Bread wheat
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Drought tolerance is derived from complex quantitative traits that are associated with different shoot and root morphological characters. This study assessed the genetic and phenotypic variation of 12 maize inbred lines and performed association analysis of 11 drought-related traits using 360 simple sequence repeats (SSRs), detecting 1,604 alleles, with an average of 4.4 alleles per locus. The average values of gene diversity (GD) and polymorphism information content (PIC) were 0.648 and 0.598, respectively. In principal component analysis (PCA), shoot fresh weight (SFW), shoot dry weight (SDW), stem weight (SW), leaf weight (LW), root fresh weight (RFW), root dry weight (RDW), and leaf area (LA) traits contributed greatly to the PCA. Association analysis was performed using a general linear model with a Q-matrix (Q GLM) and a mixed linear model with Q and K-matrices (Q + K MLM). Twelve SSR markers for drought tolerance trait were detected by Q GLM, and all maize inbred lines were clearly divided into two groups in accordance with their drought tolerance. Duplicated significant marker-trait associations (SMTAs) between Q GLM and Q + K MLM identified eight marker-trait associations involving four SSR markers that were associated with the traits of SW, SFW, RFW, and RDW with a significant level of
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The coffee value chain is a source of livelihood for millions of people across the world and yet the resilience of coffee is limited by the relatively narrow genetic base among commercial coffee cultivars. A study was conducted to determine genetic variation, heritability estimates and relationships among coffee genotypes in Zimbabwe. Quantitative morphological characteristics of twelve genotypes were recorded under field conditions. There were significant variations in coffee yield, plant height, stem girth, number of primary branches, number of bearing branches, internode length and leaf characteristics, with no significant variations in seed characteristics and number of nodes. Broad sense heritability estimates for the quantitative traits ranged from 0.03% to 91.4%, being highest for plant height, coffee yield, stem girth, leaf length and leaf area. The implications are that coffee yield and plant height are independent of significant environmental influences while seed, branching traits and leaf traits are influenced by the environment in their expression. Yield was significantly correlated to branches per plant, plant height, seed traits and stem girth. Clustering of genotypes was influenced by plant height, yield and stem girth. Overall, few traits were important in distinguishing coffee genotypes, implying narrow diversity. Hybridization, further introductions from other producer countries, coffee gene banks and/or introductions from the wild, and concerted germplasm conservation efforts are recommended.
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Cultivation of the medicinal herb
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Six durum and twelve bread wheat genotypes were evaluated under favorable and drought-stressed field conditions, and screened with thirty simple sequence repeats (SSR) markers. The traits studied were stomata frequency (STF), relative water content (RWC), flag leaf area (FLA), flag leaf weight (FLW), flag leaf dry matter content (FLD), chlorophyll a content (Chl.a), chlorophyll b content (Chl.b), grain yield/plant (GYP) and 1000-kerenl weight (TKW). Highly significant differences were observed among wheat genotypes for all the traits, indicating considerable genetic variation. Moderate to high broad-sense heritability estimates were observed for the studied traits. Under drought stress, GYP was positively correlated with RWC, FLA, FLW and TKW, whereas negatively correlated with STF. G3 (Svevo) and G6 (WK-12-1) were the most drought-tolerant durum wheat, whereas G11 (L.S-15) and G16 (SIDS-1) were the most drought-tolerant bread wheat genotypes. SSR markers analysis indicated considerable genetic variation between and within durum and bread wheat genotypes. The percentage of polymorphism ranged from 14.3% (Xgwm174-5D) to 100% (Xgwm294-2A and Xgwm573-7B), with an average of 61.4%. The polymorphism information content (PIC) ranged from 0.20 (Xwmc596-7A) to 0.48 (Xgwm294-2A), with an average of 0.33.The highest polymorphism (77.1%) was observed in the B genome followed by A (57.8%) and D (50.0%) genomes. Cluster analysis based on phenotypic data distinguished the most drought-tolerant genotypes (G6 and G11) from the remaining genotypes. Cluster analysis based on SSR markers distinguished durum from bread wheat genotypes. The study indicated that phenotypic data and SSR markers were effective in assessing the genetic diversity in the studied genotypes.
