Utilization Of Genetic Diversity Research Articles

Multi-omics analyzes of Rosa gigantea illuminate tea scent biosynthesis and release mechanisms.

Rose is an important ornamental crop cultivated globally for perfume production. However, our understanding of the mechanisms underlying scent production and molecular breeding for fragrance is hindered by the lack of a reference genome for tea roses. We present the first complete telomere-to-telomere (T2T) genome of Rosa gigantea, with high quality (QV > 60), including detailed characterization of the structural features of repetitive regions. The expansion of genes associated with phenylpropanoid biosynthesis may account for the unique tea scent. We uncover the release rhythm of aromatic volatile organic compounds and their gene regulatory networks through comparative genomics and time-ordered gene co-expression networks. Analyzes of eugenol homologs demonstrate how plants attract pollinators using specialized phenylpropanoids in specific tissues. This study highlights the conservation and utilization of genetic diversity from wild endangered species through multi-omics approaches, providing a scientific foundation for enhancing rose fragrance via de novo domestication.

Integration of genome-wide association and genomic prediction for dissecting seed protein and amino acid in foxtail millet

ContextThe exploitation and utilization of genetic variation in crop germplasm benefit genomics-informed breeding programs. The integration of genome-wide association study (GWAS) and genomic prediction (GP) holds promise for illustrating genetic basis of phenotypic variation. Currently, the use of this integrative approach for dissecting grain protein and amino acid traits remains limited in crop species. ObjectiveThe research objectives were to identify significant single nucleotide polymorphisms (SNPs) associated with seed protein and amino acids and to assess the genomic predictive ability for nutritional traits in natural population of foxtail millet. MethodsIn this study, the concentrations of seed protein and 17 amino acids were assessed in a training population consisting of 238 diverse accessions of foxtail millet. The significant SNPs associated with these phenotypes were identified by GWAS with a mix-linear model. Extensive cross-validation was performed to evaluate the accuracy of genomic prediction of seed nutritional traits. Furthermore, the genomic prediction model was optimized and externally validated in 211 untested materials with the most significant SNPs obtained from GWAS. ResultsA significant genotype variance was detected for seed protein and amino acids and broad-sense heritability (h2) ranged from 0.45 to 0.87 (P < 0.05). The GWAS identified 39 significant SNPs associated with 15 amino acids (p < 1e-06), explaining an average of 12.2% phenotypic variation per locus. The number of significant SNPs ranged from 1 (Asp, Ile, Glu) to 23 for Phe amino acid, including six SNPs associated with one or multiple amino acids. In the training population, the prediction accuracies of protein and amino acids, tested using the 10-fold cross-validation model with whole genome-wide SNPs, ranged from 0.23 (Glu) to 0.60 (Lys) with an average value of 0.44%. Population structure had little effect on the prediction accuracy. In an empirical validation experiment involving 211 untested accessions, the averaged prediction accuracy increased by 12.3% across all traits when using the 1000 top SNPs obtained from GWAS, compared with the same number of randomly selected SNPs from the entire genome. ConclusionsLarge variations of seed protein and amino acids were found in a natural population of foxtail millet. GWAS identified 39 significant SNPs associated with 15 amino acids, and six SNPs were linked to more than one trait. The 10-fold cross-validation model produced the relatively higher prediction accuracies in seed quality traits of diverse accessions. By applying the significant SNPs from GWAS to the untested accessions, the use of 1000 GWAS-top SNPs resulted in more powerful predictions for complex nutritional traits than those using the same number of randomly selected SNPs across the genome. SignificanceThe research highlights the importance and effectiveness of integrative GWAS and genomic prediction in revealing the genetic architecture of seed protein and amino acid variation in foxtail millet. The results provide valuable insights into assessment and improvement of germplasm resources for advancing precision crop phenotyping and enhancing breeding programs for crop nutritional traits.

Preliminary Dissection of Grain Yield and Related Traits at Differential Nitrogen Levels in Diverse Pre-Breeding Wheat Germplasm Through Association Mapping.

