Molecular breeding

About: Molecular breeding is a research topic. Over the lifetime, 2120 publications have been published within this topic receiving 56908 citations.

Molecular breeding of groundnut for enhanced productivity and food security in the semi- arid tropics: opportunities and challenges

Abstract: About 94% of the world groundnut (Arachis hypogaea L.) production comes from the rainfed crop grown largely by resource-poor farmers. Several biotic and abiotic stresses limit groundnut productivity, together causing annual yield losses of over US $ 3.2 billion. The Arachis species harbor genes capable of improving both seed yield and quality in addition to imparting high levels of resistance to diseases and insect pests. Many of the wild Arachis species are not cross compatible with cultivated groundnut. However, efforts to overcome incompatibility in wide crosses have started to liberate resistance genes in interspecific progenies. But these progenies carry a lot of linkage drag. Marker-assisted backcross breeding should minimize the linkage drag as it greatly facilitates monitoring of introgressed chromosome segments carrying beneficial genes from wild Arachis to cultivated groundnut. Transgenic groundnuts with resistance or tolerance to biotic and abiotic stresses have been produced and are in various stages of characterization under containment and/or controlled field conditions. Once favorable genes are introduced into cultivated groundnut through wide crossing and/or genetic transformation techniques, these genes will become ideal candidates for marker-accelerated introgression. DNA marker based genetic linkage map should enable breeders to effectively pyramid genes for good seed quality and resistance to biotic and abiotic stresses into agronomically enhanced breeding populations in a much shorter time than would be possible by conventional techniques. To date 110 SSR markers detected genetic variation in a diverse array of 24 groundnut landraces. However, substantial efforts are still required to develop sufficient PCR-based markers, particularly SSRs and SNPs, for the construction of high-density genetic linkage map and for the routine application in the molecular breeding in groundnut. The use of automated technologies will become increasingly important for large-scale germplasm characterization and realistic scale marker-assisted selection in groundnut. An international legume genomics initiative has been formed between USA Universities and the International Agricultural Research Centers of the Eco-Regional Alliance on legumes to translate the benefits of the "consensus legume genome" for rapid impacts on the genetic improvement of tropical legumes.

Advances in plant breeding strategies: Breeding, biotechnology and molecular tools

Abstract: The domestication of plants, as a bio-cultural process, is a continuous phenomenon intrinsically associated with the use of plants. Traditional and scientifi c knowledge constitute the basis of the various uses of plants from in situ harvesting to complete domestication of crops. One of the most important challenges of our time is to achieve the conservation and sustainable use of plant genetic resources of landraces, species in the process of domestication and species used in situ. The in situ conservation of agricultural biodiversity is a basic element for the development of more sustainable agroecosystems, the adaptation to climate change, the conservation of ecosystem services and to ensure local food security—a conception that is strongly linked to the local development and the protection of cultural and biological diversity. Through case studies from the Pampa Biome we will discuss the valorization of plant genetic resources through new domestication, the promotion of the use of scientifi cally developed best management practices for in situ conservation, the widening of the germplasm base for breeding programs, plant breeding for stress tolerance, the development of participatory plant breeding programs and the development of high quality products.

Novel Genomic Tools and Modern Genetic and Breeding Approaches for Crop Improvement

Abstract: In recent past, genomic tools especially molecular markers have been extensively used for understanding genome dynamics as well for applied aspects in crop breeding. Several new genomics technologies such as next generation sequencing (NGS), high-throughput marker genotyping, -omics technologies have emerged as powerful tools for understanding genome variation in crop species at DNA, RNA as well as protein level. These technologies promise to provide an insight into the way gene(s) are expressed and regulated in cell and to unveil metabolic pathways involved in trait(s) of interest for breeders not only in model-/major- but even for under-resourced crop species which were once considered "orphan" crops. In parallel, genetic variation for a species present not only in cultivated genepool but even in landraces and wild species can be harnessed by using new genetic approaches such as advanced-backcross QTL (AB-QTL) analysis, introgression libraries (ILs), multi-parent advanced generation intercross (MAGIC) population and association genetics. The gene(s) or genomic regions, responsible for trait(s) of interest, identified either through conventional linkage mapping or above mentioned approaches can be introgressed or pyramided to develop superior genotypes through molecular breeding approaches such as marker-assisted back crossing (MABC), marker assisted recurrent selection (MARS) and genome wide selection (GWS). This article provides an overview on some recent genomic tools and novel genetic and breeding approaches as mentioned above with a final aim of crop improvement.

Molecular Breeding for Rainfed Lowland Rice in the Mekong Region

Abstract: In the past 20 years, the rice-breeding program in Thailand had little success in developing new cultivars to replace Kao Dawk Mali 105 (KDML105) and Kao Khor 6 (RD6) for the tainted lowland rice environments. The main reason for the poor adoption of new cultivars by farmers is the susceptibility to diseases and unacceptable grain qualities. The conventional breeding program also takes at least 15 years from initial crossing to the release of new cultivars. A new breeding strategy can be established to shorten the period for cultivar improvement by using marker-assisted selection (MAS), rapid generations advance (RGA), and early generation testing in multi-locations for grain yield and qualities. Four generation of MAS backcross breeding were conducted to transfer genes and QTL for bacterial blight resistance (BLB), submergence tolerance (SUB), brown plant hopper resistance (BPH) and blast resistance (BL) into KDML105. Selected backcross lines, introgressed with target gene/QTL, were tolerant to SUB and resistant to BLB, BPH and BL. The agronomic performance and grain quality of these lines were as good as or better than KDML105.

Genomics-assisted breeding in fruit trees.

Abstract: Recent advancements in genomic analysis technologies have opened up new avenues to promote the efficiency of plant breeding. Novel genomics-based approaches for plant breeding and genetics research, such as genome-wide association studies (GWAS) and genomic selection (GS), are useful, especially in fruit tree breeding. The breeding of fruit trees is hindered by their long generation time, large plant size, long juvenile phase, and the necessity to wait for the physiological maturity of the plant to assess the marketable product (fruit). In this article, we describe the potential of genomics-assisted breeding, which uses these novel genomics-based approaches, to break through these barriers in conventional fruit tree breeding. We first introduce the molecular marker systems and whole-genome sequence data that are available for fruit tree breeding. Next we introduce the statistical methods for biparental linkage and quantitative trait locus (QTL) mapping as well as GWAS and GS. We then review QTL mapping, GWAS, and GS studies conducted on fruit trees. We also review novel technologies for rapid generation advancement. Finally, we note the future prospects of genomics-assisted fruit tree breeding and problems that need to be overcome in the breeding.