Evaluation of improved cassava genotypes for yield and related traits for a better breeding strategy under different agroecologies in Nigeria

This study aimed at determining shoot and root characteristics of cassava as affected by root yield and the influence of soil moisture on vegetative growth and yield. Thirty cassava genotypes were evaluated for morphological and physiological characterization in three locations in Nigeria: Ibadan, Mokwa and Zaria. Randomized complete block design was used with four replicates. Studies on the pasting properties of the genotypes were also carried out. Data were collected on plant height, stem girth, stay-green ability, garri and fresh root weight. Genotypes differed significantly ( P < 0.05) across and within locations for shoot and root characteristics. Across locations, genotype 011663 had the highest plant height (132.4 cm); 30572 had the largest stem girth (8.6 cm); and 010040 was the best stay-green (2.2). Genotype 011086 had the highest number of roots per plot (95.7), 950289 had the highest fresh root yield (24.3 t/ha), and 990554 had the highest percentage of dry matter (35.2). Trends in root yields across locations were Ibadan (28.9 t/ha), Mokwa (20.3 t/ha), and Zaria (8 t/ha). Five genotypes IITA-TMS-IBA950289, 010034, 990554, 011807, and 980581 had negligible interactions with the environment and so have broad adaptation and are considered stable; and two clones 011807 and 950166 were found to be the best for pasting properties. Breeding strategies that consider root size, total root number, harvest index, dry matter, with applications for household foods and industrial uses, will be an effective and efficient way to select genotypes for high yield.