Molecular Plant Breeding Yunbi Xu Pdf Download: Learn the Theory and Practice of Modern Plant Breedi

However, plant breeders and agricultural scientists face many challenges to integrate and exploit these newmolecular and genomics-related technologies for more rapid and efficientvariety development [15, 16]. In this article, we review the current globalrice molecular breeding lab with an emphasis on recent research and the impactof rice genomics resources. We also review some current genomics research andpromising new genotyping methodologies with high potential for appliedoutcomes. Finally, we consider the obstacles to the successful application ofmolecular genetics and genomics research in rice breeding programs and proposeideas on how some of these problems should be solved.

Molecular Plant Breeding Yunbi Xu Pdf Download

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Since marker genotyping methods were first developed in the 1980s, numerous protocolsand variations now exist. Many protocols have been refined and optimizedspecifically for the lab in which marker genotyping is conducted and willdepend on budget, equipment, and personnel. One feature of rice molecular breedinglabs is their diversity. Molecular breeding labs require a large initialcapital investment and since many labs are based in developing countries, theequipment and resources often differ markedly from those of well-funded labs indeveloped countries. The cost of marker genotyping is, therefore, a criticalfactor for the extent of MAS in rice, and this is likely to continue to be thecase for years to come given the unlikely dramatic decrease in costs.

In the context of plant breeding,there are several important considerations. Cost is critical due to the largenumber of samples breeders evaluate. Furthermore, 3 to 6 target traits usually segregatein a single population so the frequency of lines with all the desirable genecombinations is very low. This could undermine the suitability of some high-throughputwhole-genome profiling programs, although there could be numerous applicationsin basic research.

Despite the enormous potential for developing and using markers in rice, the cost ofgenotyping is still a prohibitive barrier to the wider application of MAS. Evenwith the global importance of rice, many developing countries have limitedresearch and development capability. Therefore, cost optimization of currentgenotyping protocols and the development of new cost-effective protocols shouldbe a major priority for breeding research and especially the rice molecularbreeding lab. These improvements might involve simple optimizations of current laboratorypractices, adopting new more efficient methods, or developing new MASstrategies and schemes.

QTL application research activities represent an extensive amount of time, effort,and resources. In practice, it seems that molecular breeders will ultimately have to perform this research insituations, in which important data for the application of MAS are notavailable. From experience, it is clear that breeding programs that do notundertake these activities risk wasting considerable time and resources. However,in practice, QTL application research activities may be constrained by funding,time, and resources; in some cases, these activities may be beyond the capacityof many rice molecular breeding labs. Furthermore, a breeder may decide that,based on the importance of the target trait, such QTL application research stepsdo not worth the investment in time, resources, and money, since, at the end, themarkers may not turn out to be useful for selection in their own breedingprogram.

Many activities will occur in the future ricemolecular breeding lab. Obviously, the primary objectives will be to supportand assist the breeding program in the evaluation and selection of breedingmaterial. To fulfill this duty, organizational and maintenance activities suchas organizing protocols, marker data, supplies of consumables, equipmentmaintenance, and LIMS will be critical. In-house data records for markeroptimization and parental screening will be critical; generally, the more detailedthe records, the better. This must include field and glasshouse leaf tissue collectionprotocols, which cannot be neglected.

It also seems certain that the development of custom-made markers will become morecommonplace, and so molecular breeders will need to be proficient in skillssuch as PCR primer design, DNA sequence analysis, and using bioinformaticsdatabases and tools. Considerable insilico applied genomics research will occur prior to wet-lab experimentsor before breeding populations are initiated. SNPs will be the inevitable polymorphismtarget of choice arising from current and future genomics research, so ricemolecular breeders should consider this ahead of time. Molecular breeders willalso need to keep in touch with current bioinformatics tools and futuregenomics advances.

Of course, establishing molecular breeding labs willnot be possible in many plant breeding stations, especially in developingcountries, because of limited funding and resources. However, collaboration withnational or international research institutions or universities could stillprovide opportunities for such breeding programs to gain benefits from genomicsresearch.

The parents used for developing MHP can be a representative sample of the population to which inference is desired and a core collection from a gene bank, varieties or landraces representing the elite germplasm for a breeding program, or a set of inbred lines representing a synthetic outcrossing population. MHPs have several distinct characteristics that make them very unique compared to other types of populations and very useful in genetics and plant breeding.

In addition to conventional quantitative genetics on combining ability, heterosis and hybrid performance, MHPs can be widely used in modern genetics, genomics and breeding. By high-density genotyping, MHPs can be used in GWAS for phenotypic data collected under diverse environments, including traits of agronomic importance, and heterosis and combining ability as well, which can be based on markers, alleles and haplotypes. MHPs per se and their derived secondary populations can be used in breeding for both inbred lines and hybrids. Taking 724 hybrids derived from 51 parental lines and four flowering traits as an example, we compared two independent GWAS methods, PEPIS software developed for hybrids and TASSEL software designed for inbred line populations. The two methods revealed highly consistent results with five overlapping chromosomal regions identified and used for discovery of candidate genes and QTN. Our results indicate that MHPs are powerful in GWAS for hybrid-related traits and will be widely used in the molecular breeding era. 2ff7e9595c