The Nikita Botanical Garden (NBG) has a unique Prunus L. collection (peach, apricot, plum, cherry) comprising more than 3000 accessions. NBG is also a breeding center for stone fruits, including peach (Prunus persica (L.) Batsch). In the present study a set of 85 peach cultivars bred in NBG, Europe, and North America was analyzed using 12 SSR markers to assess their genetic diversity and relatedness. The detected polymorphism level was comparable to the previous estimates of genetic variability in peach cultivars. The average number of alleles per locus was 5.67, PIC value averaged 0.49, expected, and observed heterozygosity averaged 0.52 and 0.31, respectively. Among the detected alleles, 19 (27.94%) were rare and 12 (17.65%) were unique. All studied accessions except two could be identified with the used marker set. Cluster analysis revealed some groups according to the cultivars’ pedigrees. No clear differentiation of the studied sample according to geographic origin or fruit characteristics of peach cultivars was revealed. The results provide valuable information for identification and rational management of the material preserved in the NBG peach collection.

×Trititrigia cziczinii Tsvel. is a synthetic species obtained as a result of hybridization of different wheat and wheat- grass species. ×T. cziczinii has unique characteristics, as it is a perennial species, with the ability to grow after mowing, high adaptability, resistance to diseases and pests, high protein and gluten content in the grain. All this makes it a promising new crop for agriculture. The new species is a good object for fundamental research in the field of genetics, phylogeny and evolution of cereals (Poaceae). However, there were practically no genetic studies of ×T. cziczinii. The aim of this work was to study the genetic diversity of 24 representatives of two ×T. cziczinii subspecies (ssp. Submitans and ssp. Perenne). To estimate interspecific differences, 17 samples of other tribe Triticeae species (Triticum aestivum, Triticum durum, Agropyron glaucum and Agropyron elon gatum, as well as samples of Triticum-Agropyron and TriticumElymus hybrids) were included in the analysis. For the study, AFLP method (Amplified Fragment Length Polymorphism) was chosen, which allowed us to reveal a sufficiently high polymorphism level of the studied samples. The two primer/enzyme combinations (EcoRI-ACT/MseI-CCC, EcoRI-ACT/MseI-CTA) allow ed the iden tification of 227 fragments, 224 of them were polymorphic (98.68 %), and the level of intraspecific polymorphism of 24 ×T. cziczinii samples was 68.15 %. The iden tified fragments of AFLP spectra, specific for the ×T. cziczinii representatives and the studied wheatgrass species, can be the basis for creating markers that will detect introgressions of genetic material of the genus Agropyron in the T. cziczinii ge nome. Our results indicate a greater genetic relatedness of ×T. cziczinii to T. aestivum than to representatives of the genus Agropyron. According to the cluster analysis, representatives of ×T. cziczinii and varieties of bread wheat were combined into a single subcluster, within which the samples of two species form separate groups. At the same time, the evaluation of the intraspecific genetic diversity of ×T. cziczinii showed  no reliable differentiation of representatives of the subspecies Submitans and Perenne, which is probably due to uncertain genetic nature of perenniality, the main feature that divides these subspecies. The study of the unique ×T. cziczinii collection allowed us to obtain the first data on the genetics of the species, while previous studies were focused mainly on phenotypic and economically valuable traits. AFLP analysis used in this study showed high efficiency when working with less studied species, and its results are promising and useful for understanding the genetic structure of the new species (×T. cziczinii Tsvel.).

At Pushkin and Pavlovsk Laboratories of the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) a diverse collec tion of local apple cultivars is maintained. Some of the cultivars are widely used in breeding programs for their ecological plasticity, increased adaptation to abiotic stress and disease resistance, still there have been no large-scale studies of these local cultivars for fruit storage ability. Fruit softening during storage is an important problem for apple production. Retention of desirable firmness after prolonged storage is one of the key requirements for new apple cultivars. Expansin and ethy lene biosynthesis related genes are known to be involved in control of fruit softening in apple, and gene specific molecular markers have been reported. In this study the polymorphism and allelic configuration of ethylene and expansin biosynthesis related genes Md-ACS1, Md-ACO1 and Md-Exp7 involved in control of fruit softening in 87 local apple cultivars from VIR Collection of Plant Genetic Resources were analyzed. PCR markers Md-ACS1, Md-ACO1 and SSR-marker Md-Exp7 were used in the study. The allele frequencies in the collection generally coincided with the data from previous studies. Md-ACS1 allele 2 associated with reduced ethylene production was found only in three local cultivars, while all the studied local cultivars were heterozygous for the Md-ACO1 locus, as well as most modern Russian apple cultivars. Half of the studied local cultivars were heterozygous for Md-Exp7 (198 : 202). Thirteen local cultivars with rare Md-Exp7 alleles (206, 210 and 212) were detected. No association was found between the Md-Exp7 genotype and the cultivars’ maturation time. The obtained results can be used for additional evaluation of the cultivars’ potential for breeding.

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