Molecular breeding in plants: moving into the mainstream

Abstract

Molecular breeding, including both marker-assisted breeding and genetic engineering, has experienced significant innovations and advances during the past three decades. Starting with Mendelian genetics, plant breeders have progressed from using morphological markers to protein isozymes and then ultimately to DNA-based markers, which have enabled routine genome-wide analysis. As a result, thousands of genes and quantitative trait loci (QTL) have been mapped across the major crop species, laying the foundation for marker-assisted selection (MAS) techniques, such as precise marker-assisted backcrossing, to transfer desirable loci into breeding lines. With the subsequent development of advanced MAS strategies, including QTL pyramiding, marker-assisted recurrent selection and genomic selection, marker-assisted approaches have led to rapid gains in selection for plant breeding programs. Breeding by design and genetic modeling have received great attention as designing a desirable plant based on marker and associated gene information becomes increasingly possible. Following rice as the first crop species sequenced, whole genome sequences have been increasingly available for more and more crop species, enabling genotyping by sequencing and sequence-based marker technology and molecular breeding strategies to become a viable option, one widely used in large multinational seed companies. With significant reduction of genotyping cost and increased throughput, next-generation sequencing and SNP genotyping technologies are increasingly making MAS a choice of public-sector plant breeding as well. Now crop genomic diversity can be characterized at the sequence level based on haplotype maps, and molecular breeding can be further accelerated through allele mining and haplotype-based design and selection. With all the developments and significant advances in various fields of molecular biology and their integration with platforms and tools, molecular breeding is rapidly moving into the vanguard of mainstream breeding programs. To review and evaluate new theories and technologies recently developed in relation to plant breeding, the 3rd International Conference on Plant Molecular Breeding (ICPMB) was held in Beijing, China, Sept. 5–9, 2010. The conference was organized by an International Organization Committee represented by Zhi-Kang Li (Chinese Academy of Agricultural Sciences/International Rice Research Institute), Jean-Marcel Ribaut (the Generation Challenge Program), Aimin Zhang (Chinese Y. Xu (&) Institute of Crop Sciences/International Maize and Wheat Improvement Center (CIMMYT), Chinese Academy of Agricultural Sciences, 100081 Beijing, China e-mail: y.xu@CGIAR.ORG