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'S17-2243C' (Reg. no. CV-557, PI 700003) is a semi-determinate, maturity group IV (relative maturity 4.9), non-genetically modified (non-GM) soybean [Glycine max (L.) Merr.] cultivar developed and released by the University of Missouri-Fisher Delta Research, Extension, and Education Center. S17-2243C was developed to meet the growing demands for new non-GM soybean cultivars with high yield and elevated seed oil content. S17-2243C is resistant to stem canker and charcoal rot and has tolerance to salinity conditions. Seed of S17-2243C has averaged 232 g kg(-1) of oil concentration on a dry weight basis, which was significantly higher than all check cultivars in the 2020 USDA Uniform Soybean Tests, Southern States. S17-2243C was tested against high-yielding private and public soybean cultivars from 2018 to 2021 in 80 locations across 12 states, including Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, North Carolina, Ohio, South Carolina, Tennessee, and Virginia. With high yield potential, broad adaptability, early maturity, elevated seed oil content, and non-GM traits, S17-2243C is an excellent cultivar choice for soybean growers adopting alternative growing systems and benefiting from premium prices offered for non-GM soybean products. Missouri Soybean Merchandising Council [6066-21220-014-000D]; USDA-ARS Project; [301] Published version Missouri Soybean Merchandising Council, Grant/Award Number: 301; USDA-ARS Project, Grant/Award Number: 6066-21220-014-000D Public domain – authored by a U.S. government employee

Soybean (Glycine max [L.] Merr.) production is influenced by planting date, but its impact on yield in fields infested with Macrophomina phaseolina (Tassi) Goid. is unknown. A 3-year study was conducted in M. phaseolina-infested fields to assess the effects of planting date (PD) on disease severity and yield using eight genotypes, four of which are reported to be susceptible to charcoal rot (S), and four reported with moderate resistance (MR) to charcoal rot (CR). The genotypes were planted in early April, early May, and early June under irrigated and nonirrigated conditions. There was planting date by irrigation interaction for area under the disease progress curve (AUDPC) where May PD was significantly lower compared to April and June PDs in irrigated environments but not in nonirrigated environments. Correspondingly, yield in April PD was significantly lower than that of May and June. Interestingly, yield of S genotypes increased significantly with each subsequent PD, while yield of MR genotypes remained high across all three PDs. The interaction of genotypes by PD on yield revealed that the MR genotypes DT97-4290 and DS-880 had the greatest yields in May compared to April. While May PD had a decreased AUDPC and an increased yield across genotypes, the result of this research suggests that in fields infested with M. phaseolina, early May to early June planting coupled with appropriate cultivar selection provides maximum yield potential for western Tennessee and mid-southern soybean growers.

Two infectious root diseases that cause significant yield losses worldwide in soybean (Glycine max [L.] Merr.) are charcoal rot caused by Macrophomina phaseolina (Tassi) Goid. and the soybean cyst nematode, caused by Heterodera glycines Ichinohe. The objective of this research was to evaluate resistance to charcoal rot in a set of 120 soybean accessions reported to have resistance to one or more races of soybean cyst nematode so that lines with combined resistance could be identified. These accessions were screened in an infested field in 2006 and 2007. Charcoal rot severity ranged from 1 to 5, where 1 is resistant and 5 susceptible. The results showed that out of the 120 soybean accessions tested for charcoal rot resistance 12 were identified to have moderate levels of resistance, 51 had moderate susceptibility, and 60 were susceptible. Furthermore, the accessions with moderate resistance to charcoal rot had resistance for one to two races of soybean cyst nematode. Within the lines identified with moderate resistance to charcoal rot, nine had a yellow seed coat, a desirable agronomic trait. These lines can be used as parents in soybean breeding programs for developing soybean cultivars with combined resistance to both charcoal rot and soybean cyst nematode.

Isoflavones are secondary metabolites that are abundant in soybean and other legume seeds providing health and nutrition benefits for both humans and animals. The objectives of this study were to construct a single nucleotide polymorphism (SNP)-based genetic linkage map using the ‘Forrest’ by ‘Williams 82’ (F×W82) recombinant inbred line (RIL) population (n = 306), map quantitative trait loci (QTL) for seed daidzein, genistein, glycitein, and total isoflavone contents in two environments over two years (NC-2018 and IL-2020), identify candidate genes for seed isoflavone. The FXW82 SNP-based map was composed of 2075 SNPs and covered 4029.9 cM. A total of 27 QTL that control various seed isoflavone traits have been identified and mapped on chromosomes (Chrs.) 2, 4, 5, 6, 10, 12, 15, 19, and 20 in both NC-2018 (13 QTL) and IL-2020 (14 QTL). The six QTL regions on Chrs. 2, 4, 5, 12, 15, and 19 are novel regions while the other 21 QTL have been identified by other studies using different biparental mapping populations or genome-wide association studies (GWAS). A total of 130 candidate genes involved in isoflavone biosynthetic pathways have been identified on all 20 Chrs. And among them 16 have been identified and located within or close to the QTL identified in this study. Moreover, transcripts from four genes (Glyma.10G058200, Glyma.06G143000, Glyma.06G137100, and Glyma.06G137300) were highly abundant in Forrest and Williams 82 seeds. The identified QTL and four candidate genes will be useful in breeding programs to develop soybean cultivars with high beneficial isoflavone contents.

