-1. In experiment 3 ( E3 ) the soybean, Energia cultivar RR, was sown after the wheat harvest and in the same place in order to assess if the desiccation of wheat affects the occurrence of weeds in soybean cultivar Energia BMX RR sown in succession and also if the desiccation of this soybean with diquate at a dose of 400 g.ha-1 interferes with soybean yield. In E1, among the graminicides at 7 DAA (days after application) the highest values of phytotoxicity were observed by the use of the clethodim and fenoxaprop-p-ethyl herbicides, and in subsequent assessments no differences of phytotoxicity were observed among the graminicides, which in combination with glyphosate resulted in slight increase of phytotoxicity. Among the latifolicide mixtures, glufosinate ammonium salt was the one which caused the highest phytotoxicity and the combination of these latifolicide with glyphosate resulted in lower phytotoxicity. The phytotoxicity caused by herbicides did not affect soybean productivity, but the combination of them with glyphosate promoted its improvement due to the control of weeds promoted by glyphosate. In E2 , the herbicides diquate and glufosinate ammonium salt promoted desiccation higher than 97 % of leaves and 82 % of the stalks of wheat in five days after its application, diquate having a faster action compared to glufosinate. These herbicides applied in wheat pre-harvest desiccation reduced grain moisture, promoted higher hectoliter weight and did not affect the wheat yield. In E3, the diquate and glufosinate ammonium salt applied in the desiccation of pre-harvest wheat reduced weed populations in soybean sown in succession, especially up to 14 days after soybean sowing and the desiccation of pre-harvest soybean did not affect the culture yield. / A inclusão da soja RR, resistente ao glifosato causou mudanças no manejo de plantas daninhas, visto que o glifosato tem sido utilizado com maior frequência, o que resultou na ocorrência de plantas daninhas resistentes. Portanto, são necessária técnicas de manejo que visem reduzir o número de aplicações de glifosato no sistema de produção e também a possibilidade de uso de herbicidas alternativos. Nesse sentido, foram conduzidos três experimentos na Fazenda Escola da Universidade Estadual de Ponta Grossa, município de Ponta Grossa, PR. O primeiro experimento (E1) objetivou avaliar a seletividade do glifosato utilizado de forma isolada ou em combinação com bentazona, cletodim, clorimuron etílico, fenoxaprope-p-etílico, fenoxaprope-p-etílico + cletodim, fomesafen, glufosinato-sal de amônio, imazetapir e setoxidim nas doses comerciais, nas cultivares de soja Coodetec 202RR, 206RR, 248 e 250, Brasmax Potência e Apolo e Nidera 5909, 7321 e 6411. No experimento 2 (E2), objetivou-se avaliar os efeitos da dessecação em pré-colheita do trigo e os efeitos dessa dessecação na cultura do trigo e na ocorrência das plantas daninhas na soja semeada em sucessão. Nesse experimento a cultivar de trigo utilizada foi Quartzo, dessecada na pré-colheita com diquate nas doses de 300, 400 e 500 g.ha-1 e glufosinato-sal de amônio nas doses de 300 e 400 g.ha-1. No experimento 3 (E3) a soja, cultivar Energia RR, foi semeada após a colheita do trigo e no mesmo local, visando avaliar se a dessecação do trigo afeta a ocorrência de plantas daninhas na soja, cultivar BMX Energia RR semeada em sucessão e também se a dessecação na pré-colheita dessa soja com diquate na dose de 400 g.ha-1 interfere na produtividade da soja. No E1, entre os graminicidas, aos 7 DAA os maiores valores de fitotoxicidade foram observados pelo uso dos herbicidas cletodim e fenoxaprope-p-etílico, e nas avaliações posteriores não foram observadas diferenças de fitotoxicidade entre os graminicidas, que em combinação ao glifosato resultou em ligeiro aumento da fitotoxicidade. Entre os latifolicidas, o glufosinato-sal de amônio foi o que causou maior fitotoxicidade e a combinação desses latifolicidas ao glifosato resultou em menor fitotoxicidade. A fitotoxicidade causada pelos herbicidas não afetou a produtividade da soja, mas a combinação desses ao glifosato promoveu aumento da produção em razão do controle das plantas daninhas promovido pelo glifosato. No E2, os herbicidas diquate e glufosinato-sal de amônio promoveram dessecação superior a 97% das folhas e 82% dos colmos do trigo aos cinco dias após sua aplicação, sendo o diquate de ação mais rápida em relação ao glufosinato. Esses herbicidas aplicados na dessecação em pré-colheita do trigo reduziram a umidade dos grãos, promoveram maior peso hectolitro e não interferiram na produtividade do trigo. No E3, o diquate e o glufosinato-sal de amônio aplicados na dessecação em pré-colheita do trigo reduziram a população de plantas daninhas na soja semeada em sucessão, especialmente até 14 dias após a semeadura da soja e a dessecação em pré-colheita da soja não interferiu na produtividade da cultura.

