marker-assisted selection in wheat - ictsd

Chapter 22 – Marker-assisted selection: policy considerations and options for developing countries 443IntroductionThis book provides a comprehensivedescription and assessment of MAS forincreasing the rate of genetic gain in a widerange of agriculturally important speciesusing DNA-based markers for both simpleand quantitative traits. Its various chaptersattest to the remarkable progress that hasbeen made in researching this approach.This progress has only been possiblethrough the determined pursuit of multidisciplinarity,i.e. by bringing together intoteams the skills and knowledge of individualswho could: innovate around thesuite of techniques provided by advances inmolecular biology to isolate, multiply, identifyand insert DNA sequences; produceinnovations in electronics and engineeringto miniaturize, automate and providehigh sample preparation and analyticalthroughput; use statistical and computerscience to analyse and manage the information(bioinformatics) obtained; extendknowledge of the mechanisms that regulatephysiological processes in plants andanimals; and use quantitative genetics inassociation with conventional and novelbreeding and selection approaches. Thisresearch has contributed enormously tothe processes of adapting the basic techniquesand tools of molecular biology tostudy the genetic make-up of agriculturallyimportant species at the molecular level,and to accumulating knowledge of the linkagesbetween DNA sequences and in somecases genes and traits that are importantfor the livelihoods of farmers, foresters andfisherfolk.Yet, while recognizing this admirableprogress, for most species and most traitsthat are important for both large commercialenterprises in the industrializedworld and more particularly for small-scaleand resource-poor production systems thatconstitute the livelihoods of the majorityof the rural poor in developing countries,MAS has still to deliver on its undoubtedpotential, and on the claims in academicand other circles that it would “revolutionize”the way advantageous varietiesand breeding stock are developed. As aresult, there is still a substantial mismatchbetween “the field” and the expectations ofpolicy-makers, social scientists, communitygroups and non-government organizations(NGOs), etc. In fact, the reality is that,while the approach has certainly transformedlaboratory operations, apart fromits use by the private sector in backcrossingof transgenes into elite inbred lines ofmaize and other crops and some commercialapplications in livestock, the impactsof MAS on rural livelihoods have to datefallen well short of expectations.This chapter does not dwell on thescientific and technical issues underpinningMAS, nor does it challenge eitherthe need for continued research or theunquestionably greater opportunities forscientific and technical breakthroughs andsocio-economic benefits that will surelyarise from sequencing and post-genomicsresearch – provided levels of investment ingathering and analysing phenotypic datakeep pace with molecular developments.Its focus is on the evolving political, policyand institutional settings (both nationallyand internationally) within which agricultureand agricultural S&T institutions andextension services are operating in developingcountries, and on some of the optionsopen to governments and public sectorinstitutions in these countries to engagemore forcefully in MAS-related R&D andthe diffusion of genetically improved productsgenerated through this approach toproducers. It argues that the challengesand opportunities for doing so cannot be