Submitted by PATRÍCIA MEIRIELE MARINI (patriciammarini@hotmail.com) on 2018-06-28T22:29:52Z No. of bitstreams: 1 Tese final corrigida - PATRICIA MARINI.pdf: 1191208 bytes, checksum: e96c8b003a5ccafde276681e172519cb (MD5) / Approved for entry into archive by Luciana Pizzani null (luciana@btu.unesp.br) on 2018-07-04T14:37:41Z (GMT) No. of bitstreams: 1 marini_pm_me_bot.pdf: 1191208 bytes, checksum: e96c8b003a5ccafde276681e172519cb (MD5) / Made available in DSpace on 2018-07-04T14:37:42Z (GMT). No. of bitstreams: 1 marini_pm_me_bot.pdf: 1191208 bytes, checksum: e96c8b003a5ccafde276681e172519cb (MD5) Previous issue date: 2018-05-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Meloidogyne incognita é considerado um dos nematoides de maior importância econômica em termos mundiais. Para seu adequado manejo, uma das estratégias mais eficientes é o uso de cultivares resistentes. Portanto, estratégias para otimizar os programas de melhoramento genético são necessárias. A análise de expressão gênica tem ampliado a compreensão dos mecanismos de interação planta-nematoide e acelerado o desenvolvimento de genótipos resistentes. A cultivar de aveia branca IPR Afrodite, resistente a M. incognita, e cultivares suscetíveis foram avaliadas em relação à sua tolerância a este nematoide, além de ter sido estudado o comportamentode genes candidatos que regulam sua resistência, desafiados com densidades populacionais iniciais crescentes de M. incognita, durante o seu estabelecimento e manutenção do parasitismo. Para a avaliação da tolerância, plantas cultivadas em vasos de 3.600 cm3 foram inoculadas com 0,0625 (187,5); 0,125 (375); 0,25 (750); 0,5 (1500); 1 (3000); 2 (6000); 4 (12000); 8 (24000); 16 (48000) e 32 (96000) exemplares por cm3 de solo e avaliadas aos 67 dias após a inoculação (DAI), através da mensuração do desenvolvimento das plantas, além da multiplicação do nematoide. Os resultados mostraram que, em densidades menores, IPR Afrodite apresentou fator de reprodução próximo a 1,0, sugerindo menor expressão da resistência. Em função desses resultados, experimento semelhante foi conduzido para análise da expressão gênica dessa cultivar ao nematoide, com avaliações aos 0 (imediatamente antes da inoculação), 2 e 9 DAI. A partir de reações de RT-qPCR, verificou-se que dois genes (Lrk 14 e LOX) apresentaram regulação em resposta ao nematoide e padrões de regulação diferenciados entre as cultivares. IPR Afrodite apresentou estratégias moleculares contrastantes às observadas em URS Torena, sugerindo-se que há regulação tardia e negativa em URS Torena, enquanto que, em IPR Afrodite, Lrk14 atuou como amplificador de respostas de defesa inicial, prolongando o sinal de ameaça após a detecção inicial do patógeno. O gene que codifica LOX foi desencadeado, como resposta induzida por efetores, o que geralmente resulta em reação de hipersensibilidade, como já observado em trabalhos anteriores envolvendo tal interação. / Meloidogyne incognita is considered one of the main economic important nematodes worldwide. For its management, the use of resistant cultivars is amongst the more efficient strategy. Therefore, strategies to optimize the genetic breeding programs are necessary. The gene expression analysis has amplified the comprehension about the mechanisms involved in the plant-nematode interaction and accelerated the development of resistant genotypes. The oat cultivar IPR Afrodite, resistant to M. incognita, and cultivars suscetibles was evaluated in relation to its tolerance to this nematode and, besides, the behavior of candidate genes regulating the resistance reaction was studied, challenged with crescent initial population densities of M. incognita, during its establishment and parasitism maintenance. To tolerance evaluation, plants cropped in 3,600 cm3 -pots were inoculated with 0,0625 (187,5); 0,125 (375); 0,25 (750); 0,5 (1500); 1 (3000); 2 (6000); 4 (12000); 8 (24000); 16 (48000) e 32 (96000) exemplars.cm-3 of soil and evaluated at 67 days after inoculation (DAI), through the mensuration of the plant development and nematode multiplication. Results showed that, in lower densities, IPR Afrodite showed reproduction factor values closed to 1.0, suggesting a lower resistance expression. In face of these results, a similar experiment was conducted to gene expression analysis of this cultivar to nematode, with evaluations at 0 (immediately before inoculation), 2 and 9 DAI. From RT-qPCR reactions, we could verify that two genes (Lrk and LOX) were regulated in response to nematode and that different regulatory patterns were observed between cultivars. IPR Afrodite showed molecular strategies contrasting to those observed in URS Torena, suggesting a late and negative regulation in URS Torena, while to IPR Afrodite, Lrk14 acted as an amplifier of initial defense responses, prolonging the threat signal after the initial detection of the pathogen. The gene that codifies to LOX was unleashed, as a response induced by effectors, which usually results in a hypersensitive reaction, as observed previously.