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Water deficit is a critical factor obstructing the growth and survival of plant. Therefore, researchers have been trying to develop drought-resistant varieties. To find indicators of drought stress-tolerance of cypress (
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Bitter gourd is an important vegetable of the family Cucurbitaceae, cultivated mainly in humid and subtropical Asia. Bitter gourd is a vegetable with immense health benefits due to the presence of medicinal compounds such as charantin, vicine, and polypeptide-p, which play essential roles in lessening blood glucose levels. Moreover, bitter gourd fruits are particularly rich in vitamin C, minerals, and carotenes. Here, an effort has been made to critically evaluate the extent of achievements during the enhancement and enactment of bitter gourd breeding programs with the use of latest technologies. Broadening the genetic base of cultivated bitter gourd varieties as a result of enrichment of existing resources by using wild species in breeding programs. Practical seed production technological know-how along with the use of the MS system (male sterility)/chemical-induced sterility procedure is nonetheless vital to cope with market demands. Superior yielding bitter gourd hybrids combining early maturity and resistance to biotic and abiotic stresses are regularly needed to cope with the challenge of bitter gourd production.
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Chinese jujube (
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We selected 68 Chinese maize inbred lines to understand the genetic diversity, population structure, and marker-trait associations for eight agronomic traits and 50 simple sequence repeats (SSRs) markers. In this study, effective traits, such as days of anthesis (DA), days of silking (DS), ear height (EH), plant to ear height ratio (ER), plant height (PH), and leaf width (LW) were divided into PC1 and PC2 by PCA analysis for maize inbred lines. Genetic diversity analysis revealed a total of 506 alleles at 50 SSR loci. The mean number of alleles per locus was 10.12. The averages of genetic diversity (GD) and polymorphic information content (PIC) values were 0.771 and 0.743, respectively. Based on a membership probability threshold of 0.80, the population structure revealed that the total inbred lines were divided into three major groups with one admixed group. A marker-trait association using Q + K MLM showed that nine SSR markers (bnlg1017, umc2041, umc2400, bnlg105, umc1229, umc1250, umc1066, umc2092, and umc1426) were related with seven agronomic traits. Among these SSR markers, eight SSR markers were associated with only one agronomic trait (DA, DS, ER, LL, LW, PH, and ST), whereas one SSR marker (umc1229) was associated with two agronomic traits (DA and ST). These results will help in optimizing the choice of inbred lines for cross combinations, as well as in selecting markers for further maize breeding programs.
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Chinese jujube (
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Simple sequence repeat (SSR) markers were developed from
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We evaluated genetic diversity and population structure in 32 Canadian maize inbred lines and performed association analysis for five agronomical traits and 50 simple sequence repeat (SSR) markers. Genetic diversity analysis revealed a total of 381 alleles at the 50 SSR loci. The average number of alleles per locus was 7.6. The average genetic diversity and polymorphic information content values were 0.709 and 0.676, respectively. The average major allele frequency was 0.414. Population structure analysis indicated that these maize inbred lines were comprised of four major groups and one admixed group based on a membership probability threshold of 0.80. A general linear model showed 20 marker-trait associations involving 12 SSR markers associated with the four agronomic traits except for leaf length. For these marker-trait associations, phi056, mmc0022, bnlg1621, bnlg1695, phi116, and bnlg1028 were associated with only one trait. The other nc005, bnlg1012, phi065, and umc1982 were associated with two traits. Two SSR markers, mmc0111 and umc1038, were associated with three traits. These results will help in optimizing the choice of parents for crossing combinations, as well as in selecting markers for marker-assisted selection for maize improvement.