Development of nutrient efficient cultivars depends on effective identification and utilization of genetic variation. We characterized a set of 276 pre-breeding lines (PBLs) for several traits at different levels of nitrogen application.These PBLs originate from synthetic wheats and landraces. We witnessed significant variation in various traits among PBLs to different nitrogen doses. There was ~ 4-18% variation range in different agronomic traits in response to nitrogen application, with the highest variation for the biological yield (BY) and the harvest index. Among various agronomic traits measured, plant height, tiller number, and BY showed a positive correlation with nitrogen applications. GWAS analysis detected 182 marker-trait associations (MTAs) (at p-value < 0.001), out of which 8 MTAs on chromosomes 5D, 4A, 6A, 1B, and 5B explained more than 10% phenotypic variance. Out of all, 40 MTAs observed for differential nitrogen application response were contributed by the synthetic derivatives. Moreover, 20 PBLs exhibited significantly higher grain yield than checks and can be selected as potential donors for improved plant nitrogen use efficiency (pNUE).

Unraveling Origin, History, Genetics, and Strategies for Accelerated Domestication and Diversification of Food Legumes.

Domestication is a dynamic and ongoing process of transforming wild species into cultivated species by selecting desirable agricultural plant features to meet human needs such as taste, yield, storage, and cultivation practices. Human plant domestication began in the Fertile Crescent around 12,000 years ago and spread throughout the world, including China, Mesoamerica, the Andes and Near Oceania, Sub-Saharan Africa, and eastern North America. Indus valley civilizations have played a great role in the domestication of grain legumes. Crops, such as pigeon pea, black gram, green gram, lablab bean, moth bean, and horse gram, originated in the Indian subcontinent, and Neolithic archaeological records indicate that these crops were first domesticated by early civilizations in the region. The domestication and evolution of wild ancestors into today’s elite cultivars are important contributors to global food supply and agricultural crop improvement. In addition, food legumes contribute to food security by protecting human health and minimize climate change impacts. During the domestication process, legume crop species have undergone a severe genetic diversity loss, and only a very narrow range of variability is retained in the cultivars. Further reduction in genetic diversity occurred during seed dispersal and movement across the continents. In general, only a few traits, such as shattering resistance, seed dormancy loss, stem growth behavior, flowering–maturity period, and yield traits, have prominence in the domestication process across the species. Thus, identification and knowledge of domestication responsive loci were often useful in accelerating new species’ domestication. The genes and metabolic pathways responsible for the significant alterations that occurred as an outcome of domestication might aid in the quick domestication of novel crops. Further, recent advances in “omics” sciences, gene-editing technologies, and functional analysis will accelerate the domestication and crop improvement of new crop species without losing much genetic diversity. In this review, we have discussed about the origin, center of diversity, and seed movement of major food legumes, which will be useful in the exploration and utilization of genetic diversity in crop improvement. Further, we have discussed about the major genes/QTLs associated with the domestication syndrome in pulse crops and the future strategies to improve the food legume crops.

Utilization of genetic diversity and population structure to reveal prospective drought-tolerant donors in rice

Fifty SSR markers were used to assess genetic diversity among 40 drought-tolerant, five moderately drought-tolerant, and three susceptible genotypes to identify new donors for drought tolerance in rice. Out of 50 SSR markers, 17 markers are reported to be linked to major grain yield QTLs under reproductive stage drought stress. 163 (97.7%) out of 167 alleles were found to be polymorphic. The PIC value ranged from 0 to 0.963 with an average of 0.795 per locus. The minor allele frequency varied from 0.312 (RM336) to 0.895 (RM530) with an average of 0.60. The genetic diversity ranged from 0.187 (RM530) to 0.739 (RM336) with an average of 0.51. The cluster analysis grouped all the genotypes into three major clusters at 50% level of genetic dissimilarity. Structure analysis identified two subpopulations among 48 rice genotypes. 81% and 19% of molecular variances were revealed within and among the subpopulations, respectively. The first three principal components explained over 88% of total genetic variation. Two genotypes, Kalakeri and RR-2-6 were identified as new drought-tolerant donors. Kalakeri contributes drought tolerance QTL, qDTY1.1, while RR-2-6 contributes QTLs, qDTY2.2, and qDTY2.3.

