Showing papers by "World Vegetable Center published in 2013"

Agrobiodiversity for food security, health and income

Abstract: By the year 2050, agriculture will have to provide the food and nutrition requirements of some 9 billion people. Moreover, to maintain that level of productivity indefinitely it must do so using environmentally sustainable production systems. This task will be profoundly complicated by the effects of climate change, increasing competition for water resources and loss of productive lands. Agricultural production methods will also need to recognize and accommodate ongoing rural to urban migration and address a host of economic, ecological and social concerns about the ‘high inputs/high outputs’ model of present-day industrial agriculture. At the same time, there is a need to confront the unacceptable levels of continuing food and nutrition insecurity, greatest in the emerging economy countries of Africa and Asia where poverty, rapid population growth and climate change present additional challenges and where agriculture is practiced primarily by small-scale farmers. Within this context, we here review science-based evidence arguing that diversification with greater use of highly valuable but presently under-valorised crops and species should be an essential element of any model for sustainable smallholder agriculture. The major points of these development opportunity crops are presented in four sections: agricultural farming systems, health and nutrition, environmental sustainability and prosperity of the populations. For each section, these crops and their associated indigenous knowledge are reported to bring benefits and services when integrated with food systems. In this paper, we conclude that not only a change in policy is needed to influence behaviours and practices but also strong leadership able to synergize the various initiatives and implement an action plan.

Biofortification of mungbean (Vigna radiata) as a whole food to enhance human health.

Abstract: Mungbean (Vigna radiata (L) R Wilczek var radiata) is one of the most important pulse crops grown in South, East and Southeast Asia It provides significant amounts of protein (240 g kg−1) and carbohydrate (630 g kg−1) and a range of micronutrients in diets Mungbean protein and carbohydrate are easily digestible and create less flatulence than proteins derived from other legumes In addition, mungbean is lower in phytic acid (72% of total phosphorus content) than pigeonpea (Cajanus cajan L Millsp), soybean (Glycine max L) and cereals; phytic acid is commonly found in cereal and legume crops and has a negative impact on iron and zinc bioavailability in plant-based diets Owing to its palatable taste and nutritional quality, mungbean has been used as an iron-rich whole food source for baby food The wide genetic variability of mineral concentrations (eg 003–006 g Fe kg−1, 002–004 g Zn kg−1) in mungbean indicates possibilities to improve its micronutrient content through biofortification Therefore biofortification of existing mungbean varieties has great potential for enhancing the nutritional quality of diets in South and Southeast Asia, where protein and micronutrient malnutrition are among the highest in the world This review paper discusses the importance of mungbean in agricultural production and traditional diets and the potential of enhancing the nutritional quality of mungbean through breeding and other means, including agronomic practices © 2013 Society of Chemical Industry

Nutritional Evaluation of Five African Indigenous Vegetables

Abstract: The promotion and consumption of indigenous vegetables could help mitigate food insecurity and alleviate malnutrition in developing countries. In this respect, 17 accessions (candidate breeding lines that have not yet officially been released) of five African indigenous vegetables: amaranth (Amaranthus cruentus), nightshade (Solanum scabrum), African eggplant (Solanum aethiopicum), jute mallow (Corchorus olitorius) and okra (Abelmoschus callei), previously selected for their superior agronomic and horticultural traits, were evaluated in Cameroon for minerals (Ca, Mg, K, P, Zn and Fe), proteins, and carotenoids content. Nutrient content differed significantly (P<0.001) between cultivars. Amaranth (especially line AM-NKgn) had the highest Ca, Mg, and Zn content in comparison to other genera. Nightshade had the highest K and Fe content. The highest K and Fe levels were found in nightshades BG24 and SS52, respectively. Nightshade had the highest level of protein, especially line BFS1. The highest amount of carotenoids was identified in the eggplant variety Oforiwa. The study revealed that these vegetables are important sources of some vital nutrients. Increased production and consumption of these nutrient-rich vegetables will help reduce the nutrition-related disorders in Africa.

