# Epidemiology of Yam Viruses in Guadeloupe: Role of Cropping Practices and Seed-Tuber Supply

Mame Boucar Diouf, Sébastien Guyader, Olyvia Gaspard, Eric Francius, Pierre-Yves Teycheney, Marie Umber

► To cite this version:

Mame Boucar Diouf, Sébastien Guyader, Olyvia Gaspard, Eric Francius, Pierre-Yves Teycheney, et al. Epidemiology of Yam Viruses in Guadeloupe: Role of Cropping Practices and Seed-Tuber Supply. 12th International Congress of Plant Pathology (ICPP 2023), International Society on Plant Pathology; Société Française de Phytopathologie, Aug 2023, Lyon, France. 10.3390/v14112366. hal-04197738

HAL Id: hal-04197738

https://hal.inrae.fr/hal-04197738

Submitted on 6 Sep 2023

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Distributed under a Creative Commons Attribution 4.0 International License
> Epidemiology of yam viruses in
Guadeloupe

Role of cropping practices and seed-tuber supply

Mame Boucar Diouf, Sébastien Guyader, Olyvia Gaspard, Eric Francius, Pierre-Yves Teycheney, Marie Umber

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RÉPUBLIQUE
FRANÇAISE

Liberté
Egalité
Fraternité

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> YAM – A vital root crop for the intertropical world

* Ranks 4th among the root crops (metric tons produced)

* Dietary, medicinal and cultural importance, especially in west Africa (> 95% of the worldwide production)

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> YAM – The first food crop in Guadeloupe

<figure><img src="image_8.png" /><figcaption>*Dioscorea alata*</figcaption></figure>

<figure><img src="image_9.png" /><figcaption>*D. cayenensis*</figcaption></figure>

<figure><img src="image_10.png" /><figcaption>*D. rotundata*</figcaption></figure>

<figure><img src="image_11.png" /><figcaption>*D. trifida*</figcaption></figure>

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> YAM – Constraints to the production

* Only 20-40% of the yield potential is attained:

* high requirements in soil nutrients

* competition with itself and weeds

* pests and pathogens... 🍃<u>viruses</u>

* ICTV recognizes 25 virus species worldwide

* In Guadeloupe, 9 viruses reported in yam:

* assigned genera:
    * Ampelovirus, Badnavirus, Banmivirus, Cucumovirus, Macluravirus, Potexvirus, Potyvirus, Sadwavirus, Velarivirus

* unassigned genus of *Betaflexiviridae*

* Since the advent of HTS technologies, “novel” viruses keep surfacing and being characterized at the genomic level

* Much less is known about impact and epidemiology...

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> Epidemiology of yam viruses in Guadeloupe

Methods

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2019

* 18 plots surveyed (records on what yams were grown, cropping practices, environment)

* 780 yam leaf samples collected (6 yam species, 15 cultivars)

* 46 weed leaf samples collected

2020

* 2 plots

* 117 samples of *D. alata* collected (1 yam species, 7 cultivars)

* 80 weed leaf samples collected

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> Epidemiological survey in Guadeloupe

Results: prevalence of viruses in yams

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> Epidemiological survey in Guadeloupe

Results: mixed infections

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Epidemiological survey in Guadeloupe

**Results: yam macluraviruses in Guadeloupe**

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# Epidemiological survey in Guadeloupe

## Results: yam viruses in weeds

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Weeds = reservoirs?

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INRAE

Epidemiology of yam viruses in Guadeloupe: role of cropping practices and seed-tuber supply

23 August 2023 / ICPP 2023 / Sébastien Guyader
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# Epidemiological survey in Guadeloupe

## Results: yam viruses in weeds

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INRAE

Epidemiology of yam viruses in Guadeloupe: role of cropping practices and seed-tuber supply

23 August 2023 / ICPP 2023 / Sébastien Guyader
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# Epidemiological survey in Guadeloupe

## Results: effect of crop-related variables on virus occurrence

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Weeds_management: mechanical

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Use_of_pesticides: yes

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Weeds_management: mulching

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Seed Supply: own

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> Epidemiological survey in Guadeloupe

Results: efficiency of vertical transmission

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D. trifida mother plants:
YMMV
YaV1

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Daughter tubers

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Daughter plants

96% YMMV
0% YaV1

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> Epidemiological survey in Guadeloupe

Summary

* YMMV and YaV1 are the most prevalent in Guadeloupe

* Mixed infections are predominant

* First detection of YCNV in Guadeloupe

* Weeds likely act as reservoir of YMMV

* Evidence that imported tubers from abroad can introduce viruses

* Vertical transmission: high for YMMV / non-existent for YaV1

* Some cropping practices seem to correlate with the occurrence of some viruses... but these correlations are sometimes counterintuitive

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viruses

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Article

Epidemiology of Yam Viruses in Guadeloupe: Role of Cropping Practices and Seed-Tuber Supply

Mame Boucar Diouf ¹,²,³✉, Sébastien Guyader ¹✉, Olyvia Gaspard ¹, Eric Francius ¹, Pierre-Yves Teycheney ⁴,⁵
and Marie Umber ¹,*✉

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> Acknowledgements

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malin

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RITA
GUADELOUPE
Réseau d'innovation
et de transfert agricole

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Fonds européen agricole
pour le développement rural:

L'EUROPE INVESTIT
dans les zones rurales

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AsTro

AgroSystèmes
Tropicaux

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CRB Plantes Tropicales
Antilles
INRAE
cirad

IT2
INSTITUT
TECHNIQUE
TROPICAL

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CHAMBRE
D'AGRICULTURE
GUADELOUPE