Abstract

Cassava resistance to Bemisia tabaci is a result of many plant processes which involve plant biochemical constituents, shown to be affected by genotype and environment. The objective of this study was to assess the effect of genotype × environment interactions on concentrations of tannin, flavonoid, total phenolic content, antioxidative capacity and B. tabaci resistance. Fifteen cassava genotypes were evaluated monthly for tannin, flavonoid, total phenolic content and antioxidative capacity in three locations over two seasons with varying temperatures and rainfall. In addition, data were collected on B. tabaci population density and damage. The data collected was subjected to analysis of variance and additive main effects and multiplicative interactions (AMMI) analyses. Flavonoid, total phenolic content and antioxidative capacity varied significantly (P < 0.001) across seasons with higher concentrations in season one than season two, attributed to different temperature and rainfall readings. Total phenolic content was significantly (P < 0.001) associated to antioxidative capacity (r = 0.83) and temperature (r = 0.91). Leaf damage due to adult whitefly and nymphs was significantly (P < 0.001) negatively correlated (r = -0.67) to antioxidative capacity. Genotypes UG 120257, UG 120291 and UG 120124 were shown to have high antioxidative capacity and more stable performance across environments. Temperature and B. tabaci feeding influenced concentrations of the phenolic content and antioxidative activity, as a result affected cassava resistance.

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