Development of a greenhouse assay to screen soybean varieties for resistance to aerial blight caused by Rhizoctonia solani AG1-IA.

Aerial blight, caused by the fungus Rhizoctonia solani anastomosis group (AG) 1-IA, is an economically important soybean disease in the mid-Southern US. Management has relied on fungicide applications during the season, but there is an increasing prevalence of resistance to commonly used strobilurin fungicides and an urgent need to identify soybean varieties resistant to aerial blight. Since the patchy distribution of the pathogen complicates field variety screening, the present study aimed to develop a greenhouse screening protocol to identify soybean varieties resistant to aerial blight. For this, 88 pathogen isolates were collected from commercial fields and research farms across five Louisiana parishes, and 77% were confirmed to be R. solani AG1-IA. Three polymorphic co-dominant microsatellite markers were used to explore the genetic diversity of 43 R. solani AG1-IA isolates, which showed high genetic diversity with 35 haplotypes in total and only two haplotypes common to two other locations. Six genetically diverse isolates were chosen and characterized for their virulence and fungicide sensitivity. The isolate AC2 was identified as the most virulent and was resistant to both active ingredients, azoxystrobin and pyraclostrobin, tested. The six isolates were used in greenhouse variety screening trials using a millet inoculation protocol. Of the 31 varieties screened, only Armor 48-D25 was classified as moderately resistant, and plant height to the first node influenced final disease severity. The study provides short-term solutions for growers to choose less susceptible varieties for planting and lays the foundation to characterize host resistance against this important soybean pathogen.

Novel genetic resources associated with sucrose and stachyose content through genome-wide association study in soybean (Glycine max (L.) Merr.).

The nutritional value of soybean [Glycine max (L.) Merr.] for animals is influenced by soluble carbohydrates, such as sucrose and stachyose. Although sucrose is nutritionally desirable, stachyose is an antinutrient causing diarrhea and flatulence in non-ruminant animals. We conducted a genome-wide association study of 220 soybean accessions using 21,317 single nucleotide polymorphisms (SNPs) from the SoySNP50K iSelect Beadchip data to identify significant SNPs associated with sucrose and stachyose content. Seven significant SNPs were identified for sucrose content across chromosomes (Chrs.) 2, 8, 12, 17, and 20, while thirteen significant SNPs were identified for stachyose content across Chrs. 2, 5, 8, 9, 10, 13, 14, and 15. Among those significant SNPs, three sucrose-related SNPs on Chrs. 8 and 17 were novel, while twelve stachyose-related SNPs on Chrs. 2, 5, 8, 9, 10, 13, 14, and 15 were novel. Based on Phytozome, STRING, and GO annotation, 17 and 24 candidate genes for sucrose and stachyose content, respectively, were highly associated with the carbohydrate metabolic pathway. Among these, the publicly available RNA-seq Atlas database highlighted four candidate genes associated with sucrose (Glyma.08g361200 and Glyma.17g258100) and stachyose (Glyma.05g025300 and Glyma.13g077900) content, which had higher gene expression levels in developing seed and multiple parts of the soybean plant. The results of this study will extend knowledge of the molecular mechanism and genetic basis underlying sucrose and stachyose content in soybean seed. Furthermore, the novel candidate genes and SNPs can be valuable genetic resources that soybean breeders may utilize to modify carbohydrate profiles for animal and human usage.

Effect of Planting Date and Cultivar Maturity in Edamame Quality and Harvest Window.

Edamame is a food-grade soybean [Glycine max (L.) Merr.] that is harvested immature between the R6 and R7 reproductive stages. To be labeled as a premium product, the edamame market demands large pod size and intense green color. A staggered harvest season is critical for the commercial industry to post-harvest process the crop in a timely manner. Currently, there is little information to assist in predicting the optimum time to harvest edamame when the pods are at their collective largest size and greenest color. The objectives of this study were to assess the impact of cultivar, planting date, and harvest date on edamame color, pod weight, and a newly minted Edamame Harvest Quality Index combining both aforementioned factors. And to predict edamame harvest quality based on phenological stages, thermal units, and planting dates. We observed that pod color and weight depended on the cultivar, planting date, and harvest date combination. Our results also indicated that edamame quality is increased with delayed planting dates and that quality was dependent on harvest date with a quadratic negative response to delaying harvest. Maximum quality depended on cultivar and planting and harvest dates, but it remained stable for an interval of 18-27 days around the peak. Finally, we observed that the number of days between R1 and harvest was consistently identified as a key factor driving edamame quality by both stepwise regression and neural network analysis. These research results will help define a planting and harvest strategy for edamame production in Arkansas and the United States Mid-South.

Identification of a major quantitative trait locus underlying salt tolerance in 'Jidou 12' soybean cultivar.

BACKGROUND: Identification of the quantitative trait locus (QTL) underlying salt tolerance is a prerequisite for marker-assisted selection in the salt-tolerant breeding process. METHODS: In this study, the recombinant inbred lines derived from the salt-tolerant elite soybean cultivar 'Jidou 12' and the salt-sensitive elite cultivar 'Ji NF 58' were used to identify the QTL associated with salt tolerance, using both salt tolerance rating (STR) and leaf chlorophyll content (SPAD) as indicators. RESULTS: A major salt-tolerant QTL, which was flanked by SSR markers GMABAB and Barcsoyssr_03_1421 on chromosome 3, was identified based on single-marker regression, single trait composite interval mapping, and multiple interval mapping analysis. For STR, the LOD ranged from 19.8 to 20.1; R2 ranged from 44.3 to 44.7%; and the additive effect ranged from 0.876 to 0.885 among the three mapping methods. For SPAD, the LOD ranged from 10.6 to 11.0; R2 ranged from 27.0 to 27.6%; and the additive effect ranged from 1.634 to 1.679 among the three mapping methods. CONCLUSIONS: In this study, a major QTL conditioning salt tolerance on chromosome 3 was identified. The DNA markers closely associated with the QTLs might be useful in marker-assisted selection for soybean salt tolerance improvement in Huanghuaihai, China.

Early intervention for at risk children: 3-year follow-up.

Childhood behavioral and emotional symptoms are linked with distress and dysfunction that may persist into adulthood. Effective and practical early prevention could make a significant contribution to the well-being of individuals and the functioning of communities. School-based targeted interventions are relatively easy and inexpensive to deliver and have been shown to reduce symptoms in the short term. The current study evaluates the 2- and 3-year outcome of targeted school-based drama group therapy (DGT) as compared to teaching maths and English. It shows a rapid decline in teacher-observed behavioral symptoms following DGT. By a year post intervention, symptom rates following both interventions converged and remained low throughout follow-up. Drama group therapy is rapidly effective in reducing symptoms. However, the findings also suggest that despite differing content, school-based small-group interventions are likely to share some effective components.

School-based indicated prevention: a randomised trial of group therapy.

BACKGROUND: One hundred and twenty-two children identified by teachers as at risk for behavioural or emotional problems were randomly allocated to drama-group therapy or to a curriculum-studies control, based in school. METHODS: One hundred and seventeen completed the intervention phase of the trial, which comprised 12 hour-long sessions. Post-intervention self-reports showed significant effects associated with both interventions. RESULTS: However, there was a clear advantage of group therapy over both a waiting list control and curriculum studies, according to teacher reports. This was true also of categorical analyses focusing on those with the most severe symptoms. CONCLUSIONS: These analyses confirmed sustained teacher-reported improvement over a year-long follow-up period.