The soybean cyst nematode

"The soybean cyst nematode, Heterodera glycines Ichinohe, attacks soybean roots and is a serious threat to the crop in many soybean growing areas. This tiny, parasitic roundworm is so named because the female body, when filled with eggs, is known as a cyst. Cysts may remain in and infest soil for several years. The nematodes' persistence and rapid production, along with the severe injuries they cause to host-plant roots, make the nematodes a serious agricultural threat."--First page.Einar W. Palm, J. A Wrather (Department of Plant Pathology), and Sam Anand (Department of Agronomy, College of Agriculture)Revised 11/86/8

Extension Programs Increased Missouri Cotton Farmer Use of Survey-Based Pest Management

In 1982, only 5% of Missouri cotton farmers surveyed fields for pests and used this information when selecting pest management strategies, i.e., survey based pest management (SBPM). University of Missouri faculty initiated a program that year to instruct farmers about the benefits of SBPM. They provided instruction from 1982 to 1999. During 1999, 3% of Missouri cotton farmers were surveyed by phone for their use of SBPM. That year, farmers used SBPM to protect 82% of Missouri cotton acres. In addition to better yields, the use of SBPM ensured more efficient use of all pest management strategies

Fungicide, Insecticide, and Foliar Fertilizer Effect on Soybean Yield, Seed Composition, and Canopy Retention

Soybean [Glycine max (L.) Merr.] yield has increased over time through the introduction of new varieties and improved agronomic practices. However, seed protein concentration has decreased. We conducted field studies in 2018 and 2019 to investigate the effects of fungicide, insecticide, and foliar fertilizer application on grain yield and seed quality in two soybean maturity groups (MG). In‐season treatments targeted nutrient availability and soybean canopy duration during the seed‐filling period by fungicide, insecticide, or foliar fertilizer application at the onset of this period. Biomass samples were collected at R5, R6, and R7 and partitioned into plant parts. Year, location, and MG often influenced yield and seed composition, but foliar fungicide, insecticide, or fertilizer application had no impact on these parameters

Variation in parasitic potential of Heterodera glycines populations

Fifty-eight populations of H. glycines were collected from 10 major soyabean producing states. These populations were compared for infraspecific variation in parasitic potential on soyabean genotypes 'Peking', 'Pickett', Plant Introduction (PI) 88788, PI 90763, and 'Lee 68'. Race 3 was present in 45% of locations; it was the most widespread population. Race 6 was present in 19% of the locations. Frequency of occurrence of other races (Races 1, 2, 5, 9, and 14) ranged between 3 and 9%. On the basis of reproduction on genotypes, 83% of the populations tested had genes to parasitize Pickett. All populations from Arkansas, Florida, Georgia, Iowa, North Carolina and South Carolina produced cysts on this genotype. Average level of parasitism was greatest on Pickett and lowest on PI 90763; 91% of SCN populations tested had <10% level of parasitism on PI 90763. The SCN gene frequencies demonstrated that nematode populations with predominant genes for parasitism on Pickett and Lee 68 were widespread especially in the southern soyabean producing states in the USA. Cultivation of varieties with resistance derived from Peking and Pickett in these regions should not be very effective. For management of SCN-caused yield losses, cultivation of soyabean varieties with resistance derived from PI 90763, PI 88788, and PI 437654 should be encouraged

Footnotes to Disciples History

From the mid 1950s through the 1990s, DCHS printed short publications to remind its readers about the importance of the past. The series included reprints as well as new historical studies. Footnotes to Disciples History collects this wide-ranging series into one volume. ⁃ Rice Haggard\u27s An Address to the Different Religious Societies, on the sacred import of the Christian Name (1804) ⁃ John M. Imbler\u27s Beyond Buffalo: Alexander Campbell on Education for Ministry (1992) ⁃ Report of the Proceedings of a General Meeting of Messengers from Thirteen Congregations (J.T. McVay and Alexander Campbell, 1834) ⁃ William A. Gerrards\u27s Christian Unity, Our Heritage (1986) ⁃ Alexander Campbell\u27s Lunenburg Letter (1837) ⁃ Eva Jean Wrather\u27s Alexander Campbell and His Relevance for Today (1959) ⁃ Perry Gresham\u27s The Broncho That Would Not Be Broken (1986)https://digitalcommons.acu.edu/acu_library_books/1011/thumbnail.jp

