Integrating alleles from Gossypium species into G.hirsutum is important for the enhancement of genetic variability and for creating polymorphism useful in molecular mapping studies.Through collaborative efforts,severa...Integrating alleles from Gossypium species into G.hirsutum is important for the enhancement of genetic variability and for creating polymorphism useful in molecular mapping studies.Through collaborative efforts,several species including G.barbadense,G.tomentosum,and G.mustelinum展开更多
Oryza ridleyi is an allotetraploid wild species with the HHJJ genome, and Oryza sativa is a diploid cultivated rice that has the AA genome. Although the wide hybrid between the two species is difficult to obtain, we o...Oryza ridleyi is an allotetraploid wild species with the HHJJ genome, and Oryza sativa is a diploid cultivated rice that has the AA genome. Although the wide hybrid between the two species is difficult to obtain, we overcome this difficulty by young embryo rescue. An obvious heterosis was primarily found for the plant height, tillering ability, vegetative vigor, etc. However, the hybrid panicle and culm traits were found to resemble that of the wild rice parent, O. ridleyi, for the long awns, exoteric purple stigma, grain shattering, dispersed panicles, and culm mechanical strength. Genomic in situ hybridization (GISH) analysis was subsequently performed on the mitotic metaphase chromosome of the root tips, and we determined that the hybrid is an allotriploid with 36 chromosomes and its genomic constitution is AHJ. Chemical analyses conducted on the culm of O. sativa, O. ridleyi, and their interspecific hybrids showed that major changes occurred in the xylose, glucose, and arabinose concentrations, which are correlated with the specific hemicellulose polymer and cellulose components that are important in the primary cell walls of green plants. Meanwhile, the culm anatomical analyses indicated that additional large vascular bundles and an extra sclerenchyma cell layer were found in O. ridleyi. Additionally, further thickening of the secondary cell walls of the cortical fiber sclerenchyma cells and the phloem companion cells was discovered in O. ridleyi and in the interspecific hybrids. These results imply that there may be a potential link between culm mechanical strength and culm anatomical structure.展开更多
In the genus Oryza, interspecific hybrids are useful bridges for transferring the desired genes from wild species to cultivated rice (Oryza sativa L.). In the present study, hybrids between O. sativa (AA genome) a...In the genus Oryza, interspecific hybrids are useful bridges for transferring the desired genes from wild species to cultivated rice (Oryza sativa L.). In the present study, hybrids between O. sativa (AA genome) and three Chinese wild rices, namely O. rufipogon (AA genome), O. officinalis (CC genome), and O. meyeriana (GG genome), were produced. Agricultural traits of the F1 hybrids surveyed were intermediate between their parents and appreciably resembled wild rice parents. Except for the O. sativa × O. rufipogon hybrid, the other F1 hybrids were completely sterile. Genomic in situ hybridization (GISH) was used for hybrid verification. Wild rice genomic DNAs were used as probes and cultivated rice DNA was used as a block. With the exception of O. rufipogon chromosomes, this method distinguished the other two wild rice and cultivated rice chromosomes at the stage of mitotic metaphase with different blocking ratios. The results suggest that a more distant phylogenetic relationship exists between O. meyeriana and O. sativa and that O. rufipogon and O. sativa share a high degree of sequence homology. The average mitotic chromosome length of O. officinalis and O. meyeriana was 1.25- and 1.51-fold that of O. sativa, respectively. 4',6'-Diamidino- 2-phenylindole staining showed that the chromosomes of O. officinalis and O. meyeriana harbored more heterochromatin, suggesting that the C and G genomes were amplified with repetitive sequences compared with the A genome. Although chromocenters formed by chromatin compaction were detected with wild rice-specific signals corresponding to the C and G genomes in discrete domains of the F1 hybrid interphase nuclei, the size and number of O. meyeriana chromocenters were bigger and greater than those of O. officinalis. The present results provide an important understanding of the genomic relationships and a tool for the transfer of useful genes from three native wild rice species in China to cultivars.展开更多
Human disturbances are considered to break reproduction barriers among species.Significant increases in hybridization events have been reported among a large number of taxonomic groups in anthropogenic environments,pr...Human disturbances are considered to break reproduction barriers among species.Significant increases in hybridization events have been reported among a large number of taxonomic groups in anthropogenic environments,providing novel insights into species evolution mechanisms and conservation management in the Anthropocene.The Eastern Golden Frog(Pelophylax plancyi)and BlackSpotted Frog(P.nigromaculatus)are two sympatric anuran species with a long history of mitochondrial genome introgression in highly urbanized continental East Asia.However,there is only limited understanding of the pattern of their contemporary hybridization and factors influencing their interspecific relationship under anthropogenic disturbances.Here,interspecific hybridization between P.plancyi and P.nigromaculatus at the population level was investigated in Shanghai.All except two haplotypes obtained from both species in Shanghai were mixed together,and located in the introgression clade,implying multiple ancient mitochondrial introgression events occurred in the populations of our study area.Asymmetric genetic introgression was detected by microsatellite markers,with 0.7%of P.plancyi and 14.6%of P.nigromaculatus identified as contemporary admixed individuals.Consistent with the trend of population density,higher genetic diversity of neutral microsatellite loci was found in the more abundant P.plancyi;however,variation in mitochondrial(Cyt-b)and nuclear(POMC)genes was higher in relatively rare P.nigromaculatus.The population density of P.plancyi and number of water patches within local habitats were significantly positively correlated with both occurrences and proportions of admixed individuals in the populations of P.plancyi and P.nigromaculatus.Considering the prevalent transformation of habitats in urbanized areas,these results imply that a high population density in isolated artificially altered habitats is likely to increase interspecific hybridization.Thus,population monitoring and improvement of landscape connectivity between habitats would be needed to control the intensity of interspecific hybridization between P.plancyi and P.nigromaculatus in anthropogenic-disturbed environments.展开更多
To elucidate reproductive isolating mechanisms in the Bangladesh coastal bullfrog Hoplobatrachus litoralis and its congeneric species, we performed crossing experiments using three species: H. litoralis, H. tigerinus...To elucidate reproductive isolating mechanisms in the Bangladesh coastal bullfrog Hoplobatrachus litoralis and its congeneric species, we performed crossing experiments using three species: H. litoralis, H. tigerinus and H. rugulosus. In addition, we conducted histological observations on spermatogenesis of the hybrids. The reciprocal hybrids between H. litoralis and H. tigerinus developed normally with somewhat lower viability at the metamorphosis stage compared with the controls. Most of the metamorphosed frogs became mature. On the other hand, almost all hybrids between female H. rugulosus and male H. litoralis or H. tigerinus died of underdevelopment at the tadpole stage, and only a few hybrids metamorphosed normally and survived to maturity. The inner structures of the testes of the control H. litoralis and H. tigerinus were completely normal, with seminiferous tubules filled with compact bundles of normal spermatozoa. Those of the reciprocal hybrids between H. litoralis and H. tigerinus were almost normal or slightly abnormal, with seminiferous tubules that contained pycnotic nuclei in addition to normal bundles of normal spermatozoa, which demonstrates slight abnormalities in spermatogenesis. In contrast, the hybrids between female H. rugulosus and male H. litoralis or H. tigerinus had no bundles of spermatozoa nor spermatids in the seminiferous tubules, which indicates entirely abnormal spermatogenesis. Meiotic chromosome figures in the reciprocal hybrids between H. litoralis and H. tigerinus showed slight abnormalities, with the occurrence of univalents and increase of rod-shaped bivalents. These results indicate that H. litoralis and H. tigerinus are not isolated from each other by hybrid inviability nor by hybrid sterility, although the hybrids showed somewhat abnormal spermatogenesis in hybrids and that H. rugulosus is isolated from both H. litoralis and H. tigerinus by incomplete hybrid inviability and complete hybrid sterility.展开更多