Charcoal rot is a major disease of soybean (Glycine max) caused by Macrophomina phaseolina and results in significant loss in yield and seed quality. The effects of charcoal rot on seed composition (seed protein, oil, and fatty acids), a component of seed quality, is not well understood. Therefore, the objective of this research was to investigate the impact of charcoal rot on seed protein, oil, and fatty acids in different soybean genotypes differing in their charcoal rot susceptibility under irrigated and non-irrigated conditions. Two field experiments were conducted in 2012 and 2013 in Jackson, TN, USA. Thirteen genotypes differing in charcoal rot resistance (moderately resistant and susceptible) were evaluated. Under non-irrigated conditions, moderately resistant genotypes showed either no change or increased protein and oleic acid but had lower linolenic acid. Under non-irrigated conditions, most of the susceptible genotypes showed lower protein and linolenic acid but higher oleic acid. Most of the moderately resistant genotypes had higher protein than susceptible genotypes under irrigated and non-irrigated conditions but lower oil than susceptible genotypes. The different responses among genotypes for protein, oil, oleic acid, and linolenic acid observed in each year may be due to both genotype tolerance to drought and environmental conditions, especially heat differences in each year (2012 was warmer than 2013). This research showed that the increases in protein and oleic acid and the decrease in linolenic acid may be a possible physiological mechanism underlying the plant’s responses to the charcoal rot infection. This research further helps scientists understand the impact of irrigated and non-irrigated conditions on seed nutrition changes, using resistant and susceptible genotypes.

Information on the effect of nitrogen fertilizer rates and environment on sesame seed composition and nutrition is scarce. The objective of this research was to investigate the effects of nitrogen fertilizer application rates on sesame seed yield, protein, oil, fatty acids, and mineral nutrition. A two-year (2014, 2015) field experiment was conducted. Nitrogen fertilizer (urea ammonium nitrate) solution (UAN, 32% N) was applied by side dressing to four sesame varieties (S-34, S-35, S-38, S-39) at rates of 44.7, 67.2, 89.6 and 112.0 kg·ha-1. Rate of 44.7 kg·ha-1 was used as control since this rate is traditionally recommended in the region. Increasing nitrogen application rates resulted in higher protein and oleic acid contents in two varieties in 2014, and in all varieties in 2015. Increased protein and oleic acid were accompanied by lower total oil and linoleic acid. Increased nitrogen application also resulted in higher seed N, S, B, Cu, Fe, and Zn in 2014 in S-34 and S-35, but either a decline or no clear change was observed in seed levels of these nutrients in S-38 and S-39. In 2015, increased nitrogen application resulted in significantly higher seed N in all varieties, and higher S, B, Cu, Fe, and Zn in some varieties. A significant positive correlation was observed between nitrogen application rate and yield, and with seed levels of protein, oleic, acid, N, B, Cu, Fe, and Zn. A significant negative correlation was observed between nitrogen application rate and seed oil and linoleic acid. Thus, increased nitrogen fertilizer application resulted in higher seed protein, oleic acid, and some mineral nutrients, but lower oil and linoleic acid. However, this effect depended on variety and environmental conditions. Because higher protein and oleic acid are desirable traits for sesame seed nutritional value and oil stability, regional breeders should select sesame varieties for efficient fertilizer response.

Frogeye leaf spot (FLS), caused by

Charcoal rot (CR), caused by the fungus Macrophomina phaseolina (Tassi) Goid. is a pervasive disease of economic significance on soybeans (Glycine max (L.) Merr.). Similarly, drought is the leading cause of yield loss in soybean worldwide. In this study, CR severity and seed yield were determined in irrigated and non-irrigated environments in 2011, 2012, and 2013 for thirteen soybean genotypes, nine of which were previously determined to be drought tolerant (DT). The objectives were to determine the severity of CR in the putative DT genotypes and to determine the over-all effect of CR on yield in irrigated and non-irrigated environments. Colony Forming Units (CFUs) at reproductive stage R7 were used to assess disease severity and classify each genotype's response to CR. A stress tolerance index (STI) was used to determine the relative impact of soil moisture stress (i.e. no irrigation) on the 13 genotypes. Over all three years in both irrigated and non-irrigated environments, five genotypes were consistently rated as moderately resistant to CR (MRCR) and three genotypes were consistently rated as susceptible to CR (SCR), whereas the responses of the remaining five genotypes varied between MRCR and SCR. Averaged over the three years, there was a wide range (0.36–1.09) of STI values among genotypes. Even though there was a consistent trend, there was a very weak relationship between STI and CFU's at the R7 growth stage. Regression analysis indicated that as CFUs at R7 increased, seed yield decreased, although the relationship was not significant in every year and irrigation environment. Nonetheless, across all years and irrigation environments, a pooled (global) slope indicated a yield loss of 11.5 kg ha−1 for every 1000 CFUs at R7. These data indicated that as CFUs at R7 increased, seed yield decreased in both irrigated and non-irrigated environments. However, as the relationship between CR disease severity and DT was minimal, it may be necessary to select for resistance to both traits using environments where both soil moisture stress and CR are high.

A field study was conducted in 2014 through 2016 at the University of Tennessee Research and Education Center, Milan, TN, to determine fungicide effects on frogeye leaf spot (FLS) caused by Cercospora sojina and to determine disease severity and yield under no-till and tillage. Each plot was visually rated for FLS severity based on the percent leaf area covered from 0 to 100%. The result showed that tillage did not affect severity of the disease or yield. However, there were significant effects from fungicide, year-to-year effects, and fungicide × year interactions. Among the three years, disease severity in 2016 was greater than in 2014 and 2015. Among the six fungicides, Topsin, Topguard, Quadris TOP SBX, and Priaxor significantly (P ≤ 0.05) reduced maximum disease severity in 2016. All fungicide applications improved yield relative to the untreated check. Topsin and Quadris TOP SBX, however, had consistently the highest percent yield increases. These results suggest that not all fungicides that reduced FLS severity equally protected yield, indicating that yield and environmental conditions need to be considered when making appropriate fungicide recommendations in tilled and no-till systems.

