Resistance profile of improved cassava germplasm to cassava mosaic disease in Nigeria

Title 
Resistance profile of improved cassava germplasm to cassava mosaic disease in Nigeria 
Publication Type 
Journal Article 
Authors 
Egesi CN, Ogbe FO, Akoroda M, Ilona P, Dixon A 
Year of Publication 
2007 
Publisher 
Springer 
Place Published 
New York 
Volume 
155 
Journal 
Euphytica 
Issue 
1-2 
Pagination 
215 - 224 
Date Published 
4/2007 
ISSN 
1573-5060 
URL 
http://www.springerlink.com/content/q3g1j704x008837u/ 
Keywords 
AUDPC, Cassava, Cassava mosaic disease, Genotype × environment interaction, Germplasm, Manihot esculenta ssp flabellifolia, Resistance 
DOI 
10.1007/s10681-006-9323-0 
Abstract 

Cassava mosaic disease (CMD) caused by a group of begomoviruses and transmitted by whitefly vector is a serious disease in all the cassava-growing areas of Africa. Field evaluation with replication was conducted in 2003 and 2004 in three agroecologies in Nigeria to study the response of 40 cassava genotypes to CMD and to investigate genotype × environment (GE) interactions on their reactions to CMD, using the rank-sum classification and site regression analysis model. The 40 genotypes were separated into resistant (n = 17), moderately resistant (n = 6), moderately susceptible (n = 2) and susceptible (n = 15) groups. Environments, genotypes and GE interactions were all highly significant (P < 0.0001) for the virus disease contributing 9.5%, 71.36% and 19.14%, respectively to total variation. More than 40% of the genotypes were identified as resistant to the disease. Genotypes TMS 98/0581, TMS 99/3073, TMS 97/4763, TMS M98/0040, TMS 98/0505, TMS 97/0211, TMS 97/4769, TMS 99/2123, TMS M98/0068 and TMS 97/0162 were shown to have high resistance to CMD. The study also identified Umudike, in south-east Nigeria, as having high disease severity and the most appropriate site for CMD resistance screening of genotypes. Most of the genotypes exhibited stable resistance to CMD. The implication that the availability of these resistant genotypes as identified in this study could be a source of CMD resistance for further breeding is discussed.

 
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