The progress of research on transferring elite genes from non-AA genome wild rice into Oryza sativa through interspecific hybridization are in three respects, that is, breeding monosomic alien addition lines (MAALs)...The progress of research on transferring elite genes from non-AA genome wild rice into Oryza sativa through interspecific hybridization are in three respects, that is, breeding monosomic alien addition lines (MAALs), constructing introgression lines (ILs) and analyzing the heredity of the characters and mapping the related genes. There are serious reproductive barriers, mainly incrossability and hybrid sterility, in the interspecific hybridization of O. sativa with non-AA genome wild rice. These are the 'bottleneck' for transferring elite genes from wild rice to O. sativa. Combining traditional crossing method with biotechnique is a reliable way to overcome the reproductive barriers and to improve the utilizing efficiency of non-AA genome wild rice.展开更多
As maternal parents, diploid (L202-2x) and autotetraploid (L202-4x) of Oryza sativa cv. L2O2 were crossed with O. officinalis. Embryo development and fertilization in these two crosses were comparatively studied. ...As maternal parents, diploid (L202-2x) and autotetraploid (L202-4x) of Oryza sativa cv. L2O2 were crossed with O. officinalis. Embryo development and fertilization in these two crosses were comparatively studied. There were no mature hybrid seeds obtained because all the hybridized spikelets died 30 days after pollination. The main reasons for no seed set were abnormal fertilization and development of the embryos and endosperms in the interspecific hybrids. There were doublefertilization, egg cell single-fertilization and non-fertilization in these crosses. Although 59.45% and 54.87% of hybrid embryos produced in the crosses of L202-2x/O. officinalis and L202-4x/O. officinalis, respectively, hybrid embryos ceased to develop or degenerated and plenty of free endosperm nuclei were in disaggregating state without developing cellular endosperms three days after pollination. Besides, some embryological differences in these two crosses were found, that is, the rate of double-fertilization and total rate of doubleand single-fertilization in L202-2x/O. officinalis were higher than those in L202-4x/O. officinalis. The embryo and endosperm of hybrids developed more slowly, and embryos and free endosperm nuclei were more severely degenerated in L202-4x/O. officinalis than in L202-2x/O. officinalis. Five days after pollination, a few of embryos in L202-2x/O. officinalis developed into pear-shaped ones, however, embryos in L202-4x/O. officinalis were all degenerated. Therefore, it is more difficult to obtain interspecific hybrids by wide crosses between autotetraploid of O. sativa and O. officinalis.展开更多
Studies on the reproduction and cytogenetic characterization of a primary amphidiploid Cucumis species C. hytivus Chen and Kirkbride (2n = 4x = 38) indicated that a more comprehensive cytogenetic analysis of this spec...Studies on the reproduction and cytogenetic characterization of a primary amphidiploid Cucumis species C. hytivus Chen and Kirkbride (2n = 4x = 38) indicated that a more comprehensive cytogenetic analysis of this species and its first selfed progeny would increase its potential utility in cucumber improvement. With tendrils used as source materials for mitotic analysis, chromosome numbers in all selfed progenies were 2n = 38, confirming chromosomal stability in this synthetic amphidiploid species. Detailed meiotic processes were described by comparing the primary and the selfed amphidiploids. Meiotic abnormalities, such as chromosome lagging, unequal separation, chromosome multi-polarization and polyads were observed frequently in all amphidiploid plants except for the selfed no.8, in which meiosis was arrested prior to metaphase Ⅰ. Generally, the frequency of multivalents was higher and the configurations were more complex in the selfed progenies, demonstrating a more extensive genetic exchange between cucumber and C. hystrix Chakr. Genome separation between cucumber and C. hystrix was observed through prophase Ⅰ to anaphase Ⅰ in both generations of the amphidiploids. Consequently, in addition to n = 19, a new gamete with n = 7 was produced, which was confirmed by the chromosome counts 2n = 14 in the backcrossing progenies from cucumber × amphidiploid mating. Fertility varied among the selfed amphidiploid plants. The selfed plant no.1 was found to have an improved fertility (e.g., pollen staining ability 40.8% and 25.6 seeds per fruit) and then was used as source germplasm in further introgression and gene exchange experiments.展开更多
Interspecific hybridization plays an important role in rice breeding by broadening access to desirable traits such as disease resistance and improving yields.However,interspecific hybridization is often hindered by hy...Interspecific hybridization plays an important role in rice breeding by broadening access to desirable traits such as disease resistance and improving yields.However,interspecific hybridization is often hindered by hybrid sterility,linkage drag,and distorted segregation.To mine for favorable genes from Oryza glaberrima,we cultivated a series of BC4 introgression lines(ILs)of O.glaberrima in the japonica rice variety background(Dianjingyou 1)in which the IL-2769(BC4F10)showed longer sterile lemmas,wider grains and spreading panicles compared with its receptor parent,suggesting that linkage drag may have occurred.Based on the BC5F2 population,a hybrid sterility locus,S20,a long sterile lemma locus,G1-g,and a new grain width quantitative trait locus(QTL),qGW7,were mapped in the linkage region about 15 centimorgan(cM)from the end of the short arm of chromosome 7.The hybrid sterility locus S20 from O.glaberrima eliminated male gametes of Oryza sativa,and male gametes carrying the alleles of O.sativa in the heterozygotes were aborted completely.In addition,the homozygotes presented a genotype of O.glaberrima,and homozygous O.sativa were not produced.Surprisingly,the linked traits G1-g and qGW7 showed similar segregation distortion.These results indicate that S20 was responsible for the linkage drag.As a large number of detected hybrid sterility loci are widely distributed on rice chromosomes,we suggest that hybrid sterility loci are the critical factors for the linkage drag in interspecific and subspecific hybridization of rice.展开更多
An interspecific hybrid F1 of Cucumis hystrix Chakr. x Cucumis sativus L. (NC4406) was used to establish the developmental sequence and to characterize the male and female gametophytes at cytological level for furth...An interspecific hybrid F1 of Cucumis hystrix Chakr. x Cucumis sativus L. (NC4406) was used to establish the developmental sequence and to characterize the male and female gametophytes at cytological level for further understanding of the phylogenic relationship and the mechanism of fertility or sterility in the interspecific hybrid F1 The development of male and female gametophytes was studied through meiotic analysis and paraffin section observation technique, respectively. Meanwhile, the fertility level was assessed through hybrid F1 backcrossing to cultivated cucumber 4406. Variable chromosome configurations were observed in the pollen mother cells (PMCs) of hybrid F1 at metaphase Ⅰ , e.g., univalents, bivalents, trivalents, quadravalents, etc. At anaphase Ⅰ and Ⅱ, chromosome lagging and bridges were frequently observed as well, which led to the formation of polyads and only a partial number of microspores could develop into fertile pollen grains (about 23.3%). Observations of the paraffin sections showed numerous degenerated and abnormal embryo sacs during the development of female gametophytes, and only 40% of the female gametophytes could develop into normal eight-nuclear megaspore. On an average, 22.8 and 6.3 seeds per fruit could be obtained from the reciprocal backcross. The interspecific hybrid F1 of C. hystrix x NC4406 was partially fertile; however, the meiotic behaviors of hybrid F1 showed a high level of intergenomic recombination between C. hystrix and C. sativus chromosomes, which indicated that it plays an important role for introgression of useful traits from C. hystrix into C. sativus.展开更多