Submitted by FERNANDO MARCELO CHIAMOLERA null (chiamolera@hotmail.com) on 2016-01-15T10:20:46Z No. of bitstreams: 1 Tese_Fernando_Marcelo_Chiamolera.pdf: 1436198 bytes, checksum: 44d1be3bc519c28425af3825d79d0341 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-01-15T15:20:09Z (GMT) No. of bitstreams: 1 chiamolera_fm_dr_jabo_int.pdf: 1436198 bytes, checksum: 44d1be3bc519c28425af3825d79d0341 (MD5) / Made available in DSpace on 2016-01-15T15:20:09Z (GMT). No. of bitstreams: 1 chiamolera_fm_dr_jabo_int.pdf: 1436198 bytes, checksum: 44d1be3bc519c28425af3825d79d0341 (MD5) Previous issue date: 2015-12-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As áreas de cultivo da goiabeira estão sendo significativamente reduzidas devido ao parasitismo do sistema radicular por Meloidogyne enterolobii, que associado a Fusarium solani, causam o declínio e morte das plantas, comprometendo o futuro desta cultura. A identificação de possíveis portaenxertos resistentes a M. enterolobii, desde que compatíveis, por meio da enxertia, com a goiabeira, pode ser a melhor estratégia para o manejo deste nematoide. Assim, o objetivo neste trabalho foi avaliar a reação a M. enterolobii de algumas espécies de araçás como possíveis portaenxertos de goiabeira e a viabilidade da enxertia da goiabeira ‘Paluma’ sobre os portaenxertos resistentes ao nematoide de galha, além de acompanhar o desenvolvimento dos enxertos. Para isso, foram conduzidos dois experimentos, onde no primeiro avaliou-se a reação à M. enterolobii de possíveis portaenxertos (araçazeiros) e, no segundo, a viabilidade da propagação da goiabeira ‘Paluma’ por meio da enxertia (métodos em fenda cheia e inglês simples) sobre araçazeiros resistentes. No primeiro estudo foi confirmada a resistência de Eugenia stipitata, Psidium cattleyanum ‘amarelo’ e Psidium friedrichsthalianum, os quais, juntamente com Psidium cattleyanum ‘vermelho’ e Psidium acutangulum, foram testados como portaenxertos da goiabeira ‘Paluma’ no segundo experimento. Como resultados, foi observada a incompatibilidade de ‘Paluma’ com E. stipitata e P. cattleyanum ‘amarelo’ e a baixa taxa de sobrevivência da combinação ‘Paluma’ × P. cattleyanum ‘vermelho’. Entre as combinações testadas, as melhores perspectivas para o manejo de M. enterolobii estão na enxertia de ‘Paluma’ com P. friedrichsthalianum, com taxas de sobrevivência superiores a 30%. O método de enxertia inglês simples é mais eficaz para o desenvolvimento dos enxertos da goiabeira ‘Paluma’. / The fields of cultivation of guava are being significantly reduced due to the parasitism of the root system by Meloidogyne enterolobii that associated with Fusarium solani, causing the decline and death of plants, compromising the future of this crop. The identification of possible resistant rootstocks M. enterolobii, as far as compatible by grafting with guava, may be the better strategy to manage this nematode. The objective of this study was to evaluate the response to M. enterolobii of some species of Brazilian guava trees as possible guava rootstocks and the viability of grafting of guava ‘Paluma’ on rootstocks resistant to the root-knot nematode, besides following the initial development of the grafts. For this, two experiments were conducted, where the first evaluated the reaction to M. enterolobii possible rootstocks (Brazilian guava trees) and, in the second, the viability of the propagation of guava ‘Paluma’ by grafting (methods in cleft grafting and splice grafting) on resistant Brazilian guava trees. In the first study confirmed the resistance of Eugenia stipitata, Psidium cattleyanum ‘yellow’ and Psidium friedrichsthalianum, which along with Psidium cattleyanum ‘red’ and Psidium acutangulum, were tested as rootstocks of guava ‘Paluma’ in the second experiment. As a result, we observed the incompatibility ‘Paluma’ with E. stipitata and P. cattleyanum ‘yellow’ and the low survival rate of the combination ‘Paluma’ × P. cattleyanum ‘red’. Among the combinations tested, the best prospects for M. enterolobii management are in grafting ‘Paluma’ with P. friedrichsthalianum, with survival rates exceeding 30%. The splice grafting method is most effective for the initial development of the grafts of guava ‘Paluma’.