Identification of major QTLs associated with stable resistance of tomato cultivar ‘Hawaii 7996’ to Ralstonia solanacearum

Abstract: Bacterial wilt caused by Ralstonia solanacearum is one of the most devastating diseases of tomato. Tomato cultivar ‘Hawaii 7996’ has been shown to have stable resistance against different strains under different environments. This study aimed to locate quantitative trail loci (QTLs) associated with stable resistance using 188 recombinant inbred lines (RILs) derived from ‘Hawaii 7996’ and ‘West Virginia 700.’ A new linkage map with good genome coverage was developed, mainly using simple sequence repeat markers developed from anchored bacterial artificial chromosome or scaffold sequences of tomato. The population was evaluated against phylotype I and phylotype II strains at seedling stage or in the field in Indonesia, Philippines, Taiwan, Thailand, and Reunion. Two major QTLs were identified to be associated with stable resistance. Bwr-12, located in a 2.8-cM interval of chromosome 12, controlled 17.9–56.1 % of total resistance variation. The main function of Bwr-12 was related to suppression of internal multiplication of the pathogen in the stem. This QTL was not associated with resistance against race 3-phylotype II strain. Bwr-6 on chromosome 6 explained 11.5–22.2 % of the phenotypic variation. Its location differed with phenotype datasets and was distributed along a 15.5-cM region. The RILs with the resistance allele from both Bwr-12 and Bwr-6 had the lowest disease incidence, which was significantly lower than the groups with only Bwr-12 or Bwr-6. Our studies confirmed the polygenic nature of resistance to bacterial wilt in tomato, and that stable resistance in ‘Hawaii 7996’ is mainly associated with Bwr-6 and Bwr-12.

The major quantitative trait locus for mungbean yellow mosaic Indian virus resistance is tightly linked in repulsion phase to the major bruchid resistance locus in a cross between mungbean [ Vigna radiata (L.) Wilczek] and its wild relative Vigna radiata ssp. sublobata

Abstract: Mungbean yellow mosaic Indian virus (MYMIV) and bruchid infestation are severe production constraints of mungbean in South Asia, a major global mungbean production area. Marker-assisted selection for resistance against these disorders while maintaining or even improving agronomic traits is an important step toward breeding elite mungbean varieties. This study employed recombinant inbred lines (F12) derived from a cross between MYMIV-tolerant Vigna radiata NM92 and bruchid-resistant V. radiata ssp. sublobata TC1966 to identify chromosomal locations associated with disease and insect pest resistance and seed traits. A linkage map comprising 11 linkage groups was constructed with random amplified polymorphic DNA (RAPD), sequence characterized amplified regions (SCAR), cleaved amplified polymorphic DNA (CAP), amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers. Quantitative trait loci (QTLs) for MYMIV and bruchid resistance, 100 seed weight and seed germination rate were identified. Three major QTLs for MYMIV and one major bruchid resistance locus were mapped on LG 9. The resistance alleles were contributed by the MYMIV tolerant parent NM92 and the bruchid resistant parent TC1966 respectively. One of the MYMIV QTLs was tightly linked in repulsion phase to the bruchid resistance locus. In addition, three minor QTLs for MYMIV resistance were found, where the resistance alleles were contributed by TC1966. Lines combining MYMV resistance alleles from both parents have greater resistance to MYMIV than the tolerant parent. Two minor bruchid resistance QTLs were identified in TC1966. Furthermore, three QTLs each for 100 seed weight and germination rate were detected. The markers defining the QTLs identified in this study will be useful in marker-assisted breeding of improved mungbean varieties in the future.

Mapping of QTLs in tomato line FLA456 associated with resistance to a virus causing tomato yellow leaf curl disease

Abstract: Tomato (yellow) leaf curl disease (TYLCD) is a serious threat to tomato production in the tropics and subtropics. The genetics of resistance to Tomato yellow leaf curl Thailand virus Taiwan strain (TYLCTHV-[TW]) in a highly resistant tomato line FLA456 was studied through quantitative trait loci (QTL) analysis. Four QTLs named qTy4.1, qTy6.1, qTy10.1 and qTy11.1 were detected on chromosomes 4, 6, 10, and 11, respectively, through evaluation of an F6 recombinant inbred line (RIL) population derived from a cross between FLA456 (resistant) and CLN1621L (susceptible). Gene action of all QTLs was recessive based on disease reaction of the F1. The markers SINAC1 and SLM4-34 flanked qTy4.1 on chromosome 4, and SLM11-12 and SLM11-17 defined qTy11.1, which co-located with the previously identified Ty-5 and Ty-2 loci, respectively. qTy6.1 was flanked by the markers SLM6-55 and TES-0014, and qTy10.1 by the markers SLM10-80-SLM10-46 on chromosomes 6 and 10. The LOD values of the putative QTLs ranged from 2.79 to 13.76. The phenotypic variance explained by each QTL ranged from 7.1 to 31.9 %. The four QTLs collectively contributed about 60.5 % of the phenotypic variation in resistance against TYLCTHV-[TW]. Group mean severity scores of those RILs possessing three or four qTy were generally lower than RIL groups with only one or no qTy. Given the diversity of begomoviruses that cause TYLCD across the regions, the new QTLs from FLA456 would be valuable in tomato breeding for developing varieties with durable resistance. Two QTL intervals (qTy4.1 and qTy10.1) contained virus resistance candidate genes such as CTV.22 and eukaryotic translation initiation factor 4E.

