Search

• the role of spatial and climate variables on the genetic structuring of pomegranate plant. • Identify cytogenetic and genetic clines within the pomegranate accessions of Iran. • identify the species distribution modeling and the gene flow corridor. Pomegranate (Punica granatum L.) is an important horticultural plant in Iran and has been a food source since ancient times. Despite several genetic diversity studies conducted on these taxa, there are no reports on the landscape genetics of these important plants in Iran, nor is there any information on the effects of environmental, spatial, and climatic variables on the genetic structure of pomegranate. Therefore, this study used genetics, structural equation modeling (SEM), and species distribution modeling (SDM) approaches to explore the above-mentioned objectives. We used both cytogenetic and molecular analyses (SSR and SCoT markers) of several pomegranate samples along with environmental, spatial, and climatic variables. The redundancy analysis (RDA) analysis showed a significant positive association between terminal chiasmata with the longitudinal distribution of the pomegranate accession, while total chiasma number and interstitial chiasmata have an association with the altitude. The spatial PCA analysis indicated the role played by both global and local spatial variables in the cytogenetic variability like the univalent and terminal chiasmata formation. The Mantel test indicates that the cytogenetic difference in pomegranate plants is not related to their geographical distance, while the Moran I test result shows that geographical regions with similar spatial conditions affect the cytogenetic structuring of pomegranate plants in a similar way. SEM methods showed a strong negative association between bivalent formation and the environmental variables, while they showed both positive and negative associations between some of the environmental variables and different kinds of chiasmata. The sPCA analysis of molecular data showed a significant global, and local, spatial structuring of the molecular data and the genetic cline formation within the pomegranate accessions studied. Similarly, the spatial PCA analysis of climate variables, precipitation, and temperature revealed a significant structuring of genetic diversity and the formation of genetic clines by these factors. RDA analysis identified some of the loci that are significantly associated with temperature and precipitation. Therefore, both geographical/ or spatial variables and climate factors contribute to the genetic structure of the pomegranate accessions studied. SEM models based on genetic data revealed a positive association between environmental and climate variables with genetic diversity parameters and SSR-SCoT molecular loci studied. Climate change is unlikely to hurt pomegranate growing areas due to the high genetic diversity of pomegranate plants and the diverse genetic lineages present in the country. [ABSTRACT FROM AUTHOR]

Cotton (Gossypium hirsutum L.) is an important commercial crop that is cultivated in irrigated lands. Screening and selection of cultivars showing enhanced adaptation to drought is a target of cotton breeding programs. In order to study genetic variability in cotton genotypes under drought stress, eight cotton cultivars were screened using a 17% PEG treatment. Ten pots -each containing 5 seeds from each genotype- were planted using a randomized complete block design. Pots were distributed in two groups: with seedlings facing drought stress, and with well watered seedlings that were taken as controls. Twenty inter simple sequence repeat (ISSR) loci were used to determine genetic diversity. Four of the eight genotypes namely N2G80 and GT40 were rated as showing enhanced adaptation to drought stress while SKT133 and Bakhtegan were drought sensitive. The number of effective alleles -as measured by ISSR- varied from 1.189 (SKT133) to 1.363 (GT40). GT40 and SKT133 genotypes showed the highest and lowest gene diversity and percentage of polymorphism respectively. The highest number of specific alleles occurred in plant samples that were under drought stress. The high number of specific alleles in cotton plants under drought stress supports genetic changes in repeated motif changes within microsatellite regions. This genetic difference may be due to sequence changes in the genome or epigenetics. [ABSTRACT FROM AUTHOR]

Vitis vinifera L. is one of the economically important plant crops worldwide which is a valuable food source for humans. This precious plant species has several local varieties and accessions which are continuously under selection and cultivation. Due to these human activities, the grape faces genetic homogeneity and erosion. Therefore, it is important to investigate available genetic diversity in grape plants all over the world. We aimed to study the genetic structure and diversity as well as chemical differences of seven grape cultivars in the country. We used SSR, and SRAP molecular markers for genetic diversity analyses, as well as biochemical traits. Both molecular markers showed a medium to moderate genetic variability in the studied grape cultivars (about 20% genetic polymorphism). Similarly, both molecular markers differentiated the studied cultivars into two genetic groups. AMOVA indicated significant genetic difference in these cultivars. ANOVA analysis of flavonols (quercetin, myricetin, kaempferol, and rutin) contents of seeds extract by HPLC indicated the significant difference (P <0.01) among grape cultivars. PCA biplot of cultivars based on chemical features separated these cultivars into two major groups according to their flavone and flavonoid contents. Pairwise Mantel tests performed between molecular and chemical data showed a significant association between SSR and SRAP data, but no significant association was obtained between either SSR or SRAP data with chemical features in grape cultivars studied. A heat-map constructed based on combined molecular and chemical data revealed that some of the studied grape cultivars are distinct in their genetic and chemical features. [ABSTRACT FROM AUTHOR]

The present study was aimed at researching the morphological and genetic variability in the long-styled and short-styled plant forms in four subspecies of L. mucronatum. ANOVA and PCA analysis of morphological characters revealed significant difference among the long-styled and short-styled plants in all four studied subspecies. Similarly, AMOVA and Gst test, as well as Hickory test have shown significant molecular difference among these subspecies, while PCoA plot of molecular data after 99 permutations has disclosed genetic divergence of the long-styled plants versus short-styled plants in these subspecies. STRUCTURE analysis indicated a far greater genetic differentiation between the two plant forms of L. mucronatum subsp. mucronatum. Some degree of gene exchange was identified between all four subspecies, indicating that they are not completely isolated from each other. [ABSTRACT FROM AUTHOR]

Tamarix L. accessions were collected from Sistan and Baluchestan Province of Iran, covering an area of about 60 km located in the southeast of Iran. he present investigation was performed to study the genetic structure of Tamarix populations in this province and present some information about gene low among these populations. Forty-two tree specimens were randomly collected and studied for molecular and morphological diversity. Based on morphological descriptions we recognized 3 species that were confirmed by detailed morphometric and genetic analysis. he studied tree specimens were separated in 3 distinct clusters by UPGMA clustering and principal coordinate analysis and multidimensional scaling ordination methods. Clustering of molecular (ISSR) data showed some degree of genetic variation within each species. Similarly, STRUCTURE analysis and K-means clustering revealed some degree of genetic admixture among the studied accessions. NeighborNet and reticulograms revealed some degree of gene exchange among the studied populations. AMOVA and the Hickory test showed significant genetic differences of the studied populations and the Mantel test showed significant correlation between genetic distance and geographical distance of these populations. [ABSTRACT FROM AUTHOR]