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1.
Crosses between Gossypium barbadense L and Gossypium hirsutum L. (Upland cotton) have produced limited success in introgressing fiber quality genes into the latter. Chromosome substitution lines (CSBL) have complete chromosomes or chromosome arms from G. barbadense, line 3-79, substituted for the corresponding chromosome or arms in G. hirsutum in a near isogenic background of TM-1. We top crossed nine CSBL and their parents (TM-1 and 3-79) with five cultivars. Parental lines and their F2 populations were evaluated in four environments for agronomic and fiber quality traits. The CSBL and their F2 hybrids showed wide ranges for both agronomic and fiber traits of economic importance. Genetic analysis showed that additive variances were larger than dominance variances for lint percentage, boll weight, lint yield, fiber length, strength, elongation, micronaire, and yellowness; whereas, dominance variances were larger than additive variances only for uniformity of fiber length and equal for fiber reflectance. For all traits, except boll weight and lint yield, significant additive effects of one or more chromosomes from 3-79 in TM-1 background were greater than the corresponding TM-1 chromosome. In addition, we identified specific chromosomes from G. barbadense (3-79) that carry alleles for improvements in specific fiber quality traits in Upland cotton. Favorable additive effects of individual chromosomes or chromosome segments from 3-79 relative to corresponding chromosomes or chromosomes segments from TM-1 were identified in this study as follows: Lint percentage, chromosome/arms 10, 16-15; longer fibers, chromosome/arms 01, 11sh, 26Lo; more uniform fibers, chromosomes/arms 01, 11sh, 10, 17-11; stronger fibers, chromosome/arms 01, 11sh, 12sh, 26Lo, 17-11; fiber elongation, chromosomes/arms 01, 11sh, 26Lo, 10, 17-11; reduced fiber micronaire, chromosome/arms 01, 12sh, 4-15, 16-15, 17-11; fibers with more reflectance, chromosome/arms 10, 4-15, 16-15, 17-11; fiber with less yellowness, chromosome arms 4-15, 17-11. Based on the present study, we concluded that by using CSBL, favorable fiber quality alleles can be introgressed into Upland cotton, thus greatly improving the breeder’s ability for improvement of Upland cotton for a variety of traits. These data should provide useful genetic information to the cotton breeding industry at large.  相似文献   

2.
Gossypium barbadense L. cotton has significantly better fiber quality than Upland cotton (G. hirsutum L.); however, yield and environmental adaptation of G. barbadense is not as wide as Upland. Most cotton in the world is planted to Upland cultivars. Many attempts have been made, over a considerable number of years, to introgress fiber quality alleles from G. barbadense into Upland. However, introgression barriers, primarily in the form of interspecific incompatibility, have limited these traditional approaches. The use of chromosome substitution lines (CSL) as a bridge should provide a more efficient way to introgress alleles from G. barbadense into Upland. We crossed 18 G. barbadense CSL to three cultivars and developed a random mated population. After five cycles of random mating followed by one generation of self-pollination to increase the seed supply, we grew the random mated population and used 139 G. barbadense chromosome specific SSR markers to assess a random sample of 96 plants for introgression. We recovered 121 of 139 marker loci among the 96 plants. The distribution of the G. barbadense alleles ranged from 10 to 28 alleles in each plant. Among the 96 plants we found individual plants with marker loci from 6 to 14 chromosomes or chromosome arms. Identity by descent showed little relatedness among plants and no population structure was indicated by a heat map. Using CSL we were able to develop a mostly Upland random mated population with considerable introgression of G. barbadense alleles which should be useful for breeding.  相似文献   

