Genetic diversity of Poa pratensis L. depending on geographical origin and compared with genetic markers

Genetic Diversity Assessment of Iranian Kentucky Bluegrass Accessions: I. ISSR Markers and Their Association with Habitat Suitability Within and Between Different Ecoregions

Poa pratensis L. is a commonly used cool-season turfgrass and endemic to Iran. This research was carried out to examine the genetic diversity of this plant within and between ecoregions of Iran and the impact of climatic variables and elevation on the distribution of its genotypes, as well as habitat suitability modeling. We used fifty accessions collected from six ecoregions (West, South, North, North-West and North-East) for genetic diversity assessment using 20 ISSR marker primers. The prospective ecoregions for Kentucky bluegrass production were projected using habitat suitability modeling, which took into account important environmental parameters, such as annual mean temperature, annual mean rainfall, and elevation. According to the UPMGA dendrogram, the accessions were divided into two major types and four subclasses. The genetic distance between the North and North-east accessions, as well as the Center accessions, was greater than that of the other genotypes. Center accessions had the greatest levels of polymorphism, effective number of alleles, Shannon index, and Nei's genetic diversity. The FR method was used to create the habitat suitability map based on environmental factors. Rainfall had the largest influence on the genotype distribution of P. pratensis L. The findings of this study can be used as raw materials in future breeding programs to improve and generate new cultivars with superior characteristics. It can also assist programs in identifying rare cultivars as well as preserving and developing native P. pratensis L. genotypes.

Assessing the potential of native ecotypes of Poa pratensis L. for forage yield and phytochemical compositions under water deficit conditions

Evaluation of forage yield and antioxidant activity in Poa pratensis with high quality and good spring green-up forage might help variety improvement for use under water deficit condition. Germplasm and phenotypic diversity evaluations lay a foundation for genotype selection and improvement of varieties for drought tolerance in P. pratensis. The present study was conducted to assess the genetic potential of a collection of P. pratensis accessions for drought stress and to identify the association between polyphenol compounds and forage yield traits. Vegetative clone samples of 100 accessions collected from a diverse geographical area of Iran were clonally propagated in a greenhouse and evaluated in the field under two moisture regimes (non-stress and drought stress) in 2018 and 2019. Drought stress had negative effects on fresh and dry forage yields and reduced phenotypic variances. On average, drought stress reduced fresh and dry forage yields by 45% and 28%, respectively. The results of Mantel test showed no significant correlation between forage yield traits and geographical distances. Genetic coefficients of variation for forage yield and most of the phytochemicals were lower under drought stress, suggesting that deficit irrigation may reduce genetic variation for the tested traits. The estimates of heritability were higher under non-stress conditions than under drought stress treatment for forage yield traits and few polyphenols. However, the majority of polyphenol compounds had higher heritability than forage yield traits under drought stress, which suggests the potential for indirect selection. The 'Ciakhor', 'Damavand', 'Karvandan', 'Abrumand', and 'Abr2' accessions had high quantities for polyphenols and yield traits under both moisture regimes. These accessions are promising candidates for use in variety crossing programs and for developing high-yielding varieties under water-deficit conditions.

Morphological variability and genetic diversity in Carex buxbaumii and Carex hartmaniorum (Cyperaceae) populations

Background

Carex buxbaumii and C. hartmaniorum are sister species of the clade Papilliferae within the monophyletic section Racemosae. An unambiguous identification of these species is relatively difficult due to the interspecific continuum of some morphological characters as well as the intraspecific variability. The study was aimed at determining the range of variability, both morphological and genetic, within and between these two closely related and similar species.

Methods

The sedges were collected during botanical expeditions to Armenia, Estonia, the Netherlands, and Poland. The morphological separation of the two species and their populations was tested using the Discriminant Function Analysis (DFA). The genetic variability of the 19 Carex populations was assessed in the presence of eight Inter Simple Sequence Repeat (ISSR) primers.

Results

Results of the study indicate a considerable genetic affinity between the two sedge species (mean Si = 0.619). However, the populations of C. hartmaniorum are, morphologically and genetically, more homogenous than the populations of C. buxbaumii. Compared to C. hartmaniorum, C. buxbaumii usually has wider leaf blades, a shorter inflorescence, a lower number of spikes which are shorter, but wider, and longer bracts and utricles. The AMOVA showed a larger variation between the populations of C. buxbaumii, representing 25.65% of the total variation in the taxon. Two populations of C. buxbaumii (from Poland and Estonia) are separated from the remaining populations, both genetically and morphologically; their individuals show shorter utricles and glumes, compared to the typical specimens of C. buxbaumii, and correspond with the morphology of putative infraspecific taxa described by Cajander (var. brevisquamosa and var. confusa).

Conclusions

The taxonomic status of the putative infraspecific taxa within C. buxbaumii requires further studies throughout the distribution range of C. buxbaumii, addressing habitats, morphology and genetics (including a chromosome count or a combination of different genetic methods), particularly as the variability in C. buxbaumii may be associated with the species’ polyploid origin.

SSR loci survey of technical hemp cultivars: The optimization of a cost-effective analyses to study genetic variability

Our study aimed to optimize a selection of a suitable combination of SSRs (Simple Sequence Repeats) for determination of technical Cannabis cultivars and genetic variability level. We used sequences of 23 published SSR families (107 alleles) and amplified them in 28 cultivars. One of the alleles possesses no selective information (SSR family CAN1660) due to its presence in every single tested cultivar. We excluded it, together with another 11 least informative alleles. After data filtration, we used 96 alleles to do recursive sub-sampling of random alleles' sets. We found a minimal set of 8 alleles (in three different combinations) to distinguish 28 analyzed cultivars from each other. Our results contribute to saving resources and to reduce the performance time of the molecular analysis.

Genetic differentiation between bitter and sweet asafetida plants using ISSR markers

Bitter (Ferula pseudalliacea) and sweet (Ferula assa-foetida) asafetida (Apiaceae family) are well-known economic and medicinal herbs owing to their gum. This study investigates genetic differentiation of F. pseudalliacea and F. assa-foetida using ISSR markers, to determine the effective primer and to assess the possibility of separating sweet and bitter plant populations from each other. Results showed that among 22 primers, eight markers reproduced obvious DNA patterns and revealed 234 scorable DNA bands. ISSR-16 and ISSR-55 primers had better performance than other primers according to the number of bands, PIC and Marker Index. Bitter population showed polymorphic loci (224), percentage of polymorphic loci (95.73%) and observed number of alleles (1.96 ± 0.2), while sweet populations showed the amount of these parameters as 218, 93.16% and 1.93 ± 0.25, respectively. Estimated G_st of sweet population was 0.09 and G_st of bitter population was 0.06. Comparing gene flow in bitter and sweet populations showed a lower level of gene flow between sweet populations (N_m = 4.93) compared to bitter ones (N_m = 7.89). Within group genetic similarity of sweet asafetida population was higher than between group variation of bitter and sweet populations. The highest similarity was observed between bitter populations (0.95). The highest genetic dissimilarity was also estimated between bitter and sweet populations (0.08). Cluster analysis grouped four studied populations into 13 clusters using Jaccard^'s similarity coefficient and UPGMA method. Principal coordinate analysis showed that 61.02% of total variance was explained using three components and it could completely separate populations as well as cluster analysis. These grouping correspond nearly with geographical distribution. Analysis of molecular variance showed that genetic variation within populations (87%) was more than among populations (13%). The results indicated that ISSR marker is suitable to investigate genetic diversity of asafetida populations and could separate populations of the same genera with similar germplasm.