Parametric and Non-parametric Procedures for Identifying Stable and Adapted Tropical Maize Genotypes in NLB Disease Infested Environments

Abstract

Multi-locational trials are critical for establishing stable and adaptable genotypes across different geographic areas prior to considering commercial release. The stability and adaptation of 20 tropical maize hybrids in environments infected with Northern leaf blight disease were assessed using 12 parametric and 14 nonparametric parameters across five environments. The purpose of this research is to estimate the genotype-environment interaction (GEI) for grain yield in selected maize genotypes and to identify associated stability factors to aid in the rationalization of stability analysis in Multi-Environment Trial (MET) data used in breeding programs. Except for De Kroon and Van der Laan (1981), both the combined ANOVA and nonparametric tests of GEI showed significant differences across hybrids, as well as significant crossover and non-crossover interactions. This suggests differential genotypes responses to the test environments. Spearman correlation analysis revealed significant differences between many nonparametric and parametric parameters, indicating that the two may be utilized interchangeably. Additionally, the correlation matrix and principal component analysis results from parametric and nonparametric parameters demonstrated their potential to assess the responses of maize genotypes to changing environments. G13 and G20 appeared most phenotypically stable with associated high mean yield based on the high values expressed by most parametric and nonparametric parameters.

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“…In breeding and agrobiological contexts, one of the primary ways to differentiate the plant genotypes is assessing their yield stability and adaptability (Ohunakin et al, 2021). Yield stability is a complex indicator of genotype's Assoc.…”

“…The parametric stability statistics employ univariate and multivariate approaches that are based on statistical assumptions about the distribution of genotypic, environmental, and GEI effects. The nonparametric approaches, on the other hand, are estimated based on the mean values of the response trait and the ranking of genotypes (Ohunakin et al, 2021;Pour-Aboughadareh et al, 2022;Wodebo et al, 2023). The genotypes that have consistent rankings across different environments are considered stable.…”