Molecular breeding

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

Discussion on germplasm and gene utilization in breeding of super rice.

Abstract: Breeding of super rice is a new breeding method based on semidwarf breeding and utilization of heterosis in rice.It is the result of utilization of germplasms or genes and its interaction with environment.The paper reviews the current status of integrative utilization of germplasms and genes in the breeding of super rice in China.It deals with gene introgression of indica and japonica,pyramiding and using of yield QTLs in cultivated rice,exploitation and use of the genes related with high-yielding,resistance to pests,plant and root architectures.Nowadays agronomical important genes and their closely-linked molecular markers are not enough to supply the strong basis for molecular breeding of super rice.The common cross breeding is still an effective method in breeding of super rice through interactive use of the rice germplasms.Therefore it is necessary to make great efforts to develop wide-adaptable super rice or green super rice through exploitation of genes related with high-yielding,high quality,resistance to pests and diseases,and tolerance to stresses.The modern molecular breeding methods in combination with common cross techniques should be adopted in the program of super rice breeding.

Trait physiology and crop modelling to link phenotypic complexity to underlying genetic systems.

Abstract: New tools derived from advances in molecular biology have not been widely adopted in plant breeding because of the inability to connect information at gene level to the phenotype in a manner that is useful for selection. We explore whether a crop growth and development modelling framework can link phenotype complexity to underlying genetic systems in a way that strengthens molecular breeding strategies. We use gene-to-phenotype simulation studies on sorghum to consider the value to markerassisted selection of intrinsically stable QTLs that might be generated by physiological dissection of complex traits. The consequences on grain yield of genetic variation in four key adaptive traits – phenology, osmotic adjustment, transpiration efficiency, and staygreen – were simulated for a diverse set of environments by placing the known extent of genetic variation in the context of the physiological determinants framework of a crop growth and development model. It was assumed that the three to five genes associated with each trait, had two alleles per locus acting in an additive manner. The effects on average simulated yield, generated by differing combinations of positive alleles for the traits incorporated, varied with environment type. The full matrix of simulated phenotypes, which consisted of 547 locationseason combinations and 4235 genotypic expression states, was analysed for genetic and environmental effects. The analysis was conducted in stages with gradually increased understanding of gene-tophenotype relationships, which would arise from physiological dissection and modelling. It was found that environmental characterisation and physiological knowledge helped to explain and unravel gene and environment context dependencies. We simulated a marker-assisted selection (MAS) breeding strategy based on the analyses of gene effects. When marker scores were allocated based on the contribution of gene effects to yield in a single environment, there was a wide divergence in rate of yield gain over all environments with breeding cycle depending on the environment chosen for the QTL analysis. It was suggested that knowledge resulting from trait physiology and modelling would overcome this dependency by identifying stable QTLs. The improved predictive power would increase the utility of the QTLs in MAS. Developing and implementing this gene-to-phenotype capability in crop improvement requires enhanced attention to phenotyping, ecophysiological modelling, and validation studies to test the stability of candidate QTLs.

Achieving crop stress tolerance and improvement--an overview of genomic techniques.

Abstract: The inexorable exposure of plants to the combinations of abiotic stresses has affected the worldwide food supply. The crop improvement against these abiotic stresses has been captivating approach to increase the yield and enhance the stress tolerance. By using traditional and modern breeding methods, the characters that confer tolerance to these stresses were accomplished. No doubt genetic engineering and molecular breeding have helped in comprehending the intricate nature of stress response. Understanding of abiotic stress-involved cellular pathways provides vital information on such responses. On the other hand, genomic research for crop improvement has raised new assessments in breeding new varieties against abiotic stresses. Interpretation of responses of the crop plants under stress is of great significance by studying the main role of crops in food and biofuel production. This review presents genomic-based approaches revealing the complex networks controlling the mechanisms of abiotic stress tolerance, and the possible modes of assimilating information attained by genomic-based approaches due to the advancement in isolation and functional analysis of genes controlling the yield and abiotic stress tolerance are discussed.

Marker-assisted selection for the development of improved barley and wheat lines

Abstract: Marker-assisted selection (MAS) is an efficient modern method for transferring alleles or specific chromosome segments including important agronomic traits into elite cultivars. This approach makes genotypic selection possible, whereby the selection process is more effective. The Research Institute of Plant Production Piesťany uses genetic markers linked to important traits in the following pre-breeding programmes: 1. development of winter barley lines resistant to BaYMV/BaMMV, 2. development of spring barley lines resistant to BYDV, 3. development of winter wheat lines resistant to leaf rust (gene pyramiding), 4. improvement of wheat quality by new combination(s) of known HMW-GS and/or by introduction of novel HMW-GS alleles. Several hundreds of genotypes are usually analysed for the presence or absence of linked molecular markers and selected for use in breeding programmes.