3.
Investigation of cotton nutritional components is important because its seeds provide a useful nutritional profile and can possibly serve as a biofuel resource. In this study, five cultivars, 13 cotton chromosome substitution (CS-B) lines, their donor parent, '3-79', and their recurrent parent, 'TM-1', were evaluated for seed traits over four environments. A mixed linear model approach with the jackknife method was employed to estimate variance components and to predict genotypic effects for each seed trait. Genotypic effects were more important than genotype by environment interaction for all seed traits. Chromosome associations with these seed traits were detected using the comparative method by comparing the differences between each CS-B line and TM-1. For example, chromosome 4 of 3-79 in TM-1 background was associated with reduced seed index (SI), embryo percentage, protein percentage while associated with increased seed oil percentage and seed fiber percentage. Other chromosome associations with these seed traits were also observed in this study. SI was highly correlated with three seed index traits: seed protein index, seed oil index (OI), and seed fiber index. Lint percentage, boll number, and lint yield were positively correlated with protein percentage while negatively correlated with SI and OI. SI and seed fiber content exhibited negative correlations with micronaire but positive correlations with fiber length and strength. Results suggested that agronomic traits and seed nutrition components can be improved simultaneously.  相似文献   

4.
Gossypium turneri, a wild cotton species (2n = 2X = 26, D10D10) originating from Mexico, possesses invaluable characteristics unavailable in the cultivated tetraploid cotton gene pool, such as caducous involucels at anthesis, resistance to insects and tolerance to abiotic stresses. However, transferring desired characteristics from wild species into cultivated cotton is often fraught with diverse obstacles. Here, Gossypium hirsutum (as the maternal parent) and G. turneri were crossed in the Hainan Province of China, and the obtained hybrid seeds (2n = 3X = 39, ADD10) were treated with 0.075% colchicine solution for 48 h to double the chromosome complement in order to overcome triploid F1 sterility and to generate a fertile hexaploid. Chromosome doubling was successful in four individuals. However, the new synthetic hexaploids derived from these individuals were still highly sterile, and no seeds were generated by selfing or crossing. Therefore, an embryo rescue technique was employed in an attempt to produce progenies from the new synthetic hexaploids. Consequently, a total of six large embryos were obtained on MSB2K medium supplemented with 0.5 mg l?1 KIN and 250 mg l?1 CH using ovules from backcrossing that were 3 days post-anthesis. Four grafted surviving seedlings were confirmed to be the progenies (pentaploids) of the new synthetic hexaploids using cytological observations and molecular markers. Eight putative fertile individuals derived from backcrossing the above pentaploids were confirmed using SSR markers and generated an abundance of normal seeds. This research lays a foundation for transferring desirable characteristics from G. turneri into upland cotton.  相似文献   

5.
Most forage cultivars released for the genus Paspalum belong to a section named Plicatula. The species of Plicatula are mostly apomictic and consequently the genetic diversity is locked for their genetic improvement. The objectives were to evaluate the crossability, hybrid fertility, heterosis, and genetic distances between apomictic accessions and a sexual genotype of species of Plicatula group of Paspalum. Crosses were made using 22 apomictic tetraploid accessions belonging to 12 different species as pollen donors, and a sexual tetraploid genotype induced by colchicine from a sexual diploid accession of P. plicatulum. Crossability varied between 0 and 16% among crosses. Viable hybrid offspring were recovered from 15 out of 22 crosses. The most successful crosses involved P. guenoarum, P. plicatulum, P. chaseanum, and P. oteroi. Fertility of the sampled hybrids varied between 1.6% for the cross involving P. lenticulare, and 40.1% for an intraspecific cross (P. plicatulum, accession Hojs388). The genetic distance between parents was estimated using amplified fragment-length polymorphism, and it varied between 0.34 and 0.53. There was no correlation between genetic distances and crossability or fertility of the hybrids. Hybrids from the most numerous families were classified for mode of reproduction using flow cytometric seed analysis. The ratio between sexual and apomictic hybrids varied between 0.6:1 and 1.6:1. A selected group of apomictic hybrids were evaluated for several agronomic traits in the field. Heterosis was observed for frost tolerance and cattle preference. The results indicated that gene transfer via hybridization is possible among several species of Plicatula. Superior hybrids for specific traits can be generated and fixed by apomixis.  相似文献   