Role of Plant Breeding in Coping with Climate Change for Food and Agriculture: A Review

Plant breeding has been made a crucial role for food and agriculture by studying and focusing on utilization of genetic diversity of plants adaptability and survival when their environments changes. Plant breeding efforts to help producers overcome the enormous challenges posed by climate change through the creation of new seed varieties with improved genetics from germplasm exhibiting stress tolerance. This field play decisive role in advancing crop varieties and hybrids to become more productive, high in quality, better adapted to a biotic and biotic stresses, as well as producing plants that can contribute to the reduction of greenhouse gas emissions by increasing nitrogen and CO2 input-use efficiency. However, global temperatures rising, human population, absence of urgent institute measures, limit application of new methods, lack of resources, training and capabilities, more frequent and severe drought and flooding, along with increased pressure from insects and disease, will be agriculture’s biggest challenge. On the other hand, there is great opportunities to over-come earlier mentioned problems. For instance, advances in technology have put many more tools into breeders’ hands. Technologies like molecular markers and bioinformatics and other techniques are expediting the process of analyzing and assessing traits. Keywords: Plant breeding, Climate change, Food and Agriculture DOI: 10.7176/JEES/11-1-01 Publication date: January 31 st 2021

Utilization of genetic diversity and marker-trait to improve drought tolerance in rice (Oryza sativa L.).

Drought stress is one of the main problems for the rice crop, as it reduces the production and productivity of the grain yield significantly. In Egypt, many restrictions were made on the cultivation of rice due to its high-water demand. Producing promising drought-tolerant rice cultivars combined with high yielding is one of the main targets for rice breeders. A set of 22 highly diverse rice genotypes were evaluated under normal and drought conditions. Morphological, physiological, and yield traits were recorded on each genotype. Drought susceptibility index (DSI) was estimated for six yield traits to identify the most drought-tolerant rice genotypes. A high genetic variation was found among genotypes tested in the experiment. Under normal conditions, the highest phenotypic correlation was found between grain yield (GY) and sterility percentage (SP) (-0.73**), while it was among GY and chlorophyll content (CC) (0.82**) under drought conditions. To identify quantitative trait loci (QTL) controlling yielding traits under drought and normal, asingle marker analysis was performed between all yield traits under both conditions and a set of 106 simple sequence repeat (SSR) marker alleles. The genetic association analysis revealed 14 and 17 QTL under drought and normal conditions, respectively. The most drought-tolerant genotypes were selected based on phenotypic traits, the number of QTL in each selected genotype, and the level of genetic diversity existed among the genotypes. As a result, five genotypes (Giza 178, IET1444, GZ1368-S-5-4, Nahda, Giza 14) were identified as the most promising drought-tolerant rice genotypes. Eight QTL controlling drought tolerance were identified in Giza 178, Nahda, and GZ1368-S-5-4, while four QTL were found in IET1444. The number of different QTLs were estimated among the five selected genotypes. Giza 178 and GZ1368-S-5-4 shared the same QTLs. Seven different QTLs were found among Nahda, IET1444, GZ1368-S-5-4, and Giza 14. Combining information from phenotypic traits, genetic diversity analysis, and QTL analysis was very useful in identifying the true drought-tolerant rice genotypes that can be used for crossing in the future breeding program.

