甘蓝型油菜-埃塞俄比亚芥二体附加系植株形态及细胞学鉴定

从甘蓝型油菜品种“３－６３－４－５－１”与埃塞俄比亚芥品种“Ｄｏｄｏｌｌａ”杂种Ｆ１植株开放受粉获得的Ｆ２群体中筛选出一株半不育、矮杆、甘蓝型油菜类型植株，经连续４个世代自交、分离鉴定出一个二体附加系“９２Ｉ１０９６”。细胞学观察结果，其根尖细胞染色体数２ｎ＝４０，比其母本甘蓝型油菜（２ｎ＝３８）多两条额外染色体。花粉母细胞（ＰＭＣｓ）减数分裂中期（ＭＩ）染色体构型平均为０．４７Ｉ＋１９．７７Ⅱ，     

异源三倍体水稻原生质体培养及植株再生

本试验利用二倍体栽培稻品种８２０４，染色体组型为ＡＡ，２ｎ＝２４作为母本，四倍体小粒野生稻染色体组型为ＢＢＣＣ，２ｎ＝４ｘ＝４８作父本杂交，获得异源三倍体杂交种，染色体组型为ＡＢＣ。Ｆ１根尖检查，染色体数目为２ｎ＝３ｘ＝３６。用该异源三倍体杂交种的纪穗诱导愈伤组织，经长期继代培养进行原生质体游离，获得了再生植株白化苗。试验结果表明，用琼脂糖包埋法保进原性质体再生愈伤组织。分化培养基用玉米素，激动素     

棉属[AG]与[AD]两个复合染色体组种间杂种的同工酶与核型研究

利用聚丙烯酰胺凝胶电泳法对人工合成的［ＡＧ］复合染色体组的异源四倍体与［ＡＤ］复合染色体组的陆地棉、海岛棉、夏威夷棉、黄褐棉的种间杂种Ｆ１及其亲本进行了过氧化物酶同工酶和细胞色素氧化酶同工酶分析，并对三元杂种［Ａ２×Ｇ１］ ×［ＡＤ］１及其亲本进行了核型分析。结果表明：（１）异源四倍体的基因转移到了杂种后代，并得以表达；（ ２）三元杂种［Ａ２ × Ｇ１］ ×［ＡＤ］１的核型公式为 ２ｎ＝ ４ｘ＝ ５２＝ ２Ｍ ＋ ４４ｍ（ＳＡＴ）＋６ｓｍ（ＳＡＴ），属于１Ｂ类型。     

冬小麦丰抗13缺体系和双单体系研究

冬小麦丰抗１３缺体系和双单体系研究孙荣锦杨之刚（中国农业科学院作物所，北京１０００８１）１丰抗１３缺体系小麦染色体组成是２ｎ＝６ｘ＝４２，小麦缺体是２ｎ－２＝４０，即缺少了某对染色体的单株，称缺体株。它的减数分裂中期Ⅰ染色体构型是２０″即２０个二价体...     

河北省桑属植物染色体倍数性研究

研究了桑属植物５个种３２个品种的染色体倍数性，发现宽城１０号等９个品种为三倍体（２ｎ＝３ｘ＝４２），其余为二倍体（２ｎ＝２ｘ＝２８）。     

利用人工合成甘蓝型油菜建立白菜—甘蓝附加系

采用白菜子房培养和甘蓝胚培养方法得到了带有标记性状的白菜和甘蓝种间杂种，并将这些人工合成甘蓝型油菜回交于白菜，得到３１个白菜－甘蓝单体附加系（２ｎ＝２１），和１８个双体附加系（２ｎ＝２２），为进一步对附加染色体上的所载基因定位奠定了基础。此外，还研究了附加甘蓝染色体对雄笥和雌性育性的影响，结果表明，白菜中附加甘蓝染色体可明显降低育性，特别是可显著降低附加系的自交和杂交结实率。     

4D缺体小麦与八倍体小偃麦杂交的细胞遗传学研究

利用自花结实的４Ｄ缺体小麦作母本，与中２、中５及中１００１等八倍体小偃麦杂交，获得的杂种Ｆ１植株除４Ｄ缺体×中５育性极低外，其余组合略低于普通小麦×八倍体小偃麦的自交结实率。杂种Ｆ１体细胞２ｎ＝４８。４Ｄ缺体×中２的Ｆ１花粉母细胞减数分裂ＭＩ染色体配对的平均构型为１８．８１（１５－２２）Ⅱ＋０．５７（０－３）Ⅲ＋０．１１（０－２）Ⅳ＋８．２３（６－１０）Ⅰ。观察结果同时表明：（１）单价体的分布在每个ＰＭＣ中以８为众数；（２）单价体之中的两个在多数的ＰＮＣｓ中能形成次级联合配对，说明４Ｄ与４Ｅ染色体具有部分同源关系；（３）杂种Ｆ１多数花粉母细胞中多价体的出现表明八倍体小偃麦中Ｅ染色体组具有促进部分同源染色体配对的基因。     