Mycotoxins are toxic secondary metabolites commonly found in corn and known to cause health issues to human and animals. Information on the relationship between corn grain inoculated with mycotoxins and grain nutrients (protein, oil, fatty acids, sugars, and amino acids) in corn hybrids, especially stacked-gene hybrids is very limited. The objective of this study was to investigate the nutritional advantage of stacked-gene hybrids (Stgene) over non-genetically modified organisms (non-GMO) corn or glyphosate-resistant corn (RR). The experiment was conducted in two locations (clay and sandy soils) in 2011, irrigated, and inoculated with toxigenic Aspergillus flavus using four hybrids of stacked-gene, four of RR, and two non-GMO (conventional). Non-inoculated plots were used as control. The results showed that stacked-gene hybrids had no observable nutritional advantage over RR or non-GMO as all hybrid classes accumulated adequate nutrients in their grains; this effect could be due to adequate concentrations of nutrients in the soil. Higher levels of grain protein, carbohydrates (glucose, reducing sugars, and starch), oleic acid, total amino acids, and some minerals were observed under inoculated conditions in clay and sandy soils indicated a possible osmotic adjustment role of these compounds as stress indicators and osmoprotectants under inoculated conditions. Grain nutrients in clay soil were higher than those in sandy soils; nutrient differences could be due to sandy soil possibly suffering drier conditions, especially inoculated soil, reducing nutrient uptake and nutrients mobility to the grain. This study provides advanced knowledge on the relationship between grain nutrients and mycotoxins in corn hybrids. It is also useful to the corn breeders to understand the responses of grain nutrients to fungal diseases in corn hybrids.

The seed nutrition of crops is affected by global climate changes due to elevated CO2 and temperatures. Information on the effects of elevated CO2 and temperature on seed nutrition is very limited in spite of its importance in seed quality and food security. Therefore, the objective of this study was to evaluate the effects of elevated atmospheric CO2 and temperature on seed composition (protein, oil, fatty acids, and sugars) and mineral nutrition in two soybean cultivars under controlled environments. The treatments were ambient CO2 concentrations (360 μmol mol-1) and elevated CO2 concentration (700 μmol mol-1) as well as normal temperature (26/16°C) and elevated temperature (45/35°C). Plants were grown under greenhouse conditions until the R5 stage, and then, transferred to growth chambers until full maturity (R8). Elevated temperature or a combination of elevated temperature and elevated CO2 resulted in a decrease in seed protein and linolenic acid concentrations and an increase in oil and oleic acid in cultivars Williams 82 (MGIII) and Hutcheson (MG V). Seed sucrose, glucose, and fructose decreased, whereas raffinose and stachyose remained relatively stable. Minerals also decreased under elevated CO2 and temperature. Among those that decreased were N, P, K, Zn, Fe, and B. Natural abundance of 15N and 13C isotopes was altered only under high temperature, regardless of CO2 concentration, indicating that changes in nitrogen and carbon metabolism occurred at elevated temperature. The increase in oil and oleic acid and decrease in linolenic acid are desirable, as high oleic acid and low linolenic acid contribute to the stability and longer shelf-life of oil. The combination of low protein and high oil was due to the inverse relationship between them. This study showed that seed composition and seed mineral nutrients can be affected by elevated temperature alone or elevated CO2 and temperature. This information is beneficial for selecting varieties with high seed nutritional qualities and efficient mineral nutrient use and uptake, traits that are related to seed production, seed quality, and food security. Also, it provides further knowledge on the effect of climate change on seed quality.

Genetic mapping of quantitative trait loci (QTL) associated with seed nutrition levels is almost non-existent. The objective of this study was to identify QTLs associated with seed micronutrients (iron, Fe; zinc, Zn; bororn, B; manganese, Mn; and copper, Cu) accumulation (concentration) in a population of 92 F5:7 recombinant inbred lines (RILs) that derived from a cross between MD 96-5722 (MD) and ‘Spencer’. For this purpose, a genetic linkage map based on 5,376 Single Nucleotide Polymorphism (SNP) markers was constructed using the Illumina Infinium SoySNP6K BeadChip array. The RILs were genotyped using 537 polymorphic, reliably segregating SNP markers. A total of 23 QTLs for micronutrients Fe, Zn, B, Mn, and Cu have been identified and mapped on eight linkage groups (LGs) of the soybean genome. Five QTLs were detected for Fe (qIRO001- qIRO005) on LGs N, A1, K, J, and G. Seven QTLs for Zn (qZIN001-qZIN007) on LGs D1a (Chr 1), N (Chr 3), F (Chr 5), B2 (Chr 14), J (Chr 16), A1 (Chr 5), and K (Chr 9). Two QTLs for B (qBOR001 and qBOR002) were detected on LGs N and A1. Four QTLs were detected for Mn (qMAN001-qMAN004) on LGs N, A1, K, and J, and five QTLs were detected for Cu (qCOP001- qCOP005) on LGs N, A1, K, J, and G). It was observed that the four QTLs for Zn, Cu, Fe, and Mn on LGs N (Chr 3), LG A1 (Chr 5), and LG J (Chr 16) were clustered in a similar region of the linkage groups, suggesting possible shared physiological and genetic mechanisms. The QTLs detected in this study are novel and will contribute to our understanding of the genetic basis of seed mineral nutrition. This research would allow breeders to efficiently select for higher seed nutritional qualities to meet the seed industry and human and livestock nutritional needs.

