EST sequences of Mentha piperita available in the public domain(NCBI) were exploited to develop SSR markers. A total of 1316 ESTs were assembled into 155 contigs and 653 singletons and of these, 110 sequences were fou...EST sequences of Mentha piperita available in the public domain(NCBI) were exploited to develop SSR markers. A total of 1316 ESTs were assembled into 155 contigs and 653 singletons and of these, 110 sequences were found to contain 130 SSRs, with a frequency of1 SSR/3.4 kb. Dinucleotide repeat SSRs were most frequent(72.3%) with the AG/CT(43.8%)repeat motif followed by AT/AT(16.2%). Primers were successfully designed for 68SSR-containing sequences(62.0%). The 68 primers amplified 13 accessions of M. piperita and 54 produced clear amplicons of the expected size. Of these 54, 33(61%) were found to be polymorphic among M. piperita accessions, showing from 2 to 4 alleles with an average of2.33 alleles/SSR, and the polymorphic information content(PIC) value varied between 0.13 and 0.51(average 0.25). All the amplified SSRs showed transferability among four different species of Mentha, with a highest in Mentha arvensis(87.0%) and minimum in Mentha citrata(37.0%). The newly developed SSRs markers were found to be useful for diversity analysis, as they successfully differentiated among species and accessions of Mentha.展开更多
Maize landraces White Dent and Golden Queen played a very important role in the pre-hybrid era of maize production in China. However, dozens of accessions with the same names of White Dent and Golden Queen are preserv...Maize landraces White Dent and Golden Queen played a very important role in the pre-hybrid era of maize production in China. However, dozens of accessions with the same names of White Dent and Golden Queen are preserved in China National Genebank （CNG）. The present study investigated the genetic diversity of these two important groups of maize landraces, as well as the relationships within and among them. Thirty-four landrace accessions with the name of White Dent and 10 with Golden Queen preserved in CNG were fingerprinted with 52 simple sequence repeats with tailed primer M13. Summary statistics including average number of alleles per locus, gene diversity/expected heterozygosity, and observed heterozygosity were carried out using PowerMarker ver. 3.25 software. The test of Hardy-Weinberg equilibrium （HWE） and linkage disequilibrium （LD） of all the 44 maize landrace accessions were also performed by PowerMarker. We observed a significant differentiation in terms of the average number of alleles between White Dent and Golden Queen （6.44 alleles per locus in White Dent, 4.48 in Golden Queen）, while both groups of maize landraces had a relatively high but similar gene diversity （0.61 of White Dent, 0.63 of Golden Queen）. The fixation index （FST） was only 0.0044, while the percentage of loci deviated from Hardy-Weinberg equilibrium within these two groups of White Dent and Golden Queen was 32.69 and 3.92%, respectively. The rather high genetic diversity and average number of alleles per locus confirmed that both groups of landraces had a rather broad germplasm base. The extremely low fixation index showed that there was little genetic variation between White Dent and Golden Queen and the molecular variation within these two groups was remarkably high, indicating no genetic drift between White Dent and Golden Queen and suggesting different improvement approaches to these two important groups of landraces. Hardy-Weinberg equilibrium test revealed that the group of White Dent was deviated from HWE, whereas Golden Queen was under HWE.展开更多
Molecular markers provide the opportunity toidentify marker-quantitative trait locus(QTL)associations in different environments andpopulations,and can be used to improve theefficiency of conventional plant breeding by...Molecular markers provide the opportunity toidentify marker-quantitative trait locus(QTL)associations in different environments andpopulations,and can be used to improve theefficiency of conventional plant breeding bycarrying out indirect selection through molecularmarkers linked to the interest traits of QTL展开更多
Quantification and classification of diversity ingermplasm collection is important for bothgenetic researchers and plant breeders.Someadvance was made in this area in the world(Liuet al,2000)based on SSRs and in China...Quantification and classification of diversity ingermplasm collection is important for bothgenetic researchers and plant breeders.Someadvance was made in this area in the world(Liuet al,2000)based on SSRs and in China(Xu etal,2001;2002)based on RAPDs.In thisresearch,72 cultivars including 14 latestintroduced and 30 Bt-transformed ones展开更多
To investigate the relationship between genetic distance (GD) and hybrid performance, two types of molecular markers, microsatellites (simple sequence repeats, SSRs) and intro-simple sequence repeats (ISSRs), were emp...To investigate the relationship between genetic distance (GD) and hybrid performance, two types of molecular markers, microsatellites (simple sequence repeats, SSRs) and intro-simple sequence repeats (ISSRs), were employed to detect the genetic diversity of 3 double low self-incompatible lines and 22 male parental varieties of Brassica napus from different geographical origins. Hybrids were produced in a NCⅡ mating design by hand-pollination. The result indicated that 25 parental varieties (lines) could be divided into six groups by Un-weighted Pair Group Mathematics Average (UPGMA) clustering based on GDs. SI-1300 and SI-1320 could be singly clustered into one group, respectively. Varieties from China could be separated into another group, SI-1310 and varieties from foreign countries could be separated into other three groups. The grouping was generally consistent with parental pedigrees and geographical origins. Significant differences in yield, quality and phenological period traits were observed among these parent groups. Although hybrid yield/plant showed significantly positive correlation with genetic distance based on SSR and ISSR markers, but the determination coefficient was low. It appeared to be unsuitable for using the genetic distance based on SSR and ISSR markers to predict heterosis and hybrid performance in Brassica napus.展开更多
文摘EST sequences of Mentha piperita available in the public domain(NCBI) were exploited to develop SSR markers. A total of 1316 ESTs were assembled into 155 contigs and 653 singletons and of these, 110 sequences were found to contain 130 SSRs, with a frequency of1 SSR/3.4 kb. Dinucleotide repeat SSRs were most frequent(72.3%) with the AG/CT(43.8%)repeat motif followed by AT/AT(16.2%). Primers were successfully designed for 68SSR-containing sequences(62.0%). The 68 primers amplified 13 accessions of M. piperita and 54 produced clear amplicons of the expected size. Of these 54, 33(61%) were found to be polymorphic among M. piperita accessions, showing from 2 to 4 alleles with an average of2.33 alleles/SSR, and the polymorphic information content(PIC) value varied between 0.13 and 0.51(average 0.25). All the amplified SSRs showed transferability among four different species of Mentha, with a highest in Mentha arvensis(87.0%) and minimum in Mentha citrata(37.0%). The newly developed SSRs markers were found to be useful for diversity analysis, as they successfully differentiated among species and accessions of Mentha.