Submitted by Guilherme Matos Martins Diniz null (guilhermedinizz@yahoo.com.br) on 2016-11-12T20:47:10Z No. of bitstreams: 1 Tese - Guilherme Matos Martins Diniz.pdf: 1713375 bytes, checksum: 4e35cf3867e761830ba22f92034a1e15 (MD5) / Rejected by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br), reason: Solicitamos que realize uma nova submissão seguindo a orientação abaixo: O arquivo submetido não contém o certificado de aprovação fornecido pela Seção de Pós-Graduação. . Corrija esta informação e realize uma nova submissão com o arquivo correto. Agradecemos a compreensão. on 2016-11-18T19:54:47Z (GMT) / Submitted by Guilherme Matos Martins Diniz null (guilhermedinizz@yahoo.com.br) on 2016-11-19T00:18:22Z No. of bitstreams: 1 TESE - Guilherme Matos Martins Diniz.pdf: 1878561 bytes, checksum: ae58a835b95bed9b80bdbc3c2fd5633a (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-11-22T16:25:43Z (GMT) No. of bitstreams: 1 diniz_gmm_dr_jabo.pdf: 1878561 bytes, checksum: ae58a835b95bed9b80bdbc3c2fd5633a (MD5) / Made available in DSpace on 2016-11-22T16:25:44Z (GMT). No. of bitstreams: 1 diniz_gmm_dr_jabo.pdf: 1878561 bytes, checksum: ae58a835b95bed9b80bdbc3c2fd5633a (MD5) Previous issue date: 2016-10-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os nematoides das galhas estão entre os patógenos que mais causam prejuízos em cultivos protegidos de pimentão, destacando-se as espécies Meloidogyne incognita, M. javanica e M. enterolobii. Este último já foi relatado em plantas de Capsicum spp., e vem causando problemas, pois a utilização de genótipos resistentes a outras espécies não é eficaz em seu controle. Estudos relacionados à resistência a esse patógeno, bem como a obtenção de fontes de resistência ainda são escassos, o que dificulta a adoção de programas de melhoramento genético, visando a esse fim. Sendo assim, o presente trabalho teve por objetivo estudar a herança da resistência à M. enterolobii em Capsicum frutescens. O trabalho foi desenvolvido na UNESP-FCAV, Câmpus de Jaboticabal-SP. Para o estudo da herança da resistência, foi realizado o cruzamento entre C. frutescens, resistente a M. enterolobii e uma linhagem de pimenta C24, C. chinense, suscetível a nematoide. A partir desse cruzamento, foram obtidas as gerações F1, F2, RC1 e RC2. Depois de obtidas todas as gerações necessárias para o estudo, as plantas foram inoculadas com 5.000 ovos e juvenis de segundo estádio de M. enterolobii no ato do transplantio. Após 60 dias da inoculação, realizou-se a avaliação da resistência das plantas ao nematoide, coletando-se as raízes e realizando-se os procedimentos de extração dos nematoides em laboratório. A avaliação da resistência das plantas aos nematoides foi realizada com base no fator de reprodução (FR), sendo consideradas FR ≥ 1, suscetíveis, e FR < 1, resistentes. Os dados foram avaliados pelo teste qui-quadrado e cinco metodologias de avaliação dos genes envolvidos no controle, além do teste de máxima verossimilhança para a verificação da presença de efeitos relacionados ao ambiente ou polígenes. A análise genética mostrou ausência de dominância e epistasia, indicando ação gênica somente aditiva. A dominância apresentada tendeu à suscetibilidade, indicando que a resistência é recessiva. O número de locos segregantes mostrou que apenas um gene estaria envolvido na herança da resistência à M. enterolobii. O valor de herdabilidade foi alto, evidenciando possibilidade de ganho seletivo sendo um caráter pouco afetado pelo ambiente. Todas as plantas da geração F1 foram suscetíveis, as gerações F2 e retrocruzamentos tiveram variações de sintomas do parasitismo. A hipótese de herança monogênica foi aceita, de acordo com os métodos estatísticos utilizados no estudo, até o limite de significância do qui-quadrado. O controle genético da resistência à M. enterolobii, em C. frutescens é monogênico recessivo. / Root-knot nematode are among the pathogens that cause most damage in pepper crops protected highlighting the species Meloidogyne incognita, M. javanica and M. enterolobii. The latter has been reported in plants Capsicum spp., and causes problems since the use of resistant genotypes other species is not effective as a control. Studies related to resistance to this pathogen as well as obtaining sources of resistance