AUTHOR=Jiwuba Lydia , Danquah Agyemang , Asante Isaac , Blay Essie , Onyeka Joseph , Danquah Eric , Egesi Chiedozie 

TITLE=Genotype by Environment Interaction on Resistance to Cassava Green Mite Associated Traits and Effects on Yield Performance of Cassava Genotypes in Nigeria

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 11 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.572200

DOI=10.3389/fpls.2020.572200

ISSN=1664-462X

ABSTRACT=Cassava is the primary source of carbohydrate for more than 70% of the people in Nigeria, the world's largest producer and consumer of the crop. The yields of cassava are, however, relatively low in Nigeria largely due to pests and disease infections which contribute significantly to inconsistencies in performance of cassava genotypes in different environments.Fifty-eight F1 hybrid cassava genotypes plus their two parents which served as check varieties were evaluated in three locations for two years (that is six environments). The objectives of the study were to evaluate genotype by environment interactions (GEI) on resistance to cassava green mite (CGM) associated traits and effects on yield performance of cassava genotypes in Nigeria and to identify superior genotypes that exhibit high stability which combine CGM resistance and high fresh root yield with general and specific environmental adaptation using two multivariate analyses: additive main effects and multiplicative interaction (AMMI) and genotype stability index (GSI). The combined analysis of variance based on additive main effects and multiplicative interaction (AMMI) revealed significant genotype, environment and genotype by environment interactions (GEI) for all traits. The percentage variation due to environment was higher than the percentage variation due to genotype for cassava green mite severity (CGMS), leaf retention (LR), root dry matter content (RDMC) and Fresh root yield (FRY) indicating that environment greatly influenced the expression of these traits. The percentage variation due to GEI accounted for higher percentage variation than that of genotype and environment separately for all traits, indicating the influence of genotype by environment interaction on expression of the traits. These findings indicate that the screening/evaluating for these traits requires multi-environment trials. According to GSI ranking, genotypes G31 (IBA131794), G19 (IBA131762), the check variety G52 (TMEB778) and G11 (IBA131748) were identified as the most stable and most resistant to CGM which also combine high FRY and other useful agronomic traits, suggesting it is possible to combine these traits in cassava as desired by farmers. These genotypes can be evaluated in more environments to assess their adaptability and possible recommendation for release to farmers for cultivation.