核盘菌子囊孢子萌发、释放规律及对向日葵的致病力OA

This study aimed to clarify the germination and release rules of Sclerotinia sclerotiorum ascospores and pathogenicity of different flowering period to sunflower,SH363 was used as the tested sunflower variety.The number of ascospores released by the ascospores of Sclerotinia sclerotiorum at different time in the same day and different humiditys,as well as the length of the germ tubes germinated by ascospores at different temperatures,were investigated.The sunflower discs at different flowering periods were inoculated to investigate the disease index and yield.The results showed that from different times in the same day,the time of ascospore release from the ascus was 7:30-19:30 in the same day,and the release peak was at 14:00-15:00.From the perspective of culture humidity,the ascospores released by the ascus disc under the condition of wet first and then dry were the most,which was significantly higher than under other humidity treatments.From the perspective of culture temperature,the length of the germ tube germinated by ascospores at 25℃ was significantly higher than that at other temperatures treatments,and the length of germ tube increased gradually with the increase of time and temperature.From the perspective of inoculation flowering periods,the infection effect of Sclerotinia sclerotiorum ascospores in sunflower R5.1—R5.2 period(The proportion of tubular flowers is less than 20%)was the best,the disease index was 97.92,and the yield was 517.20 kg/ha,which was 84.26%lower than that of normally growing sunflower.The infection effect of inoculation in R5.3—R5.5 period(Tubular flowers account for 21%to 50%)and R5.6-R5.8 period(Tubular flowers account for 51%to 80%)were inferior,the disease index were 85.42 and 27.08 respectively,and the yield were 1 008.15 and 2 257.05 kg/ha respectively,which were 69.32%and 31.33%lower than that of normally growing sunflower.The infection effect of inoculation in R5.8+period(The proportion of tubular flowers is over than 80%)was almost not infected,and there was no significant difference in the yield of sunflower compared with normally growing.The research results provide theoretical references and data support for the prevention and control of sunflower sclerotinia.