are still scarce, hindering the adoption of breeding programs for this purpose. Therefore, this study aimed to study the inheritance of resistance to M. enterolobii in Capsicum frutescens. The study was conducted at UNESP-FCAV in Jaboticabal-SP. To study the inheritance of resistance was the cross between C. frutescens, resistant M. enterolobii and C24 pepper strain, C. chinense, susceptible to the nematode. From this junction were obtained F1, F2, BC1 and BC2. After obtaining all generations necessary for the study, the plants were inoculated with 5.000 eggs and juveniles of second stage M. enterolobii in transplanting the act. After 60 days of inoculation was performed to evaluate the resistance of plants to nematode collecting the roots and carrying out the nematode extraction procedures in the laboratory. The evaluation of plant resistance to nematodes was performed based on the reproduction factor (RF) is considered FR ≥ 1, and RF susceptible <1 resistant. The data were analyzed by chi-square test five methods of assessing the genes involved in the control beyond the maximum likelihood test for the presence of related environmental effects or polygenes. Genetic analysis showed no dominance and epistasis indicating only additive gene action. The dominance presented tended susceptibility, indicating that resistance is recessive. The number of loci segregating showed that only one gene was involved in the inheritance of resistance to M. enterolobii. The heritability value was high showing possibility of selective gain being one character unaffected by the environment. All plants of F1 generation were susceptible, generations, F2 and backcross had variations of symptoms of parasitism. The hypothesis of monogenic inheritance was accepted, according to the statistical methods used in the study, up to the limit of significance of the chi-square. The genetic control of resistance to M. enterolobii in C. frutescens is monogenic recessive.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2015-04-20T20:30:17Z No. of bitstreams: 2 Tese - Renato Andrade Teixeira - 2013.pdf: 891118 bytes, checksum: 3dbc3af80e3adaf1035bdf07f259d219 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2015-04-20T20:35:17Z (GMT) No. of bitstreams: 2 Tese - Renato Andrade Teixeira - 2013.pdf: 891118 bytes, checksum: 3dbc3af80e3adaf1035bdf07f259d219 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-04-20T20:35:17Z (GMT). No. of bitstreams: 2 Tese - Renato Andrade Teixeira - 2013.pdf: 891118 bytes, checksum: 3dbc3af80e3adaf1035bdf07f259d219 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-02-28 / Soybean has great economic importance for Brazil, which is among the major producing countries. The crop is attacked by various pathogens and among them are the nematodes of the genera Meloidogyne that can reduce the yeld. Among the various methods of control the use of resistant cultivars is one of them, but there are several cultivars still without information about its reaction to this genera of nematodes. In this study we evaluated the response of soybean cultivars to Meloidogyne incognita race 3 and Meloidogyne javanica, and the penetration of these nematodes in soybean cultivars exposed to different inoculoum concentrations. The experiments were conducted in a greenhouse installed at the Universidade Federal de Goiás, Goiânia, GO. Seeds were planted into a sterilized substrate and the seedlings were inoculated with M. incognita or M. javanica eggs and J2. In assessing the cultivars response to the nematodes we evaluated the population density (eggs and J2/10 g root) and reproduction factor (RF) at 60 days after inoculation. In another experiment the penetration of nematodes was observed at 10 days after inoculation by counting the number of J2 and J3 within the plant tissue. 