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Background: Safflower (Carthamus tinctorius L.) is an old oilseed crop with a 1.4 GB genome size and its flowers are used for food coloring, dyes and pharmaceutical industries. It was domesticated from its putative wild ancestor Carthamus palestinus about forty-five hundred years ago in the fertile crescent region.The current study was aimed to determine the genetic diversity, population structure and to check the applicability of iPBS-retrotransposons markers., Methods and Results: Eleven POGP primers yielded 70 bands of which 61 were highly polymorphic with 87.14% polymorphism. A great level of genetic variation was examined with higher values of overall gene diversity (0.27), genetic distance (0.53), number of effective alleles (1.46), Shannon's information index (0.41) and polymorphism information contents (0.71). Analysis of molecular variance revealed high genetic variation with 79% within the population. The STRUCTURE, PCoA and Neighbor-joining analysis separated the safflower germplasm into 2 major populations and 1 un-classified population. The accessions which were from Asian countries i.e., China, Afghanistan, Turkey, Iran and Pakistan were genetically similar and clustered together in both populations A and B. The maximum genetic distance was measured 0.88 between Pakistan 26 x Pakistan 24., Conclusion: Findings of this research such as maximum diversity indices, higher PIC values showed the effectiveness and utility of POGP markers for the evaluation of genetic relationships among safflower accessions. The results of this study also showed that POGP markers are less effective compared to ISSRs, iPBS-retrotransposons and DArTSeq markers. AMOVA showed high genetic variation (79%) within a population and maximum genetic distance was found between the accessions Pakistan 26- Pakistan 24 and may be suggested as candidate parents for future breeding activities of safflower. The accessions from the fertile crescent region were clustered together and proved the origin of safflower domestication. This study highlights genetic variation among safflower germplasm and could be helpfull for parental selection and planning for future breeding programs., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Safflower (Carthamus tinctorius L.) is a multipurpose crop of dry land yielding very high quality of edible oil. Present study was aimed to investigate the genetic diversity and population structure of 131 safflower accessions originating from 28 different countries using 13 iPBS-retrotransposon markers. A total of 295 iPBS bands were observed among which 275 (93.22%) were found polymorphic. Mean Polymorphism information content (0.48) and diversity parameters including mean effective number of alleles (1.33), mean Shannon's information index (0.33), overall gene diversity (0.19), Fstatistic (0.21), and inbreeding coefficient (1.00) reflected the presence of sufficient amount of genetic diversity in the studied plant materials. Analysis of molecular variance (AMOVA) showed that more than 40% of genetic variation was derived from populations. Model-based structure, principal coordinate analysis (PCoA) and unweighted pair-group method with arithmetic means (UPGMA) algorithms clustered the 131 safflower accessions into four main populations A, B, C, D and an unclassified population, with no meaningful geographical origin. Most diverse accessions originated from Asian countries including Afghanistan, Pakistan, China, Turkey, and India. Four accessions, Turkey3, Afghanistan4, Afghanistan2, and Pakistan24 were found most genetically distant and might be recommended as a candidate parents for breeding purposes. The findings of this study are most probably supported by the seven similarity centers hypothesis of safflower. This is a first study to explore the genetic diversity and population structure in safflower accessions using the iPBS-retrotransposon markers. The information provided in this work will therefore be helpful for scientists interested in safflower breeding., Competing Interests: The authors have declared that no competing interests exist

Safflower is an underutilized and minor oilseed crop that received less attention from the scientific community compared to other oilseed crops like soybean and sunflower. Exploring the genetic basis associated with agronomic traits is crucial for markerassisted breeding of safflower. A genome-wide association study was conducted using a total of 12,232 DArTseq markers to identify the marker-trait association for important agronomic traits in an international safflower panel derived from 26 different geographical countries of the world. Statistically significant genotypic effects (p < 0.05) were observed across mean data of both locations (Pakistan and Turkey). Moderate to high heritability estimates were observed for the studied traits. Studied material showed higher performance for all traits except seeds per capitulum in Pakistan compared to Turkey. Phenotypic diversity for important agronomic traits, such as plant height (60.08 to 121.48 cm), capitula per plant (8.7 to 80.4), seeds per capitulum (15 to 42.05), and seed yield per plant (4.85 to 51.02 g), was illustrated. Seed yield per plant showed a highly significant and positive correlation with capitula per plant (0.4985***). Constellation plot analysis resulted in four groups, i.e. A, B, C, and D. Genotyping by sequencing resulted in 12,232 DArTseq markers being used for the investigation of marker-trait association through mixed linear model (Q + K) approach. DArT-38077549 showed significant association with capitula per plant, while two markers (DArT-22763576, DArT-22763253) were associated with plant height. A total of two markers (DArT-38079422, DArT-100043360) were associated with seeds per capitulum. A total of five DArTseq markers showed significant association with seed yield per plant and maximum variation was resulted by DArT-100004992. The results of this study provide a new insight to understand the genetic basis associated with agronomic traits in safflower. We envisage that significant markers identified through this investigation may be applicable in future safflower marker-assisted breeding programs. [ABSTRACT FROM AUTHOR]

Safflower is an important oilseed crop mainly grown in the arid and semi-arid regions of the world. The aim of this study was to explore phenotypic and genetic diversity, population structure, and marker-trait association for 100-seed weight in 94 safflower accessions originating from 26 countries using silicoDArT markers. Analysis of variance revealed statistically significant genotypic effects (p < 0.01), while Turkey samples resulted in higher 100-seed weight compared to Pakistan samples. A Constellation plot divided the studied germplasm into two populations on the basis of their 100-seed weight. Various mean genetic diversity parameters including observed number of alleles (1.99), effective number of alleles (1.54), Shannon's information index (0.48), expected heterozygosity (0.32), and unbiased expected heterozygosity (0.32) for the entire population exhibited sufficient genetic diversity using 12232 silicoDArT markers. Analysis of molecular variance (AMOVA) revealed that most of the variations (91%) in world safflower panel are due to differences within country groups. A model-based structure grouped the 94 safflower accessions into populations A, B, C and an admixture population upon membership coefficient. Neighbor joining analysis grouped the safflower accessions into two populations (A and B). Principal coordinate analysis (PCoA) also clustered the safflower accessions on the basis of geographical origin. Three accessions; Egypt-5, Egypt-2, and India-2 revealed the highest genetic distance and hence might be recommended as candidate parental lines for safflower breeding programs. The mixed linear model i.e., the Q + K model, demonstrated that two DArTseq markers (DArT-45483051 and DArT-15672391) had significant association (p < 0.01) for 100-seed weight. We envisage that identified DArTseq markers associated with 100-seed weight will be helpful to develop high-yielding cultivars of safflower through marker-assisted breeding in the near future. [ABSTRACT FROM AUTHOR]