Sweetpotato is a staple crop in Brazil presenting a smaller number of pathogens and diseases in comparison with other root and tuberous crops. Root-knot nematodes are among the most serious sweetpotato root pathogens. The impact of these pathogens also extends to succeeding crops. Because in Brazil, it is common to cultivate more than one crop per season, this problem is rapidly disseminated. The aim of this study was to assess the resistance of two sweetpotato clones and four commercial sweetpotato genotypes to three different Meloidogyne species. Assays were performed under greenhouse and field conditions. 'CIP BRS Nuti' and 'Canadense' were resistant to Meloidogyne incognita, M. javanica, and M. enterolobii under greenhouse conditions. This finding was obtained based on the reproduction factor < 0.2, meaning that the initial population of 5,000 nematodes was reduced to <1,000 individuals after 90 days of inoculation. Tomato and sweetpotato cultivar Beauregard, known to be susceptible to the three nematode species, were highly damaged by the pathogens. Similar results were also observed under field conditions. To our knowledge, 'CIP BRS Nuti' and 'Canadense' are the first South American commercial cultivars with triple nematode resistance.

ABSTRACT One of the main phytopathogens that cause enormous economic losses in several agricultural species, including carrots, are the root-knot nematodes belonging to the genus Meloidogyne. Thus, in order to identify the best population level for inoculum of the root-knot nematode (Meloidogyne incognita) for maximum expression of symptoms of this nematode attack on carrots, an experiment was carried out to evaluate the carrot cultivar Brasília (CBR) and the population Pop-750 (CRO). The experiment was carried out in a greenhouse at Embrapa Vegetable, Brasília-DF, in 5 L pots, with six replications, in a 4x2 factorial scheme in a completely randomized design, in the dosages of 0, 1, 5 and 10 thousand eggs and occasional juveniles of 2nd stage (E+J2R). ‘Rutgers’ susceptible tomato cultivar was used as control to verify inoculum efficiency. Inoculation was carried out 30 days after sowing and evaluation 60 days after inoculation. Gall index (GI), egg mass index (EMI), number of eggs plus occasional second stage juveniles per gram of root (E+J2R) and reproduction factor (RF) were performed. There were differences between genotypes and between inoculum levels for all variables evaluated. For CRO, inoculum levels of M. incognita from 1,000 E+J2 the plants already manifested symptoms and changes in all evaluated variables, with ideal levels around 5 to 7 thousand E+J2R, above 7 thousand E+J2R nematode multiplication to express symptoms decreased. For CBR the response variables E+J2 at root and RF inoculum levels close to 5 thousand E+J2R also present the best results, but when the characterization is based on the evaluation of GI and EMI, suitable inoculum levels would be close to 9 and 12 thousand E+J2R.

RESUMO O objetivo deste trabalho foi prospectar fontes de resistência ao nematoide-das-galhas Meloidogyne enterolobii em espécies silvestres de Solanum e híbridos com potencial para serem utilizados como porta-enxertos para solanáceas cultivadas. Vinte e três acessos de sete espécies de Solanum, bem como 35 híbridos de dois cruzamentos interespecíficos, foram caracterizados quanto à resistência a M. enterolobii. Os experimentos foram conduzidos em casa de vegetação em Brasília-DF, Brasil, em delineamento de blocos inteiramente casualizados, com quatro repetições de uma planta por vaso inoculada com ovos do nematoide, avaliadas quanto às variáveis nematológicas: índice de massa de ovos, índice de galhas, número de ovos por grama de raiz e fator de reprodução. Todos os acessos de Solanum torvum, S. paludosum e S. paniculatum apresentaram alta resistência. No caso de S. crinitum, S. macrocarpon e S. sisymbriifolium, as reações foram variadas, com seis de sete, dois de cinco e um de três acessos resistentes, respectivamente. Vinte e três dos 24 híbridos interespecíficos entre S. stramonifolium var. inerme e S. stramonifolium, e cinco híbridos interespecíficos de S. stramonifolium e S. aethiopicum gr. gilo, entre onze, também foram resistentes. Esses resultados são de interesse prático para o controle do nematoide-das-galhas, uma vez que solanáceas cultivadas resistentes a M. enterolobii são de difícil obtenção por meio de melhoramento convencional. Por isso, a identificação de resistência em espécies de Solanum compatíveis com as espécies cultivadas pode ser importante para permitir o uso como porta-enxertos.

