Charcoal Rot Research Articles

Sunflower Diseases and Downy Mildew (Plasmopara halstedii) in Adana

Sunflower (Helianthus annuus L.) is one of the most important vegetable oil sources in the world and in our country. The preference for sunflower oil in the consumption of vegetable oil increases the importance of sunflowers in our country. Rust, downy mildew, Verticillium wilt, Sclerotinia stalk and head rot, charcoal rot, blight, and leaf spot are some of the important diseases most commonly seen in sunflowers. In some years, depending on the climatic conditions, Downy mildew (Plasmopara halstedii) is widely observed and it causes an epidemic in sunflower-planted areas in the Adana province. Genetically resistant hybrids have started to be grown in Turkey in recent years due to the resistance of downy mildew disease to fungicides. The aim of the study was to determine the status of sunflower diseases and Downy Mildew disease in Adana.

Charcoal rot and root-knot nematode control on faba bean by photosynthesized colloidal silver nanoparticles using bioactive compounds from Moringa oleifera leaf extract

Charcoal rot and root-knot nematode control on faba bean by photosynthesized colloidal silver nanoparticles using bioactive compounds from Moringa oleifera leaf extract

Effects of Altering Three Steps of Monolignol Biosynthesis on Sorghum Responses to Stalk Pathogens and Water Deficit.

The drought-resilient crop sorghum (Sorghum bicolor [L.] Moench) is grown worldwide for multiple uses, including forage or potential lignocellulosic bioenergy feedstock. A major impediment to biomass yield and quality are the pathogens Fusarium thapsinum and Macrophomina phaseolina, which cause Fusarium stalk rot and charcoal rot, respectively. These fungi are more virulent with abiotic stresses such as drought. Monolignol biosynthesis plays a critical role in plant defense. The genes Brown midrib (Bmr)6, Bmr12, and Bmr2 encode the monolignol biosynthesis enzymes cinnamyl alcohol dehydrogenase, caffeic acid O-methyltransferase, and 4-coumarate:CoA ligase, respectively. Plant stalks from lines overexpressing these genes and containing bmr mutations were screened for pathogen responses with controlled adequate or deficit watering. Additionally, near-isogenic bmr12 and wild-type lines in five backgrounds were screened for response to F. thapsinum with adequate and deficit watering. All mutant and overexpression lines were no more susceptible than corresponding wild-type under both watering conditions. The bmr2 and bmr12 lines, near-isogenic to wild-type, had significantly shorter mean lesion lengths (were more resistant) than RTx430 wild-type when inoculated with F. thapsinum under water deficit. Additionally, bmr2 plants grown under water deficit had significantly smaller mean lesions when inoculated with M. phaseolina than under adequate-water conditions. When well-watered, bmr12 in cultivar Wheatland and one of two Bmr2 overexpression lines in RTx430 had shorter mean lesion lengths than corresponding wild-type lines. This research demonstrates that modifying monolignol biosynthesis for increased usability may not impair plant defenses but can even enhance resistance to stalk pathogens under drought conditions.

Yield response and pathological characterization of promising genotypes of soybean against major diseases in Madhya Pradesh

The yield potential along with multiple disease resistance in 38 promising soybean genotypes including four checks i.e. JS 20-34, JS 335, JS 20-98 and NRC 86 was assessed under field condition of JNKVV, Jabalpur whichis one of the hot spot locations for major diseases of soybean like Charcoal rot, Aerial blight and Yellow mosaic. Significant differences were observed for days to 50 per cent flowering, days to maturity, yield (kg/h) and 100 seedweight. The highest yield was obtained from JS 21-72 (2650 kg/h) followed by Himso 1689 (2255 kg/h) and JS 21-71 (2222 kg/h). Maximum 100 seed weight of 14.37g was recorded in JS 21-72 followed by JS 21-71 (14.2g) and JS 20-34 (14.16g). Out of thirty eight, the yield ofseven genotypes i.e. Himso 1688, MAUS 734, DSb 33, NRC 139, SL 1171, VLS 97 and BAUS 100 could not be recorded due to complete mortality of the plants by charcoal rot. Eight genotypes viz., JS 21-71, MACS 1566, JS 21-72, DS 3110, MACS 1620, JS 20-34(C), RSC 11-15 and Himso 1689 against charcoal rot, seven genotypes against aerial blight, eighteen genotypes against YMV and thirty-three (33) against bacterial pustule disease showed high resistance. Overall, three genotypes viz., JS 21-71, JS 21-72 and Himso 1689 exhibited absolute tomoderate resistance against charcoal rot plus absolute/highresistanceto YMV, RAB and bacterial pustule.

