Genotype by year interaction and additive and epistasis gene effects for Fusarium stalk rot resistance in doubled haploid lines of maize (Zea mays L.)

Fusarium stalk rot is the main factor reducing the quality of maize grain and leads to significant yield losses, which that ranges from 20 to 100%, depending on the degree of infection and weather conditions. Understanding its genetic mechanism is key to improving grain quality and ultimate yield. An experiment with 26 doubled haploid (DH) lines of maize was conducted in the northern part of the Lower Silesia Province in Poland over a ten-year period (2013-2022). The study assessed resistance to Fusarium stalk rot. The objectives were to evaluate genotype-year interactions for resistance to Fusarium stalk rot in maize DH lines using the additive main effects and multiplicative interaction (AMMI) model, to select DH lines that are stable across all years of testing and specific to particular environmental conditions, and to estimate additive and epistatic effects. AMMI results demonstrated a significant effect of genotype, year, and their interaction on Fusarium stalk rot resistance. The KN16 line is recommended for inclusion in further research within the breeding program due to its excellent stability and high average resistance to Fusarium stalk rot. Estimates of additive gene action effects were statistically significant in each year of the study. Estimates of epistasis (total additive by additive interaction) effects for Fusarium stalk rot resistance were also statistically significant in all ten years of the study. Only in 2013 was the epistasis effect positive (0.168). These results indicate that achieving biological advances in resistance to Fusarium stalk rot should be an important focus of ongoing maize breeding programs.