Frogeye leaf spot (FLS) of soybean, caused by Cercospora sojina, has been a problem in the southern United States for many years and has recently become a greater problem in the northern United States. Cultivars resistant to FLS have been developed for planting in the southern United States and resistance in many of these cultivars is conditioned by the Rcs3 gene. This gene conditions immunity to all known races and isolates of the pathogen. Resistance to C. sojina in soybean genotypes (cultivars and breeding lines) adapted to north-central U.S. production region is unknown. The objectives of this study were to (i) identify maturity group (MG) III, IV, and V soybean genotypes resistant to C. sojina race 11 by field screening at multiple locations over years and (ii) determine whether FLS resistance in these genotypes is likely to be conditioned by the Rcs3 gene. In total, 1,350 genotypes were evaluated for resistance to race 11 in field trials, and 13 MG III, 45 MG IV, and 15 MG V genotypes did not develop symptoms of FLS. Of these, 54 were subsequently tested for the possible presence of Rcs3 using five molecular markers located within 2 centimorgans (cM) of the gene. None of the MG III genotypes tested had the Rcs3 haplotype of cv. Davis, the source of Rcs3; six of the MG IV genotypes and seven of the MG V genotypes had the Rcs3 haplotype. This is the first report of the presence of the Rcs3 haplotype in LN 97-15076 and S99-2281. The soybean genotypes predicted to have the Rcs3 gene and other genotypes with no FLS symptoms in field trials may be useful in developing soybean cultivars with broad resistance to FLS and adapted to the northern United States.

Phomopsis longicolla is a major seed pathogen of soybean (Glycine max) in hot, humid environments. The objective of this study was to monitor the infection and development of P. longicolla on vegetative and reproductive tissues of six cultivars and to determine the relationship between this infection and subsequent seed infection and seed germination. Cultivars were grown for 3 years (2002 to 2004) without irrigation or with irrigation applied at pre- plus postflowering or at postflowering growth stages. P. longicolla was isolated most frequently from leaf, stem, pod, root, and seed. Diaporthe phaseolorum and three unidentified Phomopsis sp. were also isolated. Diaporthe aspalathi, which previously has not been reported on soybean, was also recovered from leaf samples. These isolates, however, were recovered very infrequently. Recovery of P. longicolla from roots was much lower than from leaves, stems, and pods in all years and irrigation environments. The recovery of P. longicolla from seed was affected by irrigation environments. Seed from irrigated plots had more P. longicolla than that from nonirrigated plots. Isolation of P. longicolla from seed was negatively correlated with percentage of seed germination in irrigated environments but not in the nonirrigated environment. Pod infection was correlated with seed infection in all three irrigation environments. Even though infection of leaves and stems increased with increasing moisture availability, such infection did not consistently correlate with seed infection. Seed germination and seed infection were negatively correlated with percent hard seed. This study provided the first demonstration of the seasonal progression of P. longicolla on soybean cultivars grown under three irrigation environments.

Mengistu, A., Smith, J. R., Ray, J. D., and Bellaloui, N. 2011. Seasonal progress of charcoal rot and its impact on soybean productivity. Plant Dis. 95:1159-1166. The seasonal progress of charcoal rot (caused by Macrophomina phaseolina) was measured over two growing seasons in four separate experiments: irrigated infested, irrigated non-infested, non-irrigated infested, and non-irrigated noninfested. Disease was assessed at V5, R1, R3, R5, R6, and R7 growth stages based on colony forming units (CFU) of M. phaseolina recovered from the lower stem and root tissues and the area under the disease progress curve (AUDPC). The population density of M. phaseolina increased slowly from the V5 to R6 growth stages and then rapidly from the R6 to R7 growth stages for all genotypes in all four experiments. Yield loss due to charcoal rot ranged from 6 to 33% in irrigated environments. The extent of yield loss was affected by severity of charcoal rot, which in turn was affected by year. Yield loss due to charcoal rot was consistently measured in all paired comparisons in irrigated environments, suggesting that charcoal rot can be an important disease in irrigated environments. Disease severity based on CFU accounted for more yield loss variation (42%) than did the AUDPC (36%) when used to assess disease. Growth stage R7 was found to be the optimum stage for assessing disease using CFU. In addition, screening soybean genotypes under irrigation environment may have utility in breeding programs where there is a need for evaluating soybean genotypes for both disease resistance and yield. Charcoal rot of soybean (Glycine max (L.) Merr.), caused by Macrophomina phaseolina (Tassi) Goid., is a disease of economic

Information is limited about phosphorus (P) fertilization effects on soybean seed composition. A field experiment was conducted to investigate the effects of P application rates on the concentrations of various fatty acids, protein, and oil in soybean under no-tillage on low and high testing P soils at Jackson and Milan, Tennessee from 2008 through 2011. Five P rates 0, 10, 20, 30, and 40 kg·P·ha-1 plus the recommended P fertilizer rate based on soil P testing results were arranged in a randomized complete block design with four replicates. Protein, oil, and fatty acid concentrations in seed responded differently to P fertilization. In general, protein concentrations were enhanced but oil levels decreased with increased P application rate. Palmitic and oleic concentrations responded positively to P application rate up to a certain level. However, the response of linolenic acid concentration was inconsistent (negative or positive). Stearic concentration was not influenced by P fertilization. Application of 10 kg·P·ha-1 resulted in higher production of protein and palmitic, oleic, and linolenic acids than zero P and the higher P application rates as well on the P deficient soil. Excessive P application rates could lower seed yield and the quality of some attributes in seed. In conclusion, linoleic acid concentration, a key quality attribute in soybean seed for human and animal consumption, can sometimes be enhanced by P fertilization; the indigenous soil P level and P application rate should be taken into account in breeding soybean cultivars with low linolenic acid level.