Made available in DSpace on 2017-07-25T19:30:46Z (GMT). No. of bitstreams: 1 Allan Christian de Souza.pdf: 1299031 bytes, checksum: 95fdaaa95883f295a49305c261ae0342 (MD5) Previous issue date: 2014-09-25 / The wheat quality and yield may be limited or compromised by several factors in the field, being the climatic the main by factor at the end of the crop cycle. Aiming to determine whether different harvest time combined or not with plant growth regulator application affect crop yield and wheat grain quality, four experiments were conducted, differing by cultivars type and sowing time, at Ponta Grossa city, PR, in 2013. The experimental design used in the first time for both cultivars BRS-Pardela and Quartzo) were randomized blocks, at factorial scheme (2 x 5), with our without growth regulator applications and five grain moisture contents (30, 25, 20, 15 and 13%), being four replications. The experimental design for the second time for both cultivars were randomized blocks with five grain moisture content at harvest time (30, 25, 20, 15 and 13%) being 4 replications. For the first harvesting time the growth regulator application resulted in lower thousand grain weight only for cultivate BRS-Pardela and did not affect the yield, yield components as well the industrial quality for both wheat cultivars. The different harvesting times had no effect in either yield, Falling Number (FN) or hectoliter weight (PH) for both cultivars. In the second sowing time the production components and productivity for both cultivars were not affected by the different harvest time. A linear and quadratic decrease on the PH with the delaying of harvest time was noticed for BRS-Pardela and Quartz, respectively, for the FN only the BRS-Pardela showed quadratic reduction delaying the harvest time. Keywords: Triticum aestivum; No-tillage; harvest time; industrial quality, trinexapac-ethyl. / A produtividade e a qualidade do trigo podem ser limitadas ou comprometidas por diversos fatores que a cultura sofre no campo, principalmente pelas condições climáticas no final do ciclo. Com o objetivo de determinar se diferentes épocas de colheita combinadas ou não com regulador de crescimento afetam a produtividade e qualidade dos grãos de trigo, realizaram-se quatro experimentos, diferindo pela cultivar e época de semeadura, no município de Ponta Grossa, PR, no ano de 2013. O delineamento experimental utilizado na primeira época de semeadura para as duas cultivares (BRS-Pardela e Quartzo) foi o de blocos ao acaso, em esquema fatorial (2 x 5), aplicação ou não do regulador de crescimento (na dose de 400 ml/ha do produto comercial) e cinco teores de umidade do grão na colheita (30, 25, 20, 15 e 13%), com 4 repetições. O delineamento experimental para a segunda época para as duas cultivares foi de blocos ao acaso, com 5 teores de umidade do grão na colheita (30, 25, 20, 15 e 13%) e 4 repetições. Para a primeira época a aplicação do regulador de crescimento resultou em menor massa de mil grãos apenas para a cultivar BRS-Pardela e não afetou os outros componentes de produção, produtividade e qualidade industrial das duas cultivares de trigo. As épocas de colheita não afetaram a produtividade, o Falling Number (FN) e o peso hectolitro (PH) das duas cultivares. Na segunda época de semeadura as diferentes épocas de colheita não afetaram os componentes de produção e produtividade das duas cultivares. O PH diminuiu de forma linear com o atraso da época de colheita para a BRS-Pardela e quadrática para Quartzo e o FN de forma quadrática apenas na cultivar BRS-Pardela. Portanto concluo que.