基金supported by the Special Program for Crop Germplasm Resources of the Ministry of Agriculture [(NB07-2130135-(25-30)-05]Natural Science Foundation of Beijing (6071003)+1 种基金Innovation Platform Program for Basic Research of Agricultural Breeding in Beijing (YZPT02-06)Scientific and Technological Key Project in Chongqing for Elite Variety Innovation of Rice and Maize (CSTC 2007AB1045)
文摘Maize landraces White Dent and Golden Queen played a very important role in the pre-hybrid era of maize production in China. However, dozens of accessions with the same names of White Dent and Golden Queen are preserved in China National Genebank （CNG）. The present study investigated the genetic diversity of these two important groups of maize landraces, as well as the relationships within and among them. Thirty-four landrace accessions with the name of White Dent and 10 with Golden Queen preserved in CNG were fingerprinted with 52 simple sequence repeats with tailed primer M13. Summary statistics including average number of alleles per locus, gene diversity/expected heterozygosity, and observed heterozygosity were carried out using PowerMarker ver. 3.25 software. The test of Hardy-Weinberg equilibrium （HWE） and linkage disequilibrium （LD） of all the 44 maize landrace accessions were also performed by PowerMarker. We observed a significant differentiation in terms of the average number of alleles between White Dent and Golden Queen （6.44 alleles per locus in White Dent, 4.48 in Golden Queen）, while both groups of maize landraces had a relatively high but similar gene diversity （0.61 of White Dent, 0.63 of Golden Queen）. The fixation index （FST） was only 0.0044, while the percentage of loci deviated from Hardy-Weinberg equilibrium within these two groups of White Dent and Golden Queen was 32.69 and 3.92%, respectively. The rather high genetic diversity and average number of alleles per locus confirmed that both groups of landraces had a rather broad germplasm base. The extremely low fixation index showed that there was little genetic variation between White Dent and Golden Queen and the molecular variation within these two groups was remarkably high, indicating no genetic drift between White Dent and Golden Queen and suggesting different improvement approaches to these two important groups of landraces. Hardy-Weinberg equilibrium test revealed that the group of White Dent was deviated from HWE, whereas Golden Queen was under HWE.
文摘Molecular markers provide the opportunity toidentify marker-quantitative trait locus(QTL)associations in different environments andpopulations,and can be used to improve theefficiency of conventional plant breeding bycarrying out indirect selection through molecularmarkers linked to the interest traits of QTL
文摘Quantification and classification of diversity ingermplasm collection is important for bothgenetic researchers and plant breeders.Someadvance was made in this area in the world(Liuet al,2000)based on SSRs and in China(Xu etal,2001;2002)based on RAPDs.In thisresearch,72 cultivars including 14 latestintroduced and 30 Bt-transformed ones
文摘To investigate the relationship between genetic distance (GD) and hybrid performance, two types of molecular markers, microsatellites (simple sequence repeats, SSRs) and intro-simple sequence repeats (ISSRs), were employed to detect the genetic diversity of 3 double low self-incompatible lines and 22 male parental varieties of Brassica napus from different geographical origins. Hybrids were produced in a NCⅡ mating design by hand-pollination. The result indicated that 25 parental varieties (lines) could be divided into six groups by Un-weighted Pair Group Mathematics Average (UPGMA) clustering based on GDs. SI-1300 and SI-1320 could be singly clustered into one group, respectively. Varieties from China could be separated into another group, SI-1310 and varieties from foreign countries could be separated into other three groups. The grouping was generally consistent with parental pedigrees and geographical origins. Significant differences in yield, quality and phenological period traits were observed among these parent groups. Although hybrid yield/plant showed significantly positive correlation with genetic distance based on SSR and ISSR markers, but the determination coefficient was low. It appeared to be unsuitable for using the genetic distance based on SSR and ISSR markers to predict heterosis and hybrid performance in Brassica napus.