6.
Broadening the genetic base of the C genome of Brassica napus canola by use of B. oleracea is important. In this study, the prospect of developing B. napus canola lines from B. napus?×?B. oleracea var. alboglabra, botrytis, italica and capitata crosses and the effect of backcrossing the F1’s to B. napus were investigated. The efficiency of the production of the F1’s varied depending on the B. oleracea variant used in the cross. Fertility of the F1 plants was low—produced, on average, about 0.7 F2 seeds per self-pollination and similar number of BC1 seeds on backcrossing to B. napus. The F3 population showed greater fertility than the BC1F2; however, this difference diminished with the advancement of generation. The advanced generation populations, whether derived from F2 or BC1, showed similar fertility and produced similar size silique with similar number of seeds per silique. Progeny of all F1’s and BC1’s stabilized into B. napus, although B. oleracea plant was expected, especially in the progeny of F1 (ACC) owing to elimination of the A chromosomes during meiosis. Segregation distortion for erucic acid alleles occurred in both F2 and BC1 resulting significantly fewer zero-erucic plants than expected; however, plants with?≤?15% erucic acid frequently yielded zero-erucic progeny. No consistent correlation between parent and progeny generation was found for seed glucosinolate content; however, selection for this trait was effective and B. napus canola lines were obtained from all crosses. Silique length showed positive correlation with seed set; the advanced generation populations, whether derived from F2 or BC1, were similar for these traits. SSR marker analysis showed that genetically diverse canola lines can be developed by using different variants of B. oleracea in B. napus?×?B. oleracea interspecific crosses.  相似文献   

7.
Wild Cicer species are considered to be more resistant for biotic and abiotic stresses than that of the cultivated chickpea (Cicer arietinum L.). Alien genes conferring resistance for biotic and abiotic stresses can be transferred from wild Cicer species to the cultivated chickpea but success in interspecific hybridizations has already been achieved with only two wild Cicer species. The current study was undertaken to compare fruitful heterosis in F2 and F3 for yield and yield criteria and to identify transgressive segregation in F2 and F3 in reciprocal interspecific crosses between C. arietinum and C. reticulatum Ladiz. We define fruitful heterosis as a useful parameter that can be used instead of residual heterosis. Considerable fruitful heterosis in F2 and F3 was found for number of seeds, pods per plant, biological yield, and seed yield. Maximum values of most of the characteristics in F2 and F3 were higher than that of the best parent indicating that superior progeny could be selected for yield from transgressive segregation. Progeny selection should be based on number of seeds, pods per plant, and biological yield since these characteristics had the highest direct effect on seed yield. The narrow sense heritability was found to be the highest for 100-seed weight. It was suggested that the cultivated chickpea could be used as female parent in interspecific hybridization to increase yield and yield criteria since progeny in F2 and F3 had better performance when it was used as female. In conclusion, interspecific hybridization of wild and cultivated chickpea can be used to improve yield and yield components and resistance to biotic and abiotic stresses as well.  相似文献   

8.
In a previous investigation on the reciprocal difference of interspecific hybridization between three different flower colors of Iris dichotoma and Iris domestica in the F1 offspring from crosses where I. domestica was a maternal parent were similar in morphological and cytological characters to their maternal parent. This could be evidence of apomixis; however, matroclinal progeny with complete morphological similarity to the maternal parent could be attributed to the heterozygosity for these characters in the pollen parent. The F1 plants were investigated in order to identify apomixis in I. domestica. Four matroclinal plants were randomly selected from each F1 population produced from Iris domestica × Iris dichotoma that had three different colors of flowers and were allowed to self-pollinate to establish an F2 population. All of the F2 plants had no segregation to I. domestica in their morphological characters. In addition, 13 reciprocal F1 plants were detected by 25,719 single nucleotide polymorphism (SNP) markers. When I. dichotoma plants with three different flower colors were used as maternal parents, all the progenies were genuine hybrids. When I. domestica were used as maternal parents, all the F1 plants were apomictic progenies. Apomixis of I. domestica was successfully identified and SNP markers identified F1 hybrids derived from six interspecific crosses between I. dichotoma and I. domestica, which provides a reference for authenticating offspring identity during Iris cross breeding in the future.  相似文献   

