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-Isolates of Pseudomonas veronii (DFs513), Bacillus spp. (DFs093 and DFs348), Bacillus cereus (DFs769), Rodhococcus fascians (DFs843 and DFs912) and Pseudomonas fluorescens (DFs831 and DFs842), selected for Xanthomonas axonopodis pv. phaseoli control, and a combination of some of these bacteria isolates, were evaluated for possible influence on Colletotrichum lindemuthianum transmission from naturally infected and/or infested bean seeds to seedlings. In the first trial, using the paper roll method, seeds were sown in eight replications of 25 seeds that were incubated at 20 ± 2°C. Germination percentage and pathogen incidence were evaluated. In the second trial, pathogen transmission to seedlings was evaluated in sterile substratum and incubated for 10 days. Daily emerged seedlings, pathogen incidence, leaf and root dry mass were

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Resumo -O objetivo deste trabalho foi avaliar a compatibilidade entre rizobactérias biocontroladoras pré-selecionadas e o efeito de suas combinações sobre a queima-das-bainhas (Rhizoctonia solani), a meloidoginose (Meloidogyne graminicola) e a promoção de crescimento de plantas de arroz. A compatibilidade foi determinada pela antibiose. O efeito das combinações de isolados foi avaliado por microbiolização de sementes de arroz, cultivar El Paso L144, com suspensões das rizobactérias DFs185 (Pseudomonas synxantha), DFs223 (P. fluorescens), DFs306 (ainda não identificada), DFs416 e DFs418 (Bacillus sp. Biocontrol of sheath blight and root-knot nematode and growth promotion of rice plants by rhizobacteriaAbstract -The objective of this work was to evaluate the compatibility between previously selected biocontroller rhizobacteria and the effect of their combination upon sheath blight (Rhizoctonia solani), root-knot nematode (Meloidogyne graminicola) and growth promotion in rice plants. The compatibility between these bacteria was determined by the overlay antibiosis. The effect of isolate combinations was evaluated by seed microbiolization of the rice cultivar El Paso L144 with rhizobacteria suspensions of DFs185 (Pseudomonas synxantha), DFs223 (P. fluorescens), DFs306 (unidentified), DFs416 and DFs418 (Bacillus sp.). These rhizobacteria were used alone or combined in arrangements of two, three and four isolates. The DFs223 isolate was not combined because it is incompatible with the other bacteria. Five rhizobacteria combinations (DFs185/418, DFs306/416, DFs306/418, DFs416/418, DFs185/306/418) and the isolate DFs306 stood out for reducing M. graminicola reproduction and promoting plant growth. Combination DFs185/306 presented the best results for the control of R. solani and for growth promotion. The DFs306/416 combination provided the best results for the control of the two diseases.Index terms: Meloidogyne graminicola, Rhizoctonia solani, biological control, seed microbilization, growth-promoting rhizobacteria. IntroduçãoVários microrganismos podem associar-se patogenicamente às plantas de arroz (Oryza sativa L.) e causar lesões na parte aérea e radicular, levando à redução da produção (Nunes et al., 2004 A queima-das-bainhas no arroz, causada por R. solani, ocorre em áreas temperadas e tropicais. Alguns fatores têm agravado sua incidência e severidade, como a utilização excessiva de adubação nitrogenada, alta densidade de plantas e plantio de cultivares de ciclo precoce, de baixa estatura, alto perfilhamento e de maior suscetibilidade. O cultivo do arroz sucedido por hospedeiros desse fungo leva à continuidade do ciclo do patógeno e ao aumento de inóculo (Nunes et al., 2004).

-Bipolaris oryzae and Gerlachia oryzae, which cause rice brown spot and leaf scald, respectively, are mainly disseminated by seeds. The aim of this study was to evaluate the potential of seeds microbiolization to reduce transmission of these pathogens to seedlings by using the bacteria DFs185 (Pseudomonas synxantha), DFs223 (P. fluorescens), DFs306 (unidentified) and DFs418 (Bacillus sp.). Seeds naturally infested/infected with both pathogens were immersed in suspension of these bacteria (A 540 = 0.5) individually or in saline solution (control treatment). After 30 minutes of agitation at 10 °C, 400 seeds were submitted to a sanity test through the blotter method and the isolate DFs223 was the best to reduce the incidence of B. oryzae and G. oryzae in both seed lots evaluated. Seeds treated like above were sowed in sterilized vermiculite. Seed transmission and growth promotion were recorded after 21 days of incubation in the same conditions. The isolates DFs185 and DFs306 reduced transmission of both pathogens, although the isolate DFs306 was the one wich gave the greatest growth increases. The evaluation of the in vitro antibiosis showed that isolates inhibited the mycelial growth of both pathogens, except DFs306. It is possible to affirm that these bacteria have the potential to be used as a seed treatment for seed-borne disease control.Index terms: biological control, rice brown spot, rice leaf scald, seed treatment, Oryza sativa L. Biocontrole e transmissão de Bipolaris oryzae eGerlachia oryzae para plântulas de arroz RESUMO -Bipolaris oryzae e Gerlachia oryzae causadores, respectivamente, da mancha parda e da escaldadura do arroz são principalmente disseminados por sementes. Objetivou-se com esse trabalho avaliar o potencial da microbiolização de sementes para a redução da transmissão destes patógenos das sementes para as plântulas usando as bactérias DFs185 (Pseudomonas synxantha), DFs223 (P. fluorescens), DFs306 (não identificado) e DFs418 (Bacillus sp. Termos para indexação: controle biológico, mancha parda do arroz, escaldadura do arroz, tratamento de sementes, Oryza sativa.

-The objective of this study was to evaluate the resistance of a group of clones and cultivars from the potato breeding program of Embrapa to Meloidogyne javanica. The experiment was conducted at Embrapa Temperate Climate, Pelotas / RS, under greenhouse conditions at temperatures of 25 ± 5°C. Individual potato plants of different genotypes [BRSIPR Bel, BRS F63 (Camila),, kept in pots with sterilized soil were inoculated with 5,000 eggs and J2 of M. javanica, using six replicates per treatment. The susceptible control, potato cultivar BRS Ana was inoculated with the same level of inoculum. Fifty-five days after inoculation, the number of galls on the roots of each plant was determined as well as the number of protuberances caused by nematodes in the different treatments. Then, the roots of each plant were processed for counting the number of eggs and J2, as well as determining the nematode reproduction factor (FR: final population / initial population). All genotypes were susceptible (FR> 1.00) to M. javanica. However, there were different levels of susceptibility among the cultivars tested.Keywords: Root-knot nematode. Susceptibility. Solanum tuberosum. REAÇÃO DE GENÓTIPOS DE

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