Genetic Diversity in a Worldwide Collection of Sainfoin Using Morphological, Anatomical, and Molecular Markers

Genetic information on sainfoin (Onobrychis viciifolia Scop.), an important forage species, is highly limited. In this study, genetic diversity and trait relationships of 80 sainfoin accessions were evaluated using morphological, anatomical, and inter-simple sequence repeats (ISSR) characteristics. Results of 2 yr of study indicated a wide range of variability in the germplasm using all three data sets. Based on morphological assessment, accessions were divided into three different groups that could be easily identified by traits such as palatability, resistance to powdery mildew, and percentage of plant shoot and leaf. On the other hand, great diversity was found for anatomical traits, especially vessel diameter, sieve diameter, width of phloem, and xylem/phloem ratio, possibly indicating different mechanisms of water and solute transport among populations. Results indicated that anatomical traits were less influenced by environmental constraints compared with agro-morphological traits. Accessions with high vessel diameter and large xylem diameter were may be palatable. Result of ISSR markers showed that high genetic variation among accessions can be closely related to "Isolation by distance" model, resulting in accessions falling into two main clusters (Iranian and the exotics), each having four subclusters. Most of the genetic variance was found among the accessions and less among the geographical groups. Results suggested that Asia and Eastern Europe may be the main center of diversity for this species.