Association mapping for important biotic & abiotic related traits in structured wheat population.

摘要

This study was carried out in two successive seasons; 2009/2010 and 2010/2011 using two F3:6 nurseries. The first nursery contained 276 lines and two local checks genotyped using 1925 polymorphic DArT markers, while the second nursery consisted of 278 lines plus the same local checks and genotyped using 2236 polymorphic DArT markers. The nurseries were phenotyped in six to nine environments in Nebraska. The purpose of the study was to i) determine the breadth of the genetic base of the F3:6 nurseries that we currently use in our selection process ii) apply association-mapping approaches to identify DArT markers associated with important traits in F3:6 wheat populations iii) applying genomic selection methods in our breeding program.;The results showed that the F3:6 populations had sufficient genetic diversity that would make the selection effective in improving the population productivity and adaptability to Nebraska environmental condition.;As for the second objective we applied different statistical methods to identify markers that have significant correlation with the yield, grain volume weight, disease resistance, plant height and maturity. We have been successful in identifying potential QTL s for these traits. Some of the QTLs have been published, others are novel QTLs.;The comparison of the prediction accuracy for phenotypic selection with that from genomic selection indicated that GS were 94, 64, 84, 85 and 79% as accurate as Ps for grain yield, grain volume weight, plant height, anthesis date and leaf rust, respectively. We concluded that, when factors such as heritability, relative costs of genotyping versus field evaluation, and the number of cycles of selection per year are taken into account, the efficiency of GS becomes favorable in comparison with phenotypic selection.