Role of PGPR in suppressing the growth of Macrophomina phaseolina by regulating antioxidant enzymes and secondary metabolites in Vigna radiata (L.) R. Wilczek

This study was conducted to evaluate the effect of PGPR on Vigna radiata L. resistance against Macrophomina phaseolina-associated charcoal rot. The seeds of Vigna radiata L. (cv. NM-11 and cv. Chakwal) were inoculated with two bacterial strains i.e., Pseudomonas stutzeri (KX574858) and Pseudomonas putida (KX574857). Under unstressed conditions, both PGPR were effective enough to exhibit that their inoculation imparts tolerance to plants against the infection in a much better way than untreated plants acting as a control. The Vigna radiata cv. Chakwal (V2) showed more positive response to the PGPR treatment by enhancing the contents of chlorophyll a (1.52-fold), carotenoids (95%), and sugars (2.16-fold. Although PGPR inoculation significantly enhanced the accumulation of phenolics, flavonoids, and proline by 22%, 47%, and 69% respectively. The plant growth, yield, and defense-related enzymatic activities were remarkably improved in P. putida treated plants under infected conditions. This leads to a notable amelioration in phenylalanine ammonia-lyase, polyphenol oxidase, superoxide dismutase, and peroxidase by 100%, 70%, 110%, and 21% sequentially. Pseudomonas putida conciliated inhibition in the growth of M. phaseolina and the results of the study demonstrates that P. putida is a more effective bio-fungicide than P. stutzeri. It is concluded that the biocontrol potential of P. putida is greater than that of P. stutzeri whereas the P. stutzeri exhibited greater plant growth promoting activities.

Population genomic analysis reveals geographic structure and climatic diversification for Macrophomina phaseolina isolated from soybean and dry bean across the United States, Puerto Rico, and Colombia.

Macrophomina phaseolina causes charcoal rot, which can significantly reduce yield and seed quality of soybean and dry bean resulting from primarily environmental stressors. Although charcoal rot has been recognized as a warm climate-driven disease of increasing concern under global climate change, knowledge regarding population genetics and climatic variables contributing to the genetic diversity of M. phaseolina is limited. This study conducted genome sequencing for 95M. phaseolina isolates from soybean and dry bean across the continental United States, Puerto Rico, and Colombia. Inference on the population structure using 76,981 single nucleotide polymorphisms (SNPs) revealed that the isolates exhibited a discrete genetic clustering at the continental level and a continuous genetic differentiation regionally. A majority of isolates from the United States (96%) grouped in a clade with a predominantly clonal genetic structure, while 88% of Puerto Rican and Colombian isolates from dry bean were assigned to a separate clade with higher genetic diversity. A redundancy analysis (RDA) was used to estimate the contributions of climate and spatial structure to genomic variation (11,421 unlinked SNPs). Climate significantly contributed to genomic variation at a continental level with temperature seasonality explaining the most variation while precipitation of warmest quarter explaining the most when spatial structure was accounted for. The loci significantly associated with multivariate climate were found closely to the genes related to fungal stress responses, including transmembrane transport, glycoside hydrolase activity and a heat-shock protein, which may mediate climatic adaptation for M. phaseolina. On the contrary, limited genome-wide differentiation among populations by hosts was observed. These findings highlight the importance of population genetics and identify candidate genes of M. phaseolina that can be used to elucidate the molecular mechanisms that underly climatic adaptation to the changing climate.

