Diseases of Amaranthus spp. caused by Pythium aphanidermatum and Macrophomina phaseolina

1993 ◽  
Vol 71 (9) ◽  
pp. 1219-1223 ◽  
Author(s):  
J. D. Mihail ◽  
E. R. Champaco

Experimental plantings of several species and crosses of Amaranthus were monitored during the 1990–1992 growing seasons to identify diseases that might limit commercial production of grain amaranth in Missouri. Two diseases, previously unreported on the Amaranthus spp. being evaluated in Missouri, are described. Pythium stem canker, caused by Pythium aphanidermatum, was observed when high temperatures coincided with prolonged periods of soil saturation. Tan cankers with black borders developed at the soil line on nearly mature (flowering) plants and lodging was associated with 2.7% of plants examined. Of the species and crosses examined, A. cruentus (cultivar K436) and A. hypochondriacus × A. hybridus (cultivars K432, K433, and K593) were affected most severely by the disease. Differences in susceptibility among the 11 cultivars suggest the potential for the development of disease-resistant cultivars. Charcoal rot, caused by Macrophomina phaseolina, affected A. hypochondriacus × A. hybridus (cultivars K432 and K433) growing in two mid-Missouri locations in 1990. Key words: Amaranthus cruentus, Amaranthus hypochondriacus, Amaranthus hypochondriacus × Amaranthus hybridis, charcoal rot, grain amaranth, stem canker.

Biologia ◽  
2013 ◽  
Vol 68 (4) ◽  
Author(s):  
Andrea Hlinková ◽  
Adriána Bednárová ◽  
Michaela Havrlentová ◽  
Jana Šupová ◽  
Iveta Čičová

AbstractThe oil of amaranth grain (Amaranthus spp.) is a rich source of poly-unsaturated fatty acids. In this study, we tested 10 amaranth samples representing two species (Amaranthus cruentus and Amaranthus hypochondriacus) in two consecutive years (2010, 2011). Grain oils were analysed by gas chromatography for their fatty acids profile. In 2010, oil content ranged from 6.4–8.2% for A. cruentus and 6.3–7.9% for A. hypochondriacus. In 2011, the level was 7.1–8.2% and 6.6–8.7% for A. cruentus and A. hypochondriacus, respectively. Linoleic, palmitic, and oleic acids were dominant fatty acids in all of the oil samples. The essential linoleic acid level was 33.3–38.7% (A. cruentus) and 31.7–47.5% (A. hypochondriacus) in 2010 and 34.6–39.9% (A. cruentus) and 34–44.5% (A. hypochondriacus) in 2011. The minority fatty acids, i.e. stearic, α-linolenic, and arachidic acids were also observed. Eicosenoic and behenic acids were present in the grain in trace amounts. Statistical evaluation showed a significant effect of year and species of amaranth on the levels of certain fatty acids. There was a strong positive correlation between oil content and oleic acid, and a negative correlation between oleic acid and either of the other two fatty acids, linoleic and α-linolenic ones.


2021 ◽  
Vol 11 (3) ◽  
Author(s):  
Jonathan R Nelson ◽  
Sujeet Verma ◽  
Nahla V Bassil ◽  
Chad E Finn ◽  
James F Hancock ◽  
...  

