Promoção de crescimento e controle de nematoides da soja por isolados de Bacillus spp.
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Data
2019-02-27
Autores
Nascimento, Daniel Dalvan do
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Universidade Estadual Paulista (Unesp)
Resumo
O Brasil, segundo maior produtor e também maior exportador de soja, tem grande parte da produção comprometida devido aos danos causados por nematoides. Para tanto, vários estudos têm relatado a eficiência de bactérias promotoras de crescimento no controle de nematoides nas mais diversas culturas. Diante do exposto, o objetivo desse trabalho foi selecionar isolados de três espécies de Bacillus eficientes no controle dos nematoides, Heterodera glycines, Meloidogyne incognita e M. javanica, e também, na promoção de crescimento da soja, sob diferentes formas de aplicação. Foram testados 19 isolados de Bacillus subtilis, B. velezensis (syn. B. amyloliquefaciens) e B. methylotrophicus, aplicados via Tratamento de sementes (TS) e Sulco de semeadura (SS), mais testemunhas (com e sem nematoides) e comercias [Bacillus subtilis UFPEDA 764 (TS); B. subtilis UFPEDA 764 (SS); Abamectina (TS); Cadusafós (SS)]. Avaliou-se a emergência das plântulas, altura da planta, massa fresca e seca das partes aéreas, massa fresca das raízes, número de vagens, índice de clorofila, nematoide total, nematoide por grama de raízes e fator de reprodução. Devido a existência de uma estrutura de dependência contida nas variáveis originais, realizou-se análise exploratória dos dados, via Análise de Componentes Principais (ACP), as variáveis independentes foram testadas via análise de Modelo Linear Geral (GLM). Os resultados mostraram que para as três espécies de nematoides, o método de aplicação via SS favoreceu a emergência das plântulas de soja, sendo mais eficiente que o método de aplicação via TS, ambos os métodos foram melhores que a testemunha não tratada com Bacillus spp.. Entretanto, o método de aplicação via TS foi superior comparado ao SS para as variáveis, altura da planta, massa fresca e seca das partes aéreas, massa fresca das raízes, número de vagens e índice de clorofila, bem como foi melhor para a supressão dos nematoides. Dos isolados de Bacillus spp. testados, ACB-01, ACB-08, ACB-22 e ACB-AP3 foram eficientes para promoção de crescimento da soja e supressão de H. glycines, M. incognita e M. javanica.
Brazil, the second largest producer and also the largest exporter of soybeans, has a large part of the production compromised due to damage caused by nematodes. For this, several studies have reported the efficiency of growth-promoting bacteria in the control of nematodes in the most diverse cultures. In view of the above, the objective of this work was to select isolates of three species of Bacillus spp. efficient in the control of nematodes, Heterodera glycines, Meloidogyne incognita and M. javanica and also in the promotion of soybean growth under different forms of application. Nineteen isolates of Bacillus subtilis, B. velezensis (syn. B. amyloliquefaciens) and B. methylotrophicus were tested on application by seed treatment (ST) and sowing furrow (SF), plus controls (with and without nematodes) and commercial [Bacillus subtilis UFPEDA 764 (ST); B. subtilis UFPEDA 764 (SF); Abamectin (ST); Cadusafós (SF)]. Seed emergence, plant height, fresh and dry mass of aerial parts, fresh root mass, number of pods, total chlorophyll content, total nematode, nematode per gram of roots and reproductive factor were evaluated. Due to the existence of a dependency structure contained in the original variables, an exploratory analysis of the data was carried out, via Principal Component Analysis (PCA), the independent variables were tested through GLM analysis. The results showed that for the three nematode species, the SF application method favored the emergence of soybean seedlings, being more efficient than the ST application method, both methods were better than the control not treated with Bacillus spp. However, the ST application method was superior, compared to SF, for the variables, plant height, fresh and dry mass of the aerial parts, fresh root mass, number of pods and chlorophyll content, and was better for the suppression of nematodes. Among the isolates of Bacillus spp, tested, ACB-01, ACB-08, ACB-22 and ACB-AP3 were efficient for promoting soybean growth and suppression of H. glycines, M. incognita and M. javanica.
Brazil, the second largest producer and also the largest exporter of soybeans, has a large part of the production compromised due to damage caused by nematodes. For this, several studies have reported the efficiency of growth-promoting bacteria in the control of nematodes in the most diverse cultures. In view of the above, the objective of this work was to select isolates of three species of Bacillus spp. efficient in the control of nematodes, Heterodera glycines, Meloidogyne incognita and M. javanica and also in the promotion of soybean growth under different forms of application. Nineteen isolates of Bacillus subtilis, B. velezensis (syn. B. amyloliquefaciens) and B. methylotrophicus were tested on application by seed treatment (ST) and sowing furrow (SF), plus controls (with and without nematodes) and commercial [Bacillus subtilis UFPEDA 764 (ST); B. subtilis UFPEDA 764 (SF); Abamectin (ST); Cadusafós (SF)]. Seed emergence, plant height, fresh and dry mass of aerial parts, fresh root mass, number of pods, total chlorophyll content, total nematode, nematode per gram of roots and reproductive factor were evaluated. Due to the existence of a dependency structure contained in the original variables, an exploratory analysis of the data was carried out, via Principal Component Analysis (PCA), the independent variables were tested through GLM analysis. The results showed that for the three nematode species, the SF application method favored the emergence of soybean seedlings, being more efficient than the ST application method, both methods were better than the control not treated with Bacillus spp. However, the ST application method was superior, compared to SF, for the variables, plant height, fresh and dry mass of the aerial parts, fresh root mass, number of pods and chlorophyll content, and was better for the suppression of nematodes. Among the isolates of Bacillus spp, tested, ACB-01, ACB-08, ACB-22 and ACB-AP3 were efficient for promoting soybean growth and suppression of H. glycines, M. incognita and M. javanica.
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Fitopatologia, Doenças de plantas, Controle Biológico, Nematoda, Bactérias