Humidity assay for studying plant-pathogen interactions in miniature controlled discrete humidity environments with good throughput

This paper reports a highly economical and accessible approach to generate different discrete relative humidity conditions in spatially separated wells of a modified multi-well plate for humidity assay of plant-pathogen interactions with good throughput. We demonstrated that a discrete humidity gradient could be formed within a few minutes and maintained over a period of a few days inside the device. The device consisted of a freeway channel in the top layer, multiple compartmented wells in the bottom layer, a water source, and a drying agent source. The combinational effects of evaporation, diffusion, and convection were synergized to establish the stable discrete humidity gradient. The device was employed to study visible and molecular disease phenotypes of soybean in responses to infection by Phytophthora sojae, an oomycete pathogen, under a set of humidity conditions, with two near-isogenic soybean lines, Williams and Williams 82, that differ for a Phytophthora resistance gene (Rps1-k). Our result showed that at 63% relative humidity, the transcript level of the defense gene GmPR1 was at minimum in the susceptible soybean line Williams and at maximal level in the resistant line Williams 82 following P. sojae CC5C infection. In addition, we investigated the effects of environmental temperature, dimensional and geometrical parameters, and other configurational factors on the ability of the device to generate miniature humidity environments. This work represents an exploratory effort to economically and efficiently manipulate humidity environments in a space-limited device and shows a great potential to facilitate humidity assay of plant seed germination and development, pathogen growth, and plant-pathogen interactions. Since the proposed device can be easily made, modified, and operated, it is believed that this present humidity manipulation technology will benefit many laboratories in the area of seed science, plant pathology, and plant-microbe biology, where humidity is an important factor that influences plant disease infection, establishment, and development

Separate loci underlie resistance to root infection and leaf scorch during soybean sudden death syndrome

Soybean [Glycine max (L.) Merr.] cultivars show differences in their resistance to both the leaf scorch and root rot of sudden death syndrome (SDS). The syndrome is caused by root colonization by Fusarium virguliforme (ex. F. solani f. sp. glycines). Root susceptibility combined with reduced leaf scorch resistance has been associated with resistance to Heterodera glycines HG Type 1.3.6.7 (race 14) of the soybean cyst nematode (SCN). In contrast, the rhg1 locus underlying resistance to Hg Type 0 was found clustered with three loci for resistance to SDS leaf scorch and one for root infection. The aims of this study were to compare the inheritance of resistance to leaf scorch and root infection in a population that segregated for resistance to SCN and to identify the underlying quantitative trait loci (QTL). “Hartwig”, a cultivar partially resistant to SDS leaf scorch, F. virguliforme root infection and SCN HG Type 1.3.6.7 was crossed with the partially susceptible cultivar “Flyer”. Ninety-two F5-derived recombinant inbred lines and 144 markers were used for map development. Four QTL found in earlier studies were confirmed. One contributed resistance to leaf scorch on linkage group (LG) C2 (Satt277; P = 0.004, R 2 = 15%). Two on LG G underlay root infection at R8 (Satt038; P = 0.0001 R 2 = 28.1%; Satt115; P = 0.003, R 2 = 12.9%). The marker Satt038 was linked to rhg1 underlying resistance to SCN Hg Type 0. The fourth QTL was on LG D2 underlying resistance to root infection at R6 (Satt574; P = 0.001, R 2 = 10%). That QTL was in an interval previously associated with resistance to both SDS leaf scorch and SCN Hg Type 1.3.6.7. The QTL showed repulsion linkage with resistance to SCN that may explain the relative susceptibility to SDS of some SCN resistant cultivars. One additional QTL was discovered on LG G underlying resistance to SDS leaf scorch measured by disease index (Satt130; P = 0.003, R 2 = 13%). The loci and markers will provide tagged alleles with which to improve the breeding of cultivars combining resistances to SDS leaf scorch, root infection and SCN HG Type 1.3.6.7