Made available in DSpace on 2017-07-25T19:30:50Z (GMT). No. of bitstreams: 1 Angelo Rafael Bini.pdf: 1115540 bytes, checksum: 5f12fb7c28e1eb476b199cd1f659030f (MD5) Previous issue date: 2015-08-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The adequate supply of nitrogen (N) is essential for obtaining high grain yields. However, use of high doses of N can reduce the efficiency of using the N and cause environmental contamination. The supply of N through biological fixation on corn and wheat may contribute to the sustainability of agricultural production. This study was carried out with the purpose of evaluate (i) the soil chemical attributes after seed inoculation with Azospirillum brasilense and the application of nitrogen in top dressing and (ii) plant nutrition, grain yield, nutrient uptake and N use efficiency in corn and wheat on the basis of seed inoculation with Azospirillum brasilense and nitrogen fertilization. The experiment was conducted in Ponta Grossa (PR) on a very loamy, kaolinitic, thermic Typic Hapludox (Oxisol) for 34 years under no-tillage. The experimental design used was a randomized block, in a split plot arrangement, with three replications. The plots were employed treatments with and without seed inoculation with Azospirillum brasilense and the subplots were applied four doses of nitrogen in the form of urea in corn (0, 80, 160 and 240 kg ha-1) and wheat (0, 40, 80 and 120 kg ha-1). Corn was cultivated after black oat and wheat was grown after corn. Soil samples collected at 0-10, 10-20 and 20-40 cm depths, after corn harvest, revealed no changes in pH and Al, Ca, Mg, K, P and S-SO42 - depending on the inoculation with Azospirillum, and it was observed increase in Mg content in the 10-20 cm layer in response to nitrogen fertilization. Seeds inoculation with Azospirillum did not affect the leaf contents of macronutrients in maize and wheat, and doses of nitrogen in increased levels of N, P and S in corn leaves, and N, K and Ca in the leaves wheat. The corn production was hampered by inoculation with Azospirillum without N fertilization and was favored by Azospirillum when the highest dose of N was applied (240 kg ha-1). In wheat crop, inoculation with Azospirillum increased grain yield in the treatments without N and 40 and 80 kg N ha-1, and depressed grain yield when the highest dose of N (120 kg ha-1) was applied cover. The nitrogen fertilization increased the productivity of maize and wheat grain, both in the absence and in the presence of inoculation with Azospirillum. Seeds inoculation with Azospirillum did not alter the nutrient uptake by corn and increased the extraction of P and S for the wheat crop. Nitrogen fertilization resulted in increased coverage in the extraction of N, P, Ca, Mg and S for corn, and K11 and S for wheat. Inoculation with Azospirillum favored the extraction of N for wheat crop only in the plots without N and application of the lower dose of N (40 kg ha-1) in coverage. The nitrogen fertilization increased the extraction of N for wheat crop with or without Azospirillum. Seeds inoculation with Azospirillum increased agronomic efficiency (EA) of nitrogen fertilization in corn and caused increase in the Partial Factor Productivity of N (FPPN) in wheat crop when the lowest dose of N (40 kg ha-1) was applied to cover. Inoculation of maize and wheat seeds with Azospirillum brasilense, associated with the adjustment of nitrogen fertilization, proved to be feasible capable to maximize grain yield crops in no-tillage system. / O fornecimento adequado de nitrogênio (N) é primordial para a obtenção de altos rendimentos de grãos de cereais. Entretanto, a utilização de elevadas doses de N pode reduzir a eficiência na utilização do N e causar problemas de contaminação ambiental. O fornecimento de N via fixação biológica nas culturas de milho e trigo pode contribuir para a sustentabilidade da produção agrícola. Este estudo foi realizado com o objetivo de avaliar (i) as alterações químicas do solo após a inoculação das sementes com Azospirillum brasilense e a aplicação de nitrogênio em cobertura e (ii) a nutrição das plantas, a produtividade de grãos, a extração de nutrientes e a eficiência de uso do N nas culturas de milho e trigo em função da inoculação das sementes com Azospirillum brasilense e da adubação nitrogenada em cobertura. O experimento foi realizado em Ponta Grossa (PR), em um Latossolo Vermelho distrófico textura muito argilosa há 34 anos sob plantio direto. O delineamento experimental foi o de blocos ao acaso, em parcelas subdivididas, com três repetições. Nas parcelas, foram empregados os tratamentos