Genes resistant to Aleurotrachelus socialis were transferred to the F 1 from the interspecific hybrid wild species of Manihot flabellifolia to M.esculenta and two advanced generations of backcrosses(BC 1 and BC 2).W...Genes resistant to Aleurotrachelus socialis were transferred to the F 1 from the interspecific hybrid wild species of Manihot flabellifolia to M.esculenta and two advanced generations of backcrosses(BC 1 and BC 2).We characterized the resistance of A.socialis transferred to BC 2 parents(CW67-160,CW67-130,CW67-44),MTAI-8(BC 1),resistant(CMB9B-73) and susceptible(CMB9B-104) genotypes from contrasting pools,and resistant(MEcu-72) and susceptible(CMC-40) genotypes.Whitefly demography and biology were evaluated.SSR molecular markers associated with a phenotypic response of plant resistance were detected in segregating populations(BC 2).Results showed that although female survival time was similar on all hosts,the lowest averages of longevity,fecundity and oviposition rate were observed in the resistant control MEcu- 72,only being significantly similar to the parent CW67-130.When the BC 1 and BC 2 populations were compared,it was found that A.socialis fecundity was eight times lower on CMB9B-73 progeny than on CW67-130,expressing the highest levels of resistance to the whitefly.Ten genotypes of CMB9A and CMB9B family had the best segregation.A total of 486 microsatellite primers were evaluated using bulked segregant analysis(BSA),11 showed polymorphism between the contrasting pools and only one showed significant differences between resistant and susceptible individuals.In conclusion,fecundity was the parameter that impacted most on the intrinsic rate of A.socialis population growth.展开更多
Peanut diseases seriously threaten peanut production, creating disease-resistant materials via interspecific hybridization is an effective way to deal with this problem. In this study, the embryo of an interspecific F...Peanut diseases seriously threaten peanut production, creating disease-resistant materials via interspecific hybridization is an effective way to deal with this problem. In this study, the embryo of an interspecific F1 hybrid was obtained by crossing the Silihong(Slh) cultivar with Arachis duranensis(ZW55), a diploid wild species. Seedlings were generated by embryo rescue and tissue culture. A true interspecific hybrid was then confirmed by cytological methods and molecular markers. After treating seedlings with colchicine during in vitro multiplication, the established interspecific F1 hybrid produced seeds which were named as Am1210. With oligonucleotide fluorescence in situ hybridization(Oligo FISH), molecular marker evaluations, morphological and web blotch resistance characterization, we found that: 1) Am1210 was an allohexaploid between Slh and ZW55;2) the traits of spreading lateral branches, single-seeded or double-seeded pods and red seed coats were observed to be dominant compared to the erect type, multiple-seeded pods and brown seed coats;3) the web blotch resistance of Am1210 was significantly improved than that of Slh, indicating the contribution of the web blotch resistance from the wild parent A. duranensis. In addition, 69 dominant and co-dominant molecular markers were developed which could be both used to verify the hybrid in this study and to identify translocation or introgression lines with A. duranensis chromosome fragments in future studies as well.展开更多
Oryza officinalis is one of the important wild species in the tertiary gene pool of Oryza sativa. It has a number of elite genes for rice breeding in resistance or tolerance. However, breeding barriers are so serious ...Oryza officinalis is one of the important wild species in the tertiary gene pool of Oryza sativa. It has a number of elite genes for rice breeding in resistance or tolerance. However, breeding barriers are so serious that the gene transfer is much difficult by sexual cross method between O. sativa and O. officinalis. Characteristics of the breeding barriers were systemically studied in this paper. When both the diploid (AA, 2n=2x=24) and autotetraploid (AAAA, 2n=4x=48) cultivated rice were crossed as maternal parents with O. officinalis (CC, 2n=2x=24), none F1 hybrid seeds were obtained. The young hybrid ovaries aborted at 13-16 d after pollinations (DAP). By rescuing hybrid embryos, in vitro F1 plantlets were obtained in 2x×2x combinations with the crossabilities lower than 0.5%. Lower rates of double-fertilization and abnormal development of hybrid embryo and endosperm were mainly observed in both combinations of 2x×2x and 4x×2x. Free endosperm nuclei in hybrid degenerated early at 1 DAP in a large scale. Almost no normal endosperm cells formed at 3 DAP. Development of a lot of embryos ceased at globularor pear-shaped stage as well as some degenerated gradually. The hybrid plantlets were both male and female sterility. Due to the abnormal development, a diversity of abnormal embryo sacs formed in hybrids, and hybrid pollen grains were typically abortive. It showed that conflicts of genome A and C in hybrid induced abnormal meioses of meiocytes.展开更多
Hybrid sterility between Oryza glaberrima and O. sativa seriously hampers the introgression of favorable genes from each other. In order to further understand this issue, identification and isolation of hybrid sterili...Hybrid sterility between Oryza glaberrima and O. sativa seriously hampers the introgression of favorable genes from each other. In order to further understand this issue, identification and isolation of hybrid sterility QTLs as single Mendelian factors are an effective strategy. A genetic map was constructed using a BC1 F1 population derived from a cross between an O. safiva japonica cultivar and an O. glaberrima accession. Four main-effect QTLs for pollen sterility were detected in the BC1F1. Five BC8F1 advanced backcross populations were developed via successive backcrosses based on phenotype and molecular selections. The BC8F1 populations showed bimodal distribution for pollen fertility and could be classified into semi-sterile and fertile types, fitting single Mendilian factor inheritance ratios. Three QTLs detected in the BC1F1 corresponding to qSS-3, qSS-6a and qSS-7 were mapped on chromosomes 6, 3 and 7, respectively, as single Mendilian factors.展开更多
Progenies derived from crosses between Solarium tuberosum and 2n pollen-Producing diploid hybrids, exhibit obvious hybrid vigor. The 2n pollen-producing clone can act as a bridge in crossing S. tuberosum and S. andige...Progenies derived from crosses between Solarium tuberosum and 2n pollen-Producing diploid hybrids, exhibit obvious hybrid vigor. The 2n pollen-producing clone can act as a bridge in crossing S. tuberosum and S. andigena with S. phureja. Populations from 4x-2x crosses show more unifomity and less segregation compared with that of 4x-4x crosses.The parent-offspring correlation for the traits, starch content and tuber number, is significant at 0.01 level. The regrssion equations are Y (mp-F1)=1.0 + 1.2x and Y (mp - F1) = 5.3 + 0.8x, respectively. The 2n pollen-producing clones play an impotant role in increasing tuber stach content.Estimates of the combining ability for the main yield components indicate that additive effect prodominatcs for such trais as plot yield, tuber weight per plant and starch content, whereas both additive and non-additive effects lay equal stress on mean tuber weight and non-additive effect is important for tuber number. In general, non-additive effect appears to be important in the progenies of 4x-2x crosses.Tuber number shows apparent heterosis while mean tuber weight dos not. Thus, it is necessary for 2n pollen-producing clones to be selected for high mean tuber weight and low tuber number before their use in commercial potato production.In the double cropping region of Anhui, the 4x - 2x hybrids seem to be more adaptive than S. tuberosum x S. andigena hybrids, but the yield of 4x - 2x cross is lower than that of the cross S. tuberosum x S. andigena in Harbin region.In Harbin region, the better combination type is in the from of S. andigena x (phureja-haploid Group tuberosum), and the best cross is also in the from. In Anhui, the better combination type is S. tuberosum x (phureja - haploid Group tuberosum), and the best cross is that using a variety of S. tuberosum as its parent. The progeny tubers of 4x - 2x cross have a short dormant period and are suitable for the double cropping region.展开更多
