Interspecific hybridisation betweenLimonium perigrinum Bergius andLimonium purpuratum L.

Summary Interspecific hybrids betweenLimonium perigrinum andL. purpuratum were obtained usingL. perigrinum as the female parent. No hybrids were produced by the reciprocal cross. Twelve- to 15-day-old embryos were rescued and cultured within their embryo sacs on modified B5 or KM medium. After two to three days the embryos were excised from their embryo sacs and re-plated on to fresh medium. When the embryo-derived plantlets had attained a length of 1 cm they were transferred to a modified MS medium containing BA and NAA for shoot proliferation. Plantlets were transferred to modified MS medium supplemented with IBA for 24 hours for root initiation then to a modified growth-regulator-free MS medium for root growth. After a further 28 days the plantlets were transferred to soil-less medium for acclimatisation. The hybrid characteristics of one of the 15 embryo-derived plants were determined by flow cytometry and by examination of morphological features. The mean DNA contents of 2C nuclei fromL. perigrinum, the hybrid andL. purpuratum were 13.98 pg, 16.81 pg and 19.37 pg, respectively. Mitotic and meiotic chromosome counts fromL. perigrinum andL. purpuratum showed that both parents and their hybrids had identical chromosome numbers (2n=24), and that the species were closely related. Morphological analyses of leaves and flowers showed that the hybrids displayed a number of features intermediate between both parents.Abbreviations B5 Gamborg et al. (1968) B5 medium - BA benzyl adenine - IBA indole-3-butyric acid - KM Kao and Michayluk (1975) medium - MS Murashige and Skoog (1962) medium - NAA napthalene-1-acetic acid - PVP polyvinylpyrrolidone     

白菜型油菜黄籽沙逊和芥蓝种间杂交合成甘蓝型油菜研究

人工合成甘蓝型油菜是拓宽油菜遗传育种种质资源的有效途径,也是研究芸薹属物种起源与演化的重要手段之一。为了把黄籽沙逊的黄籽性状同芥蓝的优良特性相结合,本研究利用白菜型油菜黄籽沙逊(Brassica. campestris var. Yellow Sarson Pain, 2n=AA=20)与芥蓝(Brassica albograbra, 2n=CC=18)开展了芸薹属种间杂交研究,在MS+6-BA 1.0 mg/L+NAA 0.1 mg/L+7%蔗糖+活性炭1.0 mg/L的培养基上,通过胚珠培养从授粉7 d的140个胚珠中得到6个远缘杂交胚发育而成的植株,其中1个自然加倍成为双二倍体,随后应用形态学、细胞学和分子标记的方法对双二倍体种间杂种植株进行了鉴定,结果表明杂种植株生长势较强,形态属于中间类型;根尖染色体压片观察显示杂种植株具有父母本的染色体数量之和;SSR分子标记分析表明,杂种植株包含了双亲的遗传信息,由此证明了所获杂种的真实性,这为最后自交分离获得黄籽甘蓝型油菜提供了科学依据。     

Interspecific hybrids of Cyclamen persicum and C. graecum

Summary Interspecific crosses were made to introduce the disease resistance of Cyclamen graecum into C. persicum cultivars and the abortive hybrid embryos were rescued by ovule culture. Diploid and tetraploid cultivars of C. persicum (CPD, 2n=2x=48; CPT, 2n=4x=96) were the pistillate parents and wild form of C. graecum (CG, 2n=84) were the staminate parents. After pollination, crossed ovaries were periodically collected and examined using paraffin sections. Histological observations suggested that both hybrid ovules of CPD × CG and CPT × CG should be transferred to the culture medium 35 days after pollination. Based upon this observation, crossed ovaries were collected 35 days after pollination, then ovules with placenta were explanted on culture medium and cultured in the dark at 25°C. Plantlets were induced from ovules cultured in MS medium containing 3% sucrose and 10% coconut milk. The hybrids (2n=66) derived from CPD × CG failed to yield viable seeds by self-pollination, although they showed some pollen fertility. In contrast, the hybrids (2n=90) derived from CPT × CG showed high pollen fertility and yielded viable seeds by self-pollination. Furthermore, they were resistant to disease caused by Fusarium oxysporum f. sp. cyclaminis, Erwinia herbicola pv. cyclamenae and Pseudomonas marginalis pv. marginalis.Abbreviations CPD C. persicum diploid - CPT C. persicum tetraploid - CG C. graecum     

