No abstract

-The application of a bionematicide based on chlamydospores of Pochonia chlamydosporia (Pc-10) can be an important strategy for reducing the damage caused by Meloidogyne incognita on carrot. Based on this perspective, the nematicidal effects of 0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 kg ha -1 of Pc-10 were evaluated on carrot cv. Juliana under field conditions. Carrot yield and nematode population were influenced by increasing doses of Pc-10. The application of 3.0 kg ha -1 of Pc-10 increased the marketable production of carrot roots by 41.7% compared to the untreated control, whereas the production of unmarketable roots and the nematode population in the soil were reduced by 48.7% and 61.4%. The application of 3.0 kg ha -1 of Pc-10 reduces M. incognita population and improves carrot quality and yield.Keywords: Biological control. Daucus carota. Nematophagous fungus. Root-knot nematode. EFEITO DOSE-RESPOSTA DE Pochonia chlamydosporia SOBRE Meloidogyne incognita EM CENOURA EM CONDIÇÕES DE CAMPORESUMO -A aplicação de um bionematicida à base de clamidósporos de Pochonia chlamydosporia (Pc-10) pode se tornar uma importante estratégia para reduzir os danos causados por Meloidogyne incognita em cenoura. Baseado nessa perspectiva, o efeito nematicida de 0; 0,5; 1,0; 1,5; 2,0; 2.5 e 3,0 kg ha -1 de Pc-10 foi avaliado em área de produção de cenoura cv. Juliana em condições de campo. A produtividade de cenoura e a população do nematoide foram influenciados por doses crescentes de Pc-10. A aplicação de 3,0 kg ha -1 de Pc-10 aumentou a produção de raízes comerciais de cenoura em 41,7% comparada com aquela obtida na testemunha não tratada, enquanto que a produção de raízes não-comerciais e a população do nematoide no solo foram reduzidos em 48,7% e 61,4%, respectivamente. A aplicação de 3,0 kg ha -1 de Pc-10 reduz a população de M. incognita e aumenta a qualidade e a produtividade das raízes de cenoura.Palavras-chave: Controle biológico. Daucus carota. Fungo nematófago. Nematoide de galhas.

Bacteria belonging to the genus Bacillus can promote plant growth and suppress plant-parasitic nematode populations. Based on this hypothesis, eight strains of the bacterium (SF 262, SF 264, SF 266, SF 267, SF 268, SF 271, SF 292 and SF 629) were formulated and applied as a seed treatment and/or sprayed on the soil surface with the aim of controlling Pratylenchys brachyurus in common bean under field conditions. The application of the bacterial isolates neither improved the grain yield and the root mass nor reduced the number of nematodes in the soil and in the roots of common bean. Thus none of the isolates of Bacillus spp. evaluated in this work are promising for the control of the lesion nematode on common bean.

Exposure to climatic conditions on the soil surface reduces P. chlamydosporia viability.

Few commercial genotypes of tomato are resistant to Fusarium wilt (Fusarium oxysporum f. sp. lycopersici [FOL]), especially to race 3. We developed five intraspecific hybrids of Solanum lycopersicum (FOX1 to FOX5) and assessed them for agronomic traits and resistance to FOL races 1, 2, 3, and a mixture of these races. FOX1 and FOX4 were resistant to all races and the race mixture but did not have the desired agronomic traits. Next, FOX1 and FOX4 were assessed as rootstocks of the cherry tomato Sweet Heaven. The grafting of Sweet Heaven on FOX4 did not reduce growth, gas exchange, yield, or fruit quality. When FOX1 was used as a rootstock, the fruits exhibited a reduction in firmness, fruit pulp pH, and total soluble solids by 14.3%, 1.2%, and 6.75%, respectively. Thus, the hybrid FOX4 can be used as a rootstock for Sweet Heaven to manage Fusarium wilt.

Anatomical, physiological, and biochemical analyses have been performed to predict graft compatibility. We analyzed if the concentrations of auxins, jasmonic acid, gibberellins, 1-aminocyclopropane-1-carboxylic acid, zeatin (cytokinin), salicylic acid, and abscisic acid could be used as predictors of compatibility between the rootstocks FOX1 and FOX4 (resistant to Fusarium wilt) and the scion of cherry tomatoes Sweet Heaven (SH). Self-grafted (SH/SH) and ungrafted SH plants (SH) were used as controls. Hormonal analyses were performed on leaves, at 20 and 70 days after grafting (DAG), and roots, at 20 DAG. No expressive concentrations of auxins, gibberellins, or jasmonic acid were detected. The concentrations of 1-aminocyclopropane-1-carboxylic acid, the immediate precursor of ethylene, and zeatin were altered at 20 DAG, but they stabilized at 70 DAG. Salicylic acid levels were reduced in the leaves of grafted plants at 70 DAG.The concentration of abscisic acid (ABA) in the leaves of SH grafted onto FOX1 was higher than in ungrafted and self-grafted plants at 70 DAG, suggesting some degree of incompatibility between these genotypes. The concentration of ABA in the combination FOX4/SH was similar to that in the self-grafted plants. Abscisic acid might be used as a reference phytohormone to predict graft compatibility among tomato genotypes.