Identification and genetic diversity analysis of high-yielding charcoal rot resistant soybean genotypes

Charcoal rot disease caused by Macrophomina phaseolina (Tassi) Goid is one of the most devastating diseases in soybean in India. During 2018, 226 diverse soybean genotypes were evaluated for genetic resistance under hot-spot conditions. Out of them, a subset of 151 genotypes were selected based on Percent Disease Incidence (PDI) and better agronomic performance. Out of these 151 genotypes evaluated during 2019, 43 genotypes were selected based on PDI and superior agronomic performance for further field evaluation and molecular characterization. During 2020 and 2021, these forty-three genotypes, were evaluated for PDI, Area Under Disease Progress Curve (AUDPC), and grain yield. In 2020, genotype JS 20-20 showed least PDI (0.42) and AUDPC (9.37).Highest grain yield was recorded by the genotype JS 21-05 (515.00 g). In 2021, genotype JS 20-20 exhibited least PDI (0.00) and AUDPC (0.00).Highest grain yield was recorded in JS 20-98 (631.66 g). Across both years, JS 20-20 had the least PDI (0.21) and AUDPC (4.68), while grain yield was highest in JS 20-98 (571.67 g). Through MGIDI (multi-trait genotype-ideotype distance) analysis, JS 21-05 (G19), JS 22-01 (G43), JS 20-98 (G28) and JS 20-20 (G21) were identified as the ideotypes with respect to the traits that were evaluated. Two unique alleles, Satt588 (100 bp) on linkage group K (Chromosome no 9) and Sat_218 (200 bp) on linkage group H (Chromosome no 12), were specific for thetwo resistant genotypes JS 21-71and DS 1318, respectively. Through cluster analysis, it was observed that the genotypes bred at Jabalpur were more genetically related.

Evaluation of Soybean Genotypes Yield and Yield Stability Under Charcoal Rot Disease Conditions using GGE Biplot Method

Evaluation of Soybean Genotypes Yield and Yield Stability Under Charcoal Rot Disease Conditions using GGE Biplot Method

Screening of M5 Generation Mutant Lines for Charcoal Rot Resistance in Sorghum [Sorghum bicolor (L.) Moench

This study was carried out in augmented design during rabi 2021 (November‒May) at Agriculture research station, Hagari, Karnataka, India to identify the charcoal rot resistant mutant line. Total 200 mutants and 7 checks were used to study the charcoal rot resistance in the present experiment. Charcoal rot is a major disease in the dry sorghum-growing regions of Asia, Africa, Americas and Australia. Charcoal rot disease is caused by Macrophomina phaseolina (Tassi) Goid. It appears in severe form on the improved varieties in hot dry weather with soil moisture stress. The process of mutation is recognized as one of the driving forces of evolution. Induced mutation breeding is a relatively quick method of creating variability in quantitatively inherited traits between plants. The parameters used in charcoal rot studies were lodging per cent, mean number of nodes crossed, mean length of spread and Charcoal rot index (CRI). The screening results revealed that 66 mutant lines shown moderate resistant reaction compared to the resistant check DSV-4 (0.5) and E-36-1 (0.27), among them eight mutants had exact only one node crossed by the pathogen. These mutant lines exhibited comparatively lowest number of mean nodes crossed. 84 mutant lines shown moderate resistant response to charcoal rot index trait. These resistant lines can be used for further confirmation and also for future resistant breeding programme.

First report of using Trichoderma longibrachiatum as a biocontrol agent against Macrophomina pseudophaseolina causing charcoal rot disease of lentil in Algeria

BackgroundLentil (Lens culinaris Medik.) is one of the major pulse crops in the world. The present study aimed to evaluate the effect of Trichoderma isolates to control the charcoal rot disease caused by Macrophomina pseudophaseolina recently reported on lentil plants.ResultsIn this study, antagonistic effects of seven isolates of Trichoderma spp. isolated from the rhizosphere of lentil were evaluated in vitro against Macrophomina pseudophaseolina M1. All isolates of Trichoderma significantly reduced the mycelial growth of M1 in vitro. Maximum reduction of the pathogen growth was observed at T10 (72.53%), followed by T5 (63.7%) and T6 (62.88%), while T2 caused the minimum reduction (37.33%). Likewise, Trichoderma isolates significantly reduced the size and number microsclerotia. M1 produced the minimum number of microsclerotia in the presence of T10, followed by T1 causing reduction of 68.56 and 53.37% over control, respectively. The maximum reduction of microsclerotia’s size was observed in the presence of T10 (54.92%), followed by T1 (49.84) and T8 (48.68%). Results also revealed that production of volatile metabolite, components and inhibition of the test pathogen by volatile metabolites varied among different antagonistic Trichoderma. T1 produced the most volatile compounds, followed by T2 and T3 and T10 causing mycelial growth inhibition of 41.66, 33.88, 30.55 and 30.37%, respectively. The efficacy of the antagonistic biocontrol agents on charcoal rot was evaluated in vivo. Seed treatment with T10 significantly protected lentil seedlings from M. pseudophaseolina as compared to untreated plants and also improved their growth. T10 isolate was identified based on molecular tools, using internal transcribed spaces and Translation elongation factor of ribosomal DNA. The results identified T10 as Trichoderma longibrachiatum with accession number MW818102 and OK500004 deposited in NCBI GenBank database.ConclusionThe study revealed the first report of using Trichoderma longibrachiatum as a promising biological agent against M. pseudophaseolina causing charcoal rot disease of lentil.

