Population structure and SNP detection for phytic acid, Fe and Zn in sorghum (Sorghum bicolor [L.] Moench)

Mineral malnutrition is a major challenge worldwide, particularly in developing countries where approximately 50% of children are reported to have deficiency in several micronutrients, particularly iron (Fe) and zinc (Zn). In sorghum (Sorghum bicolor (L.) Moench), unlike other crops, biofortification is still limited by the presence of many anti-nutritional factors such as phytic acid (PA). This study was conducted to determine the genetic diversity and population structure as well as identify important genetic loci associated with PA, Fe and Zn in sorghum. The PA content ranged from 0.02 to 8.61 (g/100 mL) with a mean of 1.39. The mean Fe and Zn contents of the accessions were 67.42 and 17.40 mg/kg, respectively. The Fe content ranged from 18 to 201 mg/kg while the Zn content ranged from 1 to 40 mg/kg. The cluster and principal coordinate analyses grouped the accessions into two stratifications, a grouping that was also evident from the population structure analysis, which divided the 282 accessions into two distinct groups. The marker-trait association (MTA) revealed significant SNP markers associated with PA, Fe and Zn. Four SNP markers had significant loci associated with PA. The loci had allelic effects ranging from 0.53 to 0.96. For Zn and Fe, six (5 for SNP and 2for DArT markers) and 22 (6 for SNP and 16 for DArT markers) significant MTAs were identified, respectively. This study provides information on some important genetic loci for phytic acid in sorghum toward improving Fe and Zn bioavailability.