Interest in using harvest aids (defoliants or crop desiccants) such as paraquat, carfentrazone-ethyl, glyphosate, and sodium chlorate (NaClO3) have become increasingly important to assure harvest efficiency, producer profit, and to maintain seed quality. However, information on the effects of harvest aids on seed nutrition (composition) (protein, oil, fatty acids, sugars, and amino acids) in soybean is very limited. The objective of this research was to investigate the influence of harvest aids on seed protein, oil, fatty acids, sugars, and amino acids in soybean. Our hypothesis was that harvest aid may influence seed nutrition, especially at R6 as at R6 the seeds may still undergo biochemical changes. Field experiments were conducted in 2012 and 2013 under Midsouth USA environmental conditions in which harvest aids were applied at R6 (seed-fill) and R7 (yellow pods) growth stages. Harvest aids applied included an untreated control, 0.28 kg ai ha&minus, 1 of paraquat, 0.28 kg ai ha&minus, 1 of paraquat, and 1.015 kg ai ha&minus, 1 of carfentrazone-ethyl (AIM), 6.72 kg ai ha&minus, 1 sodium chlorate, 1.015 kg ai ha&minus, 1 carfentrazone-ethyl, and 2.0 kg ae ha&minus, 1 glyphosate. Results showed that the application of harvest aids at either R6 or R7 resulted in the alteration of some seed composition such as protein, oil, oleic acid, fructose, and little effects on amino acids. In addition, harvest aids affected seed composition constituents differently depending on year and growth stage. This research demonstrated the possible alteration of some nutrients by harvest aids. This research helps growers and scientists to advance the understanding and management of harvest aids and investigate possible effects of harvest aids on seed nutrition.

NPK fertilizer briquettes (NPKBriq) and organically enhanced N fertilizer (OENF), as newly developed fertilizer products, are reported to increase maize (Zea mays L.) yield and N use efficiency, but their effects on maize grain composition are unknown. The objective of this study was to determine the effects of NPKBriq and OENF on the protein, oil, fiber, ash, and starch of maize grain. A field study was conducted at Jackson and Grand Junction, TN, during 2012 and 2013, with NPKBriq, OENF, ammonium sulfate ((NH4)2SO4) (+P and K), and urea (+P and K) as the main treatments and 0, 85, 128, and 170 kg N ha&minus, 1 as the sub treatments under a randomized complete block split plot design with four replicates. The fiber concentration was more responsive to the fertilizer source than the protein, oil, ash, and starch concentrations. OENF resulted in a higher fiber concentration than NPKBriq at 85 kg N ha&minus, 1 in 2013, averaged over the two sites. Both OENF and NPKBriq had nearly no significant effects on the concentrations of the quality attributes compared with ammonium sulfate and urea. In conclusion, the nutrient-balanced NPKBriq exerts the same or greater effects on maize grain quality relative to the commonly used nutrient management practices of urea (+P and K) and ammonium sulfate (+P and K) under normal weather conditions. OENF is an alternate N source to urea and ammonium sulfate for similar to higher maize grain quality.

This study examines the influence of livestock holding on households’ decision to participation in wood fuel production from dryland forest. Survey data were collected from 160 households in Dire Dawa administration council of Oromia state, Ethiopia following a snowball sampling technique. Binary logit regression model and descriptive statistics were used to analyze the impacts of livestock holding on households’ decision to participation in fuelwood production from dryland forest. The estimation of the model indicates that livestock and size of arable land holdings were significant factors in determining households’ participation in wood fuel production. An increase of one unit in livestock holding leads to the probability of participation in wood fuel production of households decreased by 0.118 units while the land size has a negative impact on the participation of wood fuel production. When land size increased by 1 hectare the probability of participating in wood fuel production will be decreased by 0.9 units. The mean of wood fuel producers’ livestock holding was about 5.84 TLU and 10.67 for non- wood fuel producer which indicates the negative correlation of livestock holding and wood fuel production. Thus the study concludes that households with large livestock less likely to participate in wood fuel extraction from dryland forest. Promoting sustainable livestock production with appropriate grazing plan can have a significant role in dryland forest conservation and sustainable forest management.

Charcoal rot of soybean (Glycine max (L.) Merr.), caused by Macrophomina phaseolina (Tassi) Goid., is an economically important disease worldwide. In recent years, charcoal rot has become a concern for farmers in north-western Argentina. The present work aimed to (1) evaluate disease incidence of charcoal rot; (2) assess morphological and genetic characteristics of M. phaseolina isolates from soybean and other hosts collected in north-western Argentina; and (3) compare genetic diversity between soybean isolates of M. phaseolina from Argentina and the USA. Incidence of charcoal rot evaluated in 11 locations during five growing seasons (2008–2012) was 1%, 1%, 1%, 5–10% and 90%, respectively, indicating a gradual increase over the cropping seasons. Cluster analysis by AFLP of Argentinean isolates exhibited one main group, with isolate Mp56 separated at a genetic distance of 0.70. Four main groups were identified using SSR markers at the same genetic distance, with Mp56 and Mp53 separated from them. There was no clear association between AFLP, SSR profiles, morphological characteristics or host of origin within isolates from Argentina. However, using principal coordinate analysis of SSRs, 22 isolates of M. phaseolina from soybean from north-western Argentina were clearly distinguished from 11 isolates previously collected from two states in the USA. Our results confirmed the increasing importance of charcoal rot in north-western Argentina and identified characteristics of isolates that may be useful for breeding for disease resistance and developing integrated management programmes for charcoal rot in Argentina in the future. Fil: Reznikov, Sebastian. Estación Experimental Agroindustrial Obispo Colombres (EEAOC) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA; Argentina Fil: Vellice, Gabriel. Estación Experimental Agroindustrial Obispo Colombres (EEAOC) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA); Argentina Fil: Mengistu, Alemu. USDA-ARS Crop Genetics Research Unit; Estados Unidos Fil: Arias, Renne Silva. USDA-ARS-National Peanut Research Laboratory; Estados Unidos Fil: Gonzalez, Victoria. Estación Experimental Agroindustrial Obispo Colombres (EEAOC) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA); Argentina Fil: de Lisi, Vicente. Estación Experimental Agroindustrial Obispo Colombres (EEAOC) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA); Argentina Fil: Garcia, Maria Gabriela. Estación Experimental Agroindustrial Obispo Colombres (EEAOC) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA); Argentina Fil: Rocha, Carla Maria Lourdes. Estación Experimental Agroindustrial Obispo Colombres (EEAOC) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA); Argentina Fil: Pardo, Esteban Mariano. Estación Experimental Agroindustrial Obispo Colombres (EEAOC) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA); Argentina Fil: Castagnaro, Atilio Pedro. Estación Experimental Agroindustrial Obispo Colombres (EEAOC) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA); Argentina Fil: Ploper, Leonardo Daniel. Estación Experimental Agroindustrial Obispo Colombres (EEAOC) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Tecnología Agroindustrial del Noroeste Argentino (ITANOA); Argentina

