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Author(s):  
Atefeh Sadat Mostafavi ◽  
Mansour Omidi ◽  
Reza Azizinezhad ◽  
Alireza Etminan ◽  
Hassanali Naghdi Badi

Abstract Background Rosa damascena Mill is a well-known species of the rose family. It is famous for its essential oil content. The aim of the present study was to assess the genetic diversity and population structure of a mini core collection of the Iranian Damask rose germplasm. This involved the use of universal rice primers (URP) and start codon targeted (SCoT) molecular markers. Results Fourteen URP and twelve SCoT primers amplified 268 and 216 loci, with an average of 19.21 and 18.18 polymorphic fragments per primer, respectively. The polymorphic information content for URR and SCoT primers ranged from 0.38 to 0.48 and 0.11 to 0.45, with the resolving power ranging from 8.75 to 13.05 and 9.9 to 14.59, respectively. Clustering was based on neighbor-joining (NJ). The mini core collection contained 40 accessions and was divided into three distinct clusters, centered on both markers and on the combination of data. Conclusion Cluster analysis and principal coordinate analysis were consistent with genetic relationships derived by STRUCTURE analysis. The findings showed that patterns of grouping did not correlate with geographical origin. Both molecular markers demonstrated that the accessions were not genetically diverse as expected, thereby highlighting the possibility that gene flow occurred between populations.


2021 ◽  
Author(s):  
Qingzhu Li ◽  
Yongyi Ge ◽  
Lily Yan Wang ◽  
Kehu Li

Abstract Genotypic diversity of total phenolics, flavonoid content and antioxidant capacity in the USDA rice mini-core collection was analyzed. Wide genotypic variation was found in total phenolics, flavonoid content and ABTS antioxidant capacity. Genome-wide association mapping between the three antioxidant traits and 155 SSR markers was conducted using Q + K model which takes both population structure (Q) and relative kinship (K) into consideration. A total of 23 marker trait association were identified with markers from Rc gene showed the strongest association with the three antioxidant traits. Rid12, RM484, RM162, RM5371 were commonly detected for phenolic content, flavonoids content and antioxidant capacity.


2021 ◽  
Author(s):  
Kehu Li ◽  
Yongyi Ge ◽  
Lily Yan Wang

Abstract The USDA rice mini-core collection was established to capture the diversity of an entire collection of over 18,700 accessions of global origins for efficient germplasm evaluation and exploration. Previous studies have investigated its genetic diversity and population structure using genome-wide SSR markers. Many important agronomic traits that are fundamental to rice breeding programs, however, remain to be explored. Functional markers can be developed based on polymorphic sites within genes affecting phenotypic variation in, e.g., starch physicochemical properties, nutritional qualities and biotic resistance. These markers can be used for genotyping and hence differentiating phenotypes among rice accessions. In this study, we employed 12 pairs of functional markers (SNP and Indel) to genotype all 217 accessions constituting the USDA rice mini-core. These markers are highly associated with starch physicochemical properties (intron 1 G/C SNP, 23bp duplication in exon 2, exon 6 C/A SNP, exon 10 C/T SNP of Waxy gene, GC/TT SNPs of SSIIa gene, G/C SNP of SBE3 gene), glutelin content (3.5 kb deletion in Lgc1 gene), grain length (C/A SNP in GS3 gene), brown planthopper resistance (InDel in Bph 14 gene) and rice blast resistance (InDel in Pi54 and Pit gene). Using these functional markers, all the 217 accessions of the mini-core are characterized for aforementioned agronomic traits associated alleles/genes. The results of this study will help breeders select parental materials with desirable allele/gene combinations and phenotypes among mini-core accessions for rice breeding programs.


2021 ◽  
Author(s):  
jianyin Xie ◽  
Weiping Wang ◽  
Quan Zhang ◽  
Tao Yang ◽  
Zhifang Zhang ◽  
...  

Abstract The utilization of heterosis (or hybrid vigor) is a revolutionary technology in agricultural. However, its genetic mechanisms are still unclear in plants. Here we develop, sequence and record the phenotypes of 418 hybrids from crosses between two testers and a diverse mini core collection. Phenotypic analysis showed that heterosis is an extensive but not necessary phenomenon, which varied by combinations and environments. Evidence from both GWAS on the 418 hybrids and their parents and transcriptomics of the traditional rice hybrid Liangyoupei 9, indicated that dominance and overdominance are the main genetic contributions to heterosis. Furthermore, cumulation or complementation of repulsive genetic factors may account for 37.8% of the overdominant QTL and nearly half of the genes with overdominant expression pattern. We systematically compared non-additive and additive factors and observed a common phenomenon that non-additive factors are more sensitive to background than that of additive ones across species, phenotypes, QTLs and transcription levels, further evidence from both simulations and experiment demonstrated a novel universal molecular mechanism underlying heterosis, i.e. homo-insufficiency under insufficient background (HoIIB), which expounds that heterosis in most cases is not the heterozygote advantage but the homozygote disadvantage under the insufficient genetic background. The HoIIB model can explain most known hypotheses and phenomena about heterosis, thus provides a novel theory for future hybrid rice breeding.