To identify alien chromosomes in recipient progenies and to analyze genome components in polyploidy, a genomic in situ hybridization (GISH) technique that is suitable for cotton was developed using increased stringe...To identify alien chromosomes in recipient progenies and to analyze genome components in polyploidy, a genomic in situ hybridization (GISH) technique that is suitable for cotton was developed using increased stringency conditions. The increased stringency conditions were a combination of the four factors in the following optimized state: 100:1 ratio of blocking DNA to probe, 60% formamide wash solution, 43 ℃ temperature wash and a 13 min wash. Under these specific conditions using gDNA from Gossypium sturtianum (C1 C1 ) as a probe, strong hybridization signals were only observed on chromosomes from the C1 genome in somatic cells of the hybrid F1 (G. hirsutum x G. sturtianum) (AtDtC1). Therefore, GISH was able to discriminate parental chromosomes in the hybrid. Further, we developed a multi-color GISH to simultaneously discriminate the three genomes of the above hybrid. The results repeatedly displayed the three genomes, At, Dt, and C1, and each set of chromosomes with a unique color, making them easy to identify. The power of the multi-color GISH was proven by analysis of the hexaploid hybrid F1 (G. hirsutum x G. australe) (AtAtDtDtG2G2). We believe that the powerful multi-color GISH technique could be applied extensively to analyze the genome component in polyploidy and to identify alien chromosomes in the recipient progenies.展开更多
For centuries, freesia has been one of the most important crops in the floriculture industry. Here, aqua-space samples collected from entire flowers of diploid Freesia refracta, three tetrapioid freesia cuitivars, and...For centuries, freesia has been one of the most important crops in the floriculture industry. Here, aqua-space samples collected from entire flowers of diploid Freesia refracta, three tetrapioid freesia cuitivars, and interspecific hybrids of three tetraploid freesia cultivars were analyzed using gas chromatograph coupled with mass selective detector, in all, 75 different compounds were identified. The compounds were mainly terpenes, hydrocarbons, alcohols, fatty acid esters and aromatic class compounds. Among these, iinalool was detected from all the sweet-scented flowers except for scentless white tetraploid F. hybrida. Stable inheritance of linalool between F. hybrida and their Ft progeny was observed. Based on the present analyses, the relationship between the aroma of freesia and iinalooi was discussed.展开更多
Tagetes erecta is an annual multifunctional plant which can be cultivated under a broad range of climatic conditions. Polyploidization and interspecific hybridization are applied to facilitate breeding cultivars of T....Tagetes erecta is an annual multifunctional plant which can be cultivated under a broad range of climatic conditions. Polyploidization and interspecific hybridization are applied to facilitate breeding cultivars of T. erecta with improved ornamental qualities. Colchicine treatment to the germinating seeds was proved to be a useful tool for chromosome doubling of the male sterile two-type line ‘M525AB', with the resulting frequency of polyploid seedlings ranging from 88.89%(following 0.05% w/v colchicine applied for a 3–6 h exposure period) to a maximum of100.00%(following 0.1% for 3–6 h, or 0.2% for 3 h). Morphological observation, stomatal size and density analysis, flow cytometric analysis and chromosome counting were conducted to identify the tetraploid plants. Distinctive morphological changes were observed in a notable proportion of polyploid plants. The colchicine-treated polyploid T. erecta plants showed dwarfed and more robust growth, thicker, larger and greener leaves, larger inflorescences and florets. The mutant plants identified through morphological observation all aligned as polyploid plants, thus morphological observation could be an effective method for the detection of polyploidy. The polyploid plants had significant larger stomata size over the abaxial leaf surface, whereas the density of stomata distribution was remarkably reduced. The survival rate of tetraploid cuttings(i.e. 38%)was greatly reduced compared to that of diploid plants. The fertility of tetraploid plants was also decreased, as shown by cross-pollination yields.Interspecific hybridizations between colchicine-induced tetraploid plants of a male sterile T. erecta line and the naturally tetraploid fully fertile Tagetes patula species resulted in hybrid progeny. Most of these hybrids displayed the dwarfed growth stature and compact, larger-flower morphology which is the typical ideotype of herbaceous flowers. Thus, polyploidization may be employed effectively as a means to facilitate interspecific hybridization, thereby contributing significantly to the improvement of quantitative traits of Tagetes spp.展开更多
Oryza meyeriana Baill (GG genome) is a precious germplasm in the tertiary gene pool of cultivated rice (AA genome), and possesses important traits such as resistance and tolerance to biotic and abiotic stress. How...Oryza meyeriana Baill (GG genome) is a precious germplasm in the tertiary gene pool of cultivated rice (AA genome), and possesses important traits such as resistance and tolerance to biotic and abiotic stress. However, interspeciflc crossability barrier, a critical bottleneck restricting genes transfer from O. meyeriana to cultivars has led to no hybrids through conventional reproduction. Therefore, the reasons underlying incrossability were investigated in the present report. The results showed that: (i) at 3-7 d after pollination (DAP), many hybrid embryos degenerated at the earlier globular-shaped stage, and could not develop into the later pear-shaped stage. Meanwhile, free endosperm nuclei started to degenerate at 1 DAP, and cellular endosperm could not form at 3 DAP, leading to nutrition starvation for young embryo development; (ii) at 11-13 DAP, almost all hybrid ovaries aborted. Even though 72.22% of hybrid young embryos were produced in the interspecific hybridization between O. sativa and O. meyeriana, young embryos were not able to further develop into hybrid plantlets via culturing in vitro. The main reason for the incrossability was hybrid embryo inviability, presenting as embryo development stagnation and degeneration since 3 DAP. Some possible approaches to overcome the crossability barriers in the interspecific hybridization between O. sativa and O. meyeriana are discussed.展开更多
文摘Integrating alleles from Gossypium species into G.hirsutum is important for the enhancement of genetic variability and for creating polymorphism useful in molecular mapping studies.Through collaborative efforts,several species including G.barbadense,G.tomentosum,and G.mustelinum
基金supported by the National Natural Science Foundation of China(31571624 and 31071382)the National Key Research and Development Program of China(2016YFD0102001-006)+2 种基金the National Basic Research(973)Program of China(2010CB125904-3,2013CBA01405)the Key Natural Science Project in University of Jiangsu Province,China(15KJA210004)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD)
文摘Oryza ridleyi is an allotetraploid wild species with the HHJJ genome, and Oryza sativa is a diploid cultivated rice that has the AA genome. Although the wide hybrid between the two species is difficult to obtain, we overcome this difficulty by young embryo rescue. An obvious heterosis was primarily found for the plant height, tillering ability, vegetative vigor, etc. However, the hybrid panicle and culm traits were found to resemble that of the wild rice parent, O. ridleyi, for the long awns, exoteric purple stigma, grain shattering, dispersed panicles, and culm mechanical strength. Genomic in situ hybridization (GISH) analysis was subsequently performed on the mitotic metaphase chromosome of the root tips, and we determined that the hybrid is an allotriploid with 36 chromosomes and its genomic constitution is AHJ. Chemical analyses conducted on the culm of O. sativa, O. ridleyi, and their interspecific hybrids showed that major changes occurred in the xylose, glucose, and arabinose concentrations, which are correlated with the specific hemicellulose polymer and cellulose components that are important in the primary cell walls of green plants. Meanwhile, the culm anatomical analyses indicated that additional large vascular bundles and an extra sclerenchyma cell layer were found in O. ridleyi. Additionally, further thickening of the secondary cell walls of the cortical fiber sclerenchyma cells and the phloem companion cells was discovered in O. ridleyi and in the interspecific hybrids. These results imply that there may be a potential link between culm mechanical strength and culm anatomical structure.
