关键词: 茎腐病, 抑菌, 促生作用, 成膜剂, 生物种衣剂

Abstract: Corn stalk rot is a soil borne disease commonly coourring in corn production areas of the world, and it is also one of the main diseases in corn production areas of China. In order to screen suitable antagonistic bacteria of corn stalk rot pathogen and study the effect of seed coating agent on corn growth, the antagonistic strains of corn stalk rot pathogen were screened by plate confrontation test, and the strains with potential to promote corn seed growth were further screened by measuring two physiological indexes of iron carrier and indoleacetic acid, and the screened strains were used as the activity of microbial seed coating agent. The effects of different proportion of film-forming agent on seed germination, seedling growth and strain activity of maize were studied. In this study, 5 strains of bacteria and 1 strain of Trichoderma were found to inhibit the pathogen of corn stalk rot by plate confrontation test. By further physiological indexes, 6 strains of Bacillus with potential to promote the growth of corn seeds and the ability to produce IAA and iron carriers were obtained. TXM-1 (Bacillus velezensis) and TXM-2 (Bacillus amyloliquefaciens) were selected as the active components of biological seed coating agents based on the functions of bacteria inhibition and the growth promotion. The germinating test of corn seed showed that BSCA-1 and BSCA-2 had the functions of antagonizing pathogen and promoting the growth of corn seedling. Their formulations were as follows: TXM-1 and TXM-2 as active components, sodium alginate and polyvinyl alcohol as film-forming agents, bentonite and benzophenone as additives, respectively. The best mixing ratio of the two film formers was 1∶9, which could not only promote the growth of corn, but also delay the decline rate of the activity of the film formers. The results showed that the biological seed coating agent based on two kinds of Bacillus could not only antagonize the pathogen of corn stalk rot, but also promote the growth of corn seedling, which revealed its potential to replace the chemical seed coating agent in corn planting.

Key words: corn stalk rot, antibacterial activity, promoting effect, film-forming agents, biological seed coating agent