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Varietal resistance in rice to the crab, Sesarma huzardi, in Sierra Leone

Published online by Cambridge University Press:  19 September 2011

M. Agyen-Sampong
M. Agyen-Sampong
Affiliation:
West Africa Rice Development Association (WARDA), Regional Mangrove Swamp Rice Research Station, Rokupr, P.M.Box 678, Freetown, Sierra Leone
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Abstract

A new technique of mass-screening rice seedlings for resistance to the crab, Sesarma huzardi, developed by the West Africa Rice Development Association (WARDA) at Rokupr is described.

About 500 mangrove swamp local collections and a few exotic varieties have been screened for resistance to crab damage. Only 2% of the varieties have been identified as highly tolerant. Generally, the local collections were tolerant, while none of the foreign introductions have been tolerant.

The basis of resistance appears to be morphological, which physically affects feeding mechanism; thus, some varieties were more susceptible to crab damage than others.

Degree of the heritability (hb2 = 61%) estimate indicated that there is genetic variability for tolerance. In a team-oriented research, some of the varieties are being used in the WARDA breeding programme at Rokupr.

Résumé

Cet article décrit une nouvelle technique de dépistage en masse des plants de riz quant à la resistance au crabe, Sesarma huzardi, développée par le ‘West African Rice Development Association’ (WARDA) a Rokpur.

Approximativement 500 palétuviers, des collections locales et quelques variétés exotiques ont été soummises à un test de dépistage de la résistance aux dégâts causés par le crabe. 2% seulement les variétés ont été identifiées comme très tolérantes tandisque aucune des variétés étrangères nétait tolérantes. La base de la résistance apparaît être d'ordre morphologique ce qui physiquement affecte le mécanisme d'alimentation; ainsi quelques variétés étaient plus susceptibles que d'autres aux dégâts des crabes.

L'estimation du degré d'héritabilité (hb2 = 61%) a indiqué qu il'y a variabilité génétique pour la tolérance. Dans une recherche conduite en équipe, quelques unes des variétés ont été utilisées dans le programme de croisement de cultures à WARDA, Rokupr.

Keywords

CrabSesarma huzardiricevarietal resistanceestimated heritabilityCrabeSesarma huzardirizrésistance variétalehéritabilité estimée
Type
Section V: screening techniques and methodologies for host plant resistance research
Information
International Journal of Tropical Insect Science , Volume 6 , Special Issue 3: Host Plant Resistance and its Significance in Pest Management , June 1985 , pp. 413 - 415
Copyright
Copyright © ICIPE 1985

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References

REFERENCES

Agyen-Sampong, M. (1979) Crabs, pest of rice in the tidal mangrove swamps of Sierra Leone. WARDA, Techn. Newsl. 1, 7–8.Google Scholar
Bunion, G. W. and Devane, E. H. (1953) Estimating heri-tability in tall fescue (Festuca arundinacea) from replicated clonal material. Agron. J. 45, 478–481.Google Scholar
Jordan, H. D. (1957) Crabs as pests of rice on tidal swamps. Emp. J. exp. Agric. 25, 198–206.Google Scholar
West Africa Rice Development Association (1977) Annual Report of Special Project, Rokupr.Google Scholar
West Africa Rice Development Association (1979) Annual Report of Special Project, Rokupr.Google Scholar
West Africa Rice Development Association (1983) Quinquennial Review Provisional Report, Special Project, Rokupr p. 78.Google Scholar