Abstract
Cassava (Manihot esculenta Crantz) is a crucial crop for food security and industry in the tropics, yet its productivity is constrained by genotype-by-environment (G×E) interaction and cassava mosaic disease (CMD). This study evaluated 31 cassava genotypes, including commercial varieties, breeding hybrids, and CMD-resistant introductions from CIAT and IITA, across six environments in Thailand over four years. Traits assessed included fresh root yield (FRY), starch content (SC), starch yield (SY), harvest index (HI), and CMD severity. Combined analyses of variance revealed significant effects of genotype, environment, and G×E interaction for all traits. Broad-sense heritability was high for SC (0.96), HI (0.93), and CMD severity (0.94–0.96), while FRY and SY showed moderate values. Additive Main Effects and Multiplicative Interaction (AMMI) and Multi-Trait Stability Index (MTSI) analyses identified HB100 as superior for yield stability, whereas IITA-TMS-IBA980505 (IBA505), IITA-TMS-IBA972205 (IBA205), IITA-TMS-IBA980581 (IBA581), IITA-TMS-IBA920057 (IBA057), TMEB419, and C33 consistently exhibited low CMD severity. MTSI further highlighted TMEB419, HB60, Pirun2, and KU50 as ideotypes combining high yield and disease resistance. These findings provide valuable insights for cassava improvement under CMD pressure and support breeding strategies for developing resilient, high-yielding cultivars in Southeast Asia.