Production of interspecific hybrids between <Emphasis Type="Italic">Lilium longiflorum</Emphasis> and <Emphasis Type="Italic">L. lophophorum</Emphasis> var. <Emphasis Type="Italic">linearifolium</Emphasis> via ovule culture at early stage

Interspecific hybridization was carried out between Lilium longiflorum and L. lophophorum var. linearifolium by using the cut style method of pollination, as a contrast, intraspecific hybridization between L. longiflorum ‘Gelria’ and L. longiflorum was also made, but no mature seeds and offspring were obtained from the two combinations under in vivo condition. Ovules excised from each carpel 5–35 days after pollination (DAP) were cultured on B5 or half-strength B5 medium containing sucrose at different concentrations in vitro. In L. longiflorum × L. lophophorum var. linearifolium, only 1.17% of ovules excised at 10 DAP developed into seedlings, and in L. longiflorum ‘Gelria’ × L. longiflorum, only 0.99% of ovules excised at 25 DAP developed into seedlings; none of the ovules excised at other different DAP in the two cross combinations produced any seedlings. The results showed that interspecific hybridization had a more serious post-fertilization barrier than the intraspecific hybridization, and that a lower concentration (3%) of sucrose led to better embryo development and higher percentage of seedlings in ovule cultures. All hybrid seedlings obtained were successfully transplanted to soil and grew normally. The progenies investigated were identified as true hybrids based on inter-simple sequence repeat (ISSR) analysis.     

Interspecific hybrids of Cyclamen persicum Mill. and C. purpurascens Mill. produced by ovule culture

Summary Interspecific crosses were made to introduce the scent of flowers of C. purpurascens into C. persicum cultivars and ovule culture was used to rescue the abortive hybrid embryos. Cultivars of C. persicum diploid (CPD, 2n=2×=48) and C. persicum tetraploid (CPT, 2n=4×=96) were the pistillate parents and wild species of C. purpurascens (CP, 2n=34) were staminate parents. After pollination, crossed ovaries were collected periodically and examined using paraffin sections. Histological observations suggested that both hybrid ovules of CPD x CP and CPT x CP should be transferred to culture medium 35 days after pollination. Based up on this observation, crossed ovaries were collected 28 days after pollination and ovules with placenta were transferred to MS (1962) medium containing 3% sucrose. These ovules were cultured in the dark at 25° C. The hybrids (2n=41) derived from CPD x CP had the scent of C. purpurascens, whereas the hybrids (2n=65) derived from CPT x CP had the scent of C. persicum. Although both hybrids had complete genomes from the parents and produced a few viable pollen grains, they failed to yield viable seeds by self- and cross-pollination with fertile pollen grains of C. persicum cultivars.Abbreviations CPD C. persicum diploid - CPT C. persicum tetraploid - CP C. purpurascens     

Interspecific hybridisation and genome size analysis in <Emphasis Type="Italic">Buddleja</Emphasis>

Interspecific hybrids Buddleja davidii × Buddleja weyeriana, Buddleja weyeriana × Buddleja davidii and Buddleja davidii × Buddleja lindleyana were generated using in vitro embryo rescue 10–11 weeks after manual pollination. The morphological variation within the F1 populations was limited. The F1 progeny of B. davidii × B. lindleyana was almost sterile and no F2 generation was obtained. From the other hybrids, F2 generations were made by self pollinations and back crosses. Hybrid nature of all F1 and F2 seedlings was confirmed by AFLP. Chromosome counting and genome size measurement for B. weyeriana (F2 selection of (diploid) B. globosa × (tetraploid) B. davidii) revealed a higher chromosome number (76 chromosomes) and genome size than expected, indicating 2n-gametes formation occurred during meiosis of B. globosa. The F1 hybrids B. weyeriana × B. davidii (76 chromosomes) had an intermediate genome size compared with the genome size of the parent plants, proving their hybrid nature. However, the F1 and F2 hybrids of B. davidii × B. weyeriana all had 76 chromosomes but had a lower genome size than expected, suggesting the occurrence of chromosome rearrangements in the genome of the hybrids. B. lindleyana had 38 chromosomes, while the F1 hybrids of B. davidii × B. lindleyana had 76 chromosomes. Also genome size measurements revealed that the F1 seedlings B. davidii × B. lindleyana had higher genome sizes than expected. Both the results of chromosome counting and genome size measurement indicate that 2n-gametes formation took place during meiosis of B. lindleyana.     

