A heuristic method of searching for interesting ma

Authors: Jan Bocianowski Marcin Kozak Alina Liersch Iwona BartkowiakBroda

Publish Date: 2011/04/06

Volume: 181, Issue: 1, Pages: 89-100

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Abstract

Selection of parental lines is important in plant breeding programmes Markerassisted selection is an alternative to classical selection methods which are expensive and time consuming Markerassisted selection aims to find molecular markers that are linked to genes that determine quantitative traits of interest Classical statistical methods require particular assumptions to be fulfilled which is difficult to check if the analyses are performed automatically In this article we present a heuristic method to find interesting markers for quantitative traits This method includes various strategies that depend on what makes a genotype interesting to a plant breeder This approach was applied to eighteen parental lines of winter oilseed rape F1 CMS ogura hybrids with observation of 597 markers The traits of interest were seed yield and alkenyl glucosinolate content Fiftyseven markers were selected for further study The most prominent marker was OPY 02~1830 Markerassisted selection is the first step of analysis which can then be followed up by a more formal statistical analysis for a smaller set of interesting markersSelection of parental lines is one of the most expensive stages of breeding hybrid varieties but it is also important The choice of good parent components for development of F1 hybrids strongly affects the efficiency of breeding Until recently the main method for selecting hybrid combinations was to evaluate field experiments based on general and specific combining ability This method is expensive and time consuming because it requires crosses to be conducted in experimental or diallel designs Additionally the hybrids need to be evaluated in multiple field experiments preferably in many environmentsThe development of molecular genetics and other methods for studying genotypes at the DNA level offered an opportunity to quickly assess genetic variation in qualitative and quantitative traits independently from environmental conditions Joudren et al 1996 Javidfar et al 2006 The introduction of molecular markers into breeding research revolutionised plant sciences Molecular markers enable one to studying genotypes precisely which was not possible with traditional methods of quantitative genetics In addition the results are independent of the stage of plant development or environmental conditions Contemporary applications of molecular markers include but are not limited to genotyping alleles constructing genetic maps localising quantitative trait loci QTLs identifying varieties evaluating genetic distance between hybrids or breeding lines identifying transgenes and monitoring gene flow Young 1999 Mikolajczyk 2007Linkage groups corresponding to the chromosomes of the haploid genome were constructed with molecular markers These linkage groups enabled researchers to determine the genetic structures of many plant and animal species QTL mapping helped determine the localisation and function of genes that influence various traits These techniques can be used if there is an appropriate mapping population The integration of quantitative trait locus QTL analysis with markerassisted selection MAS could potentially increase breeding efficiency Steele et al 2006 Kassahun et al 2010 Many methods for QTL detection employ a biparental mapping population Such investigations are highly relevant to understanding the genetic structure of plants However available resources limit the size of mapping populations which results in decreased precision of QTL position and effect estimates Dekkers and Hospital 2002 Schön et al 2004 The main limitation of MAS is that the biparental mapping populations used in most QTL studies do not readily translate into breeding applications Heffner et al 2009

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