sem e com inoculação das sementes com Azospirillum brasilense e, nas subparcelas, foram aplicadas quatro doses de N em cobertura, na forma de ureia, nas culturas de milho (0, 80, 160 e 240 kg ha-1) e trigo (0, 40, 80 e 120 kg ha-1). O milho foi cultivado após aveia preta e o trigo foi cultivado após o milho. Amostras de solo coletadas nas camadas de 0-10, 10-20 e 20-40 cm, após a colheita do milho, não revelaram alterações nos valores de pH e nos teores de Al, Ca, Mg, K, P e S-SO42- em função da inoculação com Azospirillum, tendo-se observado elevação nos teores de Mg na camada de 10-20 cm em resposta à adubação nitrogenada. A inoculação das sementes com Azospirillum não alterou os teores foliares de macronutrientes nas culturas de milho e trigo, e as doses de N em cobertura aumentaram os teores de N, P e S nas folhas do milho, e de N, K e Ca nas folhas de trigo. A produtividade do milho foi prejudicada pela inoculação com Azospirillum na ausência de adubação nitrogenada em cobertura e foi favorecida pelo Azospirillum quando a maior dose de N foi aplicada (240 kg ha-1). Na cultura do trigo, a inoculação com Azospirillum aumentou a produtividade de grãos nos tratamentos sem N e com 40 e 80 kg N ha-1, e deprimiu a produtividade de grãos quando a maior dose de N (120 kg ha-1) foi aplicada em cobertura. A adubação nitrogenada em cobertura aumentou a produtividade de grãos de milho e trigo, tanto na ausência como na presença de inoculação com Azospirillum. A 9 inoculação das sementes com Azospirillum não alterou a extração de nutrientes pela cultura do milho e aumentou a extração de P e S pela cultura do trigo. A adubação nitrogenada em cobertura ocasionou incremento na extração de N, P, Ca, Mg e S pelo milho, e de K e S pelo trigo. A inoculação com Azospirillum favoreceu a extração de N pela cultura do trigo somente nas parcelas sem N e com aplicação da menor dose de N (40 kg ha-1) em cobertura. A adubação nitrogenada em cobertura aumentou a extração de N pela cultura do trigo com ou sem Azospirillum. A inoculação das sementes com Azospirillum aumentou a eficiência agronômica (EA) da adubação nitrogenada em cobertura na cultura do milho e ocasionou incremento no Fator Parcial de Produtividade do N (FPPN) na cultura do trigo quando a menor dose de N (40 kg ha-1) foi aplicada em cobertura. A inoculação das sementes de milho e trigo com Azospirillum brasilense, associada com o ajuste da adubação nitrogenada em cobertura, mostrou-se viável para maximizar a produtividade de grãos das culturas em sistema plantio direto.

O trigo (Triticum aestivum L.) é uma importante cultura no Brasil. Poucas cultivares são recomendadas para produção do tipo sequeiro no Bioma Cerrado onde a escassez de água limita o rendimento de grãos. Aqui reportamos uma análise de transcriptoma do MGS1 Aliança (cultivar de trigo adaptada ao Cerrado) sob estresse de seca. Um grupo de 4.422 transcritos diferencialmente expressos foi encontrado em raízes e folhas. O número de transcritos reprimidos em raiz (1.102) foi menor que os transcritos induzidos (1.706), enquanto o oposto ocorreu em folhas (1,017 induzidos e 647 reprimidos). O número de transcritos comuns entre ambos órgaõs foi 1.249, enquanto 2.124 foram específicos para raíz e 1.049 específicos para folhas. Análises de RT-qPCR de 35 transcritos selecionados ao acaso revelou uma correlação de 0,78 com os dados de transcriptoma. Os transcritos diferencialmente expressos foram distribuídos por todos os cromossomos e componentes do genoma. O número de transcritos no genoma B foi maior do que nos genomas A e D. Ainda, um grande número de transcritos relacionados à seca foi mapeado nos cromossomos 3B, 5B e 2B. Quando consideramos ambos órgãos, 116 diferentes rotas metabólicas foram alteradas. Uma rota em comum, entre as três mais alteradas em ambos órgãos, foi o metabolismo do amido e da sacarose. A comparação de transcritos derivados de raiz e de folha permite a identificação de transcritos importantes relacionados à respota ao estresse de seca em cada um destes órgãos. Os dados obtidos, também, abrem caminho para o desenvolvimento de futuros marcadores e seleção de genes candidatos ligados à característica. Estes resultados são úteis para o entendimento de rotas metabólicas envolvidas na tolerância à seca em trigo. A informação gerada será usada, a mais longo prazo, para propósitos de transgenia. Para isto, a metodologia de duplo-haploides é desejável e uma primeira investigação sobre a eficiência de protocolo se mostrou necessária. Micrósporos são células gaméticas com capacidade de dar origem a uma nova planta via embriogênese in vitro. Plantas