World Vegetable Center

About: World Vegetable Center is a nonprofit organization based out in Tainan City, Taiwan. It is known for research contribution in the topics: Population & Agriculture. The organization has 294 authors who have published 364 publications receiving 8785 citations. The organization is also known as: AVRDC, Asian Vegetable Research and Development Center.

Application of a Preliminary Screen to Select Locally Adapted Resistant Rootstock and Soil Amendment for Integrated Management of Tomato Bacterial Wilt in Taiwan

Abstract: Host plant resistance and soil amendment (SA) have not been used extensively to manage tomato bacterial wilt caused by Ralstonia solanacearum due to their variable effects over locations. A preliminary screen was developed to increase the chances of identifying successful control measures under diverse conditions. Isolates from three production areas in Taiwan were collected and their virulence evaluated on tomato. Soil samples from four field sites were collected to evaluate ability to suppress the pathogen of SAs consisting of urea or slaked lime alone or combined at 30°C. The mixture of urea and slaked lime showed the best suppressive effect in three tested soils and was used in subsequent field experiments. Resistant eggplant (EG203) and tomato (Hawaii 7996) rootstocks, selected based on stable resistance against representative strains at the seedling stage, significantly reduced disease incidence in field experiments. EG203 grafted plants exhibited 0 to 2.8% wilted plants compared with 24.4 to 92.9% wilted nongrafted plants. Integrated use of Hawaii 7996 as the rootstock and SA provided significantly greater control of wilt than use of Hawaii 7996 as rootstock alone in only one of the four locations, whereas SA did not provide significant control effect when EG203 was used as the rootstock.

Molecular characterization of the CP gene and 3′UTR of Chilli veinal mottle virus from South and Southeast Asia

Abstract: Twenty-four isolates of Chilli veinal mottle virus (ChiVMV) from China, India, Indonesia, Taiwan and Thailand were analysed to determine their genetic relatedness. Pathogenicity of virus isolates was confirmed by induction of systemic mosaic and/or necrotic ringspot symptoms on Capsicum annuum after mechanical inoculation. The 3′ terminal sequences of the viral genomic RNA were determined. The coat protein (CP) coding regions ranged from 858 to 864 nucleotides and the 3′ untranslated regions (3′UTR) from 275 to 289 nucleotides in length. All isolates had the inverted repeat sequence GUGGNNNCCAC in the 3′UTR. The DAG motif, conserved in aphid-transmitted potyviruses, was observed in all isolates. All 24 isolates were considered as belonging to ChiVMV because of their high CP amino acid and nucleotide identity (more than 94·8 and 89·5%, respectively) with the reported ChiVMV isolates including the pepper vein banding virus (PVBV), the chilli vein-banding mottle virus (CVbMV) and the CVbMV Chiengmai isolate (CVbMV-CM1). Based on phylogenetic analysis, ChiVMV isolates including all 24 isolates tested, PVBV, CVbMV and CVbMV-CM1 can be classified into three groups. In addition, a conserved region of 204 amino acids with more than 90·2% identity was identified in the C terminal of the CP gene of ChiVMV and Pepper veinal mottle virus (PVMV), and may explain the serological cross reaction between these two viruses. The conserved region may also provide useful information for developing transgenic resistance to both ChiVMV and PVMV.