Short Communication: Agro-morphological diversity among four tomato cultivars in western Burundi

Ngezahayo F, Ngendakuriyo Jc, Bizindavyi E, Mbonihankuye C. 2019. Short Communication: Agro-morphological diversity among four tomato cultivars in western Burundi. Biodiversitas 20: 436-441. Since crop cultivars represent a reservoir of genetic diversity; essential are the understanding and the utilization of genetic variation in tomato accessions for improving the crop. The objective of the present study was to characterize 4 tomato cultivars from the western Burundi by means of 8 agro-morphological traits that could be exploited for tomato crop improvement. Tanya and P20 cultivars showed the lowest plant height but the highest flower number, fruit number and yield per cultivar. This was corroborated by a significant negative correlation between plant height and flower number, fruit number and yield per cultivar in overall results. On the other hand, Floradel and Tengerou97 cultivars have the highest stem circumference and leaf number. Cluster analysis also showed almost four clusters corresponding to one cluster for each cultivar, though Tengerou97 and Floradel tend to be grouped together. Finally, principal component analysis showed that all the eight agro-morphological traits participated in grouping tomato cultivars; particularly flower number, fruit number, plant height, and yield per cultivar. The first three principal component axes accounted for 92.465% of total variation observed among tomato cultivars. Thus, the four cultivars should all be exploited in tomato breeding and improvement programs.

Effect of genotype and some non-genetic factors on weaning weight in rabbits

The rabbit meat producers have a strong desire to improve productivity in order to maximize on financial gains. There has been a deliberate move to target improved weaning weight, which is thought to be a critical component in influencing total meat yield and economic returns. However, it has been acknowledged that weaning weight is partly influenced by individual kit genetic potential at the same time its overwhelmed by various non genetic factors. In this respect, weaning weights a complex character which reflects the influence of many biological processes namely fertility, maternal instinct, growth and viability. For the purpose of increasing production, it is reasonably to suggest that the complex inter-relationship among known various non genetic factors that influence weaning weight and the degree of their interactive effects need to be ascertained and understood in different production systems. While, genotype is a major contributor to weaning weight, environmental, nutritional and management practices also play significant roles in influencing weaning weight. There are several known environmental factors that influence weaning weight and these include feeding practices, birth weight, parity order, sex of kits, management, etc. The rabbit producers’ attention to the aforementioned factors is likely to improve weaning weight at enterprise level. It is important to note that selection for increased litter size have an adverse effect on average litter birth weight which subsequently reflects on weaning weight. The enhanced prolificacy in does has resulted in an increase in within litter variation and a larger number of kits born light. From the farmer’s performance point of view, genetic diversity utilization in crossbreeding has been the focus in improving weaning weight in commercial rabbit meat production. However, the complementary role played by nutritional status in optimization of performance in selected genotypes has been tremendous in the past two decades. Crossbreds have performed at levels consistent with different targeted rabbit meat market expectations. Generally, it is pronounced that improved nutritional regime and patterns for lactating does and their suckling kits had a positive effect on weaning weight. On the other hand, unbalanced parity structure and distribution in rabbit enterprise results in unreasonable variation in weaning weight, which impacts negatively on subsequent kits management after weaning. The purpose of this review is to discuss the influence of genotype and some non-genetic factors (litter size, birth weight, parity) on weaning weight in rabbits.

Genetic diversity studies of alfalfa germplasm (Medicago sativa L. subsp. sativa) of United States origin using microsatellite analysis

This study aimed to understand the genetic diversity and population structure of alfalfa germplasm from the United States. In this study, the population structure and genetic diversity of six alfalfa cultivars of United States origin were investigated by microsatellite analysis with 40 individuals per cultivar. A total of 312 discernible alleles were amplified from the whole genome with an average of 31.2 alleles per locus. The average values of polymorphic information content and Shannon’s information index were 0.928 and 0.133, respectively, showing high levels of genetic diversity. Two populations were identified by STRUCTURE software with principal coordinate analysis and neighbour-joining clustering. Analysis of molecular variance analysis (AMOVA) revealed that the majority of genetic variation was within cultivars (96.42%) rather than between cultivars (3.58%). In conclusion, analyses of genetic diversity and population structure may be useful for the genetic analysis and utilization of genetic variation in alfalfa breeding.