Establishment of Pathogenicity Test Method for Macrophomina phaseolina Causing Soybean Charcoal Rot

The establishment of a laboratory assay and a greenhouse assay was conducted for evaluating the pathogenicity of Macrophomina phaseolina causing soybean charcoal rot established. In the laboratory assay, microsclerotia and hyphae were used as inoculum. In the laboratory assays using microsclerotia as an inoculum, disease incidences of M. phaseolina NSW17-108 and HSM17-034 were higher at 35°C than 25°C. Of the two isolates NSW17-108 and HSM17-034, the disease incidence of HSM17-034 isolated from diseased sesame is higher than that of NSW17-108 isolated from diseased soybean. When the mycelia of M. phaseolina were used as an inoculum, the disease incidence of NSW17-108 and HSM17-034 at 35°C exceeded 80% even after only 5 days of inoculation. Even at 25°C, furthermore, that of HSM17-034 exceeded 80% 5 days later. In the pathogenicity assays at a greenhouse, toothpicks where microsclerotia were produced or microsclerotia harvested from potato dextrose agar medium were used as an inoculum. In all greenhouse assays, M. phaseolina NSW17-108 and HSM17-034 showed 40–60% of disease incidences 35–65 days after inoculation with the pathogen, depending on the inoculation method. Between the two isolates, the pathogenicity of HSM17-034 was stronger than that of NSW17-108, and this result was consistent with laboratory assay results. Since the laboratory and greenhouse test methods tested in this study have different advantages and disadvantages depending on each test method, it is thought that the test method that can meet the purpose of the study should be selected and used.

Corn stunt disease complex increases charcoal rot (Macrophomina phaseolina) under field conditions

Corn stunt disease complex increases charcoal rot (Macrophomina phaseolina) under field conditions

Use of Bacteria Isolated from Berry Rhizospheres as Biocontrol Agents for Charcoal Rot and Root-Knot Nematode Strawberry Diseases

Strawberry is a high-value crop in Spain, where fruits for fresh consumption are produced off-season and exported to central and northern European countries. Soil-borne pathogens (SBP), such as Macrophomina phaseolina and Meloidogyne hapla, are widely spread in strawberry crops in Spain. The prevalence of these pathogens is a significant barrier to producing strawberries of premium quality and at profitable yields. The current ban on fumigant pesticides drives the search for alternative SBP control methods that can simultaneously control both SBP. Twenty-nine bacterial strains were isolated and identified from strawberry and blueberry rhizospheres and screened for plant growth promotion activities as well as for biocontrol potential on M. phaseolina and M. hapla. Two of these bacterial strains (Bacillus velezensis FC37 and Pseudomonas aeruginosa AC17), together with Brevibacterium frigoritolerans Hvs8 coming from IFAPA’s bacterial collection, were selected and evaluated in planta for their biocontrol potential on strawberry SBP diseases caused by M. phaseolina and M. hapla. The three tested bacterial strains reduced charcoal rot disease severity, crown incidence and severity, and petiole colonization by M. phaseolina. Root-knot nematode (RKN) symptoms were reduced by P. aeruginosa AC17 and B. velezensis FC37, but RKN reproduction was only reduced in plants inoculated with P. aeruginosa AC17. Pseudomonas aeruginosa AC17 showed the greatest potential as a biocontrol agent candidate to be included in integrated disease management programs to control the two most prevalent soil-borne pathogens of strawberry in Spain.

