Partial Resistance of Late Wilt Disease Caused by Magnaporthiopsis maydis in Certain Egyptian Maize Hybrids

Abstract

Late wilt, triggered by Magnaporthiopsis maydis, is threatening maize productivity in temperate countries. The disease is mostly managed by genetic resistance, which is frequently exhibited partially in the field. Fifteen maize hybrids were investigated for their partial resistance to late wilt disease in two Agricultural Research Stations, Gemmeiza and Sids in the 2021 and 2022 growing seasons. Two epidemiological parameters were used to characterize this type of resistance in the examined maize hybrids at the adult plant stage: final disease incidence (FDI%) and area under disease progress curve (AUDPC). The hybrids HYTECH-TWC1100, PIONEER-SC30K9, and HYTECH-SC2031 exhibited slower disease progression (less than 7.67%) throughout the plant cycle in all trials compared with the check hybrid Boushy (above 54.63%). The genetic composition of the examined maize hybrids was responsible for more than 80% of the variability in how the hybrids responded to late wilt. In the changes of FDI (%) and AUDPC, the relative contribution of the environment (locations) was relatively low (less than 1%). Due to strong heritability estimates (up to 99%) and high values of genetic progress of more than 80% of the two parameters under the 2021 and 2022 growing seasons, the phenotypic changes were attributed to the genetic structures of the genotypes. The agronomic characteristics of the evaluated hybrids demonstrated a significant positive relationship between LWD resistance and grain yield per plant, as well as hundred kernel weight, plant height, and ear length. The principal component analysis demonstrated the significance of FDI (%) and 100 kernel weight as appropriate evidence for assessing these materials for late wilt disease.