文摘In the genus Oryza, interspecific hybrids are useful bridges for transferring the desired genes from wild species to cultivated rice (Oryza sativa L.). In the present study, hybrids between O. sativa (AA genome) and three Chinese wild rices, namely O. rufipogon (AA genome), O. officinalis (CC genome), and O. meyeriana (GG genome), were produced. Agricultural traits of the F1 hybrids surveyed were intermediate between their parents and appreciably resembled wild rice parents. Except for the O. sativa × O. rufipogon hybrid, the other F1 hybrids were completely sterile. Genomic in situ hybridization (GISH) was used for hybrid verification. Wild rice genomic DNAs were used as probes and cultivated rice DNA was used as a block. With the exception of O. rufipogon chromosomes, this method distinguished the other two wild rice and cultivated rice chromosomes at the stage of mitotic metaphase with different blocking ratios. The results suggest that a more distant phylogenetic relationship exists between O. meyeriana and O. sativa and that O. rufipogon and O. sativa share a high degree of sequence homology. The average mitotic chromosome length of O. officinalis and O. meyeriana was 1.25- and 1.51-fold that of O. sativa, respectively. 4',6'-Diamidino- 2-phenylindole staining showed that the chromosomes of O. officinalis and O. meyeriana harbored more heterochromatin, suggesting that the C and G genomes were amplified with repetitive sequences compared with the A genome. Although chromocenters formed by chromatin compaction were detected with wild rice-specific signals corresponding to the C and G genomes in discrete domains of the F1 hybrid interphase nuclei, the size and number of O. meyeriana chromocenters were bigger and greater than those of O. officinalis. The present results provide an important understanding of the genomic relationships and a tool for the transfer of useful genes from three native wild rice species in China to cultivars.
基金supported by the National Natural Science Foundation of China(32071529)the Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station(Z202204)+1 种基金Shanghai Key Lab for Urban Ecological Processes and EcoRestoration(SHUES2020B06,SHUES2021C04)the Fundamental Research Funds for the Central Universities.
文摘Human disturbances are considered to break reproduction barriers among species.Significant increases in hybridization events have been reported among a large number of taxonomic groups in anthropogenic environments,providing novel insights into species evolution mechanisms and conservation management in the Anthropocene.The Eastern Golden Frog(Pelophylax plancyi)and BlackSpotted Frog(P.nigromaculatus)are two sympatric anuran species with a long history of mitochondrial genome introgression in highly urbanized continental East Asia.However,there is only limited understanding of the pattern of their contemporary hybridization and factors influencing their interspecific relationship under anthropogenic disturbances.Here,interspecific hybridization between P.plancyi and P.nigromaculatus at the population level was investigated in Shanghai.All except two haplotypes obtained from both species in Shanghai were mixed together,and located in the introgression clade,implying multiple ancient mitochondrial introgression events occurred in the populations of our study area.Asymmetric genetic introgression was detected by microsatellite markers,with 0.7%of P.plancyi and 14.6%of P.nigromaculatus identified as contemporary admixed individuals.Consistent with the trend of population density,higher genetic diversity of neutral microsatellite loci was found in the more abundant P.plancyi;however,variation in mitochondrial(Cyt-b)and nuclear(POMC)genes was higher in relatively rare P.nigromaculatus.The population density of P.plancyi and number of water patches within local habitats were significantly positively correlated with both occurrences and proportions of admixed individuals in the populations of P.plancyi and P.nigromaculatus.Considering the prevalent transformation of habitats in urbanized areas,these results imply that a high population density in isolated artificially altered habitats is likely to increase interspecific hybridization.Thus,population monitoring and improvement of landscape connectivity between habitats would be needed to control the intensity of interspecific hybridization between P.plancyi and P.nigromaculatus in anthropogenic-disturbed environments.
基金supported by Grantsin-Aid for Scientific Research(C and B)(Nos.20510216 and 24310173)to M.Sumida from the Ministry of Education,Culture,Sports,Science and Technology,Japan
文摘To elucidate reproductive isolating mechanisms in the Bangladesh coastal bullfrog Hoplobatrachus litoralis and its congeneric species, we performed crossing experiments using three species: H. litoralis, H. tigerinus and H. rugulosus. In addition, we conducted histological observations on spermatogenesis of the hybrids. The reciprocal hybrids between H. litoralis and H. tigerinus developed normally with somewhat lower viability at the metamorphosis stage compared with the controls. Most of the metamorphosed frogs became mature. On the other hand, almost all hybrids between female H. rugulosus and male H. litoralis or H. tigerinus died of underdevelopment at the tadpole stage, and only a few hybrids metamorphosed normally and survived to maturity. The inner structures of the testes of the control H. litoralis and H. tigerinus were completely normal, with seminiferous tubules filled with compact bundles of normal spermatozoa. Those of the reciprocal hybrids between H. litoralis and H. tigerinus were almost normal or slightly abnormal, with seminiferous tubules that contained pycnotic nuclei in addition to normal bundles of normal spermatozoa, which demonstrates slight abnormalities in spermatogenesis. In contrast, the hybrids between female H. rugulosus and male H. litoralis or H. tigerinus had no bundles of spermatozoa nor spermatids in the seminiferous tubules, which indicates entirely abnormal spermatogenesis. Meiotic chromosome figures in the reciprocal hybrids between H. litoralis and H. tigerinus showed slight abnormalities, with the occurrence of univalents and increase of rod-shaped bivalents. These results indicate that H. litoralis and H. tigerinus are not isolated from each other by hybrid inviability nor by hybrid sterility, although the hybrids showed somewhat abnormal spermatogenesis in hybrids and that H. rugulosus is isolated from both H. litoralis and H. tigerinus by incomplete hybrid inviability and complete hybrid sterility.