9.
Compact growth is an important quality criterion in horticulture. Many Campanula species and cultivars exhibit elongated growth which is suppressed by chemical retardation and cultural practice during production to accommodate to the consumer’s desire. The production of compact plants via transformation with wild type Agrobacterium rhizogenes is an approach with great potential to produce plants that are non-GMO. Efficient transformation and regeneration procedures vary widely among both plant genera and species. Here we present a transformation protocol for Campanula. Hairy roots were produced on 26–90% of the petioles that were used for transformation of C. portenschlagiana (Cp), a C. takesimana × C. punctata hybrid (Chybr) and C. glomerata (Cg). Isolated hairy roots grew autonomously and vigorously without added hormones. The Cg hairy roots produced chlorophyll and generated plantlets in response to treatments with cytokinin (42 µM 2iP) and auxin (0.67 µM NAA). In contrast, regeneration attempts of transformed Cp and Chybr roots lead neither to the production of chlorophyll nor to the regeneration of shoots. Agropine A. rhizogenes strains integrate split T-DNA in TL- and TR-DNA fragments into the plant genome. In this study, regenerated plants of Cg did not contain TR-DNA, indicating that a selective pressure against this T-DNA fragment may exist in Campanula.  相似文献   

10.
A balance of maternal and paternal genetic factors, conceptually named the endosperm balance number (EBN), is required for normal endosperm development in interspecific crosses in potato. We previously found that Solanum demissum (D), a hexaploid wild species widely used in potato breeding, has a slightly lower EBN than S. tuberosum (T). To explore the genetic nature of the EBN, the berry-setting rate, seed number/berry, and seed weight were evaluated in BC1 [(D?×?T)?×?T] plants, each possessing different portions of the S. demissum chromosomes, by reciprocal crosses with D and T, and a quantitative trait locus (QTL) analysis was performed. At least 99 S. demissum-derived QTLs were detected, of which 29 were associated with differential responses to D and T. Three QTLs were possibly co-localized on chromosomes 7A and 10D1, while the remaining 23 QTLs were independently located. The QTLs in the three S. demissum homoeologous chromosomes exhibited three types of interaction: (1) positive, (2) negative, and (3) one positive and one negative effect on the same trait. We found that several major genes, one of which was localized in the S. demissum chromosome 9A, and many minor genes controlled the crossability of BC1 plants. The QTLs responsible for the differential responses to D and T were different between the BC1 plants used as male and female parents, indicating that different genes control the male and female EBNs. Consequently, we conclude that the EBN is represented by the sum of various genetic effects controlled by a large number of genes.  相似文献   

11.
Limited knowledge about genetic and physiological traits associated with drought and low temperature stresses and narrow genetic diversity in Upland cotton (Gossypium hirsutum L.) are serious impediments in its genetic improvement. The objectives of this research were to determine the genetic and physiological traits associated with drought and low temperature effects and to identify chromosomal effects on these traits using chromosome substitution (CS) lines from three alien species of Gossypium, G. barbadense, G. tomentosum, and G. mustelinum, respectively. Two experiments were conducted to study low temperature and drought stress effects during seedling emergence and early growth stages in 21 cotton CS-lines with parent, Texas Marker (TM)-1. In Experiment I, plants were grown at optimum (30/22 °C) and low (22/14 °C) temperature conditions under optimum water and nutrient conditions. In Experiment II, plants were grown at optimum water (soil moisture content of 0.167 m3 m?3) and in drought (soil moisture content 0.105 m3 m?3) conditions under optimum temperature conditions. Above- and below-ground growth traits including several root traits of the CS lines were assessed at 25 days after sowing. The findings suggest which substituted chromosome or chromosome segment from the alien species likely harbors one or more genes for higher and lower tolerance to low temperature, respectively. CS-T04 and CSB08sh showed higher and lower tolerance to low temperature, respectively and CS-T04 and CS-B22sh showed higher and lower tolerance, respectively, to drought. CS lines are valuable analytical tool and useful genetic resources for targeted exploitation of beneficial genes for drought and low temperature stresses in Upland cotton.  相似文献   

