Genetic loci associated with high grain zinc concentration and pleiotropic effect on kernel weight in wheat (Triticum aestivum L.)

Zinc deficiency in humans is recognized as a widespread public health problem worldwide, but can be combated via genetic biofortification through breeding high zinc containing wheat varieties. CIMMYT (International Maize and Wheat Improvement Center, Int.) is engaged in enhancing, among others, the grain zinc concentration (GZnC) of high-yielding wheat germplasm under the HarvestPlus initiative of the Consultative Group on International Agricultural Research consortium. In the present study, we determined GZnC in a recombinant inbred line population from the cross between PBW343 and Kenya Swara in replicated trials grown in Zn-enriched field. An integrated genetic map with 1,133 loci (diversity arrays technology and simple sequence repeats markers) covering all 21 wheat chromosomes was constructed and used for quantitative trait loci (QTL) analysis. Two novel QTL of large effect were stably detected for increasing GZnC on chromosomes 2Bc (centromeric region) and 3AL (long arm). The two QTL individually explained about 10-15 % of the total phenotypic variation. The 2Bc QTL from PBW343 have pleiotropic effect and can increase thousand-kernel weight at significant level. The QTL and the closely linked markers identified will make selection for this difficult trait feasible in breeding program.