Relationship between survival and yield related traits in Solanum pimpinellifolium under salt stress

Abstract: A subset of the Solanum pimpinellifolium collection maintained by AVRDC—The World Vegetable Center, Taiwan was evaluated to assess effects of salt stress on physiological traits and yield-related traits with the aim of identifying potential S. pimpinellifolium accessions useful for salt tolerance breeding in tomato. We undertook a comparative analysis of yield and plant survival traits under normal and salt stress conditions to obtain a first indication of the crucial traits associated with salt tolerance in S. pimpinellifolium. Although most traits of S. pimpinellifolium accessions showed a similar percent decrease in mean under salt stress compared with the cultivated checks, the former exhibited a wide range for all traits, suggesting great genetic diversity that can be exploited for the identification of salt tolerant genotypes. Genetic variability for yield and survival traits under salt stress was quantitative with low to moderate heritability. Results of correlation and path coefficient analysis revealed no correlation between any of the physiological traits with yield-related traits indicating that the ability to survive and yield under salt stress are two independent sets of traits in S. pimpinellifolium. Results of the path analysis along with heritability and genetic advance showed that shoot dry weight and K/Na ratio are the two most critical component traits for survival, while fruit number is critical for yield per plant. The large S. pimpinellifolium panel evaluated in this study revealed five genotypes possessing better survival traits, seven genotypes with good yield traits, and two genotypes combining both superior survival and yield traits under salt stress.

Genetic diversity in Capsicum germplasm based on microsatellite and random amplified microsatellite polymorphism markers.

Abstract: A sound knowledge of the genetic diversity among germplasm is vital for strategic germplasm collection, maintenance, conservation and utilisation. Genomic simple sequence repeats (SSRs) and random amplified microsatellite polymorphism (RAMPO) markers were used to analyse diversity and relationships among 48 pepper (Capsicum spp.) genotypes originating from nine countries. These genotypes covered 4 species including 13 germplasm accessions, 30 improved lines of 4 domesticated species and 5 landraces derived from natural interspecific crosses. Out of 106 SSR markers, 25 polymorphic SSR markers (24 %) detected a total of 76 alleles (average, 3.04; range, 2–5). The average polymorphic information content (PIC) was 0.69 (range, 0.29–0.92). Seventeen RAMPO markers produced 87 polymorphic fragments with average PIC of 0.63 (range, 0.44–0.81). Dendrograms based on SSRs and RAMPOs generated two clusters. All 38 Capsicum annuum genotypes and an interspecific landrace clustered together, whereas nine non-annuum (three Capsicum frutescens, one Capsicum chinense, one Capsicum baccatum and four interspecific landraces) genotypes clustered separately. Genetic variation within non-annuum genotypes was greater than the C. annuum genotypes. Distinctness of interspecific derivative landraces grown in northeast India was validated; natural crossing between sympatric Capsicum species has been proposed as the mechanism of their origin.

Analysis of sequences from field samples reveals the presence of the recently described pepper vein yellows virus (genus Polerovirus) in six additional countries.