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Boysenberry, a
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Production of spring wheat, the major crop in Mongolia, accounts for 98% of the cultivated area. Understanding genetic variability in existing gene bank accessions is critical for collection, conservation and use of wheat germplasms. To determine genetic diversity and population structure among a representative collection of Mongolian local wheat cultivars and lines, 200 wheat accessions were analyzed with 15 SSR markers distributed throughout the wheat genome. A total of 85 alleles were detected, with three to five alleles per locus and a mean genetic richness of 5.66. Average genetic diversity index was 0.69, with values ranging from 0.37–0.80. The 200 Mongolian wheat accessions were mainly divided into two subgroups based on structure and phylogenetic analyses, and some phenotypes were divergent by the subgroups. Results from this study will provide valuable information for conservation and sustainable use of Mongolian wheat genetic resources.
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Black gram [
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Sorghum is a major staple crop and vital for the marginal farmers in Asian and African countries. Landraces or germplasm lines adapted to biotic and abiotic stresses are the prime source of adaptive traits in the crop breeding programs. In order to assess the genetic variability, 141 exotic germplasm lines and 36 popular varieties were evaluated for eight agro-morphological traits. Wide range of values were observed for grain yield (6.6–124.4 g/plant), seed index (1.5–7.1 g/100 seeds), panicle length (8–44 cm) and panicle width (7.25 cm). High genotypic and phenotypic coefficient of variation was observed for grain yield per plant. The values of broad sense heritability in the sorghum core population ranged from 0.75 to 0.99. Seed weight, days to flowering, panicle width and leaf area were significantly correlated with grain yield (
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Sixty-nine
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Tomato (
objective
of this study was to determine the genetic diversity and population structure of 355 tomato accessions from Asia using 18 simple-sequence repeats (SSRs). A total of 176 alleles were detected at an average of ten alleles per SSR locus. The average major allele frequency and polymorphic information content were 0.69 and 0.39, respectively. Model-based structure analysis revealed two subpopulations (88%), including admixtures (11%) in the 355 Asian tomato accessions, consistent with clustering results based on genetic distance. The overall
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Rice varieties developed through the inter-specific crosses between Asian (
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Plant breeding programs are often used to improve varieties through creating diverse agronomic traits. During a breeding program, a lot of genetic diversities are created in the genome after different generations through homologous recombination. Genome sequencing technology has revolutionized the discovery of genes and molecular markers associated with diverse agronomic traits in crop improvement programs. Genomic research is now in the peak of success, thus creating new opportunities for crop improvement modern sequencing technology is now capable of sequencing thousands to millions of bases per run. Modern sequencing technologies enable the sequencing of different cultivars with small to complex genomes at a reasonable time and cost. These massive data can be used to identify important agronomic traits of crops such as fruit color, size, ripening, flowering time adaptation, grain yield, and quality maintenance. In addition, they can be used to develop crop varieties. This mini-review is focused on the role of genome sequencing in genomic research and plant breeding for crop improvements.
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In order to estimate genetic diversity of Korean rice landraces, rice characters and SSR markers of 76 rice germplasms were analyzed. Of 12 rice characters, amylose content (AC) showed as largest variance (4.9 to 28.9%), whereas grain length (GL) showed as the lowest variance (4.4 to 5.9 mm). In principal component analyses (PCA), the first principal component explained 60.3% of total variance, in which culm length (CL) and growth period (GP) showed as positive variance and AC showed as negative variance. The second principal component explained an additional 22.4% of the total variance, in which GP and AC showed highly positive variables and CL showed a negative variable. Forty nine SSR markers produced a total of 473 alleles with an average of 9.65 alleles. Polymorphism information content (PIC) was in the range of 0.11 to 0.93. Average observed heterozygosity ranged from 0.12 to 0.39, with an average value of 0.61. As a result of STRUCTURE analysis, 76 Korean rice landraces showed two subpopulations. In clustering analysis, rice characters and SSR markers were clustered into four groups and three groups, respectively. However, they were not significant different from each other. These results provided insight into the characteristics of Korean rice landraces, thus improving our knowledge on rice breeding.