12.
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13.
Verticillium wilt (VW, Verticillium dahliae) is a worldwide destructive soil-borne fungal disease and employment of VW resistant cultivars is the most economic and efficient method in sustainable cotton production. However, information concerning VW resistance in current commercial cotton cultivars and transfer of VW resistance from Pima (Gossypium barbadense) to Upland (Gossypium hirsutum) cotton is lacking. The objective of the current study was to report findings in evaluating commercial cotton cultivars and germplasm lines for VW resistance in field and greenhouse (GH) experiments conducted in 2003, 2006, and 2007. In the study, 267 cultivars and germplasm lines were screened in the GH, while 357 genotypes were screened in the field. The results indicated that (1) VW significantly reduced cotton yield, lint percentage, 50% span length and micronaire, but not 2.5% span length and fiber strength, when healthy and diseased plants in 23 cultivars were compared; (2) some commercial cotton cultivars developed by major cotton seed companies in the US displayed good VW resistance; (3) many Acala cotton cultivars released in the past also had good VW resistance, but not all Acala cotton germplasm are resistant; (4) Pima cotton possessed higher levels of VW resistance than Upland cotton, but the performance was reversed when the root system was wounded after inoculation; (5) VW resistance in some conventional cultivars was transferred into their transgenic version through backcrossing; and (6) some advanced backcross inbred lines developed from a cross between Upland and Pima cotton showed good VW resistance. The successful development of VW resistant transgenic cultivars and transfer of VW resistance from Pima to Upland cotton implies that VW resistance is associated with a few genes if not a major one.  相似文献   

14.
Peach powdery mildew is one of the major diseases of the peach. Various sources of resistance to PPM have thus been identified, including the single dominant locus Vr2 carried by the peach rootstock ‘Pamirskij 5’. To map Vr2, a linkage map based on microsatellite markers was constructed from the F2 progeny (WP2) derived from the cross ‘Weeping Flower Peach’ × ‘Pamirskij 5’. Self-pollinations of the parents were also performed. Under greenhouse conditions, all progenies were scored after artificial inoculations in two classes of reactions to PPM (resistant/susceptible). In addition to Vr2, WP2 segregated for three other traits from ‘Weeping Flower Peach’: Rm1 for green peach aphid resistance, Di2 for double-flower and pl for weeping-growth habit. With their genomic locations unknown or underdocumented, all were phenotyped as Mendelian characters and mapped: Vr2 mapped at the top of LG8, at 3.3 cM, close to the CPSCT018 marker; Rm1 mapped at the bottom of LG1, at a position of 116.5 cM, cosegregating with the UDAp-467 marker and in the same region as Rm2 from ‘Rubira’®; Di2 mapped at 28.8 cM on LG6, close to the MA027a marker; and pl mapped at 44.1 cM on LG3 between the MA039a and SSRLG3_16m46 markers. Furthermore, this study revealed, for the first time, a pseudo-linkage between two traits of the peach: Vr2 and the Gr locus, which controls the red/green color of foliage. The present work therefore constitutes a significant preliminary step for implementing marker-assisted selection for the four major traits targeted in this study.  相似文献   