45 days after inoculation the population density (eggs and J2/10 g root) was also evaluated. M. incognita had the RF < 1,0 in most of the cultivars tested and M. javanica had RF > 1,0 in all the cultivars. By using Moura & Régis (1987) criteria fifteen cultivars were ranked as resistant or highly resistant and none as registant to M. javanica. In general, the increase of inoculum concentration increased the amount of nematodes in the roots. / A cultura da soja tem grande importância econômica para o Brasil, a qual está entre os principais países produtores. Esta cultura é atacada por vários patógenos e entre esses estão os nematoides do gênero Meloidogyne, responsáveis pela redução de produtividade de grãos. Entre os vários métodos de controle, tem-se o uso de cultivares resistentes, mas ainda existem várias cultivares com ausência de informação sobre suas reações. Neste trabalho, avaliou-se a reação de cultivares de soja a Meloidogyne incognita raça 3 e M. javanica, e a penetração dos nematoides em cultivares de soja submetidas a diferentes concentrações de inóculo. Os experimentos forma conduzido em condições de casa de vegetação na Universidade Federal de Goiás, no município de Goiânia, GO. Para a semeadura utilizou-se copos plásticos de 400 mL de capacidade contendo substrato esterilizado composto de solo e areia na proporção de 1:1. A inoculação artificial com ovos e J2 do nematoide ocorreram treze dias após a semeadura. Na avaliação da reação das cultivares foram consideradas a densidade populacional (ovos e J2/10 g de raiz) e fator de reprodução (FR) aos 60 dias após a inoculação. A penetração dos nematoides foi avaliada aos 10 dias após a inoculação, medida pela quantidade de J2 e J3 no interior das raízes e, aos 45 dias após a inoculação, avaliou-se a densidade populacional (ovos e J2/10 g de raiz). Para a espécie M. incognita, o FR da maioria das cultivares foram abaixo de um e para M. javanica todos tiveram FR > 1,0. Assim, utilizando o critério de Moura & Régis (1987) quinze cultivares foram classificadas como resistentes ou altamente resistentes a M. incognita e todas foram consideradas suscetíveis a M. javanica. Em geral, quanto maior a concentração de inóculo maior foi a quantidade de nematoides nas raízes de soja.

O gênero Eucalyptus possui diversas espécies que apresentam grande valor comercial, sendo utilizado principalmente para produção de energia (carvão e lenha) e celulose-papel. Na literatura, entretanto, existem poucas informações acerca de nematoses nessa cultura. Além dessa carência e de sua importância econômica, o eucalipto é comumente cultivado em locais de alta incidência de Pratylenchus brachyurus e Meloidogyne incognita, além de ser consorciado com diversas outras culturas intolerantes, como por exemplo a soja. Dessa forma há uma necessidade de conhecer a reação das espécies de eucalipto a estes nematoides. Dito isso, o presente trabalho teve por objetivo testar a reação de algumas espécies de eucalipto a P. brachyurus e M.incognita. Foram realizados 6 experimentos, 5 envolvendo o nematoide das lesões e 1 com o nematoide de galhas. Os tratamentos foram inoculados com uma população inicial de nematoides e, após 90 dias, estimava-se o fator de reprodução (FR) e nematoides por grama de raiz (Nem/g). Adotou-se o critério baseado em Oostenbrink (1966), onde a espécie foi considerada suscetível quando apresenta FR >= 1 e resistente quando FR < 1. Dos eucaliptos testados, 6 apresentaram reação suscetível e 4 reação resistente para P. brachyurus. As espécies com maiores FR estão entre as mais utilizadas no Brasil, exceto E. saligna. Ressalta-se que estas não necessariamente são resistentes, necessitando apenas de um período maior para o estabelecimento do patógeno. Observou-se indícios de que E. saligna e E. camaldulensis sejam intolerantes a P.brachyurus. Para M. incognita raça 3 todas as espécies testadas foram resistentes. Aconselha-se a realização de experimentos com períodos superiores a 100 dias para uma correta classificação da reação de hospedeiro. O eucalipto é uma opção para aproveitamento de áreas infestadas com M. incognita raça 3, porém seu uso mostra-se um risco em áreas infestadas com P. brachyurus. / The Eucalyptus has several species with high commercial value and is used mainly for energy purpose (Charcoal and firewood) and paper. In the literature, however, there is little information about plant parasitic nematodes in this woody specie. In addition to this lack and its economic importance, eucalypts is also commonly cultivated in areas with high incidence of Pratylenchus brachyurus and Meloidogyne incognita, and consorted with several intolerant crops, such as soybean. Thus, there is a need to know the host status of the eucalypts species