Research of quantitative trait loci (QTL) for macronutrient accumulation in soybean seed is limited. Therefore, the objective of this research was to identify QTL related to macronutrients (N, C, S, P, K, Ca, and Mg) in seeds in 92 F5:7 recombinant inbred lines (RILs) developed from a cross between MD 96-5722 (MD) and Spencer using a total 5,376 Single Nucleotide Polymorphism (SNP) markers. A genetic linkage map based on SNP markers was constructed using the Illumina Infinium SoySNP6K BeadChip Array. The RILs were genotyped using 537 polymorphic, reliably segregating SNP markers. A total of 8 QTL for K (qPOT001-qPOT008) were identified on LGs D1b (Chr 1), N (Chr 3), A1 (Chr 5), O (Chr 10), F (Chr 13), B2 (Chr 14), and J (Chr 16). Four QTL for Mg (qMAG001-qMAG004) were identified on LGs N (Chr 3), A1 (Chr 5), J (Chr 16), and G (Chr 18). One QTL for P (qPHO001), one for C on LG J (Chr 16), one for N (qNIT001) and S (qSUL001) on the same LG J (Chr 16), and one QTL for Ca (qCAL001) on LG G (Chr 18). K and Mg QTL were clustered together on LG A1 (Chr 5) with a peak position of 9.50 cM and LOD support interval of 8.50-9.50 cM. Similar observation was noticed for P, K, Mg, C, N, and S, where the QTL were clustered on LG J (Chr 16) with peak position of 11 cM for K, P, and S, and 10 cM for C and N, and 12 cM for Mg. The LOD support intervals for all these clustered QTL were between 8.90 and 12.30 cM. The QTL clustering of these nutrients suggests possible common physiological and genetic relationships, suggesting possible similar metabolic processes and pathways for these nutrients. The inverse relationships between N:S ratio and all nutrients suggest possible use of N:S ratio as a measure for higher nutrients accumulation in seed. Since most of QTL identified in this study were not previously reported, this research will further help breeders to improve nutrient accumulation in seeds and contribute to our understanding of the physiological and genetic bases of seed nutrition quality.

Mengistu, A., Kelly, H. M., Bellaloui, N., Arelli, P. R., Reddy, K. N., and Wrather, A. J. 2014. Tillage, fungicide, and cultivar effects on frogeye leaf spot severity and yield in soybean. Plant Dis. 98:1476-1484. Frogeye leaf spot (FLS) of soybean, caused by Cercospora sojina, has been a problem in the southern United States for many years but has become an increasing problem in the northern United States more recently, causing significant yield losses. This increase in disease severity in the northern United States has been attributed to increased utilization of no-till planting and changes in climate. A field study was conducted at the University of Tennessee, Research and Education Center in Milan, TN from 2007 to 2010 to determine severity in tilled and no-till plots treated with or without fungicide at R3 and R5 growth stages. Three FLS-susceptible cultivars, one each in Maturity Groups III, IV, and V, were treated with pyraclostrobin (Headline) fungicide. Analysis of variance using the area under the disease progress curve (AUDPC) indicated no significant difference (P ≤ 0.05) in disease severity between tilled and no-till plots without fungicide. Fungicide did not significantly reduce disease under no-till, but did under tilled plots. This is the first study showing that no-till plots did not reduce or enhance the severity of FLS when no fungicide was applied. Fungicide application significantly reduced (P ≤ 0.05) disease severity and AUDPC and increased yield in tilled plots. The yield gains in tilled, fungicide-treated plots ranged from 1 to 17%. When fungicide was applied, disease severity was not reduced as significantly in no-till as in treated tilled plots, suggesting that fungicide programs under a notill system may require further study to minimize the risk of FLS

Charcoal rot (CR) disease caused by Macrophomina phaseolina is responsible for significant yield losses in soybean production. Among the methods available for controlling this disease, breeding for resistance is the most promising. Progress in breeding efforts has been slow due to the insufficient information available on the genetic mechanisms related to resistance. Genome-wide association studies (GWAS) enable unraveling the genetic architecture of resistance and identification of causal genes. The aims of this study were to identify new sources of resistance to CR in a collection of 459 diverse plant introductions from the USDA Soybean Germplasm Core Collection using field and greenhouse screenings, and to conduct GWAS to identify candidate genes and associated molecular markers. New sources for CR resistance were identified from both field and greenhouse screening from maturity groups I, II, and III. Five significant single nucleotide polymorphism (SNP) and putative candidate genes related to abiotic and biotic stress responses are reported from the field screening; while greenhouse screening revealed eight loci associated with eight candidate gene families, all associated with functions controlling plant defense response. No overlap of markers or genes was observed between field and greenhouse screenings suggesting a complex molecular mechanism underlying resistance to CR in soybean with varied response to different environments; but our findings provide useful information for advancing breeding for CR resistance as well as the genetic mechanism of resistance.

