Raças de Heterodera glycines na região Nordeste de Mato Grosso do Sul

Abstract

RESUMOO nematoide de cisto da soja, Heterodera glycines, constitui-se em um dos principais entraves à produção de soja na região Nordeste de Mato Grosso do Sul. Após um período de uso do manejo recomendado para as áreas infestadas, observou-se a ressurgência de altas densidades populacionais associada a severos danos à cultura, mesmo com a utilização de cultivares resistentes, fato que conduziu à hipótese da ocorrência de mudança nas raças do nematoide. Assim, nas safras de 2006/2007 e 2007/2008, foram amostradas lavouras de 22 propriedades nos municípios de Água Clara, Chapadão do Sul e Costa Rica, com presença confirmada de altas populações de H. glycines. Após serem multiplicadas em soja cv. BRS 133 por até três gerações, as populações oriundas de cada amostra foram submetidas ao teste padrão para a determinação de raças, com a inclusão da variedade diferenciadora Hartwig, visando detectar eventual presença das raças 4 + ou 14 + . Detectou-se a presença de quatro raças, com predominância da raça 4 (72,73% das amostras), seguida das raças 14, 5 e 6 (18,19%, 4,54% e 4,54% das amostras, respectivamente). Conclui-se que não houve significativa alteração nas raças de H. glycines que ocorrem na região Nordeste de Mato Grosso do Sul. Palavras-chave: Glycine max, distribuição, manejo, nematoide de cisto da soja, variabilidade. ABSTRACT Races of Heterodera glycines in the Northeast of Mato Grosso do Sul, BrazilThe soybean cyst nematode (SCN), Heterodera glycines, is one of the major constraint to soybean production in the Northeast of the Mato Grosso do Sul State, Brazil. After a period of recommended management of infested areas, the recent resurgence of high population densities and severe damage to soybeans, regardless of the use of resistant cultivars, has led to the hypothesis that nematode races could be changing. Thus, in 2006Thus, in /2007Thus, in and 2007Thus, in /2008 growing seasons, highly infested soil from 22 farms in the municipalities of Água Clara, Chapadão do Sul and Costa Rica were sampled. After being multiplied in soybean cv. BRS 133 for up to three generations, the SCN populations from each soil sample were submitted to standard test for the determination of races, adding the cultivar Hartwig as one of the differential hosts to eventually detect the possible presence of races 4 + or 14 + . Among the four races detected, the race 4 was predominant (72.73% of samples), followed by races 14, 5 and 6 (18.19%, 4.54% and 4.54% of the samples, respectively). There was no significant change in the races of H. glycines in the Northeast of the Mato Grosso do Sul State, Brazil.

Diseases of Edible Oilseed Crops

“…The influence of winter annual weed management on SCN population densities has received little attention to date and warrants further investigation (Johnson et al 2008). The SCN shows considerable degree of pathogenic variability all over the soybean-growing countries in the world (Dias et al 2005, Rocha et al 2008, Afzal et al 2012, Asmus et al 2012, Matsuo et al 2012). This variability is large in Brazil, where 11 races (1, 2, 3, 4, 4+, 5, 6, 9, 10, 14, and 14+) have been found.…”

Correlations and path analysis in soybean progenies with resistance source to cyst nematode (race 3)

“…shown to be higher than that observed in other countries (Asmus et al, 2012). In this context, several races of this pathogen were found, with emphasis on race 3, one of the most frequent in the several soybean producing regions of Brazil (Santana et al, 2009).…”