Tolerance to Fusarium verticillioides infection and fumonisin accumulation in maize F₁ hybrids and subsequent F₂ populations

Abstract

Fusarium verticillioides causes Fusarium ear rot (FER) in maize (Zea mays L.), thus reducing grain quality, yield, and contaminates grains with fumonisins. Grain infection by these fungi occurs before harvest and selection of parental lines resistant to fumonisin accumulation for breeding purposes is the most effective and environmentally friendly control strategy for F. verticillioides. This study intended to evaluate F1 hybrids and F2 breeding populations in Kenya for improved resistance to FER and fumonisin contamination. Trials were artificially inoculated and FER severity, F. verticillioides accumulation, and fumonisin contamination were determined. Inheritance of resistance was also determined in the F1 hybrids. CML444 × MIRTC5, R119W × CKL05015, and CML444 × CKL05015 exhibited little to no FER and had the least fungal and fumonisin contamination, respectively. Inbred lines CML495, CKL05015, and P502 had negative, significant general combining ability (GCA) estimates for F. verticillioides colonization and fumonisin contamination, but positive, significant GCA estimates for 1,000‐kernel weight, respectively. The genotype × environment interaction was the main source of variation observed in the F2 populations with R119W × CKL05015 and CML444 × CKL05015 being the most tolerant to fungal and fumonisin contamination in Kiboko and MIRTC5 × CML495 the most tolerant in Katumani.

Inheritance of resistance to Fusarium verticillioides ear rot in maize inbred lines of southern, West and Central Africa origin

“…In terms of gene effects, this was similar to the findings by Ouko et al. (2020) who found additive and nonadditive gene effects to be almost equally important for resistance to fumonisins. There was a contradiction in terms of maternal effects, as they found no significant maternal effects.…”

“…Ouko et al. (2020) found both nonadditive and additive gene effects playing a significant role in the inheritance of resistance to aflatoxins caused by A. flavus . Walker and White (2001) attributed resistance to A. flavus infection to additive gene effects, while nonadditive gene effects were associated with resistance to aflatoxin production.…”

Comprehensive diallel analysis of combining ability and heterosis to Fusarium verticillioides ear rot resistance in maize

“…If the GCA effect is significant but the SCA effect is not, only GCA can predict offspring performance (Gilbert, 1958). Some studies have indicated that FER resistance is promoted by dominant effects (Clements et al., 2004), whereas others have indicated that it results from a combination of additive and dominant effects (Hung & Holland, 2012; Nankam & Pataky, 1996; Ouko et al., 2020; Tembo et al., 2022). Given that previous studies have shown no significant maternal effects in the inheritance of FER resistance (Netshifhefhe et al., 2018; Pereira et al., 2017; Schwantes et al., 2017), we performed a genetic analysis using half‐diallel crosses.…”

“…Previous results have indicated a moderate to high correlation between inbred lines and their hybrids (Butoto et al, 2021;Löffler et al, 2011;Ouko et al, 2020). If both parents have high resistance, their hybrid will exhibit high resistance; conversely, if both parents are highly susceptible, their hybrid will also likely be highly susceptible.…”

“…Maize ear rot resistance results from both additive and dominance effects (Boling & Grogan, 1965; Löffler et al., 2011; Tembo et al., 2022). Although some studies have reported additive × dominance or dominance × dominance digenic interaction effects (Nankam & Pataky, 1996), both parents should possess resistance alleles to obtain highly resistant hybrids (Hung & Holland, 2012; Netshifhefhe et al., 2018; Ouko et al., 2020). Considering the high correlation between FER and fumonisin content, the GCA has the greatest influence on fumonisin content in maize (Butrón et al., 2006).…”