Abstract Charcoal rot caused by Macrophomina phaseolinais an increasing economic problem in annualized strawberry production systems around the world. Currently there are no effective postfumigation chemical controls for managing charcoal rot, and no information is available on the genetic architecture of resistance to M. phaseolina in strawberry (Fragaria ×ananassa). In this study, three multiparental discovery populations and two validation populations were inoculated at planting and evaluated for mortality in three consecutive growing seasons. Genome-wide SNP genotyping and pedigree-based analysis with FlexQTL™ software were performed. Two large-effect quantitative trait loci (QTL) increasing charcoal rot resistance were discovered and validated in cultivated germplasm. FaRMp1 was located on linkage group 2A in the interval 20.4to 24.9 cM, while FaRMp2 was located on linkage group 4B in the interval 41.1to 61.2 cM. Together these QTLs explained 27% and 17% of the phenotypic variance in two discovery populations consisting of elite breeding germplasm. For both QTLs, the resistant allele showed some evidence of partial dominance, but no significant interaction was detected between the two loci. As the dosage of resistant alleles increased from 0 to 4 across the two QTLs, mortality decreased regardless of the combination of alleles.A third locus, FaRMp3 on 4D, was discovered in FVC 11–58, a reconstituted F.×ananassa originating from diverse F. virginiana and F. chiloensis accessions. This locus accounted for 44% of phenotypic variation in four segregating crosses. These findings will form the basis for DNA-informed breeding for resistance to charcoal rot in cultivated strawberry.


Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1159-1166 ◽  
Author(s):  
Alemu Mengistu ◽  
J. R. Smith ◽  
J. D. Ray ◽  
N. Bellaloui

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.


Toxins ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 645 ◽  
Author(s):  
Hamed K. Abbas ◽  
Nacer Bellaloui ◽  
Cesare Accinelli ◽  
James R. Smith ◽  
W. Thomas Shier

Charcoal rot disease, caused by the fungus Macrophomina phaseolina, results in major economic losses in soybean production in southern USA. M. phaseolina has been proposed to use the toxin (-)-botryodiplodin in its root infection mechanism to create a necrotic zone in root tissue through which fungal hyphae can readily enter the plant. The majority (51.4%) of M. phaseolina isolates from plants with charcoal rot disease produced a wide range of (-)-botryodiplodin concentrations in a culture medium (0.14–6.11 µg/mL), 37.8% produced traces below the limit of quantification (0.01 µg/mL), and 10.8% produced no detectable (-)-botryodiplodin. Some culture media with traces or no (-)-botryodiplodin were nevertheless strongly phytotoxic in soybean leaf disc cultures, consistent with the production of another unidentified toxin(s). Widely ranging (-)-botryodiplodin levels (traces to 3.14 µg/g) were also observed in the roots, but not in the aerial parts, of soybean plants naturally infected with charcoal rot disease. This is the first report of (-)-botryodiplodin in plant tissues naturally infected with charcoal rot disease. No phaseolinone was detected in M. phaseolina culture media or naturally infected soybean tissues. These results are consistent with (-)-botryodiplodin playing a role in the pathology of some, but not all, M. phaseolina isolates from soybeans with charcoal rot disease in southern USA.


Animals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
Kim Margarette C. Nogoy ◽  
Jia Yu ◽  
Young Gyu Song ◽  
Shida Li ◽  
Jong-Wook Chung ◽  
...  

The amaranth plants showed high potential feed value as forage for ruminants. An in-depth study of this plant, particularly in cattle, will help extend its utilization as an alternative protein and fiber feed source in cattle feeding. In this study, the nutrient compositions of three different species of amaranth, Amaranthus caudatus L., Amaranthus cruentus L., and Amaranthus hypochondriacus L.—two varieties for each species, A.ca 74, A.ca 91, A.cu 62, A.cu 66, A. hy 30, and A. hy 48—were evaluated. The in vitro technique was used to evaluate the fermentation characteristics such as total gas production, total volatile fatty acids (VFA) concentration, pH, and ammonia concentration of the rumen fluid. Moreover, the effective degradabilities of dry matter (EDDM) and crude protein (EDCP) of the amaranth forages were determined through in situ bag technique. The amaranth forages: A. caudatus, A. cruentus, and A. hypochondriacus showed better nutritive value than the locally produced forages in Chungcheong province of Korea. The CP of the amaranth ranged from 11.95% to 14.19%, and the neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents ranged from 45.53% to 70.88% and 34.17% to 49.83%, respectively. Among the amaranth varieties, A. hypochondriacus 48 showed the most excellent ruminant feed nutrient quality (CP, 14.19%; NDF, 45.53%; and ADF, 34.17%). The effective degradabilities of dry matter (EDDM; 33–56%) and crude protein EDCP (27–59%) of the amaranth were lower compared to other studies, which could be due to the maturity stage at which the forages were harvested. Nonetheless, A. hypochondriacus 48 showed the highest EDDM (56.73%) and EDCP (59.09%). The different amaranth species did not differ greatly in terms of total VFA concentration or molar proportions, total gas production, or ammonia-N concentration. The high nutrient composition, and highly effective degradability of dry matter and crude protein, coupled with the favorable fermentation characteristics, suggest that the amaranth forages showed good to excellent feed quality for cattle.