Conservation and Dispersion of Genes Conferring Resistance to Tomato Begomoviruses between Tomato and Pepper Genomes.

In the present climate change scenario, controlling plant disease through exploitation of host plant resistance could contribute toward the sustainable crop production and global food security. In this respect, the identification of new sources of resistance and utilization of genetic diversity within the species may help in the generation of cultivars with improved disease resistance. Begomoviruses namely, Tomato yellow leaf curl virus (TYLCV) and Chilli leaf curl virus (ChLCV) are known to cause major yield losses in several economically important crop plants of the family Solanaceae. Though co-occurrence, association and synergistic interactions among these viruses in the host plants is reported, whether orthologous genetic loci in related host plants could be responsible for conferring resistance to these viruses has not been investigated yet. Several loci including Ty1, Ty2, Ty3, Ty4, and ty5 have been reported to confer resistance to leaf curl viruses in tomato. Here, we examined the pepper orthologous markers, corresponding to these QTL regions, for polymorphism between ChLCV susceptible and resistant genotypes of pepper. Further, to examine if the polymorphic markers are segregating with the disease resistance, Bulk Segregant Analysis (BSA) was performed on F2 population derived from crosses between resistant and susceptible lines. However, none of the markers showed polymorphism in BSA suggesting that the tested markers are not linked to genes/QTLs responsible for conferring resistance to ChLCV in the selected genotypes. In silico analysis was performed to study the synteny and collinearity of genes located within these QTL regions in tomato and pepper genomes, which revealed that more than 60% genes located in Ty2 and Ty4, 13.71% genes in Ty1, 23.07% in Ty3, and 44.77% genes located within ty5 QTL region in tomato are conserved in pepper genome. However, despite such a high conservation in gene content, the linkage relationship in these regions seems to be greatly affected by gross rearrangements in both the species.

Utilization of Genetic Variability in Mungbean as Food Industrial Raw Material in Indonesia

Utilization of Genetic Variability in Mungbean as Food Industrial Raw Material in Indonesia

Characterization of a Wheat Breeders' Array suitable for high-throughput SNP genotyping of global accessions of hexaploid bread wheat (Triticum aestivum).

SummaryTargeted selection and inbreeding have resulted in a lack of genetic diversity in elite hexaploid bread wheat accessions. Reduced diversity can be a limiting factor in the breeding of high yielding varieties and crucially can mean reduced resilience in the face of changing climate and resource pressures. Recent technological advances have enabled the development of molecular markers for use in the assessment and utilization of genetic diversity in hexaploid wheat. Starting with a large collection of 819 571 previously characterized wheat markers, here we describe the identification of 35 143 single nucleotide polymorphism‐based markers, which are highly suited to the genotyping of elite hexaploid wheat accessions. To assess their suitability, the markers have been validated using a commercial high‐density Affymetrix Axiom® genotyping array (the Wheat Breeders’ Array), in a high‐throughput 384 microplate configuration, to characterize a diverse global collection of wheat accessions including landraces and elite lines derived from commercial breeding communities. We demonstrate that the Wheat Breeders’ Array is also suitable for generating high‐density genetic maps of previously uncharacterized populations and for characterizing novel genetic diversity produced by mutagenesis. To facilitate the use of the array by the wheat community, the markers, the associated sequence and the genotype information have been made available through the interactive web site ‘CerealsDB’.

Genetic diversity in the rice landraces (Oryza sativa L.) of coastal Sundarbans (India) and their adaptation to the local saline condition investigated both at molecular and physiological level

Salinity is one of the major impediments to increase production in rice growing areas worldwide as the crop is sensitive to saline conditions. The key to breed new rice varieties depends on utilization of genetic diversity in landraces that possess many useful genes/alleles. The diversity present among the fifty rice accessions, collected from 4 geographical areas of Sundarbans, India, an area well known for its genetic diversity, was analysed at the genomic level by employing hyper variable microsatellite markers. As these accessions are well adapted to saline conditions, haplotype analysis conducted on Saltol locus, which has four genes that are known to confer salinity in rice, could identify eight different haplotypes. Wide variation was also seen for Na+/K+ ratio among the accessions and an association was detected between markers RM8094, RM3412 and RM493 and Na+/K+ ratio of rice plants under salinity stress. Based on the morphological, physiological and molecular analyses, Nonabokra, Kumrogoor and Kalonunia were identified as potential donors as the tolerance in these genotypes appear to be regulated by alleles other than the ones present in FL478, a well-known donor for salinity in rice.

