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.

Effects of botanical extracts and formulations against fruit fly, fruit and pod borers on tomato and yard-long bean

Abstract: Seed kernel extracts of China berry (Melia azedarach) against oriental fruit fly (Bactrocera dorsalis) and tomato fruit borer (Helicoverpa armigera), and commercial neem formulations containing azadirachtin (Biofree-I® and Thai neem 111®) against the legume pod borer (Maruca vitrata) were tested in Taiwan and Thailand to confirm their effects on oviposition, feeding, growth and development. Various extracts from M. azedarach seed kernels significantly reduced the oviposition of B. dorsalis and the efficacy was similar to Biofree-I®. The green drupe and dry seed kernel extracts of M. azedarach substantially increased larval mortality, and reduced successful pupation, pupal weight, adult emergence, fecundity and egg hatch of H. armigera larvae. Commercial neem formulations exhibited adverse morphogenic effects on various biological parameters of M. vitrata, but they did not reduce oviposition and egg hatch. M. azedarach extracts and commercial neem formulations can be employed together for the sustainable m...

Molecular Characterization of a Begomovirus Associated with Tomato Leaf Curl Disease in Uganda.

Abstract: During the summer of 2003, leaf curl symptoms were observed in tomato (Lycopersicon esculentum) plantings in the Iganga District of Uganda. Begomoviral infection was suspected. Twelve symptomatic samples were collected. Begomoviral DNA was extracted and amplified using polymerase chain reaction (PCR) with the begomovirus-specific degenerate primer pair PAL1v1978/PAR1c715 (4). The expected 1.4-kb PCR products were obtained from 11 of 12 samples. The 1.4-kb PCR product of one of the samples was cloned and sequenced. Based on the sequence of the 1.4-kb DNA product, specific primers were designed to complete the DNA-A sequence. The DNA-A consisted of 2,747 nucleotides (GenBank Accession No. DQ127170) and was found to contain seven predicted open reading frames (ORFs V1, V2, C1, C2, C3, C4, and C5). A BLAST analysis was conducted with geminivirus sequences available in the GenBank database at the National Center for Biotechnology Information (Bethesda, MD), and MegAlign (DNASTAR, Inc, Madison, WI) software was used for further comparisons. The DNA-A sequence of the virus associated with leaf curl of tomato from Uganda showed less than 79% sequence identity with cassava mosaic viruses from Uganda (GenBank/EMBL Accession Nos. AF126800, AF126802, AF126804, AF126806, and Z83257), the only begomoviruses from the country so far in the public domain. Highest sequence identity (83%) was with Tomato leaf curl Mayotte virus from Dembeni, Mayotte, Comoros Islands (ToLCYTV-[Dem], EMBL Accession No. AJ865341). Pairwise comparison with ToLCYTV-[Dem] showed 60, 88, 91, 82, 84, 86, and 80% sequence identities in the intergenic region, V2, V1, C1, C2, C3, and C4 ORFs, respectively. Only low sequence identities (ranging from 71 to 82%) were obtained with other tomato bego-moviruses reported from Africa (GenBank/EMBL Accession Nos. AF261885, AJ865337-AJ865340, AY044137-AY044139, AY502934, AY502936, AY594174, AY736854, and U73498). There was no evidence for the presence of DNA-B or DNA-beta using PCR with the DNA-B specific primer pairs DNABLC1/DNABLV2 and DNABLC2/DNABLV2 (2) and the DNA-beta primer pair Beta01/Beta02 (1), respectively. Detection of possible recombination was by RDP2 software (3) using DNA-A sequences of begomoviruses from Uganda and tomato begomoviruses from Africa. The DNA-A was found to contain a small recombinant fragment from ToLCYTV-[Dem] in the 411 to 969 nucleotide position with 92% sequence identity. Based on DNA-A sequence comparisons, the tomato leaf curl virus from Uganda most likely constitutes a distinct new begomovirus. References: (1) R. W. Briddon et al. Mol. Biotechnol. 20:315, 2002. (2) S. K. Green et al. Plant Dis. 85:1286, 2001. (3) D. P. Martin et al. Bioinformatics 21:260, 2005. (4) M. R. Rojas et al. Plant Dis.77:340, 1993.

Evaluation of the Ph‐3 gene‐specific marker developed for marker‐assisted selection of late blight‐resistant tomato

Abstract: Late blight caused by Phytophthora infestans is one of the most destructive diseases of tomato (Solanum lycopersicum L.) that mainly occurs in cool and wet environments. With the spread of the A2 mating type and new clonal lineages, fewer fungicides provide effective control of the disease, which has increased its worldwide threat. Host resistance could contribute significantly to sustainable disease control. Ph-3 is a race-specific late blight resistance gene commonly used in commercial tomato breeding. Availability of precise and easy to use gene-based markers would facilitate selection. In this study, a Ph-3 on-gene cleaved amplified polymorphic sequence (CAPS) marker, Ph3.gsm/HincII, was developed based on the published gene sequence of Ph-3. The effectiveness of the marker was evaluated along with other published Ph-3 markers using an F9 recombinant inbred line (RIL) population derived from NC 23E-2(93) × L3708. Markers Ph3.gsm/HincII and TG328/BstNI accurately genotyped the RIL population for Ph-3. In addition, Ph3.gsm/HincII was able to differentiate variable susceptible alleles. This reliable codominant DNA marker would be very useful in marker-assisted selection, particularly for resistance gene pyramiding.