Zinc and Iron Concentrations in Seeds of Wild, Primitive, and Modern Wheats

In the case of cultivated modern wheats, the variation in zinc and iron concentrations in seeds is relatively small. Moreover, environmental and management factors exert a greater effect on variation of micronutrient concentrations of modern cultivated wheats than genetic factors. Wild wheats might serve as an important source of new genetic material for increasing micronutrient concentrations in seeds. To investigate this, we studied the variation in zinc and iron concentrations in seeds of wild and primitive diploid wheats and wild tetraploid wheats. The variation was particularly large in the case of zinc. The highest concentrations of zinc were found in the seeds of ssp. boeoticum (178 mg/kg) and ssp. dicoccoides (159 mg/kg). The results demonstrate that the genetic variation in the concentrations of zinc and iron in cultivated modern tetraploid and hexaploid wheats is extremely low when compared with the variation found in wild diploid and tetraploid wheats. This suggests that wild wheats, particularly chromosomes 6A and 6B in the wild tetraploid wheats, can be considered a major source of genetic diversity for increasing zinc and iron density in the seeds of modern wheats. In view of the fact that the concentrations of protein in seeds are strongly and positively correlated with the concentrations of iron and particularly of zinc, selection and/or breeding for high zinc and iron levels in seeds may result in simultaneously high levels of protein.