Development Of Germplasm Research Articles

Phenotyping seedlings for selection of root system architecture in alfalfa (Medicago sativa L.)

BackgroundThe root system architecture (RSA) of alfalfa (Medicago sativa L.) affects biomass production by influencing water and nutrient uptake, including nitrogen fixation. Further, roots are important for storing carbohydrates that are needed for regrowth in spring and after each harvest. Previous selection for a greater number of branched and fibrous roots significantly increased alfalfa biomass yield. However, phenotyping root systems of mature alfalfa plant is labor-intensive, time-consuming, and subject to environmental variability and human error. High-throughput and detailed phenotyping methods are needed to accelerate the development of alfalfa germplasm with distinct RSAs adapted to specific environmental conditions and for enhancing productivity in elite germplasm. In this study methods were developed for phenotyping 14-day-old alfalfa seedlings to identify measurable root traits that are highly heritable and can differentiate plants with either a branched or a tap rooted phenotype. Plants were grown in a soil-free mixture under controlled conditions, then the root systems were imaged with a flatbed scanner and measured using WinRhizo software.ResultsThe branched root plants had a significantly greater number of tertiary roots and significantly longer tertiary roots relative to the tap rooted plants. Additionally, the branch rooted population had significantly more secondary roots > 2.5 cm relative to the tap rooted population. These two parameters distinguishing phenotypes were confirmed using two machine learning algorithms, Random Forest and Gradient Boosting Machines. Plants selected as seedlings for the branch rooted or tap rooted phenotypes were used in crossing blocks that resulted in a genetic gain of 10%, consistent with the previous selection strategy that utilized manual root scoring to phenotype 22-week-old-plants. Heritability analysis of various root architecture parameters from selected seedlings showed tertiary root length and number are highly heritable with values of 0.74 and 0.79, respectively.ConclusionsThe results show that seedling root phenotyping is a reliable tool that can be used for alfalfa germplasm selection and breeding. Phenotypic selection of RSA in seedlings reduced time for selection by 20 weeks, significantly accelerating the breeding cycle.

History of Sugarcane Breeding, Germplasm Development and Related Research in Myanmar

History of Sugarcane Breeding, Germplasm Development and Related Research in Myanmar

Гибрид подсолнечника Статус

The widespread saturation of crop rotations with sunflower crops contributed to the creation of favorable conditions for the emergence and wide distribution of new more aggressive races of broomrape, downy mildew and other pathogens of this crop. Sunflower varieties and hybrids resistant to previously common races have become severely affected. One of the ways to solve this problem is to develop sunflower hybrids resistant to new virulent races. The breeders had to combine high productivity and genes of resistance to new more aggressive races of broomrape and downy mildew in one genotype. The first stage of the work was development of a new breeding germplasm and selection of parental lines with breeding valuable traits from it. Based on these lines, there were developed hybrid combinations resistant to new highly virulent races of broomrape and downy mildew. The hybrid Status was developed by hybridization of a maternal line ED 47 and a paternal line ED 193. The maternal line ED 47 is single-headed, low height, resistant to the broomrape races: E, F, G, has a good combining ability. The paternal line ED 193 is branched, also resistant to broomrape (races E, F, G) and three races of downy mildew (330, 710, and 730). The hybrid Status belongs to the middle-early maturity group, duration of the growing season is 95 days. The average plant height over the years of testing was 140 cm; the plants are uniformed in height and the duration of the development phases. Seed yield of the hybrid Status exceeded the standard one (a hybrid Gorstar) by 0.25 t/ha, and oil yield – by 0.14 t/ha. The oil content of the seeds was 48.0%, the huskiness – 28.7%, the 1000 seeds weight – 60.6 g. The new hybrid is resistant to seven races of broomrape (A, B, C, D, E, F, and G) and three races of downy mildew (330, 710, and 730). A distinctive feature of it is resistance of both parent lines to broomrape. The originator of a simple interline sunflower hybrid Status is V.S. Pustovoit All-Russian Research Institute of Oil Crops.

