ABSTRACT Grafting has been increasingly used to overcome soilborne pathogens. The commercial rootstock hybrids AF-8253 (Sakata) and Fortaleza (Takii), as well as Embrapa’s new hybrid, BRS Acará, were evaluated as rootstocks for the bell pepper hybrids Margarita (Syngenta) and Pampa (Clause) as scions, under natural infestation of Ralstonia pseudosolanacearum, as well as upon artificial inoculation with a) ten Ralstonia isolates, b) one Phytophthora capsici isolate, c) Meloidogyne incognita race 1, and d) Meloidogyne enterolobii (only rootstocks for c and d). Grafted bell peppers consistently showcased a higher productivity than did non-grafted ones under natural R. pseudosolanacearum infestation, and the rootstock genotype affected fruit size distribution. Rootstocks presented higher resistance than did commercial bell pepper hybrids (scions) for 6 out of 10 Ralstonia isolates. AF-8253 and BRS Acará displayed an immune-like response to P. capsici, while Fortaleza was moderately resistant (25% symptomatic plants) and the bell pepper hybrids (scions) were susceptible (100% symptomatic plants). Rootstocks were immune to M. incognita race 1, but slightly (AF-8253 and BRS Acará) or moderately (Fortaleza) resistant to M. enterolobii. Grafting with BRS Acará, as well as with AF-8253 or Fortaleza, is recommended for managing bacterial wilt, Phytophthora blight, and root-knot nematodes.

RESUMEN El objetivo de esta investigación fue evaluar la dinámica poblacional de los nematodos Heterodera glycines raza 5 y Pratylenchus brachyurus en cultivos sucesivos de soya y garbanzo. El experimento se llevó a cabo en Campos Novos dos Parecis, estado de MT, Brasil, de febrero a mayo de 2017. Se sembraron seis cultivares de garbanzo en febrero y se evaluaron en un área naturalmente infestada de 60 ha. Se recolectaron cinco muestras de suelo al azar en ubicaciones georreferenciadas y equidistantes, formando una muestra compuesta por replicación. Se recolectaron cinco plantas por punto georreferenciado y también nuevas muestras de suelo a intervalos regulares de aproximadamente 30 d. Los nematodos se extrajeron, identificaron y contaron. Los datos fueron sometidos a análisis de varianza y regresión. Se observó una reducción en los niveles poblacionales de H. glycines raza 5 a lo largo del ciclo del garbanzo, lo que indica que es posible cultivar esta especie en sucesión con soya en presencia de este nematodo. Sin embargo, debido al mantenimiento en la población de P. brachyurus en las raíces, no se recomienda la rotación de soya con garbanzos en campos naturalmente infestados con este nematodo.

ABSTRACT The objective of this research was to evaluate the population dynamics of the nematodes Heterodera glycines race 5 and Pratylenchus brachyurus in a succession crop of soybeans and chickpeas. The experiment was carried out in Campos Novos dos Parecis, MT State, Brazil, from February to May 2017. Six chickpea cultivars were planted in February and evaluated in a naturally infested area of 60 ha. Five soil samples were collected at random in georeferenced and equidistant locations, forming a composite sample by replication. Five plants per georeferenced point and new soil samples were collected at regular intervals of about 30 d. The nematodes were extracted, identified, and counted. Data were subjected to variance and regression analyses. A reduction in the population levels of H. glycines race 5 was observed throughout the chickpea cycle, indicating that this species can be cultivated in succession with soybeans in the presence of this nematode. However, due to the maintenance in the population of P. brachyurus in the roots, rotation of soybean with chickpeas is not recommended in fields naturally infested with this nematode.

Resumo O objetivo deste trabalho foi avaliar a resistência de genótipos de grão-de-bico (Cicer arietinum) aos nematoides da galha (Meloidogyne javanica) e das lesões (Pratylenchus brachyurus), bem como verificar como estas espécies afetam essa cultura em condições de campo. O experimento foi realizado no bioma Cerrado, no estado de Goiás, Brasil, em área naturalmente infestada. Foram avaliados as cultivares BRS Aleppo, Cícero, BRS Cristalino, BRS Toro e BRS Kalifa e o genótipo Jamu 96. As variáveis avaliadas foram: fator de reprodução dos nematoides, massa fresca da parte aérea e do sistema radicular, matéria seca da parte aérea, matéria seca total das plantas, índice de clorofila, altura das plantas e rendimento de grãos. Pratylenchus brachyurus se multiplica mais do que M. javanica e diminui massa fresca da raiz, altura da planta e rendimento de grãos. Todos os genótipos são resistentes a M. javanica, principalmente Jamu 96 e a cultivar BRS Kalifa. Jamu 96 e a cultivar Cícero são suscetíveis a P. brachyurus. BRS Kalifa é a cultivar mais resistente a ambos os nematoides e apresenta maior rendimento de grãos.