Abstract: Polerovirus infection was detected by reverse transcription polymerase chain reaction (RT-PCR) in 29 pepper plants (Capsicum spp) and one black nightshade plant (Solanum nigrum) sample collected from fields in India, Indonesia, Mali, Philippines, Thailand and Taiwan At least two representative samples for each country were selected to generate a general polerovirus RT-PCR product of 14 kb length for sequencing Sequence analysis of the partial genome sequences revealed the presence of pepper vein yellows virus (PeVYV) in all 13 samples A 1990 Australian herbarium sample of pepper described by serological means as infected with capsicum yellows virus (CYV) was identified by sequence analysis of a partial CP sequence as probably infected with a potato leaf roll virus (PLRV) isolate

Application of Cytochrome Oxidase I Sequences for Phylogenetic Analysis and Identification of Thrips Species Occurring on Vegetable Crops

Abstract: Thrips are direct pests as well as vectors of important viruses infecting crop plants. One of the major constraints in studying the relationship between thrips vectors and tospoviruses is the difficulty of identifying the vector species because of high intraspecific variation among thrips populations. Molecular approaches have been used to identify species differences. In this study, partial cytochrome oxidase I (COI) sequences were used to understand the phylogenetic relationship among thrips populations, and assess their usefulness to identify and classify unknown thrips species collected from different crops. In total, 29 COI variants were obtained while examining the sequence polymorphisms in COI of 182 insects analyzed in this study, which were collected from six countries on tomato, chilli, onion, cabbage, cucumber, watermelon, Ethiopian mustard, French bean, and peanut. The phylogenetic analysis showed that the insects used in this study clustered with five distinct species-groups designated as Thrips palmi group, T. tabaci group, Frankliniella occidentalis group, Scirtothrips dorsalis group and an unclassified group. Higher intraspecific genetic variation was observed in S. dorsalis and T. palmi followed by T. tabaci and F. occidentalis. Thus, it was confirmed that the COI gene could be useful in grouping different thrips species and genera that coexist in a particular cropping system.

Complete mitochondrial genome of Scaphiodonichthys acanthopterus (Cypriniformes, Cyprinidae)

Abstract: In this study, we sequenced the complete mitochondrial genome of Scaphiodonichthys acanthopterus (Cypriniformes, Cyprinidae). This mitochondrial genome, consisting of 16,612 base pairs (bp), encoded genes for 13 protein-coding genes, two ribosomal RNAs, 22 transfer RNAs, and one non-coding control region as those found in other vertebrates, with the gene order identical to that of typical vertebrates. The control region, of 941 bp in length, is located between tRNA Pro and tRNA Phe . The overall base composition of the heavy strand shows T 25.23%, C 26.85%, A 31.96%, and G 15.95%, with a slight AT bias of 57.19%.

Genetic diversity of legume yellow mosaic begomoviruses in Indonesia and Vietnam

Abstract: High incidences of yellow mosaic symptoms were observed in soybean and yard-long bean crops in Indonesia in 2009 and in mungbean crops in Vietnam in 2011. All five soybean and 20 yard-long bean samples from Java, Indonesia, and 15 mungbean samples from Vietnam with symptoms tested positive for begomovirus infection by polymerase chain reaction (PCR) with primer pair PAL1v1978B/PAR1c715H. On the basis of collection location and the nucleotide sequence comparisons of the 1.5 kb begomoviral DNA-A components amplified, a subset of samples comprising two soybean and six yard-long bean isolates from Indonesia and five mungbean isolates from Vietnam were taken forward for more detailed examination. Sequence comparison and phylogenetic analysis of the full-length sequences of all Indonesian and Vietnam isolates alongside other legume-infecting begomoviruses revealed that all the isolates from Indonesia were Mungbean yellow mosaic India virus (MYMIV) strain-A, and all from Vietnam were Mungbean yellow mosaic virus (MYMV) strain-B. To the best of our knowledge, this is the first identification of MYMIV and MYMV associated with yellow mosaic of legumes in Indonesia and Vietnam, respectively. The epidemiological implications and potential consequences of the emergence of legume-infecting begomoviruses on legume production in these areas of Southeast Asia are discussed.

