Variation among cassava (Manihot esculenta Crantz) genotypes for storage root yield, yield components and response to cassava mosaic disease at the advanced breeding stage

Abstract

Cassava is a crucial starchy root crop cultivated worldwide in tropical and subtropical areas. Efforts have been made to improve its desirable characteristics to increase food and nutritional quality. However, the adoption of new cassava varieties can be influenced by their yield performance, which can be affected by cassava mosaic disease (CMD). The present study evaluated selected cassava genotypes' performance across two years at the advanced breeding stage. Using a randomized complete block design with two replications, 16 genotypes, a yellow root variety (TMS07/0593) and a white root (TMS30572) as checks were evaluated for yield, yield-related traits and response to CMD. There were highly significant (P < 0.001) variations among the cassava genotypes for yield-related traits, but no genetic variation was reported for fresh and dry root yields. The effect of season and genotypes × season interaction on all traits was significant only for harvest index and percentage of survival plants, respectively. Only genotype UIC-17-2428 and the two national check varieties (TMS07/0593 and TMS30572) did not resist CMD completely. At harvest, genotype UIC-17-2031 had the highest fresh root yield (39.0 t/ha), dry root yield (10.5 t/ha), and harvest index (0.63). Genotype UIC-17-58 had the highest dry matter content (37.2%) at harvesting, followed by UIC-17-46 (36.4%) while genotype UIC-17-583 had the lowest value (22.8%). The genotypes evaluated have promising premium agronomic traits. To assess their stability, genotypes with outstanding dry root yield must be evaluated across multiple environments.