Genetic Diversity in Diospyros Germplasm in the Western Caucasus Based on SSR and ISSR Polymorphism

Conservation Strategies for Aquilaria sinensis: Insights from DNA Barcoding and ISSR Markers

The evergreen tree species Aquilaria sinensis holds significant economic importance due to its specific medicinal values and increasing market demand. However, the unrestricted illegal exploitation of its wild population poses a threat to its survival. This study aims to contribute to the conservation efforts of A. sinensis by constructing a library database of DNA barcodes, including two chloroplast genes (psbA-trnH and matK) and two nuclear genes (ITS and ITS2). Additionally, the genetic diversity and structure were estimated using inter-simple sequence repeats (ISSR) markers. Four barcodes of 57 collections gained 194 sequences, and 1371 polymorphic bands (98.63%) were observed using DNA ISSR fingerprinting. The Nei's gene diversity (H) of A. sinensis at the species level is 0.2132, while the Shannon information index (I) is 0.3128. The analysis of molecular variance revealed a large significant proportion of total genetic variations and differentiation among populations (Gst = 0.4219), despite a relatively gene flow (Nm = 0.6853) among populations, which were divided into two groups by cluster analysis. There was a close genetic relationship among populations with distances of 0.0845 to 0.5555. This study provides evidence of the efficacy and dependability of establishing a DNA barcode database and using ISSR markers to assess the extent of genetic diversity A. sinensis. Preserving the genetic resources through the conservation of existing populations offers a valuable proposition. The effective utilization of these resources will be further deliberated in subsequent breeding endeavors, with the potential to breed agarwood commercial lines.

Population Analysis of Diospyros lotus in the Northwestern Caucasus Based on Leaf Morphology and Multilocus DNA Markers

Diospyros lotus is the one of the most frost-tolerant species in the Diospyros genera, used as a rootstock for colder regions. Natural populations of D. lotus have a fragmented character of distribution in the Northwestern Caucasus, one of the coldest regions of Diospyros cultivation. To predict the behavior of D. lotus populations in an extreme environment, it is necessary to investigate the intraspecific genetic diversity and phenotypic variability of populations in the colder regions. In this study, we analyzed five geographically distant populations of D. lotus according to 33 morphological leaf traits, and the most informative traits were established, namely, leaf length, leaf width, leaf index (leaf to length ratio) and the length of the fourth veins. Additionally, we evaluated the intraspecific genetic diversity of D. lotus using ISSR and SCoT markers and proposed a new parameter for the evaluation of genetic polymorphism among populations, in order to eliminate the effect of sample number. This new parameter is the relative genetic polymorphism, which is the ratio of polymorphism to the number of samples. Based on morphological and genetic data, the northernmost population from Shkhafit was phenotypically and genetically distant from the other populations. The correspondence between several morphological traits (leaf width, leaf length and first to fifth right vein angles) and several marker bands (SCoT5, SCoT7, SCoT30: 800–1500 bp; ISSR13, ISSR14, ISSR880: 500–1000 bp) were observed for the Shkhafit population. Unique SCoT and ISSR fragments can be used as markers for breeding purposes. The results provide a better understanding of adaptive mechanisms in D. lotus in extreme environments and will be important for the further expansion of the cultivation area for persimmon in colder regions.

Breeding of subtropical (Diospyros kaki L., Feijoa sellowiana Berg) and citrus crops (Citrus reticulata Blan. var. unchiu Tan.) in FRC SSC of RAS

This paper presents the results of the breeding work carried out by the Subtropical Scientific Centre of the Russian Academy of Sciences. The purpose of the research is to improve the assortment of subtropical and citrus crops. The objects of research were 230 hybrid forms, of which citrus - 138 hybrids, persimmons - 56, feijoa - 36. Currently, the breeders of the FRC SSC of RAS are working hard to develop new winter-hardy, high yielding, and high-quality cultivars resistant to growing conditions. The sources of priority traits have been identified, which are included in hybridization for the development of new cultivars with improved economic and biological traits. Over the past 5 years, the State Register of Breeding Achievements of the Russian Federation has included 3 cultivars of feijoa and 1 cultivar of kaki persimmon created in the Centre. On the test are 3 promising forms of tangerine, 2 feijoa and 1 form of kaki persimmon.