Genetic evaluation and germplasm identification analysis on ITS2, trnL-F, and psbA-trnH of alfalfa varieties germplasm resources

Abstract In this study, genetic diversity and germplasm identification of 28 alfalfa germplasm cultivars materials were evaluated by analyzing their internal transcribed spacer 2 (ITS2), trnL-F, and psbA-trnH sequences to provide the innovative reference of alfalfa varieties genetic diversity and identify research. The results showed that the fragment average length of ITS2, trnL-F, and psbA-trnH sorting sequences were 455.7 bp, 230.3 bp, and 345.6 bp, respectively. The ITS2 sequence was too conservative to reflect the individual differences between intercultivars and intracultivars in the preliminary experiment. Furthermore, trnL-F and psbA-trnH sequence differences were relatively small between intercultivars but significant between intracultivars. Alfalfa cultivars were divided into four groups by sequence similarity clustering. Alfalfa cultivars trnL-F and psbA-trnH sequences have apparent differences, showing that chloroplast conservative sequences were independent evolution. Compared with trnL-F and psbA-trnH sequences of alfalfa cultivars, psbA-trnH sequence has abundant variation sites and can better reflect the differences between cultivars than the trnL-F sequence. Therefore, the psbA-trnH sequence can identify different alfalfa cultivars and establish the DNA sequence fingerprint.