Assessment of the genetic diversity and population structure of apricot (Prunus armeniaca L.) germplasm of the Northwestern Himalaya using SSR markers

2021 ◽  
pp. 1-10
Author(s):  
Aijaz A. Wani ◽  
Khalid Hussain ◽  
Showkat A. Zargar ◽  
Faizan Ahmad ◽  
Reetika Mahajan ◽  
...  

Abstract Apricot is considered an ecologically and economically important tree species of the stone-fruit crops that is widely grown in temperate regions of the world. Very few studies on apricot genetic diversity assessment have been carried out from the regions of Kashmir and Ladakh. In this backdrop, the present study was carried out to analyse the genetic diversity and population structure of 120 apricot genotypes collected from both the regions using 21 SSR markers. A total of 52 alleles were amplified with average values of marker index (MI) = 0.7084, resolving power (RP) = 2.8690, polymorphism information content (PIC) = 0.3132, Na = 2.317, Ne = 1.720, I = 0.572, Ho = 0.284, He = 0.360 and an average polymorphism of 91.2% per assay indicating high level of genetic diversity. The neighbour-joining (NJ) dendrogram generated three main clusters among selected apricot genotypes independent of their geographical locations. Interestingly, the result of the dendrogram coincides with the results of structure analysis which showed that the 120 apricot genotypes could be assigned to three (K = 3) sub-populations and the grouping of genotypes did not follow their geographical location suggesting that they share the same genetic pool. Moreover, analysis of molecular variance showed that 73% of the variation was attributed to differences within the individuals, 25% among individuals while only 2% of the variation was observed among the populations. The present study represents the most comprehensive analysis of the genetic diversity and population structure of apricot genotypes in Kashmir and Ladakh regions of India.

Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1365
Author(s):  
Lin Chen ◽  
Tingting Pan ◽  
Huirong Qian ◽  
Min Zhang ◽  
Guodong Yang ◽  
...  

Osmanthus serrulatus Rehder (Oleaceae) is an endemic spring-flowering species in China. It is narrowly distributed in the southwestern Sichuan Basin, and is facing the unprecedented threat of extinction due to problems associated with natural regeneration, habitat fragmentation and persistent and serious human interference. Here, the genetic diversity and population structure of 262 individuals from ten natural populations were analyzed using 18 microsatellites (SSR) markers. In total, 465 alleles were detected across 262 individuals, with a high polymorphic information content (PIC = 0.893). A high level of genetic diversity was inferred from the genetic diversity parameters (He = 0.694, I = 1.492 and PPL = 98.33%). AMOVA showed that a 21.55% genetic variation existed among populations and the mean pairwise Fst (0.215) indicated moderate genetic population differentiation. The ten populations were basically divided into three groups, including two obviously independent groups. Our results indicate that multiple factors were responsible for the complicated genetic relationship and endangered status of O. serrulatus. The concentrated distribution seems to be the key factor causing endangerment, and poor regeneration, human-induced habitat loss and fragmentation seem to be the primary factors in the population decline and further genetic diversity loss. These findings will assist in future conservation management and the scientific breeding of O. serrulatus.


Plant Disease ◽  
2017 ◽  
Vol 101 (7) ◽  
pp. 1113-1118 ◽  
Author(s):  
Yonggang Li ◽  
Karen Harris-Shultz ◽  
Hongliang Wang ◽  
Phillip A. Wadl ◽  
Pingsheng Ji

Black shank, caused by Phytophthora nicotianae, occurs worldwide and is responsible for significant yield loss in tobacco production in Georgia. Management of the disease has primarily relied on utilization of tobacco cultivars with resistance to race 0 of the pathogen and application of the fungicide mefenoxam. Races of P. nicotianae currently prevalent in tobacco production in Georgia, their sensitivity to mefenoxam, and genetic diversity of the pathogen are largely unknown. To determine population structure and genetic diversity of the pathogen, simple sequence repeat (SSR) markers were used. Three races of P. nicotianae (races 0, 1, and 3) were isolated from infected tobacco plants, with race 3 identified in Georgia for the first time. The majority of isolates were identified as A2 mating type and all isolates were sensitive or intermediately sensitive to mefenoxam at 1 or 10 μg/ml, with effective concentration of mefenoxam for 50% mycelial growth reduction values ranging from <0.01 to 0.12 μg/ml. Bayesian and unweighted pair group method with arithmetic means analyses of 59 isolates using SSR markers grouped the isolates in two major groups. Group I contained 20 isolates, of which 19 isolates were collected from Berrien County. Group II contained 39 isolates collected from Bacon, Cook, Tift, and Toombs Counties as well as one sample from Berrien County. Genetic diversity of the isolates was associated with geographical location of collection, and isolates in group I were primarily (75%) race 1, whereas isolates in group II were primarily (69%) race 0. The presence of a single pathogen mating type at most of the locations implies low probability of sexual recombination that may have contributed to the low genetic diversity at a particular geographical location. Sensitivity of the isolates to mefenoxam indicates that the fungicide remains to be a potent tool for growers to combat the disease. Information generated in the study advances our knowledge about diversity and population structure of P. nicotianae, which facilitates development and implementation of effective disease management programs.


