Resistência de nogueira-macadâmia (Macadamia integrifolia Maiden e Betche) aos nematoides-das-galhas
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Data
2018-04-02
Autores
Costa, Marylia Gabriella Silva [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A nogueira-macadâmia pertence à família Proteaceae e é originária da Austrália. Sua noz é considerada a mais saborosa entre as nozes comercializadas. No Brasil, nos últimos anos, há uma expansão da macadamicultura e de seu plantio em cafezais. Além da sua consorciação com o cafeeiro, a macadâmia é uma opção de plantio em consórcio com outras culturas de ciclo curto e alternativa para o plantio em novas áreas. Embora haja um aumento da área plantada de macadâmia, as informações sobre danos causados por nematoides nessa cultura são escassas. Principalmente, aos nematoides-das-galhas, onde com frequência, as populações desses patógenos são altas em áreas cultivadas com café. No Brasil, a produção de mudas de macadâmia se dá quase que exclusivamente pelo método de enxertia, tendo como principal porta-enxerto a variedade 10-14 (Aloha). Portanto, o objetivo do trabalho foi avaliar a resistência da variedade 10-14 (Aloha) e das cultivares HAES344, HAES-660, HAES 816, IAC 4-12B, IAC 9-20 e IAC 4-20 a Meloidogyne incognita raça 2, M. paranaensis, M. exigua, M. enterolobii e M. javanica, além de estudar o ciclo de vida dos nematoides-das-galhas na variedade 10-14 (Aloha) por ser a mais utilizada como porta-enxerto na produção de mudas. O substrato de cada parcela foi infestado com aproximadamente 5.000 ovos e eventuais juvenis dos nematoides estudados, separadamente, provenientes de populações puras, processadas segundo o método proposto por Hussey e Barker. Tomateiros ‘Rutgers’ foram utilizados como padrão de viabilidade do inóculo de M. incognita raça 2, de M. enterolobii e de M. javanica, plantas de café ‘Mundo Novo’ foram utilizadas para atestar a viabilidade de M. paranaensis e M. exigua. O delineamento experimental utilizado foi inteiramente ao acaso, com cinco repetições. As avaliações foram feitas aos 120 dias após a inoculação. Os índices de galhas (IG) e índices de massas de ovos (IMO) foram obtidos de acordo com a escala de notas proposta por Taylor e Sasser. Para a obtenção do fator de reprodução (FR=PF/PI), os sistemas radiculares foram processados separadamente de acordo com o método de Coolen e D’Herde. Os experimentos para a avaliação do ciclo de vida das espécies de Meloidogyne foram montados em câmaras incubadoras (BOD) sob temperatura e fotoperíodo controlados. As plântulas de macadâmia, após a germinação, foram transplantadas para copos de 210 mL com substrato autoclavado. Para a obtenção do juvenil de segundo estágio (J2), os nematoides foram processados separadamente de acordo com a técnica proposta por Hussey e Barker, em seguida, as suspensões de cada espécie do nematoide foram colocadas em aparatos de Baermanns modificados para recipiente raso. Cinco dias após o transplante, cada plântula foi inoculada com 300 (J2) de M. incognita, M. paranaensis, M. exígua, M. enterolobii ou M. javanica. As avaliações foram aos 5, 15, 25 e 35 dias após a inoculação (DAI). Os sistemas radiculares das plantas foram lavados e coloridos com fucsina ácida para a classificação dos estádios de desenvolvimento do nematoide. Os resultados mostraram que todas as cultivares e a variedade 10-14 (Aloha) de macadâmia foram resistentes aos nematoides estudados, demostrando a resistência. Os nematoides não completaram o ciclo de vida na variedade 10-14 (Aloha), podendo ser utilizada como porta-enxerto na produção de mudas.
