Abstract only

Use of markers in wheat breeding and release of resultant varieties has progressed substantially from the cautious optimism of a decade ago. Routine screening in the CIMMYT wheat program is now applied to around 30 marker loci, with screening of around 40,000 lines per year generating around 70,000 data points. Moreover, MAS is now used routinely by partners in more advanced developing countries like China and India. Compare this with the early- mid 90?s when it was so hard to find molecular polymorphisms in wheat that a wide cross (Opata x synthetic) was the focus of ITMI. For the more cynical breeders at that time it must have seemed unlikely anything useful would come from these efforts if such a wide cross was needed to find polymorphisms and develop a map.|For molecular technology to be useful in breeding it must better identify parents for crossing and select the best segregants from those crosses. At CIMMYT our molecular research builds on our comparative strengths; our germplasm base and phenotyping capability [both in-house and through the International Wheat Improvement Network (IWIN)]. These strengths allow us to actively collaborate with researchers in advanced research institutes, contributing to the science and translating it to application in wheat improvement for and by the developing world. Examples discussed will include diversity analyses which have been applied to international nursery series. In combination with phenotypic and environmental data, this information can be used for association mapping, haplotype analysis and to direct Ecotilling efforts. These techniques have or will be applied to landraces, wild and alien wheat species to identify potentially useful new genetic variation and focus introgression and marker development on these ?best bets?.|Beyond identifying useful genetic variation, a lot of unglamorous work is usually needed to develop high throughput markers that are a cost-effective supplement or alternative to highheritability phenotyping over the 2 selection cycles per year that we have for many traits. Other factors affecting the decision to use MAS include heritability of the trait and the proportion of variation that can be accounted for by known genes or regions, the importance of the trait relative to others undergoing selection and whether MAS can be applied for them. More detailed examination of these factors and findings from modeling some realistic scenarios will be presented.

Genetic Resources Program|Global Wheat Program

English

Lucia Segura

INT2585|INT2542|INT1511|INT2692|INT0599|INT2902|INT0610

CIMMYT Staff Publications Collection