to these nematodes. With that, this work aimed to test the reaction of some Eucalyptus species to P.brachyurus and M. incognita. For this purpose six experiments were performed, five to test the lesion nematode and one to test the root-knot nematode. The treatments were inoculated and, after 90 days, it was estimated the reproduction factor (FR) and nematodes per gram of root (Nem/g). The present work adopted the criteria based on Oostenbrink (1966), where the species was considered susceptible when presenting FR >= 1 and resistant when FR < 1. Of species tested, six were susceptible hosts and four resistant host to P. brachyurus. The species with highest FR are among the most used eucalypts in Brazil, except E. saligna. It is emphasized that those species with FR < 1 are not necessarily resistant, requiring only a longer period for the pathogen establishment. There was some evidence that E. saligna and E. camaldulensis are intolerant hosts to P. brachyurus. To M. incognita Race 3 all tested species were resistant. It is advisable to perform experiments for periods longer than 100 days to a correct classification of host status. Eucalyptus is an option for utilization of areas infested with M. incognita race 3, but its use appears to be a risk in Pratylenchus brachyurus infested areas.

2 p. / Alfalfa varieties differ in fall dormancy, defined as growth during the fall. Nondormant alfalfa varieties are usually planted in mild winter areas for their ability to grow in the fall. However, fall growth of nondormant alfalfa may be undesirable in areas subject to repeated frosts or freezes. Nondormant, very nondormant, and extremely nondormant alfalfa varieties (fall dormancy class 8, 9, and 10) are adapted to elevations below 4000 feet in Arizona. Other dormancy classes not included in this publication are moderately nondormant varieties (fall dormancy class 7) which may be grown from 3000 to 5000 feet, and semi-dormant and dormant varieties (fall dormancy 6 and below) which are adapted to colder winter areas above 4000 feet.

Orientador: Silvia Renata Siciliano Wilcken / Resumo: Meloidogyne incognita é considerado um dos nematoides de maior importância econômica em termos mundiais. Para seu adequado manejo, uma das estratégias mais eficientes é o uso de cultivares resistentes. Portanto, estratégias para otimizar os programas de melhoramento genético são necessárias. A análise de expressão gênica tem ampliado a compreensão dos mecanismos de interação planta-nematoide e acelerado o desenvolvimento de genótipos resistentes. A cultivar de aveia branca IPR Afrodite, resistente a M. incognita, e cultivares suscetíveis foram avaliadas em relação à sua tolerância a este nematoide, além de ter sido estudado o comportamentode genes candidatos que regulam sua resistência, desafiados com densidades populacionais iniciais crescentes de M. incognita, durante o seu estabelecimento e manutenção do parasitismo. Para a avaliação da tolerância, plantas cultivadas em vasos de 3.600 cm3 foram inoculadas com 0,0625 (187,5); 0,125 (375); 0,25 (750); 0,5 (1500); 1 (3000); 2 (6000); 4 (12000); 8 (24000); 16 (48000) e 32 (96000) exemplares por cm3 de solo e avaliadas aos 67 dias após a inoculação (DAI), através da mensuração do desenvolvimento das plantas, além da multiplicação do nematoide. Os resultados mostraram que, em densidades menores, IPR Afrodite apresentou fator de reprodução próximo a 1,0, sugerindo menor expressão da resistência. Em função desses resultados, experimento semelhante foi conduzido para análise da expressão gênica dessa cultivar ao nematoide, com aval... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Meloidogyne incognita is considered one of the main economic important nematodes worldwide. For its management, the use of resistant cultivars is amongst the more efficient strategy. Therefore, strategies to optimize the genetic breeding programs are necessary. The gene expression analysis has amplified the comprehension about the mechanisms involved in the plant-nematode interaction and accelerated the development of resistant genotypes. The oat cultivar IPR Afrodite, resistant to M. incognita, and cultivars suscetibles was evaluated in relation to its tolerance to this nematode and, besides, the behavior of candidate genes