The objective of this work was to prospect sources of resistance to the root-knot nematode Meloidogyne enterolobii in wild Solanum species and hybrids to be used as potential rootstocks for cultivated Solanaceae. Twenty-three accessions of seven Solanum species, as well as 35 interspecific hybrids of two crosses, were characterized for their resistance to M. enterolobii. The experiments were conducted in a greenhouse in Brasilia-DF, Brazil, in a completely randomized block design with four replications of one plant per pot. Plants were inoculated with egg masses and evaluated for the nematological variables egg mass index, galls index, number of eggs per root gram and reproduction factor. Solanum torvum, S. paludosum, and S. paniculatum presented high levels of resistance. Six among seven accessions of S. crinitum were resistant, as well as two accessions among five of S. macrocarpon, and one among three of S. sisymbriifolium. Except one, the 24 interspecific hybrids among S. stramonifolium var. inerme and S. stramonifolium, as well as five interspecific hybrids of S. stramonifolium and S. aethiopicum gr. gilo, among eleven were resistant. These results are relevant, since cultivated Solanaceae species of economic importance resistant to M. enterolobii are difficult to obtain by conventional breeding. Therefore, the identification of resistance in Solanum species compatible for grafting with cultivated species can be important to enable their use as rootstocks for disease control.

In Brazil, eggplant and gilo are important for the economy of small-scale farms located mainly in the southeast states and other regions, with a significant production volume year-round in the wholesale local markets. However, these species are very susceptible to root-knot nematodes, and there are few or almost none known sources of resistance. The objective of this studywas to prospect sources of resistance to root-knot nematodesin eggplant, scarlet eggplant (gilo), as well in interspecific hybrids between these species and with wildSolanumspecies, to be used as rootstocks. In the first experiment, in 2013,10 eggplant accessions, a hybrid between eggplant andgilo, and a Solanum stramonifoliumxeggplanthybrid, were evalu41atedfor theirreaction to Meloidogyne enterolobii. In the second, in 2016, 20 accessions of gilowere evaluated for their reaction to M. incognita, M. javanica,and M. enterolobii.. And in the third experiment,in 2017,one access and two experimental eggplant hybrids, and one Solanum scuticumx eggplant hybrid, were evaluated for their reaction to M. incognita, and M. enterolobii. All the trials were stablished inagreenhouse, and characters related to root infection were evaluated in a completely randomized design with six replications of one plant per pot, usinga 1.5 L pots filled with a mixedsubstrate inoculated with each nematode species.Itwas found thatall eggplant accessions were susceptible to M. incognitaand M. enterolobii, however, BER 3150 presented lower susceptibility to M. incognita. The gilogenotypes CNPH 056, CNPH 070, CNPH 220,and CNPH 363 shownbetter response to M. incognitaand M. javanicathan the susceptibility pattern, the tomato 'Rutgers'. Other giloaccessions CNPH 070, CNPH 219,and CNPH 387 showed better or equivalent response thanthe resistant tomato 'Nemadoro' for M. enterolobii.4-the BER EG203 x S. scuticuminterspecific hybrid can be recommended as a rootstock for eggplant susceptible to M. incognita, as well the wild S. stramonifoliumvar. inerme species for M. enterolobii.

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.

