A large-scale screening of maize germplasm for resistance to multiple diseases in multi-plot demonstration for several years under natural condition

Abstract

<p indent=0mm>Disease is a major factor affecting maize production. The utilization of resistant cultivars is the most economical, safe, and effective method for controlling maize diseases. This research was finally conducted using 2000 maize germplasm accessions with extensive sources and rich genetic background to identify and evaluate the resistance to multiple diseases in multi-plot demonstration for several years under natural condition during 2016–2019. Nine diseases, including southern corn leaf blight, stalk rot, common smut, <italic>Curvularia</italic> leaf spot, southern rust, maize rough dwarf, northern corn leaf blight, gray leaf spot and head smut were investigated and evaluated in non-inoculated fields. The experimental data at 10 different sites from 2016 to 2019 showed that resistance identification under natural conditions was sensitive to environmental factors, with distinct differences among years and regions. The incidence of southern corn leaf blight was severe at multiple sites over these years and 11 maize accessions with stable resistance were screened out. Stalk rot, northern corn leaf blight, and gray leaf spot were relatively serious at several sites in four years, and 440, 356, and 423 resistant germplasm were screened out from 2000 accessions, respectively. These integrated data had considerable reference values. Curvularia leaf spot, common smut, and maize rough dwarf occurred heavily at only one plot while southern rust and head smut were not serious at all experimental sites, which should be studied further more. All in all, some maize germplasm resources with stable resistance to diverse diseases under different environments were screened out, such as JN15, 953, Shen 977, 68122, K21, SC24-1, 17MC7211, 17MC7223, Zheng 591, 161191, and so on. These results provide a significant reference for utilization and selection of germplasm for further precise inoculated identification.