文摘The progress of research on transferring elite genes from non-AA genome wild rice into Oryza sativa through interspecific hybridization are in three respects, that is, breeding monosomic alien addition lines (MAALs), constructing introgression lines (ILs) and analyzing the heredity of the characters and mapping the related genes. There are serious reproductive barriers, mainly incrossability and hybrid sterility, in the interspecific hybridization of O. sativa with non-AA genome wild rice. These are the 'bottleneck' for transferring elite genes from wild rice to O. sativa. Combining traditional crossing method with biotechnique is a reliable way to overcome the reproductive barriers and to improve the utilizing efficiency of non-AA genome wild rice.
基金supported by the Guangdong Provincial Key Project of Natural Science Foundation, China (Grant No. 021037)Guangdong Province Natural Science Foundation, China (Grant No. 7301008)+1 种基金South China Agricultural University President Foundation, China (Grant No. 2007K036)The Confocal Laser Scanning Microscope was provided by the Testing Center of South China Agricultural University, Guangzhou, China
文摘As maternal parents, diploid (L202-2x) and autotetraploid (L202-4x) of Oryza sativa cv. L2O2 were crossed with O. officinalis. Embryo development and fertilization in these two crosses were comparatively studied. There were no mature hybrid seeds obtained because all the hybridized spikelets died 30 days after pollination. The main reasons for no seed set were abnormal fertilization and development of the embryos and endosperms in the interspecific hybrids. There were doublefertilization, egg cell single-fertilization and non-fertilization in these crosses. Although 59.45% and 54.87% of hybrid embryos produced in the crosses of L202-2x/O. officinalis and L202-4x/O. officinalis, respectively, hybrid embryos ceased to develop or degenerated and plenty of free endosperm nuclei were in disaggregating state without developing cellular endosperms three days after pollination. Besides, some embryological differences in these two crosses were found, that is, the rate of double-fertilization and total rate of doubleand single-fertilization in L202-2x/O. officinalis were higher than those in L202-4x/O. officinalis. The embryo and endosperm of hybrids developed more slowly, and embryos and free endosperm nuclei were more severely degenerated in L202-4x/O. officinalis than in L202-2x/O. officinalis. Five days after pollination, a few of embryos in L202-2x/O. officinalis developed into pear-shaped ones, however, embryos in L202-4x/O. officinalis were all degenerated. Therefore, it is more difficult to obtain interspecific hybrids by wide crosses between autotetraploid of O. sativa and O. officinalis.
基金This research was partially supported by the Trans-century Training Program Foundation for the Talents by the State Education Commission of China to Dr.Chen Jinfeng,by the National Natural Science Founda-tion of China(301 70644 and 30470120)by National Hi-Tech R&D Program(2002AA241251 and 2004 AA241120)by Tang's Cornell-China Scholar Program and by Pickle Seed Research Foundation of PPI.
文摘Studies on the reproduction and cytogenetic characterization of a primary amphidiploid Cucumis species C. hytivus Chen and Kirkbride (2n = 4x = 38) indicated that a more comprehensive cytogenetic analysis of this species and its first selfed progeny would increase its potential utility in cucumber improvement. With tendrils used as source materials for mitotic analysis, chromosome numbers in all selfed progenies were 2n = 38, confirming chromosomal stability in this synthetic amphidiploid species. Detailed meiotic processes were described by comparing the primary and the selfed amphidiploids. Meiotic abnormalities, such as chromosome lagging, unequal separation, chromosome multi-polarization and polyads were observed frequently in all amphidiploid plants except for the selfed no.8, in which meiosis was arrested prior to metaphase Ⅰ. Generally, the frequency of multivalents was higher and the configurations were more complex in the selfed progenies, demonstrating a more extensive genetic exchange between cucumber and C. hystrix Chakr. Genome separation between cucumber and C. hystrix was observed through prophase Ⅰ to anaphase Ⅰ in both generations of the amphidiploids. Consequently, in addition to n = 19, a new gamete with n = 7 was produced, which was confirmed by the chromosome counts 2n = 14 in the backcrossing progenies from cucumber × amphidiploid mating. Fertility varied among the selfed amphidiploid plants. The selfed plant no.1 was found to have an improved fertility (e.g., pollen staining ability 40.8% and 25.6 seeds per fruit) and then was used as source germplasm in further introgression and gene exchange experiments.
基金The authors thank the Public Technology Service Center,Xishuangbanna Tropical Botanical Garden,Chinese Academy of Sciences for technical support.This work was supported by“One-Three-Five”Strategic Planning of Chinese Academy of Sciences(2017XTBG-T02)Strategic Leading Science and Technology Program(XDA24030301 and XDA24040308).
文摘Interspecific hybridization plays an important role in rice breeding by broadening access to desirable traits such as disease resistance and improving yields.However,interspecific hybridization is often hindered by hybrid sterility,linkage drag,and distorted segregation.To mine for favorable genes from Oryza glaberrima,we cultivated a series of BC4 introgression lines(ILs)of O.glaberrima in the japonica rice variety background(Dianjingyou 1)in which the IL-2769(BC4F10)showed longer sterile lemmas,wider grains and spreading panicles compared with its receptor parent,suggesting that linkage drag may have occurred.Based on the BC5F2 population,a hybrid sterility locus,S20,a long sterile lemma locus,G1-g,and a new grain width quantitative trait locus(QTL),qGW7,were mapped in the linkage region about 15 centimorgan(cM)from the end of the short arm of chromosome 7.The hybrid sterility locus S20 from O.glaberrima eliminated male gametes of Oryza sativa,and male gametes carrying the alleles of O.sativa in the heterozygotes were aborted completely.In addition,the homozygotes presented a genotype of O.glaberrima,and homozygous O.sativa were not produced.Surprisingly,the linked traits G1-g and qGW7 showed similar segregation distortion.These results indicate that S20 was responsible for the linkage drag.As a large number of detected hybrid sterility loci are widely distributed on rice chromosomes,we suggest that hybrid sterility loci are the critical factors for the linkage drag in interspecific and subspecific hybridization of rice.
基金This paper is translated from its Chinese version in Scientia Agricultura Sinica.This research was partially supported by the Transcentury Training Program Foundation for the Talents by the Ministry of Education of China to Dr.Chen Jinfeng(30470120)by the National Natural Science Foundation of China(30671419)+2 种基金the National Hi-Tech R&D Program(2004AA241120)the Tang Foundation Cornell-China Scholar Programthe Pickle Seed Research Foundation of Pickle Packers International.The authors sincerely thank Dr.Zhai Huqu,the President of the Chinese Academy of Agricultural Sciences for his support in this research.