Root-knot nematodes (RKN) are important pathogens on greenhouse-cultivated vegetables worldwide. The use of chemical inputs to cope with biotic stress is both more expensive and non-labor friendly. Therefore, effective control of RKN under tropical conditions is limited, but novel management methods comprising the use of microorganisms and soluble organic matter consist in promising alternatives. In the present study, water-extractable fraction of vermicomposts (WEFV) enriched or not with Trichoderma strains were evaluated for their efficiency in stimulating the growth and yield of bell pepper and tomato as well as their ability in increasing the tolerance of plants against Meloidogyne incognita. Treatments tested were: water-extractable fraction of a conventional vermicomposting process (V); water-extractable fraction of vermicompost enriched with Trichoderma asperellum (V + TA); water-extractable fraction of vermicompost enriched with Trichoderma virens (V + TV). A control treatment (water only) was also conducted for comparison. Bell pepper and tomato seedlings were inoculated with 5000 eggs and eventual second-stage juveniles (J2) of Meloidogyne incognita race 1 and treated weekly with 200 ml of each vermicompost extract. Bell pepper plants treated with V + TV increased by 13 %, 29 %, and 56 % shoot dry mass, shoot height and root mass when compared to the control, respectively. A 10-fold increase in yield for tomato plants was observed when V + TV was applied when compared to the control. Regarding biocontrol of RKN, treatment V was able to reduce the number of eggs J2 in 62 % on bell pepper and 46 % on tomato plants when compared to the control. Treatment V also decreased RKN reproduction factor in 35 % for bell pepper and in 22 % for tomato plants, when compared to the control. The use of WEFV constitutes a potentially useful alternative to manage RKN and sustain plant growth in vegetable production systems.

ABSTRACT Genetic resistance is the most suitable mechanism to control root-knot nematodes in lettuce. However, information about the resistance levels of currently used lettuce cultivars is scarce in the literature. Thus, the objective of this research was to characterize lettuce cultivars for resistance to root-knot nematodes Meloidogyne incognita (Mi) and M. javanica (Mj), aiming the identification of resistance sources for breeding, and to transfer information to the productive sector. We evaluated 97 lettuce genotypes in tree trials. In the first one (preliminary assessment), 92 lettuce genotypes were inoculated simultaneously with M. incognita race 1 and M. javanica species, 17 days after sowing. The gall index (GI) was evaluated 41 days after inoculation. In the second trial nine genotypes, selected from the first trial, were evaluated; and in the third trial, two new cultivars from Embrapa were evaluated. In the last two trials, the nematode species were inoculated separately, and the egg mass index (EMI), number of eggs per gram of roots (NEGR) and reproduction factor (RF) were also evaluated. In both trials, the lettuce cultivars Salinas 88 and Grand Rapids were used as resistant controls, as well as cultivar Irene as the susceptible control. The data were submitted to analysis of variance and treatments means grouping by Scott-Knott´s test. The crisp leaf cultivars presented a higher degree of resistance to the root-knot nematodes compared to the smooth leaf type cultivars. Cultivars Vera and Amanda present resistance to M. incognita, and Vanda to M. javanica. ‘Salinas 88’ present resistance mainly to M. javanica; while cultivar Mônica and the Embrapa cultivars BRS Leila and BRS Mediterrânea are resistant to both nematode species.

ABSTRACT Thirty seven pepper genotypes, Capsicum chinense, C. annuum and C. frutescens, were characterized for resistance to three root-knot nematode species (Meloidogyne javanica, M. incognita race 1 and M. enterolobii) aiming to find potential resistance sources to be used in breeding programs. Three experiments were carried out, in 2013, 2014 and 2016, in a greenhouse, in randomized block design and six replicates, one plant/pot. Data were submitted to analysis of variance and average clustering. All evaluated pepper genotypes were resistant or immune to M. javanica. For M. incognita race 1, all accessions of C. frutescens, evaluated in the first experiment, were resistant, whereas the six accessions of C. chinense were susceptible. For M. incognita, all genotypes of C. chinense and C. annuum, evaluated in the second experiment, were resistant. In the third experiment, evaluating C. annuum genotypes, we verified that most were susceptible to M. incognita race 1; genotypes CNPH 30118 and CNPH 6144 were resistant, though. M. enterolobii, which is the most aggressive species, with few resistance sources described, showed a tendency of greater degree of resistance in C. chinense and C. frutescens. Although most of the evaluated genotypes were susceptible, significant differences were observed regarding the degree of susceptibility. The main contribution of this study was the identification of a genotype resistant to M. enterolobii, cultivar BRS Nandaia, which can be used in breeding programs.