The analysis of genetic divergence in plant germplasm based on a set of quantitative data has revealed a low association to the divergence estimated from multicategorical data and vice versa. On the other hand, strategies involving the integration of quantitative and multicategorical information may provide more accurate estimations. Thus, this study aimed to estimate the genetic divergence in the germplasm of cassava based on the integration of quantitative and multicategorical data, targeting a greater comprehensiveness and accuracy in the estimation. Data from 10 genotypes of M. esculenta, characterized by 20 quantitative and 24 multicategorical characteristics was used in this work. The genotypes were collected from autochthonous fields from five different microregions of Brazil and evaluated in a completely randomized block design experiment with four replications. First, the analysis of genetic divergence was performed based on the distances individually obtained from the quantitative and multicategorical information. For the data integration, three strategies were adopted, the Gower's algorithm, the transformation of quantitative data by the equitable division of its amplitude into several classes, and the sum of the distance matrices, obtained from quantitative and multicategorical data. The estimates of genetic divergence from the quantitative data had a low association with that expected from the multicategorical data and vice versa. The transformation of data and the algorithm of Gower were not efficient, which resulted in low correlations with the matrices of distances obtained from the original data. The sum of matrices consisted on the strategy of higher efficiency and provided a higher comprehensiveness and accuracy in the analysis o f genetic divergence in the germplasm of cassava.

The objective of this work was to evaluate the effect of Bacillus spp. isolates on the control of Meloidogyne incognita in greenhouse and field experiments. In the greenhouse, isolates 57 (Bacillus sp.), 63 (Bacillus amyloliquefaciens), SF 194 (Bacillus sp.), SF 203 (Bacillus amyloliquefaciens), and a mixture containing the four isolates were applied to the soil surface (2 L ha -1 , 1×10 9 cfu mL -1 ), infested with 5,000 eggs of M. incognita. Sixty days after planting, the mass of the bean roots and the number of galls and eggs were evaluated. In a field naturally infested with M. incognita, the effects of isolates 57, 63, and a mixture containing both of them were observed after application to the soil surface (2 L ha -1 ), with or without seed treatment with the isolates (2 mL kg -1 ). Production, thousand-grain weight, reproductive factor, and number of eggs were evaluated at 90 days after planting. In the greenhouse, the application of the isolates did not influence neither root biomass, nor the number of galls and eggs. In the field, the application of isolates 57, 63, and the mixture 57 + 63 on the soil surface and in seed treatment did not increase total production and thousand-grain weight, nor did it reduce the nematode multiplication in the soil and in the roots of the plants. Thus, Bacillus spp. isolates 57, 63, SF 194, and SF 203 have no potential to formulate bionematicides for the control of M. incognita in common bean.Additional keywords: biological control, Phaseolus vulgaris, root-knot nematode. ResumoO objetivo deste trabalho foi avaliar o efeito de isolados de Bacillus spp. no controle de Meloidogyne incognita em casa de vegetação e em campo. Em casa de vegetação, os isolados 57 (Bacillus sp.), 63 (Bacillus amyloliquefaciens), SF 194 (Bacillus sp.), SF 203 (Bacillus amyloliquefaciens) e uma mistura contendo os quatro isolados foram aplicados na superfície do solo (2 L ha -1 , 1×10 9 ufc mL -1 ) infestado com 5.000 ovos de M. incognita. Após 60 dias do plantio, a massa das raízes de feijoeiro e os números de galhas e ovos foram avaliados. Em campo naturalmente infestado com M. incognita, avaliaram-se os efeitos dos isolados 57; 63 e uma mistura contendo os isolados 57 e 63, aplicados na superfície do solo (2 L ha -1 ), com ou sem o tratamento de sementes com os isolados (2 mL kg -1 ). A produção e a massa de mil grãos, o fator de reprodução e o número de ovos foram avaliados aos 90 dias após o plantio. Em casa de vegetação, a aplicação dos isolados não influenciou a biomassa das raízes e o número de galhas e de ovos. Em campo, a aplicação dos isolados 57; 63 e a mistura 57 + 63 na superfície do solo e em tratamento de sementes não aumentaram a produção total e a massa de mil grãos, tampouco reduziram a multiplicação do nematoide no solo e nas raízes das plantas. Assim, os isolados 57; 63; SF 194 e SF 203 de Bacillus spp. não possuem potencial para formulação de bionematicidas para o controle de M. incognita em feijoeiro.Palavras-chave adicionais: controle biológico, nematoide de galha...