小扁豆核型的比较分析

采用去壁低渗火焰干燥法制备小扁豆染色体标本观察其核型,结果表明,绿小扁豆和红不扁豆的核型公式均为２ｎ＝２ｘ＝１６＝１６ｍ＋６ｓｍ＋２ｓｔ＋２ｓｔ（ＳＡＴ）,两种小扁豆的核型类型都是３Ｂ,染色体相对长度系数组成均为２ｎ＝２ｘ＝１６＝４Ｌ＋６Ｍ２＋６Ｍ１＋４Ｓ,二者主要在第７号染色体臂比和２号染色体大小方面有明显差异。     

青海省家驴染色体核型研究

采用外周血淋巴细胞培养方法和常规染色体制备分析技术，对青海省家驴染色体核型进行了研究分析。结果表明：家驴染色体数目为２ｎ＝６２，常染色体形态类型为１６ｓＴ＋１４ｓＭ＋１４Ｍ＋１６Ｔ，性染色体类型Ｘ为ｓＭ，Ｙ为Ｔ，公母驴染色体核型式为６２，ＸＹ和６２，ＸＸ；染色体总臂数为ＮＦ＝１０７（♂），１０８（♀）。     

稻属间杂种花粉植株的细胞遗传学研究

以栽培稻０２４２８与紧穗野生稻间不育Ｆ１杂种（２ｎ＝２４，ＡＣ）为材料进行花约培养，共接种花约３２６８８个，获得再生绿苗１３株及白化苗两株，愈伤诱导率与分化率分别为０．１４％和３４．７８％。有９朱花粉绿苗长至成熟，均表现长芒、紫柱头、强感光及易落粒等野生亲本的特性。细胞学结果进一步表明，其中４株为二倍体（２ｎ＝２４），形态上琚的Ｆ１杂种相似，花粉母细胞中期Ⅰ亦只能见到少数二价体；另５株则为四倍体（     

Production of 27-, 28-, and 56-chromosome apomictic hybrid derivatives between pearl millet (2n=14) and Pennisetum squamulatum (2n=54)

Summary An interspecific hybridization program designed to transfer gene(s) controlling apomixis from Pennisetum squamulatum Fresen. (2n=6x=54) to induced tetraploid (2n=4x=28) cultivated pearl millet, Pennisetum americanum (L.) Leeke resulted in four offtype plants, two with 27 chromosomes and two with 28 chromosomes. These plants were found among 217 spaced plants established from open-pollinated seed of an apomictic 21-chromosome polyhaploid (2n=21) plant derived from an apomictic interspecific hybrid (2n=41) between tetraploid pearl millet and Pennisetum squamulatum. It appeared that a 21- (or 20-) chromosome unreduced egg from the apomictic polyhaploid united with a 7-chromosome pearl millet (2n=2x=14) gamete to produce a 28- (or 27-) chromosome offspring. Meiotic chromosome behavior was irregular averaging from 3.60 to 4.05 bivalents per microsporocyte in the 27- and 28-chromosome hybrids. The 27- or 28-chromosome hybrids, like the 21-chromosome female parent, shed no pollen, but set from 1.8 to 28 seed per panicle when allowed to outcross with pearl millet. Progeny of the 28-chromosome hybrids were uniform and identical to their respective female parents, indicating that apomixis had been effectively transferred through the egg. In addition, a 56-chromosome plant resulting from chromosome doubling of a 28-chromosome hybrid was identified. Pollen was 68 per cent stainable and the plant averaged 2.3 selfed seeds per panicle. Chromosomes of the 56-chromosome plant paired as bivalents (x=10.67) or associated in multivalents. Three to nine chromosomes remained unpaired at metaphase I. Multiple four-nucleate embryo sacs indicated the 56-chromosome hybrid was an obligate apomict. The production of 27-, 28-, and 56-chromosome hybrid derivatives were the results of interspecific hybridization, haploidization, fertilization of unreduced apomictic eggs, and spontaneous chromosome doubling. These mechanisms resulted in new unique genome combinations between x=7 and x=9 Pennisetum species.     

Characterization of morphological variation and cold resistance in interspecific somatic hybrids between potato (Solanum tuberosum L.) and S. brevidens Phil.