Full-length genome sequences of four polerovirus isolates infecting cucurbits in Taiwan determined from total RNA extracted from field samples

Abstract: Poleroviruses are not mechanically transmittable by sap inoculation, which makes their isolation and multiplication in laboratory hosts for virion extraction and genome sequence analysis difficult. A reverse-transcription polymerase chain reaction (RT-PCR) procedure was modified to amplify the entire genomes of cucurbit-infecting poleroviruses in three sections directly from RNA extracts from infected plant field samples. The procedure was used to determine the first full-length genome nucleotide sequences of four polerovirus isolates from field samples collected in Taiwan. TW1 was identified as Melon aphid-borne yellows virus (MABYV), because it had 90% for P3 and P3-5 and aa identities of 78–88% for all the other proteins. TW19 represents the first full-length sequence for the recently described Suakwa aphid-borne yellows virus (SABYV). The deduced aa sequences for all the proteins of TW19 showed >10% variation compared to all other poleroviruses, though recombination analysis suggested MABYV as the major parent and an unidentified polerovirus as minor parent. R-TW82 was identified as a strain of CABYV, as the deduced CP aa sequence showed >90% identity to that of other CABYV isolates, and recombination analysis suggested that MABYV was the major parent with CABYV the minor parent. Comparative details of the new full-length sequences and their implications on criteria for distinguishing polerovirus species are discussed.

Ex Situ Conservation of Plant Genetic Resources of Major Vegetables

Abstract: Vegetables form a large and economically important commodity group comprising a wide range of genera and species. Depending on the crop, roots, stems, leaves, flowers and fruit are consumed raw, cooked, steamed, fried or pickled. World production of vegetables and melons comprising 27 distinct commodities reached over one billion tonnes in 2009. The ten major commodities contributing to this impressive output were: fresh vegetables, not elsewhere specified; tomatoes; watermelons; dry onion; cabbages and other brassicas; cucumbers and gherkins; eggplants; carrots and turnips; green chilies and peppers, and other melons, including cantaloupes. Asia is the largest vegetable producer worldwide with China alone producing close to 52 % of world output, followed by India with 9.2 % of global production. Considering a significant overlap of crops with multiple uses, as vegetables, grains, food legumes and fibers, about one million accessions of crops used at least partially as vegetables are conserved ex situ worldwide. In a narrow sense of exclusive use of crops as vegetables, about 500,000 accessions of vegetables representing 7 % of the globally held 7.4 million accessions of plant genetic resources are maintained ex situ. Tomatoes, capsicums, melons and cantaloupe, brassicas, cucurbits, alliums, okra, and eggplant are well represented in ex situ collections at the global level, with a range between 84,000 and 22,000 accessions per vegetable group. As genetic erosion continues in situ for various reasons, complementary collecting efforts should be made with a major focus on crop wild relatives and poorly represented cultivated forms of some vegetable groups such as those described for the genera Brassica and Capsicum in this chapter. AVRDC – The World Vegetable Center plays a major role in the conservation, breeding and distribution of vegetable germplasm worldwide. The Center maintains about 58,000 accessions of vegetable germplasm, representing 170 genera and 434 species. Major vegetable crop groups, including the genera Allium, Brassica, Raphanus, Capsicum, Solanum section Lycopersicon, as well as African and Asian eggplant of the genus Solanum are briefly described in this chapter.

Genetic analysis of tolerance to Boron toxicity in the legume Medicago truncatula

Abstract: Background: Medicago truncatula Gaertn. (barrel medic) is cultivated as a pasture legume for its high protein content and ability to improve soils through nitrogen fixation. Toxic concentrations of the micronutrient Boron (B) in agricultural soils hamper the production of cereal and leguminous crops. In cereals, the genetic analysis of B tolerance has led to the development of molecular selection tools to introgress and maintain the B tolerance trait in breeding lines. There is a comparable need for selection tools in legumes that grow on these toxic soils, often in rotation with cereals. Results: Genetic variation for B tolerance in Medicago truncatula was utilised to generate two F2 populations from crosses between tolerant and intolerant parents. Phenotyping under B stress revealed a close correlation between B tolerance and biomass production and a segregation ratio explained by a single dominant locus. M. truncatula homologues of the Arabidopsis major intrinsic protein (MIP) gene AtNIP5;1 and the efflux-type transporter gene AtBOR1, both known for B transport, were identified and nearby molecular markers screened across F2 lines to verify linkage with the B-tolerant phenotype. Most (95%) of the phenotypic variation could be explained by the SSR markers h2_6e22a and h2_21b19a, which flank a cluster of five predicted MIP genes on chromosome 4. Three CAPS markers (MtBtol-1,-2,-3) were developed to dissect the region further. Expression analysis of the five predicted MIPs indicated that only MtNIP3 was expressed when leaf tissue and roots were assessed. MtNIP3 showed low and equal expression in the roots of tolerant and intolerant lines but a 4-fold higher expression level in the leaves of B-tolerant cultivars. The expression profile correlates closely with the B concentration measured in the leaves and roots of tolerant and intolerant plants. Whereas no significant difference in B concentration exists between roots of tolerant and intolerant plants, the B concentration in the leaves of tolerant plants is less than half that of intolerant plants, which further supports MtNIP3 as the best candidate for the tolerance trait-defining gene in Medicago truncatula. Conclusion: The close linkage of the MtNIP3 locus to B toxicity tolerance provides a source of molecular selection tools to pasture breeding programs. The economical importance of the locus warrants further investigation of the individual members of the MIP gene cluster in other pasture and in grain legumes.

