Quality protein introduced into waxy maize landraces of ethnic minorities

Ethnic minorities in South East Asia use waxy maize as a staple food, lacking in essential amino acids. Recently, we combined the recessive waxy and opaque2 alleles to double quality grains (w/o, pure amylopectin, high quality protein), which still must be introgressed into germplasm acceptable to ethnic minorities. Two w/o lines of Chinese and Thai background, respectively, were crossed once with two Vietnamese waxy landraces of good taste, WVN 3 and WVN 10. At the preferred harvest time for eating, dough stage, homozygous w/o F2 offspring with WVN 3 were equal in dehusked ear yield with commercial waxy hybrids and 40% superior in yield compared with WVN 10 F2 offsprings. In WVN 3 F2 crosses and F2 backcrosses with WVN 3, all w/o dehusked ears were equal in eat¬ing quality, grain protein content and a good leaf health; but the yield of dehusked ears and the grain tryptophan content was highest in the topcross. High quality germplasm is available now as a source of high quality protein for ethnic minorities. The two original w/o lines led to equal results in crosses with landraces, but their test hybrid was extremely high-yielding, indicating a good potential to breed for commercial high protein quality snacks in South East Asia

Morphological characterization and classification of cassava (Manihot esculenta Crantz) in Vietnam

The aim of this study was to establish the morphological basis for the classification of major cassava cultivars (Manihot esculenta Crantz) planted in Vietnam. Twenty typical descriptors were observed in various specific growth stages. Four traits related to mature leaves and two traits related to leaf veins were detected in cassava plant after the 4-month stage. At the same time, 12 root- and stem-related descriptors were collected in cassava plants from 8-months to harvest. We found that two traits in the apical leaves can be observed in every growth stage. A classification tree based on these traits was constructed with 6 essential morphological descriptors to recognize the 7 most common cassava cultivars in Vietnam. KM 140 variety is distinguished by purplish-red in apical leaves, while KM 98-7 can be classified with straight or linear shapes of central leaflet. The irregular orientation of the petiole is a unique descriptor of local cultivar XVP. In the case of SM 937-26, weak foliar scars are observed. Finally, KM 94, KM 419, and KM 98-5 varieties can be classified by the color of the stem epidermis. These morphological descriptors will be a foundation to classify all cassava varieties planted in Vietnam.

Characterization of cassava production systems in Vietnam.

Using a nationally representative survey of cassava-growing households in Vietnam and a robust method of varietal identification based on DNA fingerprinting, this paper provides a broad picture of cassava production and socio-economic characteristics of cassava producers in the country. It presents a descriptive analysis of cassava production practices, varietal use, varietal preferences, as well as cassava utilization, and marketing. Results indicate that more than 85% of the cassava area in Vietnam is planted to improved varieties. The average yield at national level is 19 tons per hectare. About 69% of total cassava produced per household is sold as either fresh roots and/or dried chips. The remaining 31% is either for own consumption or for livestock feed. Of all the six regions surveyed, the Southeast is characterized by the most intensive cassava production practices. It also has the largest average cassava area per household, the highest percentage of tractor use, and a higher percentage of fertilizer application on cassava fields. The findings suggest that there are huge challenges for sustainable cassava intensification, specifically in identifying the needs for market diversification, dealing with emerging pests and diseases, and implementing adequate soil management practices. This is particularly challenging in a system that is driven by the need to maximize output with minimum investment. Future research and development should focus on integrated value chain development with multiple actors focusing attention on integrated pest and disease management, seed systems development, breeding for resistance and earliness, and climate change adaptation, among others

Genomic regions and candidate genes selected during the breeding of rice in Vietnam

Vietnam harnesses a rich diversity of rice landraces adapted to a range of conditions, which constitute a largely untapped source of diversity for the continuous improvement of cultivars. We previously identified a strong population structure in Vietnamese rice, which is captured in five Indica and four Japonica subpopulations, including an outlying Indica-5 group. Here, we leveraged that strong differentiation and 672 native rice genomes to identify genomic regions and genes putatively selected during the breeding of rice in Vietnam. We identified significant distorted patterns in allele frequency (XP-CLR) and population differentiation scores (FST) resulting from differential selective pressures between native subpopulations, and later annotated them with QTLs previously identified by GWAS in the same panel. We particularly focussed on the outlying Indica-5 subpopulation because of its likely novelty and differential evolution, where we annotated 52 selected regions, which represented 8.1% of the rice genome. We annotated the 4576 genes in these regions and selected 65 candidate genes as promising breeding targets, several of which harboured alleles with nonsynonymous substitutions. Our results highlight genomic differences between traditional Vietnamese landraces, which are likely the product of adaption to multiple environmental conditions and regional culinary preferences in a very diverse country. We also verified the applicability of this genome scanning approach to identify potential regions harbouring novel loci and alleles to breed a new generation of sustainable and resilient rice

