1.Institute of Crop Sciences, Chinese Academy of Agricultural Sciences / National Key Facility for Crop Gene Resources and Genetic Improvement;2.Institute of Plant Protection, Gansu Academy of Agricultural Sciences;3.Maize Research Institute, Shanxi Agricultural University
The Project of Sanya Yazhou Bay Science and Technology City (SKJC-2020-02-001)；Agricultural Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences, Project for Storing Corn in Science and Technology
Ear rot is one of the most devastating diseases in maize production in China, which seriously affects the yield and quality of maize and threatens the health of humans and animals. Breeding and using excellent ear rot resistant varieties is the most economical and effective measure to prevent and control maize ear rot. Using silk channel inoculation, 346 maize inbred lines at home and abroad were identified and evaluated for resistance to Fusarium ear rot (FER) and Gibberella ear rot (GER) (caused by Fusarium verticillioides and F. graminearum, respectively) at two sites in Changping, Beijing and Sanya, Hainan. A comprehensive analysis of the data from the two sites showed that there were 1, 43, 106, 147 and 49 accessions exhibiting high resistance (HR), resistance (R), moderate resistance (MR), susceptibility (S), and high susceptibility (HS) to FER, accounting for 0.3%, 12.4%, 30.6%, 42.5%, and 14.2% of the total 346 materials, respectively, and there were 10, 32, 55, 79, and 170 accessions exhibiting HR, R, MR, S, and HS to GER, accounting for 2.9%, 9.3%, 15.9%, 22.8%, and 49.1% of the total 346 materials, respectively. Forty-one maize inbred lines exhibited HR, R, or MR to both FER and GER. Among them, line 15-TL-1224 exhibited HR to both FER and GER, lines T351-1 and 18-QTL-25 exhibited HR to GER and R to FER, and 3 lines exhibited R to both FER and GER, which were all precious resources resistant to ear rot. The correlation analysis of FER and GER resistance among the above 41 resistant accessions and 144 susceptible germplasms was conducted. The correlation coefficient between FER and GER resistance among the 41 resistant accessions was 0.24, while that among the 144 susceptible germplasms was -0.16. Using 40 pairs of polymorphic SSR primers, 183 alleles (Na) were amplified in the 41 resistant lines, with polymorphic site percentage (PPB) of 100.00%. The average number of alleles (Na), effective allele number (Ne), Nei's gene diversity (H), and Shannon's information index (I) were 3.7556, 7.6923, 0.6596, and 1.4458, respectively. The average polymorphic information content (PIC) was 0.326, varying from 0.0513 to 1.0000 for each marker. Using UPGMA cluster analysis, the 41 resistant accessions were divided into 7 subgroups, namely PB, Lan, unknown, PA, LRC, BSSS, and TSPT, which exhibited high genetic diversity among the 41 inbred lines. The PA subgroup contained the most numerous resistant germplasms. The results would provide guidance and reference for the selection and utilization of resistance sources in breeding.