Evaluation of genetic stability in cryopreserved Solanum tuberosum

Cryopreservation is a technology of high importance in the storage of plant germplasm for long periods; however, the practical application of this technology for the preservation of plant materials isuseful only if it does not lead to the genetic changes in the plant of interest. In the present investigation, the genetic stability of potato (Solanum tuberosum L.) plantlets of the cultivars Agria and Marphonastored under cryopreservation and non-cryopreservation conditions was studied using amplified fragment length polymorphism (AFLP) technique. Also, flow cytometric studies were performed todetect if there were probably any changes in the level of polyploidy. Seven primer combinations were used in the AFLP studies. Agria plantlets kept under non-cryopreserved conditions were approximatelyof average 97% genetic similarity to those of the same cultivar stored under cryopreservation conditions. With the cultivar of Marphona, full (100%) homology was found between plantlets stored under cryopreservation and non-cryopreservation conditions. Comparative studies on the polyploidy levels of the plantlets of both cultivars conserved under two above-mentioned storage conditionsindicated that cryopreservation technique did not cause any changes in polyploidy levels

Evaluation of genetic diversity in the subspecies of Aegilops tauschii using microsatellite markers

Twenty four SSR primer pairs were used to determine the genetic diversity in the subspecies of Aegilops tauschii . All microsatellite markers showed a high level of polymorphism. The average number of alleles observed was relatively similar in subsp. tauschii (9.00) to that in strangulata (8.30). The tauschii group had also similar average PIC value (0.80) with the strangulata group (0.77). The range of similarity was higher in subsp. tauschii than subsp. strangulata , reflecting a higher level of genetic variation in the first subspecies. Cluster and PCO analyses revealed a relative pattern of differentiation between two taxonomic classified subspecies, but there were some exceptional accessions in each group, reflecting possible intermediate forms between these two subspecies. Wide distribution of alleles found in both subspecies can be used for wheat improvement

Genetic diversity of Aegilops crassa and its relationship with Aegilops tauschii and the D genome of wheat

Simple sequence repeat (SSR) DNA markers were used to characterize the genetic diversity in 70 accessions of Aegilops crassa from Iran as well as to determine relationships among these accessions with 9 accessions of Aegilops tauschii (subsp. tauschii and strangulata ) and 5 Triticum aestivum landraces. All twenty SSR primer pairs were polymorphic and identified a total number of 149 alleles corresponding to an average of 7.5 alleles per locus. The highest and lowest PIC values were obtained in subsp. strangulata and Ae. crassa accessions, respectively. Data obtained were used to estimate genetic similarity using the Dice coefficient, and dendrogram was constructed using the UPGMA method. The dendrogram separated the 84 accessions into two main groups. All species grouped according to their genomes. A good level of genetic diversity was observed in the accessions of Ae. crassa , even in geographically close regions, which can be used in the broadening of the genetic base of bread wheat. In addition, T. aestivum and subsp. tauschii were clustered further away from Ae. crassa , confirming probably chromosomal rearrangements in the Dgenome of Ae. crassa during the processes of evolution

Comparative assessment of SSAP, AFLP and SSR markers for evaluation of genetic diversity of durum wheat (triticum turgidum l. var. durum)

Comparative assessment of genetic diversity of 122 durum wheat genotypes (Triticum turgidum L. var. durum) was performed using 73 SSAP polymorphic fragments, 123 AFLP polymorphic loci and 104 SSR alleles. SSAP and AFLP data showed a clear demarcation between the cultivars and landraces and SSR data classified cultivars and landraces according to their origin. Furthermore, the estimated genetic diversity of Iranian landraces was higher compared to the foreign entries and a loss of genetic diversity was observed from landraces to cultivars. This study determined that differences in genetic relationships revealed by SSAP, AFLP and SSR distances could not be attributed solely to differences in the level of polymorphism detected by each marker system. The molecular evidence of genetic diversity decrease of the durum wheat gene pool further strengthens the strategic relevance of undertaking appropriate genetic conservation measures for food security