Assessment of major determinants of phenotypic variation for a transplanting seedling

Selections of desirable traits and exploration and utilization of genetic diversity have always been used as an essential tool in plant breeding. The present study was an attempt to investigate general and specific determinants of phenotypic variation among a data set of seedling characters and genotypes efficiency for a transplanting seedling. For this purpose 48 advance genotypes with three control cultivars Basmati-385, JP5 and Kangnai29 were grown in a replicated field trail and evaluated for 16 traits that were reported earlier as contributing traits of seedling vigor. ANOVA showed high CV% for SRFW, SRDW, WC, SSFW, SSDW, SFW, SDW, while lowest was found for SH followed by SLL. PCA extracted two components with 66.75% of variability. The PC1 comprised of SFW, SDW, SSFW, SSDW, SRFW, SRDW, WC as positive meaningful loading while one DG as negative one with overall 38.69% of variability. The PC2 carried 5 significant loadings i.e. SVI, SH, SLL, SLW and SLA with 28.068% of variation. The meaningful traits of PC1 and PC2 were the sub-derived variables of SH and SFW respectively. These findings pave a criterion for selection which will enable one to choose a best genotype at seedling that withstands lodging and having the ability to carry large and heavy panicle at adult stage. Apart from these, the less variability for SH and high variation in SFW indicated the capability of elite lines. The elite lines 97-m, 111-m, 161-s, Abbasi2, 105-m, 86-L, 29-s, 136-L, 158-2-L, 130-s, 14-L, 10-s, 127-m, 26L, 179-s, 19-L, 79-L, 184-s, 07-m, 17-L, 109-L, 186-m, 12-L, 52-L, M2, 69-m and 96-m were more vigorous and withstand disease attack due to its high seedling biomass and short stature that one could effectively use in further improvement of rice.

가축육종을 위한 유전체 선발의 새로운 접근(총설)

Selection based on phenotype in the traditional manner does not help in tracking the selected gene. Molecular genetics has revolutionized the old established breeding techniques. A new epoch of molecular markers has been acquainted for genetic improvement of livestock. This study is engaged on the neoteric molecular markers used in various fields of livestock. DNA markers are more encouraging in selecting genomes that have recombination events close to the target gene. Molecular markers rely on DNA assay and are better than the morphological and biochemical markers. In this study DNA-based molecular markers developed during the past decagons for animal genome analysis are reviewed. Mapping of molecular markers provide a framework, required for its subsequent use in the selection procedure. Molecular techniques help in the utilization of genetic variability in breeding population. At the same time livestock genomes play important role in human genomics and their role for understanding human genomics cannot be overlooked. Recently, in the epigenetic and transcriptomic studies, RNA sequencing as a part of next generation sequencing has revolutionized the approach and ongoing trends of analysis. Keeping in mind the goals, these molecular techniques can be implemented successfully by following well defined, crisp and integrated strategy.

Utilization of genetic diversity and its association characters in mungbean [Vigna radiata(L.) Wilczek

Phenotypic and genotypic coefficient of variation, heritability, genetic advance, correlation coefficient and path coefficient analysis were estimated for yield and yield components in 35 genotypes of mungbean. High heritability estimates coupled with high genetic advance were observed for seed yield per plant, 100 grain weight, plant height, seeds/pod and days to flowering. Yield was positive and significantly correlated with number of pods/plant, number of seeds/pod and 100 grain weight. Pods/plant seeds/pod and 100 grain weight contributed maximum positive and direct effect for yield indicating those emphasis should be given on these three for developing high yielding mungbean variety suitable for rain-fed and irrigated conditions.

