Effects of Trichoderma-Induced Suppressive Soil on Fusarium Wilt of Tomato
Twenty-two isolates of Fusarium spp. were isolated from stems and roots of tomato plants showing symptoms of foliar wilting and brown discoloration of the vascular systems. Differentiation of the isolates based on cultural and morphological characteristics had identified twelve isolates of F. oxy...
Saved in:
| Main Author: | |
|---|---|
| Format: | Thesis |
| Language: | English English |
| Published: |
2005
|
| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/6201/1/FP_2005_21.pdf http://psasir.upm.edu.my/id/eprint/6201/ |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Institution: | Universiti Putra Malaysia |
| Language: | English English |
| Summary: | Twenty-two isolates of Fusarium spp. were isolated from stems and roots of
tomato plants showing symptoms of foliar wilting and brown discoloration of the
vascular systems. Differentiation of the isolates based on cultural and
morphological characteristics had identified twelve isolates of F. oxysporum, six
isolates of F. solani, two isolates of F. moniliforme, one isolate of F.
chlamydosporum and one isolate of F. lateritium. However, the colonies of
Fusarium oxysporum f. sp. lycopersici (FOL) appearance are not easy to
distinguish from those of the non-pathogenic F. oxysporum even though they
can be differentiated from other species. Species aggregates of Fusarium were
further distinguished based on the DNA polymorphism. Twenty 10-mer primers
were used in the initial screening of the fungal DNA and three (OPC-11, OPC-15
and OPC-18) were selected. Based on UPGMA clustering, two main clusters
were defined. F. oxyspomm were grouped in Cluster I and F. solani were
grouped in Cluster II. The other isolates of F. moniliforme, F. chlamydosporum
and F. lateritium were distinctly isolated from these two main clusters.
Pathogenicity testing was carried out on tomato cultivars Baccarat 322 and
Cherry to further confirmed the differentiation between FOL and other forms of
F. oxysporum. Isolate MI produced symptoms of Fusarium wilt on Baccarat 322
and Cherry, and therefore identified as Fusarium oxysporum f. sp. lycopersici
(FOL). However, percentage of disease incidence was higher on Baccarat 322
variety (65.55%) compared to Cherry (29.44%). Histopathological studies of
infected stems of tomato inoculated by isolate MI further confirmed the
presence of fungal mass in the xylem vessels. Tomato plants with Trichodermainduced
suppressive soil (UPM 40 and UPM 23) individually and as mixture
(UPM 2340) gave increased in plant height, fresh weight and dry weight of leaf
and root, early flower initiation and increase in yield compared to control.
Disease incidence of Fusarium wilt was significantly lower at week 12 (12%)
when treated with UPM 2340, followed by UPM 40 (21%), UPM 23 (29.5%) and
compost alone (59.5%). Control gave the highest value of disease incidence of
100% at week 12. The experiment carried out in this study indicated that
treatments with UPM 2340, UPM 40 and UPM 23 improved vigor of tomato
plants and was effective in inducing suppressiveness against Fusarium wilt
development, suggesting their potential role as biological control in the
management of Fusarium wilt. |
|---|