Use of genetic variation of Iranian peanuts (Arachis hypogaea L.) to develop mapping populations

Peanut is one of the most important oilseed crops in the world. Genomic research of cultivated peanut has lagged behind that of other crop species because of the paucity of polymorphic DNA markers found in this crop. Identification of molecular genetic diversity in cultivated peanut will help with effective genetic conservation along with establishing efficient breeding programmes in this crop. The present study was initiated to establish genetic diversity and relationships in the peanut collection in Iran using simple sequence repeat (SSR) markers. Thirteen SSR primer pairs generated 80 alleles among 68 peanut accessions, with an average of 6.15 alleles per locus. Polymorphic information content (PIC)-values were high and ranged from 0.47 (Locus pPGPseq-2C11) to 0.95 (Locus PM183), with a mean value of 0.80. Several accession- and group-specific markers were identified that could be effectively used for identification purposes. High genetic variability was found in the collection. Dice genetic similarity coefficients ranged from 0.08 (D15-A5) to 1 (A8-A10-A12 and E12-E14). A unweighted pair-group method using arithmetic average (UPGMA) dendrogram and principal-component analysis (PCA) revealed two distinct clusters with three sub-clusters in cluster one that is not group-based on morphological classification of accessions in groups A, B, C, D, and E. Some accessions in the same sub-cluster or group had the same pedigree, but the dendrogram was not fully in accordance with pedigree information. Analysis of molecular variance (AMOVA) for five groups as A, B, C, D and E showed a higher level of genetic variation within groups as compared with between groups (83% versus 17%). Results indicated that these previously classified groups do not truly categorize the accessions. Genetic variation detected within the Iranian peanut collection can be utilized for selection of diverse parents for breeding and development of mapping populations.