Natural Variation And Identification Of Microelements Content In Seeds Of Einkorn Wheat (Triticum Monococcum)

Abstract

Micronutrient deficiencies in human beings are common problems, especially in developing world. Among the micronutrient deficiencies,zinc (Zn) and iron (Fe) deficiencies are particularly important affecting severely health of humans. Major reason for thewidespread occurrence of micronutrient deficiencies in human beings is the high and monotonous consumption of cereal-basedfoods with very low content of micronutrients. An increase in concentration of Zn and Fe in grain is, therefore, a high-priorityresearch area. Exploitation of large genetic variation for Zn and Fe existing in cereals germplasm is an important approachto minimize the extent of Zn and Fe deficiencies in developing world. In the present study, the variation for seed contentof micronutrients (Zn, Fe, Mn and Cu) in 54 accessions of einkorn wheat (Triticum monococcum) was tested. The accessions have been first grown under same field conditions in 2 locations in Turkey, and the seeds obtainedfrom the field trials were analyzed for micronutrients. In addition, a mapping population with 168 recombinant inbred lineswhich were grown in 4 locations in Germany, Turkey and Italy has also been tested for the variation of micronutrients in seedsand analyzed for identification of QTLs associated with micronutrient content in seeds The results obtained showed existenceof large genotypic variation in content of micronutrients. The contents of Zn and Fe among the 54 einkorn wheat accessionsvaried from 0.21 to 2.16 μg seed-1 for Zn with an average of 1.19 μg seed-1 and from 0.54 to 3.09 μg seed-1 for Fe with an average of 1.15 μg seed-1. There was a close positive relationship between seed contents of Fe and Zn. The genetic basis of this variation was elucidatedby QTL analysis, using a mapping population comprising 168 recombinant inbred lines that was developed from a cross between2 cultivated Einkorn genotypes (e.g., ID-362 bread-making quality poor and ID-331 bread-making quality good). From the parentsID-362 had always more Zn than the other parent in all four locations. The four locations presented different mean values,varying from 1.09 to 2.16 μg seed-1 for Zn content, from 0.83 to 1.97 μg seed-1 for Fe content, from 1.43 to 1.97 μg/seed-1 for Mn content and from 0.14 and to 0.24 μg seed-1 for Cu content. Pooling the results of the four trials, a major QTL, common to all four microelements and explaining from10 to 30% of the variation (depending on the mineral assayed), was observed only on the chromosome 5, and not on the otherchromosomes. The Einkorn germplasm tested had a significant variation for micronutrients, especially Zn and this variationcould be exploited inbreeding programs. Chromosome 5 likely carries the genes affecting micronutrient accumulation in Einkornseeds