15.
Previous studies reported that some genotypes with introgressed Festuca chromosome segment(s) in Lolium genome showed enhanced winter hardiness compared to Lolium. The aim of this study was to search comprehensively for the Festuca pratensis chromosome regions affecting winter hardiness-related traits when introgressed into the Lolium perenne genome. Association between F. pratensis introgression and winter hardiness-related traits (fall and winter hardiness indexes, early-spring dry matter yield, and freezing tolerance) were screened in the diploid introgression populations (n = 203) that had some F. pratensis chromosome segments introgressed. Eighty-four intron markers corresponding to unique rice genes randomly distributed across the genome were used for genotyping. Winter hardiness of almost all plants in the introgression populations was lower than that of the F. pratensis and triploid hybrid parents, but the average was higher than that of L. perenne. A significant positive effect of F. pratensis introgression on early-spring dry matter yield was detected on chromosome 7. This quantitative trait locus (QTL) was confirmed by linkage analysis using a backcross population with F. pratensis introgression in the target region of chromosome 7. However, the contribution of the newly identified QTL was rather small (6.7–9.6%), suggesting that superior winter hardiness of F. pratensis compared to L. perenne is conferred by multiple small-effect QTLs. We also detected a previously unreported negative effect of Festuca introgression on winter hardiness. Newly obtained QTL information in this study would contribute to the design of Festuca/Lolium hybrid breeding.  相似文献   

16.
Polyploid breeding offers the possibility of increased variability in the search for improved growth, site adaptation and disease resistance in tropical acacias. A key focus of breeding in Vietnam has been the production and testing of vigorous triploid clones which are expected to have the added advantage of being sterile. Triploids obtained by manual crosses between diploid and tetraploid trees or by bulk screening of seedlings derived from open-pollinated seedlots were verified using flow cytometry. Thirteen clones are under field testing for growth rate, tree form and fertility. Six of these are now reproductively mature and flowered as prolifically as diploids. However no pollen germinated, either on agar or on their own stigmas under controlled pollination. Only one clone (X01—F1 hybrid of tetraploid A. mangium and diploid A. auriculiformis) produced open pollinated pods on 0.05% of hermaphrodite flowers and these contained an average of 1.3 filled seeds per pod, about one-fifth the number observed in diploids. Less than 25% of germinated progeny from this triploid clone survived at 3 months after sowing and survivors were severely stunted with arrested growth. Ploidy and genotype analysis revealed them to be predominantly aneuploids, ranging from hyperdiploid to hypotetraploid with 95% being selfs. We are confident that we can select triploid clones which will be effectively infertile if deployed in plantations and may be of particular value in situations where the normal prolific natural regeneration of tropical acacias is highly undesirable.  相似文献   

17.
Interspecific hybrids were developed between Trifolium alexandrinum cultivar Wardan × Trifolium vesiculosum and T. alexandrinum cultivar BL1 × T. vesiculosum through embryo rescue, as the crosses failed to set seed under natural conditions. Trifolium vesiculosum was used as a donor/male parent in this study as it is reported to possess tolerance to stem rot and high forage yield. Fertilization in crossed florets of the crosses was manifested from the recovery of swollen ovaries (< 7.80%) and confirmed from the presence of one degenerated ovule in most (> 93.00%) of the swollen ovaries. The hybrid embryos at various developmental stages (heart, torpedo and cotyledonary) were rescued at a frequency of 2.56% from Wardan × T. vesiculosum and 6.12% from BL1 × T. vesiculosum. Differentiation occurred only in the cotyledonary stage embryos, resulting in 17 putative interspecific hybrid plantlets. The assessment of plantlet hybridity through SSR markers (for the alleles inherited from the donor parent), micromorphological leaf traits (leaf texture and stomata) and morphological characters (plant height, leaflet length and width) confirmed production of two interspecific hybrids designated as AV1 and BV3 representing both the crosses. AV1 displayed moderate resistance and BV3 was resistant to stem rot.  相似文献   

