| Broomcorn millet(Panicum miliaceum L.) is the crop with characteristics in arid and semi-arid areas of the northwest China; it has an important and irreplaceable position in the western industrial development of agriculture and crop structure adjustment. Its grain is nutritious, and the traditional Chinese herbal drug. With health effects and medicinal value, broomcorn millet has great potential in the development of modern functional foods. Smut is an important disease in the production of broomcorn millet, causing serious damage to the yields and quality, therefore the study to smut, the election and cultivation of anti-smut varieties, the research of smut pathogenesis and control techniques are very important to improve the yield and quality of broomcorn millet.In this study, 397 broomcorn millet germplasm introduced from abroad and collected home in recent years were used as the test material, field experiments and laboratory analyzes were combined as the research method, smut resistance identification, effect of pesticides on the growth of smut fungi and broomcorn millet, analysis of physiological indexes, such as leaf protective enzymes and non-enzymatic substances were carried out, the main conclusions are as follows:(1) Saturated seed inoculation method could infect broomcorn millet effectively, results of two years’ identification showed that of all varieties, susceptible varieties were more than disease-resistant varieties, and in particular, there were only small number of varieties with high resistance. The incidence of species from different parts of the distribution are not the same, most of the varieties from Shanxi were susceptible varieties, only 1.19 percent were high resistant varieties, but Shaanxi have the highest percentage of high resistant varieties, accounting for 55.56%. According to the correlation analysis, agronomic traits and disease resistance had no clear correlation.(2) Six kinds of pesticides were evaluated from two aspects of pathogens and host comprehensively. Each pesticide within a certain range of concentration could play a certain extent of inhibition to smut pathogen, which the comprehensive evaluation of tebuconazole had the most significant effect. But drug treatment also inhibited the germination and growth of broomcorn millet seed, and had impacts on a lot of agronomic traits during the growth period. Although there was no significant difference between the various pesticides and control checks, there was still need to pay attention when carrying out spraying in production.(3) After infection with smut, the activity of SOD, POD and PAL in the protective enzyme system changed significantly correlated with disease resistance. SOD responded rapidly in the early course, and PAL played its role in the late growing period. POD activity had different trend in varieties with different resistance levels. Resistant varieties could inhibit the accumulation of membrane lipid peroxidation products MDA in the early course and soluble protein content in the medium-term growth of resistant varieties had increased, but there was no significant correlation with the resistance.In the early course of the disease, key enzymes in the AsA-GSH cycle, only APX had fast response, and GR played a major role in the susceptible varieties, the content of AsA and GSH also had a significant correlation with the resistance level in filling stage. Two pathogenesis-related proteins, β-1,3-glucanase and chitinase were co-regulated to play their biggest role in the three-leaf stage and filling stage. There was a significant correlation between disease resistance and total soluble sugar content, but no clear relationship with reducing sugar content. Except the content of soluble protein and reducing sugar, the rest of the indicators at different growth stages was significantly correlated with the resistance of broomcorn millet. These indicators could be used to identify the resistance of broomcorn millet, at early growth stage they could help to determine varieties resistance, lay the foundation for breeding and to accelerate the breeding process. |
