| Summary: | 碩士 === 國立臺灣大學 === 植物醫學碩士學位學程 === 105 === Strawberry (Fragaria x ananassa Duchesne) is an economically important herbaceous plant belonging to family Rosaceae, and seedling production is usually the limiting factor during strawberry cultivation. In Taiwan, the annual seedling demand could be up to 25 million. Currently, strawberry seedlings are mainly propagated with runners (stolons) from healthy mother plants, and the biggest bottleneck is how to screen for healthy seedlings and disease management in the nurseries. According to the survey, the high replanting rate in the field is mainly due to latent infection of seedings by Colletotrichum gloeosporioides and Fusarium oxysporum f. sp. fragariae (Fof). If latent infection can be prevented effectively, disease severity in the field can be controlled better. In addition to propagating seedlings from healthy mother plants, raising seedlings from or directly utilizing micropropagated strawberry plants should increase opportunities to obtain healthy seedlings. However, transplantation of micropropagated seedlings without proper hardening procedures into the field usually leads to problems, such as poor growth and yield, and such seedlings are usually pricy, so the farmers dislike to use micropropagted seedlings. Piriformospora indica is a root endophytic fungus isolated in India with characteristics of wide host range and ability to promote plant growth and enhance plant tolerance to various stresses. In this study, I attempted to promote strawberry growth and tolerance to biotic stresses by biohardening of micropropagated strawberry with P. indica. Hopefully, an alternative mean for cultivation of healthy seedlings could be provided in the future. The results showed that no matter media, root soaking or drenching inoculation method was used, the longer the treatment, the higher the inoculation and the root colonization rates. Compared to the control group, inoculation of P. indica by root soaking for 1 and 3 days can increase the biomass of tissue culture seedlings and these treatments resulted in the highest seedling vigor index among all the groups. After root soaking in 1×105 spores/mL P. indica for 3 days and biohardening for one month, the strawberry seedlings were inoculated with 104 spores/mL C. gloeosporioides. Significant lower disease severity can be observed in P. indica-treated plants compared to the water-treated control 9 days after pathogen inoculation. Inoculation of 106 spores/mL Fof, disease severity of the P. indica-treated group was similar to the control group. In conclusion, P. indica treatment can increase biomass of micropropagated strawberry and its tolerance to anthranose but not Fusarium wilt of strawberry.
|
|---|