Abstract The objective of this work was to evaluate the resistance of chickpea (Cicer arietinum) genotypes to the root-knot (Meloidogyne javanica) and root-lesion (Pratylenchus brachyurus) nematodes, as well as to verify how these species affect this crop in field conditions. The experiment was carried out in the Cerrado biome in the state of Goiás, Brazil, in a naturally infested area. The BRS Aleppo, Cícero, BRS Cristalino, BRS Toro, and BRS Kalifa cultivars and the Jamu 96 genotype were evaluated. The assessed variables were: nematode reproduction factor, fresh mass of the aerial part of the plant and of the root system, dry matter of the aerial part of the plant, total dry matter of the plants, chlorophyll index, height of the plants, and grain yield. Pratylenchus brachyurus multiplies more than M. javanica, decreasing root fresh matter, plant height, and grain yield. All genotypes are resistant to M. javanica, especially Jamu 96 and cultivar BRS Kalifa. Jamu 96 and cultivar Cícero are susceptible to P. brachyurus. BRS Kalifa is the cultivar most resistant to both nematodes and shows the highest grain yield.

Resumo: O objetivo deste trabalho foi avaliar o método de inoculação de sementes de cenoura com meio batata-dextrose-ágar (BDA) acrescido de manitol. O fungo escolhido para testar a metodologia foi o Alternaria radicina. O restritor hídrico foi adicionado ao meio BDA de modo a obter os potenciais osmóticos de 0,6 MPa, 0,8 MPa, 1,0 MPA e 1,2 MPa. O crescimento micelial foi avaliado, e não foi observado inibição do crescimento em nenhum dos potenciais osmóticos, em relação a testemunha. As sementes foram distribuídas sobre as colônias fúngicas para a infecção, onde permaneceram por 48, 72, 96, 120 e 144 horas nos potenciais osmóticos 0,0 MPa (controle), 0,6 MPa, 0,8 MPa, 1,0 MPa e 1,2 MPa, respectivamente. Para avaliar os efeitos da colonização foram realizados testes de germinação, sanidade e emergência. Os potenciais osmóticos avaliados apresentaram porcentagens semelhantes de plântulas anormais e sementes mortas no teste de germinação. No teste de sanidade, maiores porcentagens de infecção foram observadas nos potenciais osmóticos 1,0 MPa e 1,2 MPa. O potencial -1,2 MPa apresentou a menor porcentagem de emergência. Assim, o uso de manitol -1,2 MPa é sugerido como um método eficaz para a infecção de sementes de cenoura com para fins de pesquisa.

Abstract: This study aimed at evaluating the method of inoculation of carrot seeds in a potato-dextrose-agar medium (PDA) added of mannitol. Alternaria radicina was the fungus chosen to test such methodology. The osmosis-controlling agent was employed to obtain the osmotic potentials of 0.6 MPa, 0.8 MPa, 1.0 MPa and 1.2 MPa. In comparison with the control treatment, no significant mycelial growth inhibition was noticed at any of the osmotic potentials considered. The seeds were distributed over the fungal colonies for infection, where they remained for 48, 72, 96, 120 and 144 hours, at the osmotic potentials of 0.0 MPa (control), 0.6 MPa, 0.8 MPa, 1.0 MPa and 1.2 MPa, respectively. Tests of germination, sanitization and emergence were performed to evaluate the effects of colonization. Regarding the germination, the different osmotic potentials resulted in similar percentages of abnormal seedlings and dead seeds. As for the sanitization testing, higher infection rates were observed at the osmotic potentials of 1.0 MPa and 1.2 MPa. The lowest percentage of emergence was found at -1.2 MPa, therefore suggesting that this osmotic potential (produced with mannitol) might be used for infecting carrot seeds for research purposes.

O objetivo deste trabalho foi avaliar a estabilidade e a adaptabilidade de oito genótipos de cenoura (três cultivares e cinco populações), em 17 ambientes, nas regiões nordeste, centro-oeste, sudeste e sul do Brasil, nos anos agrícolas 2009/10, 2010/11 e 2011/12. Os experimentos foram conduzidos entre novembro e janeiro de cada ano, conforme o calendário agrícola dos produtores. A parcela experimental foi composta de área igual a 1,0 m², em delineamento de blocos ao acaso, com três repetições. Os tratos culturais foram similares aos usados pelos produtores. Na colheita, as raízes comercializáveis foram quantificadas e os valores transformados para t ha-1. Realizouse a análise de variância e, posteriormente, a análise de fatores e a análise de regressão bissegmentada, visando ao estudo de estabilidade e adaptabilidade. Nenhum genótipo apresentou adaptabilidade ampla. A análise de fatores conseguiu agrupar menos de 50% dos ambientes avaliados. O genótipo ideal não foi encontrado pela análise de regressão. O cultivar 'BRS Planalto' foi o mais adaptado, pelo método da regressão bissegmentada, enquanto, pela análise de fatores, 'Brasília', CNPH-600 e CNPH-589 mostraram-se mais adaptados. Os resultados obtidos por essas metodologias demonstram a dificuldade de recomendação de um cultivar para todas as regiões produtoras e que programas regionalizados devem ser iniciados. A utilização dos dois métodos associados permite a tomada de decisões mais segura acerca do comportamento dos genótipos de cenoura.