2020 ◽  
Author(s):  
Sandy Jan E. Labarosa ◽  
Neah Rosandra Sevilla ◽  
Dindo Agustin A. Tabanao ◽  
Nenita B. Baldo ◽  
Helen L.V. Ebuña ◽  
...  

ABSTRACTOryza rufipogon Griff. or ‘Rufi’ is the wild progenitor of the cultivated rice, Oryza sativa L. In the Philippines, Rufi was previously known to be found only in Lake Apo, Bukidnon. However, a new population was identified in Lake Napalit in the same province. Based on previous morphological diversity assessment, both populations are unique for at least three characters, i.e., leaf, culm, and awn lengths. Environmental parameters such as rainfall and air temperature also differed between the two lakes. With these, an assessment of Rufi’s genetic diversity at the molecular level is beneficial to further ascertain its usefulness in rice breeding and gain insights on its conservation status. Thus, this study estimated the degree of genetic diversity and determined the population structure of 41 samples of natural Rufi populations in the Philippines using SSR markers. A total of 98 genome wide polymorphic SSR markers were selected to examine the genetic diversity and structure of Rufi populations, along with seven rice cultivars for comparison. Results showed that Philippine Rufi populations have lower genetic diversity compared to cultivated rice accessions and other Rufi populations in Southeast Asia and China. This low genetic diversity suggested that Rufi populations might be in a genetic bottleneck, perhaps due to observed unsustainable farming practices near their habitat and lack of awareness of their importance. A significant population structure and differentiation were determined using the STRUCTURE and phylogenetic analyses. Population differentiation might be due to geographic isolation which prevented gene flow between the two populations and the unique climatic conditions between the two lakes.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Yunyao Yang ◽  
Ruiqing He ◽  
Jian Zheng ◽  
Zenghui Hu ◽  
Jing Wu ◽  
...  

Abstract Background Lilac (Syringa oblata) is an important woody plant with high ornamental value. However, very limited genetic marker resources are currently available, and little is known about the genetic architecture of important ornamental traits for S. oblata, which is hindering its genetic studies. Therefore, it is of great significance to develop effective molecular markers and understand the genetic architecture of complex floral traits for the genetic research of S. oblata. Results In this study, a total of 10,988 SSRs were obtained from 9864 unigene sequences with an average of one SSR per 8.13 kb, of which di-nucleotide repeats were the dominant type (32.86%, 3611). A set of 2042 primer pairs were validated, out of which 932 (45.7%) exhibited successful amplifications, and 248 (12.1%) were polymorphic in eight S. oblata individuals. In addition, 30 polymorphic EST-SSR markers were further used to assess the genetic diversity and the population structure of 192 cultivated S. oblata individuals. Two hundred thirty-four alleles were detected, and the PIC values ranged from 0.23 to 0.88 with an average of 0.51, indicating a high level of genetic diversity within this cultivated population. The analysis of population structure showed two major subgroups in the association population. Finally, 20 significant associations were identified involving 17 markers with nine floral traits using the mixed linear model. Moreover, marker SO104, SO695 and SO790 had significant relationship with more than one trait. Conclusion The results showed newly developed markers were valuable resource and provided powerful tools for genetic breeding of lilac. Beyond that, our study could serve an efficient foundation for further facilitate genetic improvement of floral traits for lilac.


2020 ◽  
Author(s):  
Yunyao Yang ◽  
Ruiqing He ◽  
Jian Zheng ◽  
Zenghui Hu ◽  
Jing Wu ◽  
...  

Abstract Background: Lilac (Syringa oblata) is an important woody plant with high ornamental value. However, very limited genetic marker resources are currently available, and little is known about the genetic architecture of important ornamental traits for S. oblata, which is hindering its genetic studies. Therefore, it is of great significance to develop effective molecular markers and understand the genetic architecture of complex floral traits for the genetic research of S. oblata.Results: In this study, a total of 10,988 SSRs were obtained from 9,864 unigene sequences with an average of one SSR per 8.13 kb, of which di-nucleotide repeats were the dominant type (32.86%, 3,611). A set of 2,042 primer pairs were validated, out of which 932 (45.7%) exhibited successful amplifications, and 248 (12.1%) were polymorphic in eight S. oblata individuals. In addition, 30 polymorphic EST-SSR markers were further used to assess the genetic diversity and the population structure of 192 cultivated S. oblata individuals. 234 alleles were detected, and the PIC values ranged from 0.23 to 0.88 with an average of 0.51, indicating a high level of genetic diversity within this cultivated population. The analysis of population structure showed two major subgroups in the association population. Finally, 20 significant associations were identified involving 17 markers with nine floral traits using the mixed linear model. Moreover, marker SO104, SO695 and SO790 had significant relationship with more than one trait.Conclusion: The results showed newly developed markers were valuable resource and provided powerful tools for genetic breeding of lilac. Beyond that, our study could serve an efficient foundation for further facilitate genetic improvement of floral traits for lilac.


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