Interspecific hybridisation of soybeans and perennial Glycine species indigenous to Australia via embryo culture

Summary Five sterile hybrids (2n=59) between a synthetic amphiploid of Glycine tomentella (2n=38) and G. caneseens (2n=40) as female and soybean cultivars Lincoln and Hark as males have been produced by embryo or ovule culture using transplanted endosperm. The hybrid plants are twining perennials like the female parent but possess a number of morphological characters which reflect the presence of the soybean genome. Indophenol oxidase isozymes from leaf extracts also provide good evidence of the hybrid nature of the cultured plants. These hybrids open the way for the exploitation of the diverse germplasm resources of the perennial Glycine species in soybean breeding.     

Interspecific hybridization between sunflower and wild perennial Helianthus species via embryo rescue

Interspecific crosses were made between the cultivated sunflower inbred line HA89 and accessions of five wild perennial Helianthus species (H. giganteus L., H. laevigatus T. & G., H. resinosus Small, H. pauciflorus Nutt. and H. decapetalus L.) resistant to broomrape ( Orobanche cernua Loefl.). Using the genetic male-sterile isogenic version of that line as female, successful reciprocal crosses were also obtained with all these wild species except with H. decapetalus. Five-day-old hybrid embryos were excised and cultured in vitro. In all cases, few mature plants were obtained from embryos in early developmental stages (early heart and globular) but up to 28% mature plants were obtained from embryos in later stages of development. Very immature embryos were difficult to excise without damage. Hybrid embryos and mature plants were obtained from all five wild species. Interspecific hybrid embryos from different wild species showed distinct developmental potentials, the proportion of hybrid embryos in different developmental stages varying among species. Differences in the proportion of hybrid embryos at the several developmental stages were also obtained for the reciprocal crosses (cultivated × wild), which showed higher proportion of fully developed embryos. Hybrids involving H. giganteus and cultivated sunflower were difficult to obtain without the use of embryo culture. Embryo culture proved to be an useful tool to overcome post-zygotic hybrid incompatibility in different Helianthus spp., and facilitated interspecific transfer of resistance to O. cernua. This revised version was published online in July 2006 with corrections to the Cover Date.     

Interspecific hybridization between Solanum melongena and Solanum macrocarpon: study of the F1 hybrid plants

Summary Egg plant is one of the most common vegetable crop grown in India and other parts of the world. The cultivated egg plant Solanum melongena is found to be susceptible to the shoot and fruit borer (Leucinodes orbonalis). Whereas the species Solanum macrocarpon is resistant. In order to incorporate the resistance of shoot and fruit borer to the cultivated egg plant, an interspecific hybridization between Solanum melongena and Solanum macrocarpon and reciprocals were carried out. The hybrids were found to be sterile, the investigations revealed that the failure of seed set in hybrids is due to the ovule abortion. In order to overcome the sterility, the colchicine has been applied to the interspecific hybrids.     

Interspecific hybrids and possible phylogenetic relations in grain amaranths

Summary Phylogenetic relations among the three species in grain amaranth need investigation to provide information for breeding experiments germplasm conservation efforts, and decision on evolutionary patterns in the grain types. Hybrid development from crosses between species was studied to find out genetic relationship between them. Interspecific crosses were made among Amaranthus hypochondriacus, A. caudatus and A. cruentus in the glasshouse. The F₁ plants were relatively easy to obtain but had low pollen fertility (10.3–15.1%) and low seed set. A few of these hybrids did not produce seeds. Only a few F₁ seeds obtained in crosses between A. cruentus and A. caudatus. All the F₁ plants from these crosses died at the seedling stage. Crosses between A. cruentus and A. hypochondriacus produced few seeds. Most of the F₁ plants obtained from the seeds died at the seedling stage with only four plants growing to maturity but were sterile. Based on hybrid development, it was suggested that A. hypochondriacus and A. caudatus were genetically closer than the other two combinations of species studied. A. cruentus seemed to be genetically closer to A. hypochondriacus than it was to A. caudatus.Research was supported by Grand No. AMA-KE-4-83-22. (CRG GRANT) from the National Academy of Science, U.S.A.     

Outcrossing and isolation requirement in kenaf (Hibiscus cannabinus L.)

Summary To find the isolation distance in Hibiscus cannabinus L. (kenaf), experiments were conducted for three years with two planting designs. The extent of cross pollination irrespective of the planting designs was inversely related with the distance. At a distance beyond 10.0 m, the contamination was found to be absent. Directions had no influence on the contamination. The amount of contamination varied considerably between the years.     