The timing of harvest is a major factor affecting seed quality in soybean, particularly in Midsouthern USA, when rain during harvest period is not uncommon. The objective of this research was to evaluate the effects of time of harvest on soybean seed quality (seed composition, germination, seed coat boron, and lignin) in high germinability (HG) breeding lines (50% exotic) developed under high heat. The hypothesis was that seeds of HG lines possess physiological and genetic traits for a better seed quality at harvest maturity and delayed harvest. A 2-year field experiment was conducted under irrigated conditions. Results showed that, at harvest maturity, the exotic HG lines had higher seed protein, oleic acid, sugars, seed coat boron, and seed coat lignin, but lower seed oil compared with the non-exotic checks (Control), confirming our hypothesis. At 28 days after harvest maturity (delayed harvest), the content of seed protein, oleic acid, sugars, seed coat boron, and seed coat lignin were higher in some of the HG lines compared with the checks, indicating a possible involvement of these seed constituents, especially seed coat boron and seed coat lignin, in maintaining seed coat integrity and protecting seed coat against physical damage. Highly significant positive correlations were found between germination and seed protein, oleic acid, sugars, and seed coat boron and seed coat lignin. Highly significant negative correlation was found between germination and oil, linoleic acid, seed coat wrinkling, shattering, and hard seed. Yields of some HG lines were competitive with checks. This research demonstrated that time of harvesting is an important factor influencing seed protein and oil production. Also, since high oleic acid is desirable for oxidative stability, shelf-life and biodiesel properties, using HG lines could positively influence these important traits. This result should suggest to breeders of some of the advantages of selecting for high seed coat boron and lignin, and inform growers of the importance of timely harvest for maintaining high seed quality.

Although the Early Soybean Production System (ESPS) in the Midsouthern USA increased seed yield under irrigated and non-irrigated conditions, heat stress and drought still lead to poor seed quality in heat sensitive soybean cultivars. Our breeding goal was to identify breeding lines that possess high germination, nutritional quality, and yield potential under high heat and dryland production conditions. Our hypothesis was that breeding lines derived from exotic germplasm might possess physiological and genetic traits allowing for higher seed germinability under high heat conditions. In a two-year field experiment, breeding lines derived from exotic soybean accessions, previously selected for adaptability to the ESPS in maturity groups (MG) III and IV, were grown under non-irrigated conditions. Results showed that three exotic breeding lines had consistently superior germination across two years. These lines had a mean germination percentage of greater than 80%. Two (25-1-1-4-1-1 and 34-3-1-2-4-1) out of the three lines with ≥80% germination in both years maintained high seed protein, oleic acid, N, P, K, B, Cu, and Mo in both years. Significant (P < 0.05) positive correlations were found between germination and oleic acid and with K and Cu in both years. Significant negative correlations were found between germination and linoleic acid, Ca, and hard seed in both years. There were positive correlations between germination and N, P, B, Mo, and palmitic acids only in 2013. A negative correlation was found between germination and green seed damage and linolenic acid in 2013 only. Seed wrinkling was significantly negatively correlated with germination in 2012 only. A lower content of Ca in the seed of high germinability genotypes may explain the lower rates of hard seed in those lines, which could lead to higher germination. Many of the differences in yield, germination, diseases, and seed composition between years are likely due to heat and rainfall differences between years. The results also showed the potential roles of seed minerals, especially K, Ca, B, Cu, and Mo, in maintaining high seed quality. The knowledge gained from this research will help breeders to select for soybean with high seed nutritional qualities and high germinability.

Frogeye leaf spot (FLS), caused by Cercospora sojina, causes significant damage to soybean in the U.S. One control strategy is the use of quinone outside inhibitor (QoI) fungicides. QoI resistant isolates were first reported in Tennessee (TN) in 2010. To investigate the disease dynamics of C. sojina, we collected 437 C. sojina isolates in 2015 from Jackson and Milan, TN and used 40 historical isolates collected from 2006-2009 from TN and ten additional states for comparison. A subset of 186 isolates, including historical isolates, were genotyped for 49 single nucleotide polymorphism (SNP) markers and the QoI resistance locus, revealing 35 unique genotypes. The genotypes clustered into three groups with two groups containing only sensitive isolates and the remaining group containing all resistant isolates and a dominant clonal lineage of 130 isolates. All 477 C. sojina isolates were genotyped for the QoI locus revealing 344 resistant and 133 sensitive isolates. All isolates collected prior to 2015 were QoI sensitive. Both mating type alleles (MAT1-1-1 and MAT1-2) were found in Jackson and Milan, TN and recovered from single lesions suggesting sexual recombination may play a role in the epidemiology of field populations. Analysis of C. sojina isolates using SNP markers proved useful to investigate population diversity and to elaborate on diversity as it relates to QoI resistance and mating type.