Farmer Field Schools on Chili Peppers in Aceh, Indonesia: Activities and Impacts

Abstract: An evaluation of a farmer field school (FFS) program for chili peppers was conducted to measure impacts on farmers’ knowledge of chili pepper integrated crop management (ICM) in Aceh Province, Indonesia. Chili production was selected as the target intervention topic because of its importance in Aceh's economy. Quantitative and qualitative methods were used to assess impacts of FFS; 270 FFS-graduate farmers were interviewed and eight farmer groups were surveyed. By integrating descriptive and simple statistical analyses, we measure immediate impacts of FFS, which also makes this study's methods and findings different from others in the literature. The results show that farmers’ knowledge on agricultural practices increased significantly due to FFS. In addition, in the future, farmers expected that their chili yields would increase and their pesticide use would decrease. FFS improved farmer cohesiveness and information sharing. Farmers’ knowledge of insect pests, diseases and natural enemies increased consi...

Evaluation of bio-pesticides against legume pod borer, Maruca vitrata Fabricius (Lepidoptera: Pyralidae), in laboratory and field conditions in Thailand

Abstract: The legume pod borer (Maruca vitrata) is a major destructive insect found on the yard-long bean, causing serious damage from the flowering stage. Because growers mostly rely on synthetic pesticides to control this insect, it has developed resistance to some pesticides. Information on the efficacy of bio-pesticides against this pest in Thailand is scarce. This study was conducted to evaluate the effects of selected bio-pesticides against M. vitrata. Among six commercially available bio-pesticides, only Bacillus thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai were found to be more effective against M. vitrata under laboratory conditions, while neem was least effective. In a field trial undertaken between June and September 2011, both B. thuringiensis formulations significantly reduced pod damage compared with untreated plots of the yard-long bean. A similar efficacy pattern was observed during the second field trial between October 2011 and January 2012. These results suggest that B. thuringiensis formulations could become important components in an integrated pest management strategy for controlling M. vitrata on the yard-long bean in Thailand. However, the results of the current study imply the need for additional field trials with combinations of microbial, botanical, and chemical pesticides rather than a single bio-pesticide per treatment in the management of M. vitrata.

Oviposition dynamics and larval development of Helicoverpa armigera on a highly preferred unsuitable host plant, Solanum viarum

Abstract: Oogenesis and oviposition dynamics of female moths of tomato fruitworm, Helicoverpa armigera Hubner (Lepidoptera: Noctuidae), were compared in a monoculture of tomato (Solanum lycopersicum L.) and in mixtures with a highly preferred but unsuitable host plant, Solanum viarum Dunal. Female H. armigera provided with S. viarum laid many more eggs than those provided with tomato, both in choice and no-choice experiments. Gravid female moths did not display any preference for oviposition neither between young or old plants of S. viarum or tomato, nor between young and old leaves of S. viarum. Larval mortality and larval developmental period significantly increased, with subsequent reduction in pupal weight, when H. armigera larvae fed on S. viarum leaves compared to a meridic diet. Oviposition of female moths significantly increased in tomato in the presence of S. viarum volatiles. However, in screen cages with an increasing percentage of S. viarum as a trap crop, the number of eggs laid on tomato as the main crop was the same. The results of this study are discussed in light of the possibility of using S. viarum as a ‘dead-end’ trap crop.