Sugarcane Breeding, Germplasm Development and Supporting Genetics Research in Vietnam

Sugarcane Breeding, Germplasm Development and Supporting Genetics Research in Vietnam

Historical Notes, Germplasm Development, and Molecular Approaches to Support Sugarcane Breeding Program in Indonesia

Historical Notes, Germplasm Development, and Molecular Approaches to Support Sugarcane Breeding Program in Indonesia

Sugarcane Breeding and Germplasm Development in the Philippines

Sugarcane Breeding and Germplasm Development in the Philippines

Sugarcane Breeding, Germplasm Development and Related Molecular Research in China

Sugarcane Breeding, Germplasm Development and Related Molecular Research in China

Targeting of SPCSV-RNase3 via CRISPR-Cas13 confers resistance against sweet potato virus disease.

Sweet potato (Ipomoea batatas) is one of the most important crops in the world, and its production rate is mainly decreased by the sweet potato virus disease (SPVD) caused by the co‐infection of sweet potato chlorotic stunt virus (SPCSV) and sweet potato feathery mottle virus. However, methods for improving SPVD resistance have not been established. Thus, this study aimed to enhance SPVD resistance by targeting one of its important pathogenesis‐related factors (i.e., SPCSV‐RNase3) by using the CRISPR‐Cas13 technique. First, the RNA targeting activity of four CRISPR‐Cas13 variants were compared using a transient expression system in Nicotiana benthamiana. LwaCas13a and RfxCas13d had more efficient RNA and RNA virus targeting activity than PspCas13b and LshCas13a. Driven by the pCmYLCV promoter for the expression of gRNAs, RfxCas13d exhibited higher RNA targeting activity than that driven by the pAtU6 promoter. Furthermore, the targeting of SPCSV‐RNase3 using the LwaCas13a system inhibited its RNA silencing suppressor activity and recovered the RNA silencing activity in N. benthamiana leaf cells. Compared with the wild type, transgenic N. benthamiana plants carrying an RNase3‐targeted LwaCas13a system exhibited enhanced resistance against turnip mosaic virus TuMV‐GFP and cucumber mosaic virus CMV‐RNase3 co‐infection. Moreover, transgenic sweet potato plants carrying an RNase3‐targeted RfxCas13d system exhibited substantially improved SPVD resistance. This method may contribute to the development of SPVD immune germplasm and the enhancement of sweet potato production in SPVD‐prevalent regions.

The Gossypium anomalum genome as a resource for cotton improvement and evolutionary analysis of hybrid incompatibility.

Cotton is an important crop that has been the beneficiary of multiple genome sequencing efforts, including diverse representatives of wild species for germplasm development. Gossypium anomalum is a wild African diploid species that harbors stress-resistance and fiber-related traits with potential application to modern breeding efforts. In addition, this species is a natural source of cytoplasmic male sterility and a resource for understanding hybrid lethality in the genus. Here, we report a high-quality de novo genome assembly for G. anomalum and characterize this genome relative to existing genome sequences in cotton. In addition, we use the synthetic allopolyploids 2(A2D1) and 2(A2D3) to discover regions in the G. anomalum genome potentially involved in hybrid lethality, a possibility enabled by introgression of regions homologous to the D3 (Gossypium davidsonii) lethality loci into the synthetic 2(A2D3) allopolyploid.

Progress in soybean functional genomics over the past decade.

SummarySoybean is one of the most important oilseed and fodder crops. Benefiting from the efforts of soybean breeders and the development of breeding technology, large number of germplasm has been generated over the last 100 years. Nevertheless, soybean breeding needs to be accelerated to meet the needs of a growing world population, to promote sustainable agriculture and to address future environmental changes. The acceleration is highly reliant on the discoveries in gene functional studies. The release of the reference soybean genome in 2010 has significantly facilitated the advance in soybean functional genomics. Here, we review the research progress in soybean omics (genomics, transcriptomics, epigenomics and proteomics), germplasm development (germplasm resources and databases), gene discovery (genes that are responsible for important soybean traits including yield, flowering and maturity, seed quality, stress resistance, nodulation and domestication) and transformation technology during the past decade. At the end, we also briefly discuss current challenges and future directions.

