marker-assisted selection in wheat - ictsd

398Marker-assisted selection – Current status and future perspectives in crops, livestock, forestry and fishto screen for traits whose expressiondepends on geographical considerations.Using molecular markers, breeders inone location can screen for the presenceof an allele (or alleles) associated withtraits expressed only in other locations.• Multiple genes, multiple traits. MASoffers potential savings when there is aneed to select for multiple traits simultaneously.With conventional methods, it isoften necessary to conduct separate trialsto screen for individual traits.• Biological security considerations. MASoffers potential advantages over selectionbased on the use of potentially harmfulbiological agents (e.g. artificial viralinfections or artificial infestations withinsect pests), which may require specificsecurity measures.In view of the above-mentioned factors,it is desirable to consider MAS approacheson a case-by-case basis, taking into accountfactors such as the importance of a trait inthe overall breeding scheme, the amount ofavailable resources in terms of both staff andoperational expenditures, and the nature ofthe breeding materials. There are no “onesize fits all” recommendations that can bemade for MAS approaches. Usually, nobreeding scheme focuses on improving justone trait. At current levels of capacity, MASis likely to be used to achieve genetic gainsfor single traits such as host plant resistanceto pests and/or diseases. Therefore,MAS activities should be integrated into anoverall breeding programme.Challenges for developing countriesThe rapid expansion of agricultural biotechnologyis generating a wide array ofmethodologies with potential applications,and therefore national programmesin developing countries face the difficultchallenge of identifying priority areas forinvestment. To complicate matters further,the private sector dominates many fields ofbiotechnology research and therefore hasproprietary rights to many technologies andproducts that have immediate applicationsin developing countries (e.g. transgenictechnology). This is quite different fromconventional plant breeding technologies,most of which were developed by publiclyfundedresearch programmes and thus haveremained more accessible.There is no single answer to meetingthese challenges, especially as developingcountries are not uniform in their publicagricultural research capacities. Broadlyspeaking, developing countries fall into thefollowing categories:• countries (a few) with strong publicsector research infrastructure enablingbiotechnology applications, as well asupstream research capability to developtools for their own specific needs;• countries with intermediate capacity inapplied plant breeding, as well as inusing biotechnology tools that are publiclyavailable or can be acquired throughbilateral partnerships with the privatesector;• countries (a considerable number) withmoderate plant breeding capacity andpractically no, or very little, capacity forbiotechnology applications.More advanced developing countrieswith major commercial farming sectors aremore likely to succeed in adopting agriculturalbiotechnology. In addition, thepresence of commercial opportunities willattract investment by private industry andthus allow the country to benefit fromfuture advances in biotechnology. This isnot always a positive outcome for the publicsector because, as competition increases,it may be more difficult to justify largepublic investments in biotechnology. This