First Report of Bhendi yellow vein mosaic virus Associated with Yellow Vein Mosaic of Okra (Abelmoschus esculentus) in Thailand

Abstract: A disease of okra (Abelmoschus esculentus) causing yellowing veins and mosaic on leaves and fruit has emerged in Thailand. Incidences of 50 to 100% diseased plants were observed in fields in Kanchanaburi and Nakhon Pathom provinces in 2009 and 2010, respectively. Leaf samples were collected from three and four diseased plants in Kanchanaburi and Nakhon Pathom, respectively. All seven samples tested positive for begomovirus by PCR using universal primer pair PAL1v1978B/PAR1c715H (3). One sample from Kanchanaburi also tested positive by ELISA using Okra mosaic virus (Genus Tymovirus) antiserum (DSMZ, Braunschweig, Germany). When the nucleotide sequences of the 1.5 kb begomovirus PCR products were compared they were found to share 99.1 to 99.5% identity with each other, and 97.5 to 97.7% identity to Bhendi yellow vein mosaic virus Okra isolate from India (GenBank Accession No. GU112057; BYVMV-[IN: Kai:OY: 06]). The complete DNA-A sequence for a Kanchanaburi isolate (JX678967) was obtained using abutting prim...

Molecular Characterization of Begomoviruses Infecting Sauropus androgynus in Thailand

Abstract: Begomoviruses were detected in leaf samples of Sauropus androgynus (L.) Merr. plants showing leaf curling with or without yellowing symptoms in Kamphaeng Saen, Nakhon Pathom, Thailand in 2009 and 2010. From eight plants with symptoms, 17 complete begomoviral DNA-As were amplified by polymerase chain reaction and sequenced. No DNA-B was detected in any of the plants. All the DNA-As had the characteristic begomovirus genome organization of six open reading frames, two in the virion-sense orientation and four in the complementary orientation. Sequence comparison of these virus isolates indicated that one isolate belongs to Tomato leaf curl New Delhi virus, 12 isolates belong to Ageratum yellow vein virus and four isolates belong to a novel species with the tentative name Sauropus leaf curl virus. Five of the eight samples were found to be co-infected by isolates of two different begomovirus species. Recombination analysis indicated that all but one of the isolates were probably the product of one or more recombination events. The results indicated that S. androgynus plants act as natural hosts as well as potential nurseries for genetic recombination between begomovirus species and strains.

Development of best practices for ex situ conservation of radish germplasm in the context of the crop genebank knowledge base

Abstract: Information about crop-specific best practices for ex situ conservation of plant genetic resources has been difficult to find until recently. The CGIAR, together with national and regional partners, started to fill that gap by publishing best practices on the crop genebank knowledge base (CGKB -http://cropgenebank.sgrp.cgiar.org/), a website specifically developed and officially launched in 2010 to provide easy access to knowledge about all aspects of ex situ conservation of specific crops to genebank managers and ex situ conservation researchers. A collaborative study, undertaken by Bioversity International with eight national and international genebanks, utilized the framework provided by the CGKB to develop and publish radish conservation best practices. This paper focuses on two aspects of this study: (1) Differences in procedures and practices in radish conservation currently applied in five key genebank activities, namely, acquisition of germplasm, viability testing and monitoring, seed drying, seed storage, and regeneration. While in a few cases genebanks agreed on a specific best practice to recommend, in others it was not desirable to identify one practice as superior to another, therefore a range of existing practices is described as a variety of equivalent options. The results highlight the importance of proactive genebank management aimed at meeting the standards within the specific context in which a genebank operates. (2) The framework and template provided by the CGKB in guiding the development of genebank best practices, and the CGKB as an excellent resource to widely and freely share best practices with the global community to support the effective management of crop genebanks.

First Report of Bacterial Wilt Caused by Ralstonia solanacearum on Roselle in Taiwan.