regulating the resistance reaction was studied, challenged with crescent initial population densities of M. incognita, during its establishment and parasitism maintenance. To tolerance evaluation, plants cropped in 3,600 cm3 -pots were inoculated with 0,0625 (187,5); 0,125 (375); 0,25 (750); 0,5 (1500); 1 (3000); 2 (6000); 4 (12000); 8 (24000); 16 (48000) e 32 (96000) exemplars.cm-3 of soil and evaluated at 67 days after inoculation (DAI), through the mensuration of the plant development and nematode multiplication. Results showed that, in lower densities, IPR Afrodite showed reproduction factor values closed to 1.0, suggesting a lower resistance expression. In face of these results, a similar experiment was conducted to gene expression analysis of this cultivar to nematode, with evaluations at 0 (immediately before inoculation), 2 and 9 DAI. From RT-qPCR... (Complete abstract click electronic access below) / Doutor

Thesis (M.A. Agriculture. (Plant Production)) -- University of Limpopo, 2021 / Root-knot (Meloidogyne species) nematodes are host to most plant species, with the success of most crops being dependent upon proper nematode management tactics. Sweet potato (Ipomoea batatas L.) is highly susceptible to root-knot nematodes, with physical damage being visible on roots. The withdrawal of highly effective fumigant synthetic nematicides from the agrochemical markets resulted in a need to investigate alternative strategies for managing high nematode population densities, with the use of nematode resistance being the most preferred strategy. The objectives of this study were (1) to establish whether sweet potato cv. 'Blesbok' would be resistant to M. javanica under greenhouse conditions, (2) to investigate whether cucurbitacin containing phytonematicides would be comparable to Velum synthetic nematicide in suppressing Meloidogyne species. For Objective 1, treatments comprised 0, 5, 25, 125, 625, 3125 and 15625 eggs and second-stage juveniles (J2), had six replications and validated in time. Uniform sweet potato cuttings were transplanted in 20-cm diameter plastic pots, filled with steam pasteurised (300°C for 1 hour) loam soil. At 56 days after inoculation, plant growth, plant nutrient and nematode variables were assessed using analysis of variance and subjected to lines of the best fit. Treatments had significant (P ≤ 0.05) effects on eggs and highly significant (P ≤ 0.01) effects on J2, final nematode population densities (Pf) and the reproductive factor (RF), contributing 39, 45, 42 and 92% in total treatment variation (TTV) of the respective variables. Treatments did not have significant effects on plant variables. Calcium, K, Mg and Fe versus M. javanica levels each exhibited negative quadratic relations, with the models being explained by associations from 59 to 96%. In contrast, Zn versus M. javanica levels exhibited positive quadratic relation, with the model being explained by 80 and 98% association and optimised at 125 M. javanica units. For Objective 2, four treatments, namely, untreated control, Nemarioc-AL phytonematicide, Nemafric-BL phytonematicide and Velum had 10 replications and also validated in time. The plantlets with well-developed root system were transplanted under field conditions. Data for Object 2 did not comply with the requirements for ANOVA and were therefore subjected to Principal Component Analysis (PCA). Nemafric-BL phytonematicide treatment in both experiments reduced eggs, J2 in roots and J2 in soil and RP of Meloidogyne species, with the results being comparable to those of Velum synthetic nematicide. Nemarioc-AL phytonematicide reduced J2 in roots and in soil of Meloidogyne species, without affecting eggs in roots and RP. Nemafric-BL phytonematicide and Velum each increased plant growth variables in Experiment 1 and Experiment 2, whereas Nemarioc-AL phytonematicide did not have significant effects on plant growth variables. Velum chemical nematicide stimulated the accumulation of most essential nutrient elements in leaf tissues of the test cultivar, followed by Nemafric-BL phytonematicide, whereas Nemarioc-AL phytonematicide had no significant effects on the accumulation of essential nutrient elements. The study had two major outcomes, namely, (1) that the efficacy of Nemafric-BL phytonematicide was comparable to that of Velum chemical nematicide in suppression of population densities of Meloidogyne species in cv. ′Blesbok′ under field conditions and (2) that cv. ′Blesbok′ was tolerant to M. javanica and therefore, it was not necessary to investigate the mechanisms of nematode resistance. / Agricultural Research Council (ARC) and National Research Foundation (NRF)

