NATURAL VARIATION AND IDENTIFICATION OF MICROELEMENTS CONTENT IN SEEDS OF EINKORN WHEAT (TRITICUM MONOCOCCUM)

摘要

Micronutrient deficiencies in human beings are common problems, especially in developing world. Among the micronutrient deficiencies, zinc (Zn) and iron (Fe) deficienciesare particularly important affecting severely health of humans. Major reason for thewidespread occurrence of micronutrient deficiencies in human beings is the high andmonotonous consumption of cereal-based foods with very low content of micronu-trients. 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 cerealsgermplasm is an important approach to minimize the extent of Zn and Fe deficiencies indeveloping world. In the present study, the variation for seed content of micronutrients(Zn, Fe, Mn and Cu) in 54 accessions of einkorn wheat (Triticum monococcum) wastested. The accessions have been first grown under same field conditions in 2 locationsin Turkey, and the seeds obtained from the field trials were analyzed for micronutrients. In addition, a mapping population with 168 recombinant inbred lines whichwere grown in 4 locations in Germany, Turkey and Italy has also been tested for thevariation of micronutrients in seeds and analyzed for identification of QTLs associatedwith micronutrient content in seeds. The results obtained showed existence of large genotypic variation in content of micronutrients. The contents of Zn and Fe among the 54 einkorn wheat accessions varied from 0.21 to 2.16 mu g seed~(-1) for Zn with an average of 1.19 mu g seed~(-1) andfrom 0.54 to 3.09 mu g seed~(-1) for Fe with an average of 1.15 mu g seed~(-1). There was aclose positive relationship between seed contents of Fe and Zn. The genetic basis ofthis variation was elucidated by QTL analysis, using a mapping population comprising168 recombinant inbred lines that was developed from a cross between 2 cultivatedEinkorn genotypes (e.g., ID-362 bread-making quality poor and ID-331 bread-makingquality good). From the parents ID-362 had always more Zn than the other parent inall four locations. The four locations presented different mean values, varying from1.09 to 2.16 mu g seed~(-1) for Zn content, from 0.83 to 1.97 mu g seed~(-1) for Fe contentfrom 1.43 to 1.97 mu g/seed~(-1) for Mn content and from 0.14 and to 0.24 mu g seed~(-1)for Cu content. Pooling the results of the four trials, a major QTL, common toall four microelements and explaining from 10 to 30% of the variation (dependingon the mineral assayed), was observed only on the chromosome 5, and not on theother chromosomes. The Einkorn germplasm tested had a significant variation formicronutrients, especially Zn and this variation could be exploited inbreeding programs.Chromosome 5 likely carries the genes affecting micronutrient accumulation inEinkorn seeds.