Abstract: Roselle (Hibiscus sabdariffa L.) is a herbaceous plant belonging to the Malvaceae family. Its calyxes are rich in vitamin C and anthocyanins and are used to make roselle drink and hibiscus tea. Roselles are grown in counties of Taitung, Pingtung, and Chiayi in Taiwan. In addition to a few local cultivars, the major cultivar currently grown in Taiwan is Roselle cv. Victor. In April of 2012, a wilt disease appeared on seedlings of a cultivar, Chiada 1, at the Chungpu Township of Chiayi County. Mature plants were free from this disease. Leaves appeared weak and drooping when they were still green, followed by collapse of the whole plant a few days later. Browning of vascular and pith tissues was evident, especially at the base of the stem. A whitish mass of bacteria oozed from the cut end of diseased stems, suggesting that bacteria might be the cause of this disease. A total of 15 bacterial strains were collected. Colonies on tetrazolium chloride medium (3) were round to oval and fluidal, each with a pink or red center after incubation at 30°C for 48 h. When tobacco leaves were infiltrated with these strains, a hypersensitive reaction (HR) typical of phytopathogenic bacteria was induced. All strains produced the expected amplicon (282 bp) after PCR with the Ralstonia solanacearum-specific primer pair, AU759f and AU760r (4). Three hexose alcohols (mannitol, sorbitol, and dulcitol), rather than three disaccharides (lactose, maltose, and cellobiose), were utilized, which suggests R. solanacearum biovar 4 (2). R. solanacearum phylotype I was determined by phylotype-specific multiplex PCR (1). Pathogenicity of the strains was tested on roselle, tomato, pepper, and eggplant. Young plants of the various species were inoculated at the four- to six-leaf stage by soil drenching with 30 ml of bacterial suspension (about 108 CFU/ml). Control plants were inoculated with sterile water. Each treatment comprised eight plants with a single plant in each pot. Plants were incubated in a greenhouse at 25 to 31°C and 56 to 93% humidity. Wilting was observed 4 to 6 days after inoculation, while the control did not wilt. To find the correlation between plant growth stage and resistance to the pathogen, 2-, 3-, 4-, and 5-week-old roselle plants cv. Chiada 1 were transplanted into artificially infested soil. Eight plants in each treatment were planted with a single plant in each pot. The disease incidences for plants of different ages were 75%, 62.5%, 50%, and 12.5%, respectively. This study showed that resistance increases with plant age. Hence, if older seedlings are transplanted, the risk of bacterial wilt of roselle can be reduced. To our knowledge, this is the first report of R. solanacearum on roselle in Taiwan. References: (1) M. Fegan and P. Prior. Bacterial Wilt Disease and the Ralstonia solanacearum Species Complex, page 449. C. Allen et al., eds. The American Phytopathological Society. St. Paul, MN, 2005. (2) A. C. Hayward. J. Appl. Bacteriol. 27:265, 1964. (3) A. Kelman. Phytopathology 44:693, 1954. (4) N. Opina et al. Asia Pac. J. Mol. Biol. Biotechnol. 5:19, 1997.

Molecular-Phylogenetic Characterization of Arrestin-2 from Maruca vitrata (Lepidoptera: Crambidae)

Abstract: Most physiological processes to external stimulants rely upon intracellular signal transduction mediated by ligand binding of G-protein-coupled receptors. The G-protein signaling pathway is deactivated by arrestin-2 binding, which is indispensable for receptor internalization and recycling. We identified the full-length cDNA encoding arrestin-2 in Maruca vitrata F. using rapid amplification of cDNA ends. The open reading frame of MaviArr2 is 1,221 bp in length, encoding 407 amino acids. The alignment of the known arrestin-2 amino acid sequences from other insects revealed that MaviArr2 has the highest similarity (98.8%) to the monarch butterfly, but shows low homology (53.9–60.7%) with ants and bees. A certain number of highly conserved protein-binding motifs were identified from the deduced MaviArr2 amino acids, demonstrating their function as receptor deactivators in signal transduction pathways in cells. The genomic DNA sequence of MaviArr2, amplified by polymerase chain reaction, is 1,779 bp ...

Acceptability of bitter gourd (Momordica charantia L.) recipes with different cooking methods

Abstract: Diabetes mellitus is an increasing world health problem; particularly the prevalence of type 2 diabetes has assumed epidemic in developing countries. It is mainly due to the environmental, dietary and lifestyle behavioral factors that control the progress of this disease. Nutrition is often said to be the cornerstone of diabetes care. The nutritional management of diabetes can affect long term health and quality of life. There is increasing evidence that complications related to diabetes are associated with oxidative stress induced by the generation of free radicals. Bitter gourd (Momordica charantia L. ) is a common food in Indian cuisine and has been used extensively in folk medicine as a remedy for diabetes. Medicinal value of bitter gourd has been attributed to its high antioxidant properties due in part to phenols, flavonoids, isoflavones, terpenes, anthroquinones and glucosinolates. Hypoglycaemic effect of bitter gourd extracts have been demonstrated in various animal models of insulin resistance.