文摘An interspecific hybrid F1 of Cucumis hystrix Chakr. x Cucumis sativus L. (NC4406) was used to establish the developmental sequence and to characterize the male and female gametophytes at cytological level for further understanding of the phylogenic relationship and the mechanism of fertility or sterility in the interspecific hybrid F1 The development of male and female gametophytes was studied through meiotic analysis and paraffin section observation technique, respectively. Meanwhile, the fertility level was assessed through hybrid F1 backcrossing to cultivated cucumber 4406. Variable chromosome configurations were observed in the pollen mother cells (PMCs) of hybrid F1 at metaphase Ⅰ , e.g., univalents, bivalents, trivalents, quadravalents, etc. At anaphase Ⅰ and Ⅱ, chromosome lagging and bridges were frequently observed as well, which led to the formation of polyads and only a partial number of microspores could develop into fertile pollen grains (about 23.3%). Observations of the paraffin sections showed numerous degenerated and abnormal embryo sacs during the development of female gametophytes, and only 40% of the female gametophytes could develop into normal eight-nuclear megaspore. On an average, 22.8 and 6.3 seeds per fruit could be obtained from the reciprocal backcross. The interspecific hybrid F1 of C. hystrix x NC4406 was partially fertile; however, the meiotic behaviors of hybrid F1 showed a high level of intergenomic recombination between C. hystrix and C. sativus chromosomes, which indicated that it plays an important role for introgression of useful traits from C. hystrix into C. sativus.
基金The Generation Challenge Program (GCP), CIAT, Colombia, for their funding
文摘Genes resistant to Aleurotrachelus socialis were transferred to the F 1 from the interspecific hybrid wild species of Manihot flabellifolia to M.esculenta and two advanced generations of backcrosses(BC 1 and BC 2).We characterized the resistance of A.socialis transferred to BC 2 parents(CW67-160,CW67-130,CW67-44),MTAI-8(BC 1),resistant(CMB9B-73) and susceptible(CMB9B-104) genotypes from contrasting pools,and resistant(MEcu-72) and susceptible(CMC-40) genotypes.Whitefly demography and biology were evaluated.SSR molecular markers associated with a phenotypic response of plant resistance were detected in segregating populations(BC 2).Results showed that although female survival time was similar on all hosts,the lowest averages of longevity,fecundity and oviposition rate were observed in the resistant control MEcu- 72,only being significantly similar to the parent CW67-130.When the BC 1 and BC 2 populations were compared,it was found that A.socialis fecundity was eight times lower on CMB9B-73 progeny than on CW67-130,expressing the highest levels of resistance to the whitefly.Ten genotypes of CMB9A and CMB9B family had the best segregation.A total of 486 microsatellite primers were evaluated using bulked segregant analysis(BSA),11 showed polymorphism between the contrasting pools and only one showed significant differences between resistant and susceptible individuals.In conclusion,fecundity was the parameter that impacted most on the intrinsic rate of A.socialis population growth.
基金supported by the national natural Science Foundation of China (31801397)the Henan Province Young Talents Lifting Project,China (2018HYTP003)+2 种基金the Independent Innovation Foundation of Henan Academy of Agricultural Sciences,China (2019ZC13)the earmarked fund for China Agriculture Research System (CARS-13)the Henan Provincial Agriculture Research System,China (S2012-05)。
文摘Peanut diseases seriously threaten peanut production, creating disease-resistant materials via interspecific hybridization is an effective way to deal with this problem. In this study, the embryo of an interspecific F1 hybrid was obtained by crossing the Silihong(Slh) cultivar with Arachis duranensis(ZW55), a diploid wild species. Seedlings were generated by embryo rescue and tissue culture. A true interspecific hybrid was then confirmed by cytological methods and molecular markers. After treating seedlings with colchicine during in vitro multiplication, the established interspecific F1 hybrid produced seeds which were named as Am1210. With oligonucleotide fluorescence in situ hybridization(Oligo FISH), molecular marker evaluations, morphological and web blotch resistance characterization, we found that: 1) Am1210 was an allohexaploid between Slh and ZW55;2) the traits of spreading lateral branches, single-seeded or double-seeded pods and red seed coats were observed to be dominant compared to the erect type, multiple-seeded pods and brown seed coats;3) the web blotch resistance of Am1210 was significantly improved than that of Slh, indicating the contribution of the web blotch resistance from the wild parent A. duranensis. In addition, 69 dominant and co-dominant molecular markers were developed which could be both used to verify the hybrid in this study and to identify translocation or introgression lines with A. duranensis chromosome fragments in future studies as well.
基金supported by the Key Project of the Natural Science Foundation of Guangdong Province, China (021037)the Natural Science Foundation of Guangdong Province, China (9151064201000067)+1 种基金the Special Fund for Agro-Scientific Research in the Public Interest, China (201003021)the Joint Fund of the National Natural Science Foundation of China-Guangdong Province (U0631003)
文摘Oryza officinalis is one of the important wild species in the tertiary gene pool of Oryza sativa. It has a number of elite genes for rice breeding in resistance or tolerance. However, breeding barriers are so serious that the gene transfer is much difficult by sexual cross method between O. sativa and O. officinalis. Characteristics of the breeding barriers were systemically studied in this paper. When both the diploid (AA, 2n=2x=24) and autotetraploid (AAAA, 2n=4x=48) cultivated rice were crossed as maternal parents with O. officinalis (CC, 2n=2x=24), none F1 hybrid seeds were obtained. The young hybrid ovaries aborted at 13-16 d after pollinations (DAP). By rescuing hybrid embryos, in vitro F1 plantlets were obtained in 2x×2x combinations with the crossabilities lower than 0.5%. Lower rates of double-fertilization and abnormal development of hybrid embryo and endosperm were mainly observed in both combinations of 2x×2x and 4x×2x. Free endosperm nuclei in hybrid degenerated early at 1 DAP in a large scale. Almost no normal endosperm cells formed at 3 DAP. Development of a lot of embryos ceased at globularor pear-shaped stage as well as some degenerated gradually. The hybrid plantlets were both male and female sterility. Due to the abnormal development, a diversity of abnormal embryo sacs formed in hybrids, and hybrid pollen grains were typically abortive. It showed that conflicts of genome A and C in hybrid induced abnormal meioses of meiocytes.
基金funded partially by the Ministry of Science and Technology Foundation of China(Grant No.2006CB708207)the Ministry of Agriculture,China(Grant No.2009ZX08009-107B)
文摘Hybrid sterility between Oryza glaberrima and O. sativa seriously hampers the introgression of favorable genes from each other. In order to further understand this issue, identification and isolation of hybrid sterility QTLs as single Mendelian factors are an effective strategy. A genetic map was constructed using a BC1 F1 population derived from a cross between an O. safiva japonica cultivar and an O. glaberrima accession. Four main-effect QTLs for pollen sterility were detected in the BC1F1. Five BC8F1 advanced backcross populations were developed via successive backcrosses based on phenotype and molecular selections. The BC8F1 populations showed bimodal distribution for pollen fertility and could be classified into semi-sterile and fertile types, fitting single Mendilian factor inheritance ratios. Three QTLs detected in the BC1F1 corresponding to qSS-3, qSS-6a and qSS-7 were mapped on chromosomes 6, 3 and 7, respectively, as single Mendilian factors.