Laboratory Evaluation Of Different Botanicals And Bioagents Against Rhizoctonia Bataticola Causing Root Rot Of Soybean

Soybean (Glycine max (L.) Merill) is the world’s most important oilseed crop, accounting for nearly half of total oilseed acreage and production. It is susceptible to diseases such as anthracnose, charcoal rot, bacterial blight, yellow mosaic virus, and others that pose a threat to soybean production. Root rot caused by Rhizoctonia bataticola is an important and major limiting factor for seed yield. Evaluation of four bioagents and seven different botanicals against Rhizoctonia bataticola were carried out in laboratory to determine their efficacy. Among the botanicals tested in laboratory at a concentration of 10% using the poisoned food technique, Azadirachta indica recorded the highest inhibition (62.96%) of R. bataticola mycelial growth and was significantly superior to the other treatments. This was followed by Oscimum sanctum (58.88%) and Milletia pinnata (58.88%). The dual culture technique was used to test the in vitro efficacy of bioagents against R. bataticola. Trichoderma asperellum inhibited growth the most (87.50%), followed by Trichoderma harzianum (81.38%).

Real-time PCR early detection of Trichoderma treatments efficiency against cotton charcoal rot disease

The charcoal rot (CRD) disease agent, the soil fungus Macrophomina phaseolina, survives by developing reproductive units (spores and pycnidia) and infects various host plants. In cotton plants, the disease can lead to dehydration and death of the host plant at late-season stages. Pima cv. cotton plants, the leading cotton crop in Israel, are particularly susceptible to this disease. Developing biological pesticides against soil diseases is at the forefront of scientific research globally and their importance is increasing due to the world's trend towards a reduction in the use of chemical fungicides. In this work, eight Trichoderma isolates were tested under laboratory conditions against M. phaseolina. Two T. longibrachiatum isolates (T7507 and T7407) and a T. asperellum isolate (P1) achieved promising results. The bioprotective properties of these isolates' secreted metabolites were evaluated in solid and liquid cultures. The T7407 strain was the most influential in the solid medium with 55% inhibition capacity; the P1 strain excelled in the liquid medium with 62% inhibition capacity. The three M. phaseolina isolates were then tested in seedlings (up to 42 days) against controls: non-infected plants, infected unshielded plants, and plants treated with non-influencing Trichoderma isolate (O.Y. 14707). The bio-shielding agents were added directly to the seeds with the sowing in this growth room pathogenicity assay. At the experiment's end, the T. longibrachiatum (T7407) treatment markedly improved the plants' wet weight (45%), height (32%) and phenological development (56%) compared to the non-influencing Trichoderma species control. Since the disease is commonly latent in sprouts, statistical differences in the plants' growth parameters are challenging to reach, as occurred here. Still, the real-time PCR tracking of the pathogen DNA inside the plants' roots revealed dramatic changes. The pathogen DNA dropped to near-zero levels in the T. longibrachiatum- and T. asperellum-treated plants. Interestingly, the O.Y. 14707 isolate, which showed no bioprotective properties in the lab tests or plants' growth indices, had a similar significant repression impact on the pathogen roots infection. The results of this work demonstrate the importance of the early molecular assessment of preventive treatment effectiveness against M. phaseolina before a full growing season evaluation.

Registration of ‘S17‐2243C’: A non‐genetically modified maturity group IV soybean cultivar with high yield and elevated oil concentration

Abstract‘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.

Mellein: Production in culture by Macrophomina phaseolina isolates from soybean plants exhibiting symptoms of charcoal rot and its role in pathology.

Macrophomina phaseolina (Mp) is a fungal pathogen proposed to enter host roots by releasing toxins that induce local necrosis in roots allowing entry of hyphae. Mp is reported to produce several potent phytotoxins, including (-)-botryodiplodin and phaseolinone, but isolates that do not produce these phytotoxins retain virulence. One hypothesis explaining these observations is that some Mp isolates may produce other unidentified phytotoxin(s) responsible for virulence. A previous study of Mp isolates from soybean found 14 previously unreported secondary metabolites using LC-MS/MS, including mellein, which has various reported biological activities. This study was conducted to investigate the frequency and amounts of mellein produced in culture by Mp isolates from soybean plants exhibiting symptoms of charcoal rot and to investigate the role of mellein in any observed phytotoxicity. LC-MS/MS analysis of cell-free culture filtrates (CCFs) from 89 Mp isolates revealed that 28.1% produced mellein (49-2,203 µg/L). In soybean seedlings in hydroponic culture, Mp CCFs diluted to 25% (vol/vol) in hydroponic growth medium induced phytotoxic symptoms with frequencies of 73% chlorosis, 78% necrosis, 7% wilting, and 16% death, and at 50% (vol/vol) induced phytotoxicity with frequencies of 61% chlorosis, 82% necrosis, 9% wilting, and 26% death. Commercially-available mellein (40-100 µg/mL) in hydroponic culture medium induced wilting. However, mellein concentrations in CCFs exhibited only weak, negative, insignificant correlations with phytotoxicity measures in soybean seedlings, suggesting that mellein does not contribute substantially to observed phytotoxic effects. Further investigation is needed to determine if mellein plays any role in root infection.