The macadamia nut belongs to the Proteaceae family, is originally from Australia, and is considered one of the most flavorful nuts in the market. In Brazil, macadamia nuts have been increasingly planted alongside coffee. In addition to its consortium with this crop, macadamia can also be planted alongside other short cycle cultures, and is also an alternative to planting in new areas. Although an increase in planted macadamia areas has been observed, information on nematode damage to this crop is scarce, mainly regarding root-knot nematodes, which are frequently observed in high populations in coffee crop areas. In Brazil, the production of macadamia seedlings occurs almost exclusively by the grafting method, with the 10-14 (Aloha) variety as the rootstock. In this context, the aim of this research was to evaluate the resistance of macadamia variety 10-14 (Aloha) and macadamia cultivars, HAES-344, HAES-660, HAES 816, IAC 4-12B, IAC 9-20 and IAC 4-20 to Meloidogyne incognita race 2, M. paranaensis, M. exigua, M. enterolobii and M. javanica, and to study the life cycle of root-knot nematodes in the variety 10-14 (Aloha), as it is the most frequent rootstock for seedling production. The substrate of each plot was infested with approximately 5,000 nematode eggs, separately, from pure populations processed according to the Hussey and Barker method. 'Rutgers' tomatoes were used as the viability standard for the M. incognita race 2, M. enterolobii and M. javanica inocula. 'Mundo Novo' coffee plants were used to confirm M. paranaensis and M. exigua viability. The experimental design was completely randomized, with five replications and the evaluations were carried out at 120 days after inoculation. The Gall index (GI) and egg mass index (EMI) were obtained according to the scale proposed by Taylor and Sasser. To calculate the reproduction factor (RF = PF/PI), the root systems were processed separately according to the Coolen and D'Herde method. The experiments carried out for the Meloidogyne species life cycle evaluation were mounted in incubators (BOD) under controlled temperature and photoperiod. After germination, Macadamia seedlings were transplanted into 210 mL bowls with autoclaved substrate. To obtain the juvenile second stage (J2), the nematodes were processed separately according to the technique proposed by Hussey and Barker. Suspensions of each nematode species were placed in a Baermanns apparatus, modified to a shallow container. Five days after transplantation, each seedling was inoculated with 300 (J2) M. incognita, M. paranaensis, M. exigua, M. enterolobii or M. javanica. Evaluations were carried out at 5, 15, 25 and 35 days post-inoculation (DPI). The plant root systems were washed and stained with acid fuchsin for nematode development stage classification. The results indicate that all macadamia cultivars and variety 10-14 (Aloha) were resistant to the studied nematodes, demonstrating resistance. The nematodes did not complete their life cycle on the 10-14 (Aloha) variety, indicating that it may be used as the rootstock for seedlings.
The macadamia nut belongs to the Proteaceae family, is originally from Australia, and is considered one of the most flavorful nuts in the market. In Brazil, macadamia nuts have been increasingly planted alongside coffee. In addition to its consortium with this crop, macadamia can also be planted alongside other short cycle cultures, and is also an alternative to planting in new areas. Although an increase in planted macadamia areas has been observed, information on nematode damage to this crop is scarce, mainly regarding root-knot nematodes, which are frequently observed in high populations in coffee crop areas. In Brazil, the production of macadamia seedlings occurs almost exclusively by the grafting method, with the 10-14 (Aloha) variety as the rootstock. In this context, the aim of this research was to evaluate the resistance of macadamia variety 10-14 (Aloha) and macadamia cultivars, HAES-344, HAES-660, HAES 816, IAC 4-12B, IAC 9-20 and IAC 4-20 to Meloidogyne incognita race 2, M. paranaensis, M. exigua, M. enterolobii and M. javanica, and to study the life cycle of root-knot nematodes in the variety 10-14 (Aloha), as it is the most frequent rootstock for seedling production. The substrate of each plot was infested with approximately 5,000 nematode eggs, separately, from pure populations processed according to the Hussey and Barker method. 'Rutgers' tomatoes were used as the viability standard for the M. incognita race 2, M. enterolobii and M. javanica inocula. 'Mundo Novo' coffee plants were used to confirm M. paranaensis and M. exigua viability. The experimental design was completely randomized, with five replications and the evaluations were carried out at 120 days after inoculation. The Gall index (GI) and egg mass index (EMI) were obtained according to the scale proposed by Taylor and Sasser. To calculate the reproduction factor (RF = PF/PI), the root systems were processed separately according to the Coolen and D'Herde method. The experiments carried out for the Meloidogyne species life cycle evaluation were mounted in incubators (BOD) under controlled temperature and photoperiod. After germination, Macadamia seedlings were transplanted into 210 mL bowls with autoclaved substrate. To obtain the juvenile second stage (J2), the nematodes were processed separately according to the technique proposed by Hussey and Barker. Suspensions of each nematode species were placed in a Baermanns apparatus, modified to a shallow container. Five days after transplantation, each seedling was inoculated with 300 (J2) M. incognita, M. paranaensis, M. exigua, M. enterolobii or M. javanica. Evaluations were carried out at 5, 15, 25 and 35 days post-inoculation (DPI). The plant root systems were washed and stained with acid fuchsin for nematode development stage classification. The results indicate that all macadamia cultivars and variety 10-14 (Aloha) were resistant to the studied nematodes, demonstrating resistance. The nematodes did not complete their life cycle on the 10-14 (Aloha) variety, indicating that it may be used as the rootstock for seedlings.
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Palavras-chave
Meloidogyne incognita, M. paranaensis, M. exigua, M. enterolobii, Ciclo de vida, Life cycle