Whitefly infestation and feeding damages on root nutrient and phytochemical properties of selected cassava (Manihot esculenta crantz) West African and Ugandan germplasm

Abstract

Cassava is a significant contributor to food security and an income source for smallholder farmers in Uganda. Nevertheless, less research has been done to fully select cassava germplasm that is resistant to cassava whitefly based on designing laboratory experiment samples for the biochemical and nutrient composition. The study was conducted to assess the whitefly resistant biochemical and nutrient composition exhibited by Ugandan and West African ccassava germplasm. Nine (9) cassava germplasm from the total of 30 clones based on their field performance were collected and were run in triplicate in the laboratory. Data on eleven (11) biochemical and nutrient characters were collected and analysed using AOAC standard methods. The analysis of variance showed significant to very highly significant differences (Tukey’s test, p<0.05) among the tested germplasm for both biochemical and nutrient. The concentration of Hydrogen cyanide ranged from (2.33 to 45.34 ppm) for UGC1702386 and UGC1703673 respectively, Total flavonoid content (0,08 to 0.35 mg QE/g dw), Lignin content (40.18 to 89.74 %), Total phenolic content (0.50 and 1.28 mg/ GAE/g dw), total tannin content (0,17 to 11.33 mg TA/g dw). For the nutrition composition, total carotenoidcontent(62.60to560.20ppm), drymattercontent(14.9to45.60%),totalprotein content (1.92 to 8.35 mg/g), total carbohydrate content (2.18 to 4.78 to μg/g), total reducing sugars (31.95 to 162.48) and total starch content (79.26 to 28.33 mg/g). Correlation matrix heatmap revealed highest positive association (96%) between total carbohydrate content and reducing sugars followed by starch and percentage dry matter with 76%. Whereas, the principle component biplot generally explained the total variation of 74% for both cassava germplasm, nutrition profiles and whitefly resistant biochemicals with PCA 1 and PCA 2 contributed 55.5% and 18.6% respectively. This study found the presence of high whitefly resistant biochemical and nutrient variability among the tested cassava’ roots exposed to whitefly in a natural environment and could be used to select cassava germplasm with desirable whitefly resistant biochemical composition in future cassava breeding work.