Molecular breeding

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

Current achievements and future prospects in the genetic breeding of chrysanthemum: a review

Abstract: Chrysanthemum (Chrysanthemum morifolium Ramat.) is a leading flower with applied value worldwide. Developing new chrysanthemum cultivars with novel characteristics such as new flower colors and shapes, plant architectures, flowering times, postharvest quality, and biotic and abiotic stress tolerance in a time- and cost-efficient manner is the ultimate goal for breeders. Various breeding strategies have been employed to improve the aforementioned traits, ranging from conventional techniques, including crossbreeding and mutation breeding, to a series of molecular breeding methods, including transgenic technology, genome editing, and marker-assisted selection (MAS). In addition, the recent extensive advances in high-throughput technologies, especially genomics, transcriptomics, proteomics, metabolomics, and microbiomics, which are collectively referred to as omics platforms, have led to the collection of substantial amounts of data. Integration of these omics data with phenotypic information will enable the identification of genes/pathways responsible for important traits. Several attempts have been made to use emerging molecular and omics methods with the aim of accelerating the breeding of chrysanthemum. However, applying the findings of such studies to practical chrysanthemum breeding remains a considerable challenge, primarily due to the high heterozygosity and polyploidy of the species. This review summarizes the recent achievements in conventional and modern molecular breeding methods and emerging omics technologies and discusses their future applications for improving the agronomic and horticultural characteristics of chrysanthemum.

Comparison of PCR-based molecular marker analyses of Musa breeding populations

Abstract: Progress in the breeding of plantain and banana has been restricted by the complex genetic structure and behaviour of cultivated polyploid Musa. Genetic improvement has been hindered due to the large amount of space required for growth and maintenance of plant populations, in addition to the long growth cycle and the low levels of fertility and seed viability characteristic of cultivated genotypes. Molecular marker assisted breeding has the potential to dramatically enhance the pace and efficiency of genetic improvement in Musa. This study was conducted to compare different PCR-based marker systems (RAPD, VNTR and AFLP) for the analysis of breeding populations generated from two diverse Musa breeding schemes. All three assays detected a high level of polymorphism between parental genotypes and within progeny populations. As expected, AFLP assays had by far the highest multiplex ratio while VNTR analysis detected the highest levels of polymorphism. AFLP analysis of a full-sib tetraploid hybrid population confirmed previous reports based on VNTR analysis, of a high frequency of recombination during 2n (3x) gamete formation by a triploid plantain landrace. In addition, both VNTR and RAPD analyses of a full-sib triploid hybrid population suggested a high frequency of homoeologous recombination during n (2x) gamete formation by tetraploid hybrids. In general, there was a poor correlation between estimates of genetic similarity based on different types of marker. The implications of these findings for the molecular breeding of Musa crops are discussed.

Recent progress on the genetics and molecular breeding of brown planthopper resistance in rice

Abstract: Brown planthopper (BPH) is the most devastating pest of rice. Host-plant resistance is the most desirable and economic strategy in the management of BPH. To date, 29 major BPH resistance genes have been identified from indica cultivars and wild rice species, and more than ten genes have been fine mapped to chromosome regions of less than 200 kb. Four genes (Bph14, Bph26, Bph17 and bph29) have been cloned. The increasing number of fine-mapped and cloned genes provide a solid foundation for development of functional markers for use in breeding. Several BPH resistant introgression lines (ILs), near-isogenic lines (NILs) and pyramided lines (PLs) carrying single or multiple resistance genes were developed by marker assisted backcross breeding (MABC). Here we review recent progress on the genetics and molecular breeding of BPH resistance in rice. Prospect for developing cultivars with durable, broad-spectrum BPH resistance are discussed.

Multiple cold resistance loci confer the high cold tolerance adaptation of Dongxiang wild rice (Oryza rufipogon) to its high-latitude habitat.

Abstract: Dongxiang wild rice is phylogenetically close to temperate japonica and contains multiple cold resistance loci conferring its adaptation to high-latitude habitat. Understanding the nature of adaptation in wild populations will benefit crop breeding in the development of climate-resilient crop varieties. Dongxiang wild rice (DXWR), the northernmost common wild rice known, possesses a high degree of cold tolerance and can survive overwintering in its native habitat. However, to date, it is still unclear how DXWR evolved to cope with low-temperature environment, resulting in limited application of DXWR in rice breeding programs. In this study, we carried out both QTL mapping and phylogenetic analysis to discern the genetic mechanism underlying the strong cold resistance. Through a combination of interval mapping and single locus analysis in two genetic populations, at least 13 QTLs for seedling cold tolerance were identified in DXWR. A phylogenetic study using both genome-wide InDel markers and markers associated with cold tolerance loci reveals that DXWR belongs to the Or-III group, which is most closely related to cold-tolerant Japonica rice rather than to the Indica cultivars that are predominant in the habitat where DXWR grows. Our study paves the way toward an understanding of the nature of adaptation to a northern habitat in O. rufipogon. The QTLs identified in DXWR in this study will be useful for molecular breeding of cold-tolerant rice.

Molecular progress on the mapping and cloning of functional genes for blast disease in rice (Oryza sativa L.): current status and future considerations.

Abstract: Rice blast disease, which is caused by the fungal pathogen Magnaporthe oryzae, is a recurring problem in all rice-growing regions of the world. The use of resistance (R) genes in rice improvement breeding programmes has been considered to be one of the best options for crop protection and blast management. Alternatively, quantitative resistance conferred by quantitative trait loci (QTLs) is also a valuable resource for the improvement of rice disease resistance. In the past, intensive efforts have been made to identify major R-genes as well as QTLs for blast disease using molecular techniques. A review of bibliographic references shows over 100 blast resistance genes and a larger number of QTLs (∼500) that were mapped to the rice genome. Of the blast resistance genes, identified in different genotypes of rice, ∼22 have been cloned and characterized at the molecular level. In this review, we have summarized the reported rice blast resistance genes and QTLs for utilization in future molecular breeding programmes to introgress high-degree resistance or to pyramid R-genes in commercial cultivars that are susceptible to M. oryzae. The goal of this review is to provide an overview of the significant studies in order to update our understanding of the molecular progress on rice and M. oryzae. This information will assist rice breeders to improve the resistance to rice blast using marker-assisted selection which continues to be a priority for rice-breeding programmes.