The objective of this work was to prospect sources of resistance to root-knot nematode Meloidogyne enterolobii in Solanum species with potential to be used as rootstocks for cultivated Solanaceae. Nine accessions of Solanum sessiliflorum, 27 accessions of S. lycocarpum, 21 accessions of S. acanthodes, 22 accessions of S. scinericum and 26 accessions of S. scuticum for resistance to M. enterolobii. Rutgers and Nemadoro tomatoes were used as susceptible and resistant controls, respectively. The experiment was conducted in a greenhouse at Embrapa Vegetables, Brasília-DF, Brazil, in a completely randomized design with six replications. The experimental unit was a represented by a single plant grown in a plastic pot containing 3 L of substrate. 4000 eggs and eventual juveniles of second stage M. enterolobii were inoculated per pot. At 119 days after inoculation, gall index (Gi), egg mass index (EMI), number of eggs per root gram (NE) and reproduction factor (Fr) were evaluated. Data were subjected to analysis of variance and grouping of treatments by Scott-Knott. It was verified that S. acanthodes and S. Lycocarpum are species with high resistance to M. enterolobii, with accessions being classified identified as immune. S. scuticum also has great potential, as several resistant accessions were identified, although some accessions were quite susceptible; whereas for S. subinerme only 4 resistant accessions were identified, although all others presented a reproduction factor much lower than tomato cv. Nemadoro as control; and all evaluated S. sessiliflorum accessions were susceptible.

A resistencia genetica e o mecanismo mais indicado para o controle dos nematoides-das-galhas em alface. No entanto sao escassas na literatura informacoes sobre os niveis de resistencia das principais cultivares de alface utilizadas atualmente no pais. Estas informacoes sao importantes para direcionar cruzamentos visando o desenvolvimento de novas cultivares resistentes, tambem para o setor produtivo, que pode utilizar aquelas caracterizadas como resistentes no manejo da doenca a campo. Assim, os objetivos do trabalho foram realizar uma selecao preliminar de cultivares de alface com resistencia ao nematoide-das-galhas, posteriormente uma caracterizacao mais precisa das mais promissoras, e por fim a caracterizacao de novas cultivares lancadas pela Embrapa, visando a identificacao de fontes de resistencia para utilizacao no melhoramento, e o repasse de informacoes para o setor produtivo. Foram avaliados 96, 15 e 5 genotipos de alface, com delineamento em blocos ao acaso com 12, 6 e 6 repeticoes de parcelas com 1 planta/vaso, respectivamente, no primeiro, segundo e terceiro experimentos. Nos tres experimentos foram utilizadas como testemunhas resistentes as cultivares de alface Salinas 88 e Grand Rapids, como suscetivel a cultivar Irene e como padrao de suscetibilidade e para verificar a viabilidade do inoculo utilizou-se plantas de tomateiro cultivar Rutgers. No primeiro experimento (avaliacao preliminar) as especies M. incognita raca 1 e M. javanica foram inoculadas simultaneamente 17 dias apos semeadura. Quarenta e um dias apos avaliou-se o indice de galhas (IG) nas raizes. Nos segundo e terceiro ensaios as especies de nematoides foram inoculadas separadamente e avaliado tambem o Indice de Massa de Ovos (IMO), Numero de Ovos por Grama de Raizes (NOGR) e o Fator de Reproducao (FR). Os dados foram submetidos a analise de variância e agrupamento de medias dos tratamentos por Scott-Knott. Foi possivel concluir que as cultivares do tipo crespa apresentaram maior grau de resistencia aos nematoides-das-galhas em comparacao as cultivares do tipo lisa; as cultivares Vera e Amanda apresentam resistencia ao M. incognita , e Vanda ao M. javanica . Salinas 88 apresenta resistencia principalmente ao M. javanica ; enquanto que a cultivar Monica e as cultivares da Embrapa BRS Leila e BRS Mediterrânea, sao resistentes a ambas as especies de nematoides.

