| The disease of Fusariu Root Rot is one of the common diseasesthat occurred in pepper production and many areas of domestic and international, and which directly affects the yield and quality of pepper, and also causes serious economic losses. In recent years, the increasing of pepper cultivation area in Gansu province plays asignificant role in agriculture production and farmers’ incomeincreasing. However, with the enlargement of pepper cultivation area in greenhouse and the increasing of multi-croppingindex in field, the disease of Fusarium Root Rot wasseverelythreatened to the pepper production. Therefore, the present study was to identify the species of pathogens responsible for Fusarium Root Rot disease, which was regarded as the research basis; and to determine the pathogenicity differencein pathogens of Fusarium Root Rot; and to screenthedisease of Fusarium Root Rotresistance germplasm resources, which provided a vital theoretical basis for disease resistance breeding, and formulated a scientific and effective disease managementmeasures in field. The main results are as follows:1. Fusarium Root Rot on pepper was the most common and potaentially the serious disease of greenhouse pepper in Gansu, China. The disease usually scattered wilt in the field. The most severe cases occured total peppers could died. The commonly primary symptom in field was slightly wilting of leaf, the plant growed slowly. As the disease developing, the overground stems and leaves wilted and yellowed gradually, with most of them lodging and dying. Sometime there was the pink colour of mycelium and sporodochia visible at basal stem. The roots rotted and had few and breakable fibrils. In the cases of seriousness, water-soak and rotappeared on basal stems and roots. When infection occured in seedling, the lesions become water-soaked and flaccid, the collapse and wither. The seedlings falled over.2. Pathogens were isolated by using tissue isolation techniques, and were identified based on morphological characters and TEF sequence analysis after pathogenicity tests. Four Fusarium species could cause Fusarium root rot of pepper in Gansu, China. They were Fusarium solani, F. oxysporum, F. semitectum and F. verticillioides. A total of 125 single-spore-culture were obtained of which, 65 cultures were identified as F. solani, 48 cultures identified as F. oxysporum, 7cultures being F. semitectum and 5 cultures being F. verticillioides. All four Fusarium species could cause root rot of pepper by pathogenicity test. F. solani and F. oxysporum were dominant pathogens, with isolation frequency eing 52.0% and 38.4%, respectively. And this is the first report that F. semitectum and F. verticillioides could also cause pepper root rot.3.The pathogenicity of pathogens were determined by improve culture plate method in order to explore their difference, results indicated that incidenceof four Fusarium species all beyond 95.00%, disease index ranged from 60 to 70. Pathogenicity differences among the four species were not definite. While beteen the strains of F. oxysporum and F. solani were obvious. GS45-2 and GS3-4, with disease index reaching 67.22 and 63.33, but GS28-9and GS5-1were 35.56 and 36.11. Among the strains of F. solani, GS45-3 and GS46-2 disease index were 66.67 and 63.34, respectively. GS46-2. 45-8-1was 15.56.4. Resistance of 21 varieties of pepper large-sized planted in Gansu province were scanningto pepper Fusarium root rot, results indicated that there was no immune variety. There were14 resistant varietyto F. oxysporum. 14 varieties were found to be resistant to F. solan, the of the 11 varieties were resistance to F. semitectum. Hangjiao8, Longjiao8, Jinfu, Lacui12 and Jimei118 showed resistant to most of pathogenic bacteria, while Hangjiao5, Jinjiao1, Dayingxiong etal showed susceptible or extreme susceptible to them. The resistance of other tested varieties to diverse pathogenic bacteria was not completely the same. |
PDF Full Text Request