18.
Black rot caused by Xanthomonas campestris pv. campestris (Xcc) (Pam.) is the most devastating disease of cauliflower (Brassica oleracea var. botrytis L.; 2n = 2x = 18), taking a heavy toll of the crop. In this study, a random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) derived sequence characterized amplified region (SCAR) markers linked to the black rot resistance locus Xca1bo were developed and evaluated as a screening tool for resistance. The RAPD marker OPO-04833 and ISSR marker ISSR-11635 were identified as closely linked at 1.6 cM distance to the black rot resistance locus Xca1bo. Both the markers OPO-04833 and ISSR-11635 were cloned, sequenced and converted into SCAR markers and validated in 17 cauliflower breeding lines having different genetic backgrounds. These SCAR markers (ScOPO-04833 and ScPKPS-11635) amplified common locus and showed 100% accuracy in differentiating resistant and susceptible plants of cauliflower breeding lines. The SCAR markers ScOPO-04833 and ScPKPS-11635 are the first genetic markers found to be linked to the black rot resistance locus Xca1bo in cauliflower. These markers will be very useful in black rot resistance marker assisted breeding.  相似文献   

19.
Forsythia suspensa and F. ‘Courtaneur’ were used as female parents to cross with Abeliophyllum distichum in 2011 and an intergeneric hybrid of F. suspensa × A. distichum was obtained, though with very low seed set. The morphological characteristics, flower fragrance and volatile organic compounds of flowers were analysed. The intergeneric hybrid had intermediate morphological characteristics of both parents and flower fragrance and was confirmed as a true intergeneric hybrid by amplified fragment length polymorphism (AFLP) markers. Compared with its mother parent (F. suspensa), flowers of the intergeneric hybrid are pale yellow with delicate fragrance. Volatile organic compounds of flowers were retrieved by purge-and-trap techniques, and determined by gas chromatography and mass spectrometry (GC–MS). The main volatile organic components of F. suspensa were isoprenoids, while the main volatile organic components of A. distichum and the hybrid of F. suspensa × A. distichum were aliphatics. To determine the time and the site of intergeneric hybridizing barriers occured, the pollen tubes’ behavior after pollination was observed under fluorescence microscopy. It was found that significant pre-fertilization incompatibility existed in intergeneric crossing combinations [F. ‘Courtaneur’ (Pin) × A. distichum (Thrum) and F. suspensa (Pin) × A. distichum (Thrum)], and only a few pollen tubes of A. distichum penetrated into the ovaries of Forsythia. In our research, an intergeneric hybrid between Forsythia and Abeliophyllum was obtained for the first time, which will provide a solid foundation for expanding the flower color range of Forsythia and breeding fragrant-flowered cultivars.  相似文献   

20.
Molecular markers such as simple sequence repeats (SSR) are a useful tool for characterizing genetic diversity of Gossypium germplasm. Genetic profiles by DNA fingerprinting of cotton accessions can only be compared among different collections if a common set of molecular markers are used by different laboratories and/or research projects. Herein, we propose and report a core set of 105 SSR markers with wide genome coverage of at least four evenly distributed markers per chromosome for the 26 tetraploid cotton chromosomes. The core marker set represents the efforts of ten research groups involved in marker development, and have been systematically evaluated for DNA polymorphism on the 12 genotypes belonging to six Gossypium species [known collectively as the cotton marker database (CMD) panel]. A total of 35 marker bins in triplex sets were arranged from the 105 markers that were each labeled with one of the three fluorescent dyes (FAM, HEX, and NED). Results from this study indicated that the core marker set was robust in revealing DNA polymorphism either between and within species. Average value of polymorphism information content (PIC) among the CMD panel was 0.65, and that within the cultivated cotton species Gossypium hirsutum was 0.29. Based on the similarity matrix and phylogenetic analysis of the CMD panel, the core marker set appeared to be sufficient in characterizing the diversity within G. hirsutum and other Gossypium species. The portability of this core marker set would facilitate the systematic characterization and the simultaneous comparison among various research efforts involved in genetic diversity analysis and germplasm resource preservation.  相似文献   

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