Marker-assisted backcrossing (MABC) for improved salinity tolerance in rice (Oryza sativa L.) to cope with climate change in Vietnam

Abstract Salinity is the most common abiotic stresses leading to the reduction of rice yield in many rice-growing areas of the world. Improvement in salt tolerance of rice for target stress regions is one of the important objectives of many breeding programs. In this study, we are currently applying a MABC (marker-assisted backcrossing) system on foreground selection, recombinant selection followed by background selection for development of Vietnamese rice variety that can tolerate salinity of rised sea water. The highly salt tolerant FL478 was used as a donor to transfer Saltol QTL into Bacthom 7 recipient rice cultivar. A total of 368 SSR markers were conducted to identify 8 markers in Saltol locus and 81 markers in other loci with total of 89 (24%) polymophic markers between the parents, out of which 88 markers were then applied to analyze genotyping of each backross generation with three steps of selection. The results showed that, the best plants of BC3F1 generation carry segments of the donor (11.16 -12.6 Mb), which had 96.8% -100 % of the recipient genome. This study revealed that the introgression lines can be directly developed into the salinity tolerance variety, which suitable for cultivating in coastal areas of Vietnamese Deltas. The MABC aids in the transfer of target chromosome segments and may improve the recovery of the recipient genome if background selection is employed

Towards a Framework for High-Performance Simulation of Livestock Disease Outbreak: A Case Study of Spread of African Swine Fever in Vietnam

International audienceThe spread of disease in livestock is an important research topic of veterinary epidemiology because it provides warnings or advice to organizations responsible for the protection of animal health in particular and public health in general. Disease transmission simulation programs are often deployed with different species, disease types, or epidemiological models, and each research team manages its own set of parameters relevant to their target diseases and concerns, resulting in limited cooperation and reuse of research results. Furthermore, these simulation and decision support tools often require a large amount of computational power, especially for models involving tens of thousands of herds with millions of individuals spread over a large geographical area such as a region or a country. It is a matter of fact that epidemic simulation programs are often heterogeneous, but they often share some common workflows including processing of input data and execution of simulation, as well as storage, analysis, and visualization of results. In this article, we propose a novel architectural framework for simultaneously deploying any epidemic simulation program both on premises and on the cloud to improve performance and scalability. We also conduct some experiments to evaluate the proposed architectural framework on some aspects when applying it to simulate the spread of African swine fever in Vietnam

Simulation of precision feeding systems for swine

International audiencePrecision livestock farming has become an inevitable trend for agricultural industry in the world. In that field, precision feeding is widely acknowledged because of its potential to reduce feed costs, environmental footprint and to improve animal health and welfare. Precision feeding involves modern multidisciplinary technologies such as information technology, mechanics, electronics, automation, etc. Such a system consists of automatic troughs linked to a computer system to exploit data collected from the individual animals (e.g. body weight, feed intake and feeding behaviour), and/or from ambient sensors. Data is processed and analysed based on mathematical models to make predictions, warnings for farmers or to formulate diets that fit requirements of each individual animal at each production period. However, implementing such a system often requires high investment, which may go beyond the capabilities of smallholders and small/medium laboratories. Furthermore, the risk of implementing by design but not conforming to reality is very high. To avoid this problem, we introduce an agent-based modelling approach to simulate precision feeding systems for swine. Two simulation experiments were conducted to provide predictions about the growth of individual pigs and the usefulness of precision feeding systems over classic feeding models

Southeast Asian waxy maize (Zea mays L.), a resource for amylopectin starch quality types?

Amylose-free (waxy) maize has been a vegetable (cooked ears) and staple food in Southeast Asia for centuries, resulting in hundreds of landraces (LRs) across the region. The recessive waxy allele induces soft grains with preferred cooking and flavour properties. We hypothesized that eating preferences resulted in the additional selection for different starch properties, reflected in altered starch granule morphology or amylopectin structure. A total of 41 LRs were available as starting material that had been used by different ethnic groups in Vietnam and Thailand. Unluckily, some LR were not pure waxy, but we successfully regained the original pure waxy status for most. Twenty LR were chosen for analysis of starch traits according to their purity. Four different waxy mutations were identified, including two unknown alleles. This is a strong proof for parallel independent selection of waxy maize in the region. Starch granule morphology and size were similar among all LRs. Gelatinization properties differed only between waxy and wild-type LR, and all waxy LR were comparable to a commercial waxy hybrid. The fine structure of waxy amylopectin had fewer short chains compared with that in wild-type. So far, the differences observed in starch properties are likely associated exclusively with the waxy trait. Despite the strong selection for amylose-free starch, there was no evidence for additional region wide selection for other special starch properties in our collection. In conclusion, all analyses did not encourage further targeted research on allelic variation of other starch metabolism genes for future use in the food and feed industry.ISSN:1479-2621ISSN:1479-263