duplo-haploides geradas pela cultura de micrósporos isolados são completamente homozigotas e representam uma importante ferramenta para estudos genéticos e melhoramento de plantas O processo androgenético é desencadeado por diferentes pré-tratamentos de estresse, os quais são empregados para mudar os micrósporos da rota gametofítica para a rota esporofítica. Embora a cultura de micrósporos isolados tenha inúmeras vantagens, importantes limitações tem impedido sua apliação em larga escala. Diferenças genotípicas na resposta androgenética e na formação de plantas albinas ainda constituem desafios. Embora o albinismo seja principalmente uma característica genética, pré-tratamentos e meios de cultura apropriados podem evitar este fenômeno até certo ponto. A resposta androgenética de cinco genótipos de trigo brasileiro foi avaliada no presente estudo. Dois pré-tratamentos foram testados: frio (4°C) e ácido 2-hidroxinicotinico (100 mg/L). O frio foi melhor que o pré-tratamento químico, produzindo mais plantas verdes em quatro de cinco genótipos. Somente dois genótipos brasileiros tratados com ácido 2-hidroxinicotinico produziram plantas, e um deles apenas uma única planta albina. Nossos reultados mostram, também, que o meio semilíquido (contendo 10% de Ficoll) promoveu uma maior resposta androgenética que o meio líquido, aumentando o número de embriões e plantas regeneradas. / Wheat (Triticum aestivum L.) is an important crop cultivated in Brazil. Few cultivars are recommended for rainfed production in the Cerrado Biome where water scarcity limits grain yield. Here we report a transcriptome analysis of MGS1 Aliança (a wheat cultivar adapted to the Cerrado) under drought stress. A set of 4,422 differentially expressed transcripts was found in roots and leaves. The number of down-regulated transcripts in roots (1,102) was lower than the up-regulated transcripts (1,706), while the opposite occurred in leaves (1,017 induced and 647 repressed). The number of common transcripts between the two tissues was 1,249, while 2,124 were specific to roots and 1,049 specific to leaves. Quantitative RT-PCR analysis of 35 randomly selected transcripts revealed a 0.78 correlation with the transcriptome data. The differentially expressed transcripts were distributed across all chromosomes and component genomes. The number of transcripts on the B genome was greater than on the A and D genomes. Additionally, a greater number of drought related transcripts was mapped on chromosomes 3B, 5B and 5D. When considering both tissues, 116 different metabolic pathways were changed. One common pathway, among the top three changed pathways in both tissues, was starch and sucrose metabolism. The comparison of root- and leaf-derived transcripts allows the identification of important transcripts related to water stress response in each of these tissues. It also paves the way for future marker development and selection of candidate genes linked to that trait. These results are useful for understanding the metabolic pathways involved in wheat drought response. The information generated will be used for transgenic wheat purposes. For this the doubled-haploid method is desirable and an investigation about the protocol eficiency is needed. Microspores are gametic cells with capacity to give rise to a new plant via in vitro embryogenesis. Doubled haploid plants generated by isolated microspore culture are completely homozygous and represent an important tool for plant genetics and breeding research. This process is triggered by different stress pretreatments, which are employed to switch microspores from gametophytic to a sporophytic pathway. Although isolated microspore culture has innumerous advantages, important limitations have prevented its application on a large scale. Genotypic differences in androgenic response and the formation of albino plants remain great challenges. Although albinism is a major genetic characteristic, appropriated pretreatments and culture medium can avoid this phenomenon to some extent. The androgenic response of five Brazilian wheat genotypes was evaluated in the present study. Two pretreatments were tested: cold (4°C) and 2-hydroxynicotinic acid (100 mg/L). Cold was better than chemical pretreatment, producing more green plants in four out of five genotypes. Only two Brazilian genotypes treated with 2-hydroxynicotinic acid produced plants, and one of them produced a single albino plant. Our results also show that semi-liquid medium (containing 10% Ficoll) promoted a higher androgenic response than did liquid medium, increasing the number of embryos and regenerated plants.