Summary Somatic hybrids between Solanum tuberosum L. cv. Gracia (2n=4x=48) and Solanum brevidens Phil. (2n=2x=24) were produced via fusion of mesophyll protoplasts. Selection of the protoplast derived putative hybrid calli was based on their vigorous growth. Additive isozyme patterns and chromosome numbers as well as the expression of parental morphological characters have proved the hybrid origin of the selected regenerants. Extensive chromosome loss during the regeneration process resulted in aneuploid hybrids with high frequency. Genomic instability could not be detected in these plants during the period of vegetative propagation. Regenerants from hybrid tissues exhibited wide morphological variation especially in tuber formation. The detailed morphological analysis based on the use of multivariate method (principal component analysis, PCA) enabled to identify morphological groups among the hybrid clones. The positioning of hybrid clones in the PCA space could not be correlated with chromosome numbers. The genomic ratio represented by the tetraploid and diploid parents influenced the morphology of somatic hybrid population according to the applied analytical system. Two selected hybrid clones have exhibited an intermediate degree of frost tolerance compared to the parents, based on the recovery of plants from lower buds after freezing of potted plants.     

埃塞俄比亚芥与白菜型油菜间六倍体杂种的获得及其生物学特性研究

通过杂交和染色体加倍人工合成了埃塞俄比亚芥×白菜型油菜间的三倍体和六倍体杂种，并对其进行了细胞学鉴定、气孔观察以及一些生理生化特性的分析。在染色体记数、原位杂交和分子标记印证的基础上，比较了两种不同染色体加倍方法的效率；生理生化分析显示，六倍体杂种植株叶片的游离脯氨酸含量、质膜相对透性、Vc含量和叶绿素含量与三倍体杂种植株相比都有明显的差别。     

Intergeneric hybrids and an amphiploid between Elymus canadensis and Psathyrostachys juncea

Summary Fifty four hybrid plants between Elymus canadensis and Psathyrostachys juncea were obtained by handpollination and embryo culture. The average cross compatibility between both species was 31.2 percent. One amphiploid plant was induced by colchicine treatment. The hybrid and amphiploid plants resembled P. juncea in appearance but showed a higher plant height and dry matter yield than the parents. The hybrids showed extremely low pollen stainability and were completely sterile. With the exception of one plant (2n=3x+1=22), all hybrid plants were allotriploids (SHN, 2n=3x=21). The amphiploid plant (SSHHNN, 2n=6x=42) showed 58.9% pollen stainability and 11.6% seed fertility.Mean chromosome associations of the hybrids and amphiploid at metaphase I were 0.02IV+0.06III+2.03II+16.91I and 0.07III+18.00II+5.85I, respectively. Lagging chromosomes, chromosome bridges, abnormal cytokinesis, and micronuclei were occasionally observed at the anaphase, telophase, or tetrad stage.     

A New Intergeneric Hybrid between Triticum aestivum L. and Agropyron fragile (Roth) Candargy: Variation in A. fragile for Suppression of the Wheat Ph-Locus Activity

New intergeneric hybrids were obtained between Triticum aestivum L. cv. Tukuho’ (2n = 6x = 42, AABBDD) and Agropyron fragile (Roth) Candargy PGR 8097 (2n = 4x = 28, PPPP) at a frequency of 1.06 %, through the use of direct embryo culture and in ovulo embryo culture. Such hybrids could be used to transfer barley yellow dwarf virus (BYDV) resistance and winterhardiness into bread wheat. The somatic chromosome number in all the hybrid plants was 2n = 5x = 35, as expected. Considerable variation in chromosome pairing was observed among the different hybrid plants. Average meiotic chromosome configuration at metaphase I was 17.29 Is + 6.57 rod Us + 1.97 ring Us + 0.18 III + 0.03 IV + 0.002 VI. The high level of chromosome pairing in some F₁ hybrids was attributed to Ph-suppressor gene(s) present in A. fragile. The hybrids could not be backcrossed to wheat, but amphiploid seeds have been obtained by colchicine treatment.     

克服甘薯组(Section batatas)种间杂交不亲和性研究再报

甘薯组Ａ系列野生种Ｉ．ｔｒｉｌｏｂａ和Ｂ系列栽培种徐薯１８杂交授粉后１１～２０天的胚珠培养获得了试管苗和杂种植株，观察比较了杂种和两亲的形态特征，进行了细胞学鉴定。同时一植株的不同细胞中，染色体数均多于３０，但有变异，变动在３８～５６范围内，杂种植株的花器中，雌雄蕊结构发生变异，全部花朵没有出现雄蕊，雌蕊却有１～５套。用Ｂ系列２个野生种和栽培种的６个品种的花粉与杂种植株回交授粉，均不结实，这些异常     