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Soybean [
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This study was carried out to evaluate the genetic diversity and relationships among fifty-six blackberry (
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A set of five Korean rice cultivars and seven drought-tolerant indica lines were screened under irrigated non-stress and drought-stressed conditions in the 2011 and 2012 dry seasons at IRRI, Philippines. The drought-stressed experiment received mild to moderate stress. Under drought stress, ‘IR86918-B-439-B’ had the highest grain yield among all tested lines and ‘Hanarembyeo’ had the highest grain yield among the five Korean rice cultivars. ‘IR86918-B-439-B’ also had the highest yield under irrigated non-stress conditions. The grain yield of ‘Hanareumbyeo’ was similar to ‘IR86918-B-439-B’ under non-stress conditions. SSR marker analysis was performed using 125 SSR markers for detection of polymorphic markers between the Korean rice cultivars and the drought-tolerant indica lines, and for genetic diversity analysis. Twelve polymorphic markers were identified in the region of three major drought QTLs (DTY1.1, DTY2.2, DTY3.1) in two of the Korean rice cultivars and three of the drought-tolerant lines. These polymorphic markers will be useful as foreground genotyping markers for drought-QTL introgression in Korean rice genetic backgrounds.
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Indian spinach (
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Assessment of the genetic variation and biochemical traits among various germplasm collections are necessary for utilization of valuable genetic resource and effective strategies of germplasm conservation. The aims of this study were to analyze the genetic diversity using SSR markers and compare protein, oil content and fatty acid composition of about 185 soybean germplasm which is comprised of Korean landraces and collections from six different global regions. Seventy two SSR markers were selected based on their distribution on the 17 genetic linkage groups of soybean. A total of 784 alleles were detected from all accessions, with an average of 10.9 alleles per microsatellite locus. The genetic diversity observed was high wherein three distinct groups were formed containing several subgroups according to their geographic origins. Biochemical contents assay revealed significant differences in their protein and oil contents. Generally, the crude protein content was highest among India and Myanmar collections, while oil content was highest among accessions from USA and China. A negative correlation was observed between protein and oil contents, and between oleic and linolenic acids. The highest value observed for biochemical content among all germplam tested was 45.8% for crude protein, 26.7% for crude oil and 35.7% for oleic acid composition. Our study provided a better understanding of genetic relationships and geographical origin among various germplasm collections, and it could contribute to more efficient utilization of valuable genetic resources.
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The present study investigated the isolation and characterization of 34 polymorphic microsatellite markers developed from
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A total of 23 elite rice cultivars from eight countries were evaluated for cold tolerance using two screening methods at Chuncheon Substation, National Institute of Crop Science (NICS), Republic of Korea. The rice cultivars Jinbu, Mustaqillik, and Avangard showed cold tolerance and high spikelet fertility (63–79%) in cold-water irrigation screening. Under greenhouse screening, five cultivars (Giza 177, Avangard, Mustaqillik, Jinbu, and Jungan) showed high cold tolerance and high spikelet fertility (71–81%). Simple sequence repeat (SSR) marker analysis of 21 genotypes revealed two major clusters, the
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Brown rice contains beneficial phytonutrients such as antioxidants, anthocyanins and oryzanol, and oryzanol is one of the major components. However, the information of oryzanol contents and genetic data are limited in Korean rice landraces to use the genetic resources. This study was conducted to investigate varietal differences of the oryzanol content and analyze the genetic diversity using SSR marker about 196 Korean rice landraces. Among tested germplasm, the total γ-oryzanol values showed the high variation ranged from 9.8 to 55.9 mg 100g−1 and an average content value was 27.2 mg 100g−1. Particularly, IT007903, IT007714, IT006622 and IT006125 accessions were showed γ-oryzanol contents higher than 50mg 100g−1. The 24-methylene cycloartenyl ferulate was the most prevalent with an average value of 29.9% among the total γ-oryzanol components, and followed by cycloartenyl ferulate (26.7%). Genetic diversity among 196 landrace accessions was evaluated based on 46 SSR markers carrying total 396 alleles. The mean values of observed (HO) and expected heterozygosities (HE) were 0.009 and 0.497, respectively, indicating a considerable amount of polymorphism within this collection. A genetic distance-based phylogeny grouped into seven clusters with genetic distance (GD) value was 0.6. According to the phylogenetic analysis, roughly 7 clusters were divergent, and the γ-oryzanol content values showed statistical differences by the four groups (
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