Adaptation of tropical maize germplasm to temperate environments

Maize (Zea mays L.) is one of few crops that can offer significant genetic gains with the utilization of genetic diversity. Genetically broad-based germplasm has the potential to contribute useful and unique alleles to U.S. Corn Belt breeding programs not present in current U.S. genome sequences (e.g. B73, NAM, etc.). Our objectives were to determine if unique tropical genetic materials have been effectively adapted to temperate environments and how their agronomic performance was relative to adapted populations. An important long-term objective of the Iowa and North Dakota maize breeding programs has been, in addition to the typical elite by elite line pedigree selection cultivar development process, to adapt exotic and unique germplasm, maximize their genetic improvement, and develop unique products for breeding and commercial uses. Stratified mass selection methodology for earliness has been utilized for the adaptation of tropical and temperate populations to Iowa and North Dakota environments. This method has allowed screening of up to 25,000 genotypes per population cycle at a rate of one cycle per year. In addition, the estimated cost per year our programs had for the adaptation of each population was less than $2,000 which could successfully be applied in any breeding program across the globe. This cost has been less than 1 % of the total cost for finding minor genes on the same trait. Our results showed the successful adaptation of exotic populations was independent from genetic background. We can speculate there are a few major genes responsible for most of flowering date expression. We encourage the use of technology to target traits according to their genetic complexity. Stratified mass selection at the phenotypic level has been successful. Each of the populations with either 25 of 100 % tropical germplasm are available for anyone who may desire to expand the germplasm base of their breeding programs with tropical germplasm adapted to temperate mid- and short-season U.S. Corn Belt environments.

Genetic assessment of safflower (Carthamus tinctorius L.) collection with microsatellite markers acquired via pyrosequencing method

A genetic evaluation of safflower germplasm collections derived from different geographical regions and countries will provide useful information for sustainable conservation and the utilization of genetic diversity. However, the molecular marker information is limited for evaluation of genetic diversity of safflower germplasm. In this study, we acquired 509 putative genomic SSR markers for sufficient genome coverage using next-generation sequencing methods and characterized thirty polymorphic SSRs in safflower collection composed of 100 diverse accessions. The average allele number and expected heterozygosity were 2.8 and 0.386, respectively. Analysis of population structure and phylogeny based on thirty SSR profiles revealed genetic admixture between geographical regions contrary to genetic clustering. However, the accessions from Korea were genetically conserved in distinctive groups in contrast to other safflower gene pool. In conclusion, these new genomic SSRs will facilitate valuable studies to clarify genetic relationships as well as conduct population structure analyses, genetic map construction and association analysis for safflower.

Genetic variability of watermelon accessions based on microsatellite markers

We analyzed the genetic variability of 40 watermelon accessions collected from 8 regions of Northeastern Brazil using microsatellite markers, in order to suggest strategies of conservation and utilization of genetic variability in this species. These accessions are not commercial cultivars. They were sampled in areas of traditional farmers that usually keep their own seeds for future plantings year after year. An UPGMA dendrogram was generated from a distance matrix of the Jaccard coefficient, based on 41 alleles of 13 microsatellite loci. Analysis of molecular variance was made by partitioning between and within geographical regions. The similarity coefficient between accessions ranged from 37 to 96%; the dendrogram gave a co-phenetic value of 0.80. The among population genetic variability was high ( (^)ϕST = 0.319). Specific clusters of accessions sampled in 3 regions of Maranhão were observed while the other 5 regions did not presented specific clusters by regions. We conclude that watermelon genetic variability is not uniformly dispersed in the regions analyzed, indicating that geographical barriers or edaphoclimatic conditions have limited open mating. We suggest sampling a greater number of populations, so regional species diversity will be better represented and preserved in the germplasm bank.