Reaction of Cassava Genotypes to the Cassava Mosaic Disease in Three Distinct Agroecologies in Nigeria

Abstract

Nine cassava genotypes were grown at six representative sites in Nigeria for 3 years to study their response to cassava mosaic disease (CMD), investigate the influence of genotype × environment (G × E) interactions on their reactions to the disease, and identify genotypes with stability to the disease, using the Additive Main Effects and Multiplicative Interaction statistical model. Environments, genotypes and G × E interactions were highly significant (P < 0.01) for the disease. The G × E interactions accounted for 19.5% of the treatment sums of squares for CMD and influenced the relative ranking of genotypes across environments. The magnitude of the G × E interaction effect for CMD was larger than that of genotypes. Examination of the G × E interaction structure revealed specific areas where screening of cassava genotypes for resistance to CMD could be performed best. The study identified genotypes such as TMS 30001 and 63397 with resistance to CMD and CMD‐stable clone U/41044, which could be distributed to growers, and sites such as Ibadan and Ubiaja with high CMD severity for screening genotypes for reaction to CMD.

Evaluation of Cassava Cultivars for Resistance to Cassava Mosaic Disease and Yield Potential in Central African Republic

“…This stage also corresponded to the end of the rainy season and the beginning of the dry season, which in term of temperature and rainfall is the most favourable period, as reported in several studies (Hahn et al 1980;Fauquet and Fargette 1990;Ngeve et al 2003;Adriko et al 2012). This stage also corresponded to the end of the rainy season and the beginning of the dry season, which in term of temperature and rainfall is the most favourable period, as reported in several studies (Hahn et al 1980;Fauquet and Fargette 1990;Ngeve et al 2003;Adriko et al 2012).…”

“…Damara and Pissa could be areas of high and low inoculums, respectively (Ogbe et al 2003;Mallowa et al 2006). Disease evolution reflects fluctuations in whitefly populations following seasons but also largely depends on plant age (Hahn et al 1980;Fauquet and Fargette 1990;Sserubombwe et al 2001;Ngeve et al 2003;Adriko et al 2012). For example, in acid soils, CMD incidence or severity is known to be less important (Hahn et al 1980).…”

Reaction of White Guinea Yam (Dioscorea rotundata Poir.) Genotypes to Virus Diseases in Four Agroecological Zones in Nigeria

“…Analysis of variance ( anova ) has always been relevant in the analysis of two‐way data (Shafii et al., 1992). Though anova may be effective in identifying the main effects among sources of variability, it does not give an insight into the underlying G × E interaction because it is additive (Ngeve et al., 2003). It is necessary to employ other techniques such that the multiplicative effects of the G × E components would be presented, and be able to identify the existing interactions.…”

“…The Additive Main Effects and Multiplicative Interaction (AMMI) model is an appropriate statistical technique that incorporates both additive and multiplicative components and is thus able to identify existing G × E interactions in any two‐way data analysis (Gauch, 1993). The AMMI model also separates the additive variance from the multiplicative variance, and then applies principal component analysis (PCA) to the interaction which is the residual portion from the anova so as to extract a new set of co‐ordinate axes (Ngeve et al., 2003). The AMMI method classifies genotypes into stable and unstable groups using the positive and negative IPCA1 index.…”

Introgression of root protein and yield traits from backcross hybrids between cassava and its wild progenitor (Manihot esculenta ssp flabellifolia)

“…The use of Genotype by environment interactions is a means by which clones are tested for a wide adaptation to a range of environments with higher yield (Ngeve et al, 2003;Aina et al, 2007;Okechukwu and Dixon, 2009). The contribution of genotype sum of squares to total sum of squares in yield and quality traits was significant, which indicated a large genetic component.…”