Thesis (M. Agric. (Plant Protection)) -- University of Limpopo, 2019 / Plant extracts exhibited broad spectrum of activities against root-knot (Meloidogyne species) nematodes and had long been considered as an attractive alternative due to their being biodegradable and posing limited risk hazards to the environment, animal and human health. Additionally, the materials had been dubbed as being of low-input costs and had been viewed as being easy to apply in agricultural systems. The objective of the current study was to investigate the efficacy of paint-brush flower (Kleinia longiflora) either as fermented or granular formulations on suppression of M. javanica and their related effects on growth of tomato (Solanum lycopersicum) plants under field and greenhouse conditions. Fermented crude extracts were applied at 0, 2, 4, 8, 16, 32 and 64%, whereas granular materials were applied at 0, 2, 4, 6, 8, 10 and 12 g. Regardless of the product, the treatments were arranged in randomised complete block design (RCBD), with 12 replications. Kleinia longiflora plants were collected from the wild, chopped into pieces, oven-dried at 52⁰C and fermented in effective microorganisms (EM) for 14 days, whereas the remained were retained for use as granular formulation. Tomato seedlings cv. ꞌFloradadeꞌ were used as test plants inoculated with 2500 eggs and second-stage juveniles (J2) of M. javanica. At 56 days after the treatments, nematode and plant variables were collected, prepared using appropriate methodologies and subjected to analysis of variance using Statistix 10.0 software to generate means. Plant variables were subjected to the Curve-fitting Allelochemical Response Data (CARD) computer-based model to generate appropriate biological indices. Nematode and mineral elements variable means were subjected to lines of the best fit. Findings showed second-stage juveniles (J2) in roots, J2 in soil, eggs and Pf under increasing concentration were highly significant and exhibited negative quadratic relationship. The model explained the associations by 82, xvii 81, 74 and 76%, respectively. In granular formulation, the product had no significant effects on nematode population densities. The fermented crude extracts significantly affected and exhibited positive quadratic relations for dry fruit mass, chlorophyll content, dry shoot mass, number of flowers, plant height, number of fruit and stem diameter of tomato plants. The model explained the relationship by 97, 94, 95, 96, 94, 97 and 96%, respectively. In contrast, in granular formulation, the product had significant effects and positive exhibited quadratic relations on Chlorophyll content under field and greenhouse, plant height, dry root mass and dry shoot mass. The model explained the relationships by 52, 45, 56, 47 and 59%, respectively. Plant variables and increasing concentration of the products exhibited density-dependent growth patterns for both formulations, with overall sensitivity (∑k) values of 1 and 11, respectively. In fermented liquid and granular formulations, the Mean Concentration Stimulation Point (MCSP) values were derived at 1.97% and 2.84 g, respectively. The increasing concentration of fermented K. longiflora also had significant effects and exhibited negative quadratic relations on the accumulation of K, Na and Zn in leaf tissues of tomato plants. The model explained the associations with 87, 94 and 94%, respectively. In conclusion, the findings in the current study suggested that the nematicidal chemicals in K. longiflora could not be released through irrigation water but could be released into solution through microbial degradation. Also, at low concentration suitable for use without inducing phytotoxicity, the products in either formulation could improve the accumulation of certain nutrients in leaf tissues of tomato plants.

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