2021 ◽  
Vol 12 ◽  
Author(s):  
Ahsan Irshad ◽  
Huijun Guo ◽  
Shoaib Ur Rehman ◽  
Xueqing Wang ◽  
Jiayu Gu ◽  
...  

Manipulation of genes involved in starch synthesis could significantly affect wheat grain weight and yield. The starch-branching enzyme (SBE) catalyzes the formation of branch points by cleaving the α-1,4 linkage in polyglucans and reattaching the chain via an α-1,6 linkage. Three types of SBE isoforms (SBEI, SBEII, and SBEIII) exist in higher plants, with the number of SBE isoforms being species-specific. In this study, the coding sequence of the wheat TaSBEIII gene was amplified. After the multiple sequence alignment of TaSBEIII genome from 20 accessions in a wheat diversity panel, one SNP was observed in TaSBEIII-A, which formed the allelic marker allele-T. Based on this SNP at 294 bp (C/T), a KASP molecular marker was developed to distinguish allelic variation among the wheat genotypes for thousand grain weight (TGW). The results were validated using 262 accessions of mini core collection (MCC) from China, 153 from Pakistan, 53 from CIMMYT, and 17 diploid and 18 tetraploid genotypes. Association analysis between TaSBEIII-A allelic variation and agronomic traits found that TaSBEIII-A was associated with TGW in mini core collection of China (MCC). The accessions possessing Allele-T had higher TGW than those possessing Allele-C; thus, Allele-T was a favorable allelic variation. By analyzing the frequency of the favorable allelic variation Allele-T in MCC, it increased from pre-1950 (25%) to the 1960s (45%) and increased continuously from 1960 to 1990 (80%). The results suggested that the KASP markers can be utilized in grain weight improvement, which ultimately improves wheat yield by marker-assisted selection in wheat breeding. The favorable allelic variation allele-T should be valuable in enhancing grain yield by improving the source and sink simultaneously. Furthermore, the newly developed KASP marker validated in different genetic backgrounds could be integrated into a breeding kit for screening high TGW wheat.


Plant Science ◽  
2021 ◽  
Vol 308 ◽  
pp. 110910
Author(s):  
Jian-Min Song ◽  
Muhammad Arif ◽  
Yan Zi ◽  
Sing-Hoi Sze ◽  
Meiping Zhang ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Hari D. Upadhyaya ◽  
M. Vetriventhan ◽  
Vania C. R. Azevedo

Information on photoperiod and temperature sensitivity of sorghum germplasm is important to identify appropriate sources for developing cultivars with a broad adaptation. The sorghum mini core collection consisting of 242 accessions along with three control cultivars were evaluated for days to 50% flowering (DFL) and plant height in two long-day rainy and two short-day post-rainy seasons, and for grain yield and 100-seed weight in the two post-rainy seasons. Differences in DFL and cumulative growing degree days (CGDD) in the rainy and post-rainy seasons were used to classify the accessions for photoperiod and temperature sensitivity. Results revealed 18 mini core landraces as photoperiod and temperature insensitive (PTINS), 205 as photoperiod sensitive and temperature insensitive (PSTINS), and 19 as photoperiod and temperature-sensitive (PTS) sources. The 19 PTS sources and 80 PSTINS sources took less DFL in the long-day rainy seasons than in the short-day post-rainy season indicating their adaptation to the rainy season and a possible different mechanism than that trigger flowering in the short-day sorghums. In all three groups, several accessions with desirable combinations of agronomic traits were identified for use in the breeding programs to develop climate-resilient cultivars and for genomic studies to identify genes responsible for the photoperiod and temperature responses.


2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaojing Zhou ◽  
Jianbin Guo ◽  
Manish K. Pandey ◽  
Rajeev K. Varshney ◽  
Li Huang ◽  
...  

Peanut is an important legume crop worldwide. To uncover the genetic basis of yield features and assist breeding in the future, we conducted genome-wide association studies (GWAS) for six yield-related traits of the Chinese peanut mini-core collection. The seed (pod) size and weight of the population were investigated under four different environments, and these traits showed highly positive correlations in pairwise combinations. We sequenced the Chinese peanut mini-core collection using genotyping-by-sequencing approach and identified 105,814 high-quality single-nucleotide polymorphisms (SNPs). The population structure analysis showed essentially subspecies patterns in groups and obvious geographical distribution patterns in subgroups. A total of 79 significantly associated loci (P < 4.73 × 10–7) were detected for the six yield-related traits through GWAS. Of these, 31 associations were consistently detected in multiple environments, and 15 loci were commonly detected to be associated with multiple traits. Two major loci located on chromosomal pseudomolecules A06 and A02 showed pleiotropic effects on yield-related traits, explaining ∼20% phenotypic variations across environments. The two genomic regions were found 46 putative candidate genes based on gene annotation and expression profile. The diagnostic marker for the yield-related traits from non-synonymous SNP (Aradu-A06-107901527) was successfully validated, achieving a high correlation between nucleotide polymorphism and phenotypic variation. This study provided insights into the genetic basis of yield-related traits in peanut and verified one diagnostic marker to facilitate marker-assisted selection for developing high-yield peanut varieties.


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