Response of sorghum lines carrying recently identified brown midrib (bmr) mutations to stalk rot pathogens and water deficit

AbstractSorghum (Sorghum bicolor) is drought‐tolerant and has diverse germplasm for food, feed, forage and bioenergy. However, stalk diseases reduce quality and yield of biomass and grain, especially under drought. Previously, brown midrib (bmr) mutations in monolignol biosynthesis were shown to reduce lignin content and alter composition but were not more susceptible to stalk diseases than wild‐type lines. Recently characterized bmr mutations were shown to affect flavonoid biosynthesis (chalcone isomerase; bmr30‐1) or 1‐carbon metabolism (folylpolyglutamate synthase; bmr19‐1107, bmr19‐1168 and bmr19‐1937). Two other mutations, bmr29‐1 and bmr31‐1, have not yet been characterized. The six mutations were incorporated into elite genetic backgrounds (RTx430, BTx623 and BWheatland) to develop near‐isogenic lines containing each mutation. Using peduncle inoculations with Fusarium thapsinum and F. proliferatum (Fusarium stalk rot) and Macrophomina phaseolina (charcoal rot) under well‐watered conditions, most bmr lines were at least as resistant as the corresponding wild type, except for RTx430 bmr19‐1937 that had significantly longer mean lesion lengths when inoculated with M. phaseolina. Based on significantly reduced lesion lengths following inoculations with F. proliferatum and F. thapsinum, respectively, bmr29‐1 and bmr31‐1 lines were screened using basal stalk inoculations under well‐watered and water‐deficit conditions. The bmr lines were at least as resistant as the corresponding wild‐type lines. Wild‐type BTx623 was highly susceptible to M. phaseolina under water deficit, but near‐isogenic bmr29‐1 and bmr31‐1 lines had significantly shorter mean lesion lengths. Incorporation of these mutations can increase resistance to stalk pathogens in cultivar and hybrid development for feed, bioenergy and production of biomass‐based green chemicals.

Charcoal Rot Severity and Soybean Yield Responses to Planting Date, Irrigation, and Genotypes

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.

Registration of ‘S16‐5503GT’ soybean cultivar with high yield, broad adaptation, and glyphosate tolerance

Abstract‘S16‐5503GT’ (Reg. no. CV‐555, PI 700002) is a semi‐determinate, late‐maturity group IV (relative maturity, 4.8), glyphosate‐tolerant, high‐yielding soybean [Glycine max (L.) Merr.] cultivar developed and released in 2021 by the University of Missouri‐Fisher Delta Research, Extension, and Education Center (MU‐FDREEC) soybean breeding program. Southern U.S. growers’ preference for high‐yielding, early‐maturing cultivars with glyphosate tolerance and broad disease resistance motivated the development of S16‐5503GT soybean. It was evaluated in a total of 92 environments across 12 U.S. mid‐southern states from 2017 to 2021 for yield and agronomic traits. Across all testing environments, S16‐5503GT yielded 4,258 kg ha−1, which was equivalent to 108% of the non‐Xtend check mean and 102% of the Xtend check mean, ranking in the top 19% overall. In the 2021 Southern State Variety Trials, S16‐5503GT yielded 4,455 kg ha−1 and ranked in the top 43% overall. S16‐5503GT is resistant to soybean cyst nematode races 3 (HG type 5.7) and 5 (HG type 2.5.7) and moderately resistant to race 2 (HG type 1.2.5.7). It is also resistant to southern root‐knot nematode, reniform nematode, frogeye leaf spot, charcoal rot, and brown stem rot and is tolerant to extreme salinity conditions. The broad disease resistance package combined with high‐yielding performance and wide adaptability across multiple mid‐southern states make S16‐5503GT an excellent cultivar choice for soybean growers in the southern United States, where late‐maturity group IV varieties are in demand.