Distribution and virulence of fungal species isolated from yam (<i>Dioscorea</i> spp.) tubers in three agroecological zones of Nigeria

Dania, Victor Ohileobo; Fadina, O. O.; Ayodele, Maria; Kumar, Pardeep

doi:10.1080/09670874.2019.1629041

Cited by 3 publications

(1 citation statement)

References 15 publications

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“…El hongo Lasiodiplodia theobromae o morfotipo DZC1-1 presentó en este estudio un porcentaje de ocurrencia 3,6 %; este hongo ha sido asociado por muchos investigadores como un hongo de alta virulencia y patogenicidad sobre los tubérculos de varias especies (Ali et al, 2020;Gwa & Ekefan, 2017). "Los tubérculos afectados por L. theobromae, muestran podredumbre seca, con tejidos de coloración negra y aspecto pulverulento" (Dania et al, 2019). L. theobromae no solo se ha obtenido en enfermedades en los tubérculos, sino que ha estado relacionado también con la pudrición de frutas (Peixinho et al, 2019).…”

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Hongos asociados a la pudrición seca de tubérculos de ñame (Dioscorea rotundata Poir.) en Córdoba, Colombia

et al. 2021

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Introducción. La pudrición seca es una enfermedad que ha adquirido gran importancia en Colombia debido a que ocasiona la pérdida de los tubérculos del ñame (Dioscorea rotundata Poir.), tanto en campo como en almacenamiento, afecta los ingresos económicos y la productividad de los pequeños productores. Es escasa la información respecto a los agentes causales de esta enfermedad, por lo que no se tienen claras las estrategias para el manejo de esta problemática. Objetivo. Identificar y caracterizar hongos asociados a la pudrición seca de tubérculos de ñame. Materiales y métodos. Esta investigación se realizó entre marzo y octubre del año 2019, en la zona costanera del departamento de Córdoba en el Caribe colombiano. Se colectaron tubérculos de ñame en almacenamiento, debido a que los agricultores los conservan como semillas para próximas cosechas. En laboratorio se aislaron de las lesiones los hongos asociados, se caracterizaron y luego se identificaron a través de la amplificación de la región ITS (Internal Transcribed Spacer) del DNA ribosomal. Resultados. Se aislaron veintiocho crecimientos fúngicos asociados a la pudrición seca de los tubérculos del ñame, los cuales se agruparon en once morfotipos, de los cuales se identificaron diez especies, pertenecientes a nueve géneros fúngicos. Conclusión. Seis hongos podrían estar asociados a la pudrición seca de los tubérculos de ñame en la zona costanera de Colombia. Estos serían: Lasiodiplodia theobromae, Fusarium solani, Rhizopus oryzae, Neocosmospora rubicola, Neoscytalidium dimidiatum y Curvularia aeria.

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Section: Discussionunclassified

Hongos asociados a la pudrición seca de tubérculos de ñame (Dioscorea rotundata Poir.) en Córdoba, Colombia

et al. 2021

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Near-term impact of climate variability on yam rot incidence over a humid tropical region: projections in CORDEX-Africa scenarios

Okoro

Akalazu

2021

Renew. Agric. Food Syst.

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The global population is projected to be enormous by the mid-21st century, whereas, most essential crops being sustained by the rain-fed agriculture are threatened by climate change. Therefore, the study investigated the projected near-future effect of rainfall variability on rot incidence and yam production in humid tropical Nigeria. Production data from the Food and Agriculture Organization and the Nigeria National Bureau of Statistics showed the significant increasing trend in the annual yam output. The field survey conducted in 2018 showed that the maximum percentage of rot incidence occurred in July. Climate Research Unit observational rainfall data from 1979 to 2018 showed the nonsignificant trend in the interannual rainfall variability; however, it showed low variability and a significant decreasing trend in the July rainfall. A pathogenicity test on yam samples confirmed rot by fungi, bacteria and nematodes as virulent pathogens, whereas, the nutritional qualities of the rotted yams were indicated. Monthly rainfall and rot incidence showed positive correlation (r = 0.84, significant at 99% from t-test). The positive characteristic impact values indicated that increase (decrease) in the monthly rainfall corresponds to increase (decrease) in the magnitude of monthly percentage rot incidence. Thus, the significantly decreasing rainfall reduced the quantity of rot incidence and consequently increased the annual yam production for the period. Selected CoOrdinated Regional Downscaling EXperiment-Africa models and the ensemble mean showed a good measure of agreement with observational rainfall in the historical experiments. The efficiencies of the bias-corrected outputs in the representative concentration pathway (RCP) 4.5 and 8.5 indicated improved ‘reasonable’ performances. Bias-corrected projections of the July rainfall showed an increasing trend in both the RCPs, which indicate a potential increase in rot incidence and the consequent decline in annual yam production. The findings are imperative in sustaining the global food supply.

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Biological potentials of Landolphia owariensis leaf methanolic extract against pathogenic fungi isolates from different Dioscorea species

Okechukwu,

Adesanya

2024

Pure and Applied Chemistry

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Regarding economic significance, the Dioscoreaceae family, which includes the well-known Dioscorea (yam) species, is the fourth most important tuber crop globally. A basic meal found all across the world, yams encourage and ensure the food security of households. Although they are challenging to preserve and store however a post-harvest deterioration control must be developed. Over the years, Nigerian farmers have employed medicinal herbs to manage post-harvest pest invasion; nevertheless, the scientific basis for this fungal management has not yet been well documented. As a result, Landolphia owarensis leaf extract was used as a biological control, and fungi were isolated from Dioscorea cayenensis, Dioscorea alata, and Discorea rotundata. Samples of yam tubers – both rotten and healthy – were procured in the markets and brought to the lab for fungus isolation and identification. Leaves of Landolphia oweriensis were collected, air-dried, milled, and macerated in pure methanol for 72 h, extracted and concentrated with a rotary evaporator. The agar-well diffusion method was used for the biological control assay against the fungal isolates. The biological control results were presented as mean ± SD (standard deviation) while analysis of variance (Anova) was used to deduce least significant difference (LSD). A total number of 605 fungi isolates were observed in which D. cayenensis had the highest, 50.58 %, D. alata and Discorea rotundata 24.71 % respectively. Aspergillus niger and Aspergillus fumigatus were found in the three species while Aspergillus flavus, Rhizopus stolonifer, Collentotricum spp. and Penicillium spp. in either of the species. L. owarensis methanolic leaves extracts possesses biological potentials against Colletotrium spp., A. fumigatus, A. niger and A. flavus only. The problem of postharvest fungal invasion of Dioscorea species can be solved with the inhibition observed with L. owarensis methanolic leaves extracts as a biological control measure thereby sustaining food security in the world.

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Distribution and virulence of fungal species isolated from yam (Dioscorea spp.) tubers in three agroecological zones of Nigeria

Cited by 3 publications

References 15 publications

Hongos asociados a la pudrición seca de tubérculos de ñame (Dioscorea rotundata Poir.) en Córdoba, Colombia

Hongos asociados a la pudrición seca de tubérculos de ñame (Dioscorea rotundata Poir.) en Córdoba, Colombia

Near-term impact of climate variability on yam rot incidence over a humid tropical region: projections in CORDEX-Africa scenarios

Biological potentials of Landolphia owariensis leaf methanolic extract against pathogenic fungi isolates from different Dioscorea species

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