Establishment of Molecular Identity in 142 Sweet Sorghum Varieties

Abstract

DNA identity (ID) is highly effective and efficient to distinguish crop varieties regardless of their similarities in phenotypes. To establish the DNA ID constitution in sweet sorghum, we screened 103 SSR primer pairs that covered 10 linkage groups in 10 varieties of the crop, and selected 41 primer pairs with clear polymorphic bands. These SSR primers were then amplified in 142 accessions of domestic and exotic sweet sorghum germplasm. A total of 189 polymorphic bands were obtained with 2-11 bands per primer locus (averaging 4.6 bands). The polymorphism information content (PIC) of the 41 SSR loci ranged from 0.089 to 0.850 with an average of 0.543. There was great difference of specific index in the germplasm tested, which ranged from 109.1 to 454.7 with an average of 189.0. Based on allele number, 11 primers, i.e., Xtxp329, Xtxp258, Xtxp113, Xtxp303, Xtxp61, Xtxp201, Xtxp141, Xtxp91, Xtxp47, Xtxp217, and Xtxp67, were selected to construct DNA fingerprint of the 142 genotypes. The combination of the 11 primers showed effectiveness to distinguish these genotypes, suggesting that they could be used in molecular ID of sweet sorghum.