Production of interspecific hybrids between Glycine max and G. tomentella through embryo culture

Summary Interspecific hybrids have been obtained in an incompatible cross between Glycine max and G. tomentella through the in vitro culture of hybrid embryos. The percentage of successful pod setting in the crosses averaged 12.8% but there were marked differences depending on the soybean cultivar used as the female parent. Hybrid embryos at globular to heart stages were extracted from the embryo sac 15–25 days after pollination and cultured in vitro. Hybrid plants were successfully obtained by culturing the embryos on B5 medium supplemented with 0.1 mg/l IBA followed by culture on B5 medium supplemented with 0.1 mg/l TBA plus 0.25 mg/l 2-iP. The F1 plants resembled the wild male parent in growth form, but had an intermediate leaf shape between that of the parents.     

Intraspecific somatic and sexual hybridisation between dihaploid lines of Solanum tuberosum L.: evaluation of morphological traits and resistance to late blight Phytophthora infestans (Mont.) de Bary in the foliage

Intraspecific tetraploid somatic and sexual hybrid plants have been resynthesised following protoplast fusion and by sexual crosses between two dihaploid potato (Solanum tuberosum) lines each possessing complementary agronomic traits. The dihaploid PDH 40 possesses good tuber shape and yield but has foliage susceptibility to late blight (Phytophthora infestans). On the other hand, the dihaploid PDH 727 possesses resistance to blight in the foliage but has a low yield of small and irregular shaped tubers. Since it was only possible to use a partial selection strategy based on culture media to facilitate recovery of somatic hybrid plants-further morphological and esterase isozyme based characterisations were performed to identify somatic hybrid plants from amongst the non-hybrid plant material. When the blight resistance of both the intraspecific somatic and sexual hybrid plants was assessed there was no significant difference in the mean resistance value and it was intermediate between those of their parents. However, the range of resistance was much wider among the sexual hybrids than among the plants derived from somatic fusion. An assessment of tuber yield between tetraploid sexual and somatic hybrids showed no significant difference and it was higher than that of either parent value. The implication of these results in the context of potato genetics and breeding is discussed.     

Interspecific hybridization in the genus Arachis through embryo culture

Summary The embryos of a cultivated tetraploid peanut (Arachis hypogaea), a wild diploid species (A. villosa), and their hybrid embryos, which generally abort in nature, were cultured in vitro and the plants have been successfully transferred to the soil. The hybrids showed triploid chromosome number (3x=30). The significance of wide hybridization in peanut-improvement programs is discussed.     

Cytomorphological studies in an intergeneric hybrid between Gossypium hirsutum L. (2n=52) and Hibiscus panduraeformis Burm.

Summary An intergeneric hybrid (2n=38) between Gossypium hirsutum L. (2n=52) × Hibiscus panduraeformis Burm. (2n=24) was obtained by pollinating about 2000 flower buds of G. hirsutum var. Gregg Male Sterile with pollen from H. panduraeformis. The F₁ hybrid was intermediate in plant habit, but possessed gossypol glands and nectaries on the leaves, bolls containing seeds with fuzz and lint as dominant characters of G. hirsutum. Flowers with yellow corolla and anthers; purple petal spot, profuse growth of epidermal hairs on all plant parts including the boll sutures, and jassid tolerance were dominant characters of H. panduraeformis. The partial fertility of the F₁ indicated the possibilities of combining jassid and drought tolerance of H. panduraeformis with the desired economic characters of G. hirsutum for rainfed cultivation.The F₁ hybrid showed various meiotic irreguarities and about 40% pollen sterility. Formation of the normal bivalents occurred quite frequently suggesting a close relationship between the parental species. The sterility observed in the hybrid may be due to small structural differences between the chromosomes of the two genera and meiotic abnormalities.     

Interspecific hybridization between Coffea arabica L. and tetraploid C. canephora P. ex Fr. I. Fertility in F1 hybrids and backcrosses to C. Arabica

Summary The interspecific (C. arabica × tetraploid C. canephora) F₁ hybrid showed a low but highly variable fertility. An almost complete restoration to normal fertility was observed in individual trees of BC₁ and BC₂ generations with C. arabica as recurrent parent. From a comparison of various tests of fertility, it was found that pollen viability is a satisfactory measure of fertility.     