2021 ◽  
Vol 84 (2) ◽  
pp. 459-465
Author(s):  
Marco Masi ◽  
Francisco Sautua ◽  
Roukia Zatout ◽  
Stefany Castaldi ◽  
Lorenzo Arrico ◽  
...  

2003 ◽  
Vol 28 (2) ◽  
pp. 131-135 ◽  
Author(s):  
Álvaro M. R. Almeida ◽  
Lilian Amorim ◽  
Armando Bergamin Filho ◽  
Eleno Torres ◽  
José R. B. Farias ◽  
...  

The increase in incidence of charcoal rot caused by Macrophomina phaseolina on soybeans (Glycine max) was followed four seasons in conventional and no-till cropping systems. In the 1997/98 and 2000/01 seasons, total precipitation between sowing and harvest reached 876.3 and 846.9 mm, respectively. For these seasons, disease incidence did not differ significantly between the no-till and conventional systems. In 1998/99 and 1999/00 precipitation totaled 689.9 and 478.3 mm, respectively. In 1998/99, in the no-till system, the disease incidence was 43.7% and 53.1% in the conventional system. In 1999/00 the final incidence was 68.7% and 81.2% for the no-till and conventional systems, respectively. For these two seasons, precipitation was lower than that required for soybean crops (840 mm), and the averages of disease incidence were significantly higher in the conventional system. The concentration of microsclerotia in soil samples was higher in samples collected in conventional system at 0 - 10 cm depth. However, analysis of microsclerotia in roots showed that in years with adequate rain no difference was detected. In dry years, however, roots from plants developed under the conventional system had significantly more microsclerotia. Because of the wide host range of M. phaseolina and the long survival times of the microsclerotia, crop rotation would probably have little benefit in reducing charcoal rot. Under these study conditions it may be a better alternative to suppress charcoal rot by using the no-till cropping system to conserve soil moisture and reduce disease progress.


2008 ◽  
Vol 9 (1) ◽  
pp. 16 ◽  
Author(s):  
J. A. Wrather ◽  
J. G. Shannon ◽  
T. E. Carter ◽  
J. P. Bond ◽  
J. C. Rupe ◽  
...  

Charcoal rot caused by Macrophomina phaseolina is a common disease of many crops including common bean and soybean. Incidence and severity of charcoal rot are enhanced when plants are drought stressed. Resistance to this pathogen in some common bean genotypes was associated with drought tolerance. Resistance to M. phaseolina among soybean genotypes has not been identified, although a few have been rated moderately resistant based on less root tissue colonization by this pathogen compared to other genotypes. A few soybean genotypes have been rated as slow-wilt or drought-tolerant. The reaction of drought-tolerant soybean to M. phaseolina compared to intolerant or drought-sensitive genotypes has not been determined. Our objective was to determine if there were differences in root colonization by M. phaseolina between drought-tolerant and drought-sensitive soybean genotypes. Drought tolerance of the soybean genotypes and root colonization by M. phaseolina at the R6 and R8 stages of growth were not related in this study. Some drought-tolerant soybean genotypes may resist root colonization by M. phaseolina, but our results suggest that this is not true for all drought-tolerant genotypes. Accepted for publication 21 March 2008. Published 18 June 2008.


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