The objective of this study was to evaluate the stability and adaptability of eight genotypes of carrots (three cultivars and five populations) in 17 environments in the Northeast, Midwest, Southeast and Southof Brazil in the crop years 2009/10, 2010/11 and 2011/12. The experiments were grown from November to January of each year according to the farmers' crop calendar. The plot was composed of an area with 1.0 m² in a randomized block design with three replications. The cultural practices were the same used by the farmers. At harvest, the marketable roots were quantified and the values converted to tha-1. Analysis of variance was performed and after that, the factor analysis and bissegmented regression analysis to study the stability and adaptability. None of the genotypes showed wide adaptability. Factor analysis was able to cluster less than 50% of the evaluated environments. The ideal genotype was not found by regression analysis. The 'BRS Planalto' cultivar was the most adaptedby the bissegmented regression method while 'Brasília' CNPH-589 and CNPH-600 were the most adapted by factor analysis. The results obtained by these methods demonstrate the difficulty of recommending a cultivar for all producing regions and regionalized programs should be initiated. The use of the two associated methods allows safer decisions concerning the behavior of genotypes of carrot.

Entre as estratégias para o controle da ferrugem da soja cita-se a nutrição mineral equilibrada. Objetivou-se, neste trabalho, verificar o efeito do cálcio e do potássio na severidade da ferrugem (Phakopsora pachyrhizi), na fotossíntese potencial e na nutrição de plantas de soja. O delineamento experimental foi em blocos casualizados, com 25 tratamentos, 4 repetições e 2 plantas por repetição. Utilizou-se esquema fatorial 5 x 5, com 5 doses de K (4, 5, 6, 7, 8 mmol L-1), combinadas com 5 doses de Ca (3, 5, 7, 9, 11 mmol L-1). As plantas foram inoculadas no estádio V4 e, após nove dias, iniciaram-se avaliações da severidade da ferrugem pelas porcentagens de tecido lesionado, as quais foram transformadas em área abaixo da curva de progresso da doença (AACPS).Também foram avaliados a fotossíntese potencial e o teor de nutrientes na matéria seca de raiz, caule e folhas. O suprimento de Ca reduziu a AACPS em todas as doses de K. O suprimento de K também reduziu a AACPS nas doses 5, 7 e 11 mmol L-1 de Ca. A menor AACPS foi observada na combinação das doses de 8 e 11 mmol L-1 de K e Ca, enquanto a maior AACPS foi observada nas doses de 4 e 5 mmol L-1 de K e Ca. As plantas tratadas com as doses 6 e 5 mmol L-1 de K e Ca e 5 e 5 mmol L-1 de K e Ca apresentaram melhor resposta fotossintética. Com o incremento das doses de K na solução, houve aumento dos teores foliares de K e redução linear dos teores foliares de Ca. Com o incremento das doses de Ca em solução nutritiva verificaram-se aumentos nos teores desse elemento e redução linear dos teores de K nas folhas.

A balanced mineral nutrition is among the strategies for the control of Asian soybean rust. This work aimed to evaluate the severity of the soybean rust (Phakopsora pachyrhizi), the potential photosynthesis and the nutrition of soybean plants with different levels of K and Ca. The experiment was arranged in a randomized block design with 25 treatments, 4 repetitions and 2 plants per repetition. A 5 x 5 factorial scheme with 5 doses of K (4, 5, 6, 7, 8 mmol L-1) combined with 5 doses of Ca (3, 5, 7, 9, 11 mmol L-1) was used. Plants were inoculated at growth stage V4 and after nine days weekly evaluations of disease severity were carried out using percentage of injured tissues, which were transformed into area under the disease progress curve (AUDPCS). Potential photosynthesis and nutrient content in the root, stem and leaf dry matter were also evaluated. The supply of Ca reduced AUDPCS at all doses of K. The supply of K also reduced the AUDPCS at the doses of 5, 7 and 11 mmol L-1 of Ca. The smallest AUDPCS was observed at the combination 8 and 11 mmol L-1 of K and Ca, respectively, while the largest AUDPCS was observed at the doses of 4 and 5 mmol L-1 of K and Ca. The plants treated with 6 and 5 mmol L-1 of K and Ca and 5 and 5 mmol L-1 of K and Ca showed better photosynthetic response. Increasing doses of K in the solution promoted increase in K leaf contents and linear decrease in Ca leaf levels. Increasing the levels of Ca in nutrient solution promoted an increase in the content of this element and a linear reduction of K levels in the leaves.