Interspecific hybridization between Coffea arabica L. and tetraploid C. canephora P. Ex Fr. II. Meiosis in F1 hybrids and back crosses to C. Arabica

Summary Melosis was studied in Coffea arabica, in induced tetraploid C. canephora, in their F₁ hybrid (arabusta hybrid) and in backcross generations of the hybrid with C. arabica as recurrent parent. Irregularities were observed, consisting of univalents (especially in the arabusta hybrid), multivalents (especially in tetraploid C. canephora) and uneven distribution of chromosomes at first anaphase. Chromosome distribution was improved by backcrossing. Meiotic irregularities wer negatively correlated with pollen fertility.     

胚珠培养获得秘鲁番茄与栽培番茄种间杂种具有非温敏抗根结线虫基因Mi-3

以含有Mi-3抗根结线虫基因的秘鲁番茄(Lycopersicon peruvianum)LA2823为父本,栽培番茄（Lycopersicon esculentum)高代优良自交系为母本,授粉后20～30d摘取幼果。将从幼果中分离出的直径大于2mm的胚珠放置在营养分化培养基上培养。2～4周后胚芽、胚根分别由两端伸出。培养的胚珠还可以通过体细胞胚发生途径产生胚芽。获得的种间杂种对根结线虫的抗性表型与野生种父本完全相同,在植物学性状上亦与其父本秘鲁番茄更相近。以栽培番茄为母本进行回交,成熟果实与母本相似,但其种子即使放置在MS培养基上也不能萌发。对回交种子胚败育现象进行了探讨。     

Interspecific Hybridization in the Genus Lens Applying in Vitro Embryo Rescue

Summary Four different hybridization experiments were carried out to obtain interspecific hybrids with Spanish cultivars of lentil (Lens culinaris M.). In hybridization experiments I and II, undertaken with only pollination and pollination with the addition of gibberellic acid after fertilization, respectively, no lentil hybrids were recovered. A single interspecific hybrid with L. odemensis was obtained in experiment III using the embryo rescue protocol of Cohen et al. (1984), in this case, a crossing efficiency of 0.11% and a rescue efficiency of 2.5% were obtained. Hybridization experiment IV used a specific embryo rescue protocol developed in this study. In this experiment, ovule-embryos of 18 DAP were cultured on MS salts with 1% sucrose and 1 μ M IAA + 0.8 μ M KN; after two weeks, embryos were released from the ovular integuments and cultured on the same medium for another two weeks in upright position. Afterwards, the embryos were transferred to test tubes containing the same medium and one month later plantlets were obtained. Using the above protocol, out of a total of 1707 pollinations, 6 interspecific hybrids with L. odemensis, 2 with L. nigricans and one with L. ervoides were recovered, yielding on average a crossing efficiency of 0.53% and an average rescue efficiency of 8.26%. Taking into consideration only the interspecific crossing blocks in which hybrids were recovered, the crossing efficiency with L. odemensis was 9%, while with both L. nigircans and L. ervoides the crossing efficiencies were 3%. Rescue efficiencies based on hybrids recovered per number of ovules cultured ranged between 50–100%.     

Interspecific hybrids between helianthus PetiolarisNutt. and H. Annuus L.: Effect of backcrossing on meiosis

Summary Interspecific substitutions of the nucleus of Helianthus annuus (2n=34) into the cytoplasm of H. petiolaris (2n=34) were obtained by successive backcrossing using cultivated sunflower, H. annuus, as the recurrent pollen parent.Meiosis in the F₁ was characterized by multivalents, suggesting that 10 of the 34 chromosomes were heterozygous for chromosomal interchanges. An additional pair of chromosomes also contained a paracentric inversion. Continued backcrossing resulted in rapid elimination of the meiotic aberrations evident in the F₁. In the BC₁, 1 of 11 plants had normal meiosis and by the BC₂, only 13 of 54 plants had meiotic aberrations similar to those of the F₁. However, trisomic progeny (2n=35) were found in 3 of the 11 BC₁ plants and 20 of the 54 BC₂ plants. No meiotic aberrations were observed in BC₃ or BC₄ plants. Plants with indehiscent anthers, and considered to be male sterile (M.S.), first occurred in the BC₁ and, by the BC₂, 51 of 54 plants were M.S. All 19 BC₃ and 16 BC₄ plants were M.S. Preliminary investigations suggest that the pollen from such plants is sterile and that the sterility is cytoplasmic rather than genetic.Disc-flower measurements were a useful technique for selecting samples at the correct stage of microsporogenesis, but could not be used to distinguish between successive backcrosses.