Genotype × Environment Interaction and Stability Analysis of Selected Cassava Cultivars in South Africa

• Published in: Plants (Basel) Vol. 12; no. 13; p. 2490
• Main Authors: Amelework, Assefa B, Bairu, Michael W, Marx, Roelene, Laing, Mark, Venter, Sonja L
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 29.06.2023; MDPI
• Subjects: Agricultural production; Agriculture; AMMI model; Analysis; Botanical research; breeding sites; Cassava; Corn; Cultivars; Dry matter; Environmental aspects; Environmental conditions; Farmers; Food industry; Food security; Genetic aspects; Genotype & phenotype; genotype × environment interaction; Genotype-environment interactions; Genotypes; Germplasm; Industrial applications; Manihot esculenta; Physiological aspects; Plant breeding; Plant genetics; Seasonal variations; stability; Stability analysis; Variance analysis; Nigeria; South Africa; AMMI model; breeding sites; Manihot esculenta; genotype × environment interaction; stability
• ISSN: 2223-7747; 2223-7747
• DOI: 10.3390/plants12132490

Cassava ( Crantz) is an important root crop worldwide. It is adapted to a wide range of environmental conditions, exhibiting differential genotypic responses to varying environmental conditions. The objectives of this study were: (1) to examine the effect of genotype, environment and genotype × environment interaction (GEI) on fresh root yield (FRY) and dry matter content (DMC); and (2) to identify superior genotypes that exhibit high performance for the traits of interest using the genetic tools of additive main effects and multiplicative interaction (AMMI) and genotype stability index (GSI) analysis. Eleven cassava genotypes were evaluated in a randomized complete block design at six trial sites in South Africa. The combined analysis of variance based on AMMI revealed significant genotype, environment and GEI for the traits. The percentage variation due to GEI was higher than the percentage variation due to genotype for FRY, reflecting differential genotypic responses across the experimental sites. The proportion of variance due to genotype variation was larger for DMC. Genotype stability index (GSI) showed that UKF3 (G6), 98/0002 (G2) and P4/10 (G5) were the highest yielding and most stable genotypes for FRY, and 98/0002 (G1), UKF3 (G6) and UKF9 (G11) were the highest yielding and most stable genotypes for DMC. Cultivars 98/0002 and UKF3 were identified as providing high stability with superior fresh root yield and DMC. These genotypes could be recommended to farmers for food, feed and industrial applications without the need for further breeding. The AMMI-2 model clustered the testing environments into three mega-environments based on the winning genotypes for FRY and DMC. Mabuyeni (KwaZulu-Natal), Shatale (Mpumalanga) and Mandlakazi (Limpopo) would be the best testing sites in future cassava-genotype evaluation and breeding programs. This study provides a baseline for a future study on the GEI of cassava varieties, using a larger set of genotypes, factoring in seasonal variation.