QTL identified for stay-green in a multi-reference nested association mapping population of wheat exhibit context dependent expression and parent-specific alleles

A stay-green phenotype is useful for adaptation of wheat to end-of-season drought conditions. We identified quantitative trait loci (QTL) for stay-green traits, as well as for height, days to anthesis and yield, in a multi-reference nested association mapping (MR-NAM) population of wheat (Triticum aestivum L.) in two environments differing in degree of drought stress experienced post-anthesis. The MR-NAM population consisted of three inter-related nested association mapping populations developed by nesting 11 diverse adaptation donors within three common reference parents, adapted to the northern, southern and western cropping regions of Australia, respectively. The construction of the MR-NAM population enables the assessment of the effect on a trait of multiple alleles at any particular locus, in different genetic backgrounds, and facilitates concurrent QTL mapping and germplasm development. This approach enabled identification of parent-specific alleles and context dependent expression. Using a new statistical method specifically developed to identify QTL in MR-NAM populations, we identified 65 QTL for stay-green traits. Co-location was observed between (i) trait by loci associations for some of the different stay-green traits, (ii) for QTL between the two environments, and (iii) between QTL for stay-green traits, plant height and grain yield. Some QTL co-located with those identified in other studies however, others are likely novel. Genetic markers associated with QTL for stay-green can be applied in breeding to enrich populations for stay-green traits in early generations of selection, prior to field testing in yield plots, in particular for the development of wheat cultivars targeted to end-of-season drought-stressed environments. This information is important for breeders, because it facilitates identification of the sources of the most promising alleles at particular loci for specific genetic backgrounds and growing environments.

History and Current Status of Sugarcane Breeding, Germplasm Development and Supporting Molecular Research in South Africa

History and Current Status of Sugarcane Breeding, Germplasm Development and Supporting Molecular Research in South Africa

Efficient CRISPR/Cas9 Genome Editing in Alfalfa Using a Public Germplasm

Because its ability to acquire large amounts of nitrogen by symbiosis, tetraploid alfalfa is the main source of vegetable proteins in meat and milk production systems in temperate regions. Alfalfa cultivation also adds fixed nitrogen to the soil, improving the production of non-legumes in crop rotation and reducing the use of nitrogen fertilizers derived from fossil fuel. Despite its economic and ecological relevance, alfalfa genetics remains poorly understood, limiting the development of public elite germplasm. In this brief article, we reported the high-efficiency of alfalfa mutagenesis by using the public clone C23 and the CRISPR/Cas9 system. Around half of the GUS overexpressing plants (35S-GUS under C23 genomic background) transformed with an editing plasmid containing two sgRNAs against the GUS gene and the Cas9 nuclease exhibited absence of GUS activity. Nucleotide analysis showed that the inactivation of GUS in CRISPR/Cas9-editing events were produced via different modifications in the GUS gene, including frameshift and non-sense mutations. Using the CRISPR/Cas9 system and two sgRNAs, we have also edited the alfalfa gene NOD26, generating plants with different doses of alleles at this locus, including complete gene knockout at high efficiency (11%). Finally, we discuss the potential applications of genome-editing technologies to polyploid research and to alfalfa improvement public programs.

Raman Spectroscopy as a Robust New Tool for Rapid and Accurate Evaluation of Drought Tolerance Levels in Both Genetically Diverse and Near-Isogenic Maize Lines.

Improving drought tolerance of crops has become crucial due to the current scenario of rapid climate change. In particular, development of new maize germplasm with increased drought tolerance is viewed as a major breeding goal to ensure sustainable food and feed production. Therefore, accurate rapid phenotyping techniques for selection of superior maize genotypes are required. The objectives of this study were to determine whether Raman microscopy technique can be applied for accurate assessment of drought-tolerance levels in both genetically diverse and near-isogenic maize lines that differ in their levels of drought-tolerance. Carotenoid degradation is known to be a direct stress response initiated by reactive oxygen species during osmotic stress such as drought. Using Raman mapping, we observed real-time changes in the rate of carotenoid degradation in chloroplasts that was dependent on the strength of osmotic stress. In addition, we showed that the rate of carotenoid degradation as measured by Raman spectroscopy correlates directly with drought tolerance levels of diverse maize genotypes. We conclude that Raman technique is a robust, biochemically selective and non-invasive phenotyping technique that accurately distinguishes drought tolerance levels in both genetically diverse and near-isogenic maize genotypes. We conclude that this technique can be further developed to render it suitable for field-based early assessment of breeding materials with superior drought-tolerance traits.

