Molecular and phenotypic characterization of a collection of white grain sorghum [Sorghum bicolor (L.) Moench] for temperate climates

Sorghum [Sorghum bicolor (L.) Moench] is a subsistence crop and the main food for populations in arid or semiarid regions and it is appreciated for the production of gluten-free products, forages, raw materials for industrial transformation and packaging. The end-use of different sorghum purposes having various plant or kernel characteristics require specific breeding programs to develop the desired ideotype. Sorghum grains can be classified according to kernel color, tannins and polyphenols content: white, yellow, red, brown, and black. White sorghum is characterized by a low level of total phenolic content and tannins. The advantage of using white sorghum is: increased protein digestibility, nutritional composition and consumer acceptance similar to other cereals. A collection of 117 white grain sorghums was characterized using 10 SSRs and preliminary agronomic observations were made for main traits. SSR analysis revealed from 10 to 33 alleles per locus.Observed heterozygosity was lower than expected according to the reproduction system of sorghum. Phylogenetic analysis revealed 6 main groups of genotypes. Only one group is constituted by genotypes with the same geographical origin (Egypt) while other groups are admixtures of different countries. The principal coordinate analysis revealed good correspondence between genetic profiles and groups evidenced by similar agronomic performances.