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journal1 ›› 2019, Vol. 35 ›› Issue (1): 112-119.DOI: 10.16409/j.cnki.2095-039x.2019.01.016

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Screening of Hypovirulent Strains and Optimization of Induction Condition for Its Cross-Protection against Verticillium Wilt on Sunflower

ZHAO Yingjie, WANG Dong, ZHAO Xin, ZHAO Jun, JING Lan, ZHOU Hongyou   

  1. Engineering and Technological Research Center of Crop Protection in Cold and Dry Region of Inner Mongolia/College of Agricultural, Inner Mongolia Agricultural University, Hohhot 010019, China
  • Received:2018-03-26 Online:2019-02-08 Published:2019-01-31

Abstract: Sunflower Verticillium wilt is one of soil-borne diseases which are difficult to control. In this study, a hypovirulent strain Vn-1 of Gibellulopsis nigrescens. was screened and obtained by virulence index and disease index evaluation. It was the first time to clarify that strain Vn-1 can induce the cross-protection against sunflower Verticillium wilt. In order to find the best conditions for cross-protection of strain Vn-1, interval days and induced concentration were optimized. Under the optimal conditions, it was conducted to test the persistence of the cross-protection and its effect on sunflower growth. The results showed that the optimized condition was 5 d as interval days and 1×106 cfu/mL as induced concentration. Under the optimized condition, the highest control efficacy of strain Vn-1 against sunflower Verticillium wilt reached up to 72.27%, and the efficacy could maintain over 30% after 44 days by challenge inoculation. Under the optimal condition, plant height and root length of the sunflower were significantly improved, indicating that strain Vn-1 can reduce the inhibitory effect of virulent strains on the growth of sunflower plants.

Key words: hypovirulent strains, cross-protection, sunflower Verticillium wilt, induce

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