Este trabalho teve como objetivo a caracterizacao de 37 genotipos de pimenta das especies Capsicum chinense , C. annuum e C. frutescens , quanto a resistencia a tres especies de nematoides-das-galhas, Meloidogyne javanica, M. incognita raca 1 e M. enterolobii , visando prospectar potenciais fontes de resistencia para serem utilizadas no melhoramento. Para isso, foram realizados tres experimentos, em 2013, 2014 e 2016, em casa de vegetacao, com delineamento em blocos casualizados e seis repeticoes de parcelas constituidas por uma planta/vaso. Os dados foram submetidos a analises de variância e de agrupamento de medias. Todos os genotipos de pimenta avaliados foram resistentes ou imunes a M. javanica . Para M. incognita raca 1 , todos os quatro genotipos de C. frutescens avaliados no primeiro experimento foram resistentes, enquanto que os seis genotipos de C. chinense foram suscetiveis. Ainda para M. incognita , todos os genotipos avaliados no segundo experimento, de C. chinense e C. annuum, foram resistentes. Para o terceiro experimento, com genotipos de C. annuum , a grande maioria foi suscetivel a M. incognita raca 1, mas os genotipos CNPH 30118 e CNPH 6144 foram resistentes. Quanto a M. enterolobii , que e a especie mais agressiva, e ha poucas fontes de resistencia descritas, houve uma tendencia de maior grau de resistencia em C. chinense e C. frutescens , e apesar da maioria dos genotipos avaliados serem suscetiveis, foram observadas diferencas significativas quanto ao grau de suscetibilidade, e a principal contribuicao deste trabalho foi a identificacao de um genotipo resistente, a cultivar BRS Nandaia, sendo possivel explorar esta fonte de resistencia no melhoramento.

O objetivo deste trabalho foi verificar a reação de genótipos de grão-de-

ABSTRACT Root-knot nematodes cause great damage to vegetable crops in Brazil, besides having a large range of host plants, such as weeds. Weeds can maintain the inoculums or even favor the multiplication of these nematodes. In this study we evaluated the reaction of selected weed species, present in a vegetable production area, to root-knot nematodes Meloidogyne incognita and M. enterolobii. The trials were conducted in a greenhouse at Embrapa Hortaliças, Brasília-DF, in a completely randomized design with six replicates. Fifteen weed species were evaluated for M. incognita race 1, and 16 weed species were evaluated for M. enterolobii. Two tomato cultivars were evaluated as resistance and susceptibility standards. Gall index (IG), egg mass index (IMO), number of eggs per gram of roots (eggs/g roots) and reproduction factor (FR) were evaluated. M. enterolobii survives and multiplies more easily in weeds collected in vegetable production areas than M. incognita race 1 and, the great majority of weed species evaluated in this study are hosts of both nematode species. Only the species Urena lobata, Sonchus oleraceus, Euphorbia heterophylla, Melampodium perfoliatum and Tagetes sp. were immune to M. incognita race 1. All evaluated species are either hosts or favor the multiplication of M. enterolobii. The species which are the most susceptible to M. incognita race 1, and therefore require greater control of crops infected by this nematode are Ipomoea nil, I. triloba and Eleusine indica, and for M. enterolobii are I. nil, Solanum americanum, Hyptis suaveolens, Portulaca oleracea, I. triloba and Euphorbia heterophylla.

O objetivo desse trabalho foi avaliar a reacao de clones avancados de batata do programa de melhoramento da Embrapa a Meloidogyne incognita em campo naturalmente infestado.