Distribution and Virulence Phenotypes of Heterodera glycines in Missouri

Abstract

The soybean cyst nematode, Heterodera glycines, is the most economically important pathogen of soybean in Missouri. Knowledge of the nematode's distribution and ability to adapt to resistant varieties is important for determining crop losses and establishing research priorities. No previous surveys of Missouri have provided reliable population density and phenotypic diversity data; therefore, we conducted a random survey to obtain both. Two samples from each of 200 fields were collected; 392 samples were processed for extractions of cysts and eggs. Two hundred and forty seven (63%) of the samples had detectable cyst nematode populations, which ranged from 15 to 149,700 eggs per 250 cm3 of soil. The lowest average population densities were observed in the east-central region of Missouri (2,260 eggs per 250 cm3 of soil), and the highest were observed in the northeast (9,238 eggs per 250 cm3 of soil), but among the eight regions sampled, mean population densities did not differ significantly. These population densities were potentially responsible for losses worth over $58 million in 1999 in Missouri. Race tests were conducted on populations from 183 samples. In order of frequency, races 3, 1, and 2 accounted for 86% of H. glycines populations. Nearly 60% of the populations were virulent (able to produce females) on plant introduction (PI) 88788, which is the source of resistance for most H. glycines-resistant cultivars. More than a third of the populations were virulent on cv. Peking, another common resistance source. Very few populations were virulent on PI 90763 or PI 437654, suggesting that these sources of resistance should be exploited more frequently.

The Soybean Rhg1 Locus for Resistance to the Soybean Cyst Nematode Heterodera glycines Regulates the Expression of a Large Number of Stress- and Defense-Related Genes in Degenerating Feeding Cells

“…The SCN (Heterodera glycines 'Ichinohe') inbred populations PA3 and TN19 were obtained from a publicly available collection at the University of Illinois at Urbana-Champaign and mass selected according to standard procedures (Niblack et al, 1993) on soybean cv Williams 82 and PI 437654, respectively. HG type tests (Niblack et al, 2002) confirmed that the PA3 population was HG type 0 and the TN19 population was HG type 1-7.…”

Genomic DNA sequence comparison between two inbred soybean cyst nematode biotypes facilitated by massively parallel 454 micro-bead sequencing

“…A collection of SCN inbred lines (selected by single cyst descent (half-sib matting) for over 30 generations) is maintained at 27°C in a greenhouse facility on appropriate host plants using plastic crocks as described by (Niblack 1993). TN10 was selected on tomato (cultivar Tiny Tim) and TN20 was selected on the SCN resistant soybean cultivar Hartwig.…”

Influência da intensidade da murcha-de-fusário no rendimento do caupi

“…Com bases nessas informações, sistemas de previsão poderão ser desenvolvidos e estratégias de controle, principalmente o uso de variedades resistentes, podem ser otimizadas. Em regiões onde há alta DI, deverão ser recomendadas variedades mais resistentes; à semelhança do que ocorre para nematóide dos cistos da soja nos Estados Unidos (Niblack et al, 1993).…”