Harnessing translational research in wheat for climate resilience.

Despite being the world's most widely grown crop, research investments in wheat (Triticum aestivum and Triticum durum) fall behind those in other staple crops. Current yield gains will not meet 2050 needs, and climate stresses compound this challenge. However, there is good evidence that heat and drought resilience can be boosted through translating promising ideas into novel breeding technologies using powerful new tools in genetics and remote sensing, for example. Such technologies can also be applied to identify climate resilience traits from among the vast and largely untapped reserve of wheat genetic resources in collections worldwide. This review describes multi-pronged research opportunities at the focus of the Heat and Drought Wheat Improvement Consortium (coordinated by CIMMYT), which together create a pipeline to boost heat and drought resilience, specifically: improving crop design targets using big data approaches; developing phenomic tools for field-based screening and research; applying genomic technologies to elucidate the bases of climate resilience traits; and applying these outputs in developing next-generation breeding methods. The global impact of these outputs will be validated through the International Wheat Improvement Network, a global germplasm development and testing system that contributes key productivity traits to approximately half of the global wheat-growing area.

Sugarcane Breeding, Germplasm Development and Supporting Genetic Research in Argentina

Sugarcane Breeding, Germplasm Development and Supporting Genetic Research in Argentina

History and Current Status of Sugarcane Breeding, Germplasm Development and Molecular Biology in India

History and Current Status of Sugarcane Breeding, Germplasm Development and Molecular Biology in India

Sugarcane Breeding, Germplasm Development and Supporting Genetics Research in Thailand

Sugarcane Breeding, Germplasm Development and Supporting Genetics Research in Thailand

Vegetable Breeding Strategies

Variation present in vegetables provides plentiful of opportunity for development of breeding lines and hybrids. Germplasm development depends on incorporation of approaches such as MAGIC population, use of wild relatives, genetic transformation for transferring resistance gene and gene pyramiding. These approaches are most reliable to improve qualitative as well as quantitative characters. Since conventional methods are time consuming, molecular techniques are also utilized at appropriate stages to enhance swiftness of line development. Molecular approaches includes many tools but marker assisted selection is best to use in vegetable breeding programme. It helps to rapid back cross breeding also selection of resistance or qualitative lines from segregating populations. Double haploid is one of finest methods to create diverse pure lines in short interval. There are many ways to incorporate diverse gene in single line through double haploid technology. Hybridization mating such as line x tester or diallel are common methods instead combination breeding method is very result oriented as compared with others. The success rate of specific combination breeding is as much as double as associated with other ones.

Sugarcane Breeding in Reunion: Challenges, Achievements and Future Prospects

All over the world, sugarcane breeding programs are developing new, high-yielding cultivars that are resistant to major diseases to improve the profitability and sustainability of the sugar-energy industries they serve. In Reunion Island, sugarcane genetic improvement efforts began in 1929. Many challenges had to be overcome. Continuous breeding efforts have been made to develop varietal resistances to control some major diseases and are still going on today. Given the extreme agroclimatic diversity that characterizes the different production areas of the industry, it was necessary to gradually develop a large network of seven decentralized breeding programs to support genetic progress throughout the whole industry. This article provides an overview of the sugarcane breeding program of Reunion. It describes historical achievements and gives detailed information about germplasm development, variety exchanges, breeding program and selection scheme and procedures. A review is also made on applied genetics research activities supporting variety improvement. Further progress depends on the optimized functioning of the current breeding program, which has never been so largely extended in terms of target environments. The article discusses prospects of genomics breeding applications in the complex genetic context of sugarcane, which will require large multidisciplinary collaborations.