文摘Progenies derived from crosses between Solarium tuberosum and 2n pollen-Producing diploid hybrids, exhibit obvious hybrid vigor. The 2n pollen-producing clone can act as a bridge in crossing S. tuberosum and S. andigena with S. phureja. Populations from 4x-2x crosses show more unifomity and less segregation compared with that of 4x-4x crosses.The parent-offspring correlation for the traits, starch content and tuber number, is significant at 0.01 level. The regrssion equations are Y (mp-F1)=1.0 + 1.2x and Y (mp - F1) = 5.3 + 0.8x, respectively. The 2n pollen-producing clones play an impotant role in increasing tuber stach content.Estimates of the combining ability for the main yield components indicate that additive effect prodominatcs for such trais as plot yield, tuber weight per plant and starch content, whereas both additive and non-additive effects lay equal stress on mean tuber weight and non-additive effect is important for tuber number. In general, non-additive effect appears to be important in the progenies of 4x-2x crosses.Tuber number shows apparent heterosis while mean tuber weight dos not. Thus, it is necessary for 2n pollen-producing clones to be selected for high mean tuber weight and low tuber number before their use in commercial potato production.In the double cropping region of Anhui, the 4x - 2x hybrids seem to be more adaptive than S. tuberosum x S. andigena hybrids, but the yield of 4x - 2x cross is lower than that of the cross S. tuberosum x S. andigena in Harbin region.In Harbin region, the better combination type is in the from of S. andigena x (phureja-haploid Group tuberosum), and the best cross is also in the from. In Anhui, the better combination type is S. tuberosum x (phureja - haploid Group tuberosum), and the best cross is that using a variety of S. tuberosum as its parent. The progeny tubers of 4x - 2x cross have a short dormant period and are suitable for the double cropping region.
基金the National Natural Science Foundation of China (30571184)Jiangsu Provincial Natural Science Foundation (BK2007166)+3 种基金the Tenth Five-year Plan of the National Key Program (2004BA525B05)the 111 Project(B08025) the Eleventh Five-year Plan of the National Sci-technologicalSupporting Program (2006BAD13B04-1-08)the Changjiang Scholars and Innovative Research Team in University and the Teaching and Research AwardProgram for Outstanding Young Teachers in Higher Education Institutions ofMinistry of Education (MOE), China.
文摘To identify alien chromosomes in recipient progenies and to analyze genome components in polyploidy, a genomic in situ hybridization (GISH) technique that is suitable for cotton was developed using increased stringency conditions. The increased stringency conditions were a combination of the four factors in the following optimized state: 100:1 ratio of blocking DNA to probe, 60% formamide wash solution, 43 ℃ temperature wash and a 13 min wash. Under these specific conditions using gDNA from Gossypium sturtianum (C1 C1 ) as a probe, strong hybridization signals were only observed on chromosomes from the C1 genome in somatic cells of the hybrid F1 (G. hirsutum x G. sturtianum) (AtDtC1). Therefore, GISH was able to discriminate parental chromosomes in the hybrid. Further, we developed a multi-color GISH to simultaneously discriminate the three genomes of the above hybrid. The results repeatedly displayed the three genomes, At, Dt, and C1, and each set of chromosomes with a unique color, making them easy to identify. The power of the multi-color GISH was proven by analysis of the hexaploid hybrid F1 (G. hirsutum x G. australe) (AtAtDtDtG2G2). We believe that the powerful multi-color GISH technique could be applied extensively to analyze the genome component in polyploidy and to identify alien chromosomes in the recipient progenies.
基金Supported by the National Natural Science Foundation of China(30570170) the Bureau of Science and Technology of Changchun,China(2006 258) the analysis and testing foundation of Northeast Normal University
文摘For centuries, freesia has been one of the most important crops in the floriculture industry. Here, aqua-space samples collected from entire flowers of diploid Freesia refracta, three tetrapioid freesia cuitivars, and interspecific hybrids of three tetraploid freesia cultivars were analyzed using gas chromatograph coupled with mass selective detector, in all, 75 different compounds were identified. The compounds were mainly terpenes, hydrocarbons, alcohols, fatty acid esters and aromatic class compounds. Among these, iinalool was detected from all the sweet-scented flowers except for scentless white tetraploid F. hybrida. Stable inheritance of linalool between F. hybrida and their Ft progeny was observed. Based on the present analyses, the relationship between the aroma of freesia and iinalooi was discussed.
基金supported by grants from the National Natural Science Foundation of China (31201647, 31672181)
文摘Tagetes erecta is an annual multifunctional plant which can be cultivated under a broad range of climatic conditions. Polyploidization and interspecific hybridization are applied to facilitate breeding cultivars of T. erecta with improved ornamental qualities. Colchicine treatment to the germinating seeds was proved to be a useful tool for chromosome doubling of the male sterile two-type line ‘M525AB', with the resulting frequency of polyploid seedlings ranging from 88.89%(following 0.05% w/v colchicine applied for a 3–6 h exposure period) to a maximum of100.00%(following 0.1% for 3–6 h, or 0.2% for 3 h). Morphological observation, stomatal size and density analysis, flow cytometric analysis and chromosome counting were conducted to identify the tetraploid plants. Distinctive morphological changes were observed in a notable proportion of polyploid plants. The colchicine-treated polyploid T. erecta plants showed dwarfed and more robust growth, thicker, larger and greener leaves, larger inflorescences and florets. The mutant plants identified through morphological observation all aligned as polyploid plants, thus morphological observation could be an effective method for the detection of polyploidy. The polyploid plants had significant larger stomata size over the abaxial leaf surface, whereas the density of stomata distribution was remarkably reduced. The survival rate of tetraploid cuttings(i.e. 38%)was greatly reduced compared to that of diploid plants. The fertility of tetraploid plants was also decreased, as shown by cross-pollination yields.Interspecific hybridizations between colchicine-induced tetraploid plants of a male sterile T. erecta line and the naturally tetraploid fully fertile Tagetes patula species resulted in hybrid progeny. Most of these hybrids displayed the dwarfed growth stature and compact, larger-flower morphology which is the typical ideotype of herbaceous flowers. Thus, polyploidization may be employed effectively as a means to facilitate interspecific hybridization, thereby contributing significantly to the improvement of quantitative traits of Tagetes spp.
基金Supported by the Guangdong Provincial Key Project of the National NaturalScience Foundation (021037)Guangdong Provincial Natural Science Foun-dation (7301008).
文摘Oryza meyeriana Baill (GG genome) is a precious germplasm in the tertiary gene pool of cultivated rice (AA genome), and possesses important traits such as resistance and tolerance to biotic and abiotic stress. However, interspeciflc crossability barrier, a critical bottleneck restricting genes transfer from O. meyeriana to cultivars has led to no hybrids through conventional reproduction. Therefore, the reasons underlying incrossability were investigated in the present report. The results showed that: (i) at 3-7 d after pollination (DAP), many hybrid embryos degenerated at the earlier globular-shaped stage, and could not develop into the later pear-shaped stage. Meanwhile, free endosperm nuclei started to degenerate at 1 DAP, and cellular endosperm could not form at 3 DAP, leading to nutrition starvation for young embryo development; (ii) at 11-13 DAP, almost all hybrid ovaries aborted. Even though 72.22% of hybrid young embryos were produced in the interspecific hybridization between O. sativa and O. meyeriana, young embryos were not able to further develop into hybrid plantlets via culturing in vitro. The main reason for the incrossability was hybrid embryo inviability, presenting as embryo development stagnation and degeneration since 3 DAP. Some possible approaches to overcome the crossability barriers in the interspecific hybridization between O. sativa and O. meyeriana are discussed.