Alternative methods are needed to assess the severity of charcoal rot disease [Macrophomina phaseolina (Tassi) Goid] in soybean [Glycine max (L.)] plant tissue. The objective of this study was to define the relationship between light reflectance properties and microsclerotia content of soybean stem and root tissue. Understanding that relationship could lead to using spectral reflectance data as a tool to assess the severity of charcoal rot disease in soybean plants, thus reducing human bias associated with qualitative analysis of soybean plant tissue and cost and time issues connected with quantitative analysis. Hyperspectral reflectance measurements (400-2490 nm) were obtained with a non-imaging spectroradiometer of non-diseased and charcoal rot diseased ground stem and root tissue samples of six soybean genotypes (“Clark”, “LD00-3309”, “LG03- 4561-14”, “LG03-4561-19”, “Saline”, and “Y227-1”). Relationships between the reflectance measurements and tissue microsclerotia content were evaluated with Spearman correlation (rs) analysis (p < 0.05). Moderate (rs = ±0.40 to ±0.59), strong (rs = ±0.60 to ±0.79), and very strong (rs = ±0.80 to ±1.00) negative and positive statistically significant (p < 0.05) monotonic relationships were observed between tissue spectral reflectance values and tissue microsclerotia content. Near-infrared and shortwave-infrared wavelengths had the best relationships with microsclerotia content in the ground tissue samples, with consistent results obtained with near-infrared wavelengths in that decreases in near-infrared spectral reflectance values were associated with increases in microsclerotia content in the stem and root tissue of the soybean plants. The findings of this study provided evidence that relationships exist between tissue spectral reflectance and tissue microsclerotia content of soybean plants, supporting spectral reflectance data as a means for assessing variation of microsclerotia content in soybean plants. Future research should focus on the modelling capabilities of the selected wavelengths and on the feasibility of using these wavelengths in machine learning algorithms to differentiate non-diseased from charcoal rot diseased tissue.

Soybean seed is a major source of phytochemical compounds that impact human health nutrition and livestock meal. Charcoal rot is a disease caused by the fungus Macrophomina phaseolina (Tassi) Goid, and thought to infect the plants through roots by a toxin-mediated mechanism, resulting in yield loss and poor seed quality, especially under drought conditions. Limited information is available on the effect of charcoal rot on seed phytochemical compounds and mineral nutrition in soybean. Therefore, the objective of this research was to investigate the effect of charcoal rot infection on seed phenol, seed coat lignin, isoflavones, and minerals using susceptible (S) (DK 3964) and moderately resistant (MR) (AG 3905) maturity group (MG)III soybean cultivars to charcoal rot. A two-year field experiment was conducted, and infested soil with charcoal rot (infested soil conditions, INF) or control (non-infested soil conditions, NINF) was used. The results showed that the moderately resistant genotype had higher concentrations of seed phenolics, total isoflavones, and seed coat lignin under infested and non-infested conditions and under irrigated or non-irrigated conditions compared with the susceptible genotype. The same general trend was found for seed K, Ca, P, Mn, Zn, B, and Cu concentrations in the moderately resistant genotype compared with the susceptible genotype. Our research demonstrated that these seed phytochemical constituents may explain the differences between susceptible and moderately resistant cultivars and may play an important role in the resistance to charcoal rot.

Laboratory and field studies were conducted to assess the effects of glyphosate on Macrophomina phaseolina culture growth in vitro and the disease severity of charcoal rot in soybean fields at Stoneville, MS and Jackson, TN. Glyphosate inhibited M. phaseolina growth in a linear dose dependent manner when technical grade glyphosate acid (GlyCry) was used; however, growth was inhibited in an exponential dose dependent manner when a commercial formulation of glyphosate-potassium salt (Gly-K salt) was used. The glyphosate GR50 values (glyphosate concentration required to cause a 50% reduction) in culture radial growth ranged from 0.25 to 9.94 mM among the M. Phaseolina isolates, temperatures, and formulations. The three isolates differed in response to various concentrations across the three temperature regimes. Among the three isolates, TN 410 was the most sensitive for both GlyCry (GR50 ¼ 7.74 mM) and Gly-K salt (GR50 ¼ 0.25 mM) at 30 � C. This research indicates that glyphosate has the ability to inhibit growth of M. phaseolina in culture in vitro. The preliminary field studies demonstrated that application of glyphosate to glyphosate-resistant soybeans did not enhance or reduce the severity of charcoal rot in a no-till field in TN but had some suppressing effect in a tilled environment in MS when single applications were made at growth stage V3 and V6. Published by Elsevier Ltd.

Previous research has shown that the effect of potassium fertilizer on soybean ([Glycine max (L.) Merr.] seed composition (protein, oil, fatty acids, and isoflavones) is still largely unknown. Therefore, the objective of this research was to investigate the effects of potassium application on seed protein, oil, fatty acids, and isoflavones under Midsouth environmental conditions. A three-year experiment was conducted in two locations (Milan, TN and Jackson, TN). Potassium (K) rates were applied in the form of K2O at a rate of 0 (Control, C), 45 (T1), 90 (T2), 134 (T3), and 179 (T4) kg·ha-1 in a randomized complete block design. The results showed that increasing the K application rate did not result in consistent effects on yield. However, increasing K application rate did increase protein, oleic acid, and individual and total isoflavone concentrations at both locations in 2008 and 2009. In Jackson in 2010, the increase of K rate did not change oleic acid, but resulted in an increase in glycitein and genistein isoflavone concentrations. In 2010, increasing K application rate increased protein concentrations, decreased individual and total isoflavones, and did not change oleic acid concentration at Milan. At the highest rate of K, 179 kg·ha-1, yield and some seed composition constituents were negatively impacted. Generally, K concentration in leaves at V5, R1, R3, and seed at harvest maturity stage (R8) increased with the increase of K rate applications. The research demonstrated that K application can alter seed composition, but this alteration depended on location, environmental stress factors, mainly heat and drought, K level in soil, and K application rate. Higher rates of K application may negatively impact seed composition constituents.