marker-assisted selection in wheat

Chapter 1 – An overview of the issues 11Economic factorsAs with any new technology promisingincreased benefits, the costs of applicationmust also be considered. According toDekkers and Hospital (2002), “economicsis the key determinant for the application ofmolecular genetics in genetic improvementprogrammes. The use of markers in selectionincurs the costs that are inherent to moleculartechniques. Apart from the cost of QTLdetection, which can be substantial, costsfor MAS include the costs of DNA collection,genotyping and analysis.” For example,Koebner (2003) suggested that the currentcosts of MAS would need to fall considerablybefore it would be used widely in wheatand barley breeding. In practice, therefore,although MAS may lead to increased geneticresponses, decision-makers need to considerwhether it may be cost-effective or whetherthe money and resources spent on developingand applying MAS might instead bemore efficiently used on improving existingconventional breeding programmes oradopting other new technologies.Little consideration has been givento this issue. Some results have, however,been published recently from studiesat the International Maize and WheatImprovement Center (CIMMYT) in Mexicoon the relative cost-effectiveness of conventionalselection and MAS for differentmaize breeding applications. One applicationconsidered by Morris et al. (2003) wasthe transfer of an elite allele at a single dominantgene from a donor line to a recipientline. Here, conventional breeding is lessexpensive but MAS is quicker. For situationslike this, where the choice betweenconventional breeding and MAS involvesa trade-off between time and money, theysuggested that the cost-effectiveness ofusing MAS depends on four parameters: therelative cost of phenotypic versus markerscreening; the time saved by MAS; the sizeand temporal distribution of benefits associatedwith accelerated release of improvedgermplasm and, finally, the availability tothe breeding programme of operating capital.They conclude that “all four of theseparameters can vary significantly betweenbreeding projects, suggesting that detailedeconomic analysis may be needed to predictin advance which selection technology willbe optimal for a given breeding project.”In the applications considered byCIMMYT, the costs of developing molecularmarkers associated with the trait ofinterest were not considered, as it wasassumed that they were already available.There is a distinction between developmentcosts (e.g. identifying molecular markers onthe genome, detecting associations betweenmarkers and the traits of interest) andrunning costs (typing individuals for theappropriate markers in the selection programme)of MAS. Development costs canbe considerable, so developing countriesneed to consider whether to develop theirown technology or, alternatively, to importthe technology developed elsewhere, ifavailable.Another aspect to be considered is how toevaluate the economic benefits of MAS. Fora publicly-funded breeding programme, itshould include economic benefits to farmersfrom genetic improvement of their plants oranimals. For private companies on the otherhand, the impacts of using MAS on theirmarket share, and not on rates of geneticimprovement, would be of greatest interest.The economics of MAS are consideredin more detail later, in particular inChapter 19.MAS versus conventional methodsAlthough conventional breeding programmesthat rely on phenotypic records