Chromosome doubling and fertility study of Alstroemeria aurea × A. caryophyllaea

Self-pollinations of a diploid (2n = 2x = 16) interspecific hybrid Alstroemeria aurea × A. caryophyllaea, resulted in no seeds. Backcrosses of the hybrid with parent A. aurea did not produce any seeds. In an attempt to restore the hybrid fertility, an efficient in vitro procedure has been developed and applied effectively in the chromosome doubling of the diploid hybrid. Forty-one percent of the treated plants were proven to be truly tetraploid by chromosome counts and stomatal measurements after applying 0.2 to 0.6% colchicine for 6 to 24 hours. Over 87.5% of these colchicine-induced tetraploids were stable and retained their tetraploidy after one year of growth. The fertility of the hybrid was not restored although the pollen stainability was increased from 0 to 12% after chromosome doubling. Cytological studies on the pollen mother cells (PMCs) of the sterile diploid hybrids revealed abnormal meiotic behaviors. In addition, aneuploid chromosome numbers, ranging from 2n = 1 to 2n = 18, were observed in over 45% of the PMCs examined. PMCs of the colchicine-induced tetraploids showed that meiotic chromosome pairings were normal in most cases (1.59_I + 15.07_II + 0.05_III + 0.03IV). These results indicate that the sterility of this hybrid is not only caused by parental chromosome differences, but other complex fertility/sterility-regulating mechanisms are involved too. This revised version was published online in July 2006 with corrections to the Cover Date.     

Variation for crossability in a reciprocal,interspecific cross involvingHordeum vulgare andH. lechleri

Summary Several crossing series including the hexaploid (2n=6x=42), South American speciesHordeum lechleri and diploid (2n=2x=14) cultivated barley (H. vulgare) were performed. Barley functioned better as the paternal than as the maternal parent in all cases. Viable offspring were only obtained from one hybrid combination when barley was used as the maternal parent. There was an environmental influence on the success of crosses. A high seed set was counteracted by a lower germination frequency. The outcome is that different crossing series give similar results. As a result of chromosome elimination and in a few cases duplication of especially the barley chromosomes, the chromosome numbers of the offspring (239 plants) varied from 2n=21 (trihaploids ofH. lechleri) to 2n=30. Fifty-five % of the plants were euploid with the number expected for a hybrid (2n=28). The frequency of hyperploids, euploids, hypoploids (2n=22–27) and trihaploids varied by year, locality, type (winter/spring) of barley,H. lechleri population, and crossing direction.     

The transfer of triazine resistance from Brassica napus L. to B. oleracea L. III. First backcross to parental species

Summary Atrazine resistant Brassica napus × B. oleracea F₁ hybrids were backcrossed to both parental species. The backcrosses to B. napus produced seeds in both directions but results were much better when the F₁ hybrid was the pollen parent. Backcrosses to B. oleracea failed completely but BC₁s were rescued by embryo culture both from a tetraploid hybrid (2n = 4x = 37; A₁C₁CC) and sesquidiploid hybrids (2n = 3x = 8; A₁C₁C). Progeny of crosses between the tetraploid hybrid and B. oleracea had between 25 and 28 chromosomes. That of crosses between the sesquidiploid hybrid and B. oleracea had between 21 and 27. A few plants that had chromosome counts outside the expected range may have originated from either diploid parthenogenesis, unreduced gametes or spontaneous chromosome doubling during in vitro culture. Pollen stainability of the BC₁s ranged from 0% to 91.5%. All the BC₁s to B. oleracea were resistant to atrazine.     

Production and characterization of intergeneric hybrids between Brassica oleracea and a wild relative Moricandia arvensis

Intergeneric crosses were made between Brassica oleracea and Moricandia arvensis utilizing embryo rescue. Six F₁ hybrid plants were generated in the cross‐combination of B. oleracea × M. arvensis from 64 pods by the placenta‐embryo culture technique, whereas three plants were produced in the reciprocal cross from 40 pods by the ovary culture technique. The hybrid plants were ascertained to be amphihaploid with 2n = 23 chromosomes in mitosis and a meiotic chromosome association of (0–3)II + (17–23)I at metaphase I (M I). In the backcross with B. oleracea, some of these hybrids developed sesquidiploid BC₁ plants with 2n = 32 chromosomes that predominantly exhibited a meiotic configuration of (9II + 14I) in pollen mother cells. The following backcross of BC₂ plants to B. oleracea generated 48 BC₃ progeny with somatic chromosomes from 2n = 19 to 2n = 41. The 2n = 19 plants showed a chromosomal association type of (9II + 1I) and a chromosomal distribution type of (9¹/₂ + 9¹/₂) or (9 + 10) at M I and M II, respectively. These facts might suggest that they were monosomic addition lines (MALs) of B. oleracea carrying a single chromosome of M. arvensis that could offer potential for future genetic and breeding research, together with other novel hybrid progeny developed in this intergeneric hybridization.