Haploid Wheat Induction by Crosses Between Different Ploidy Wheat and Different Populations of Maize

Haploid embryo and plant producing frequencies were studied by crossesing diploid, tetraploid and hexaploid wheat with landraces,hybrids and inbred lines of maize. It showed significant differences among the wheat and maize populations. The tetraploid and hexaploid wheat were better than the diploid. High frequencies were obtained by using tetraploid wheat of Triticum turgidum cv. TG14 and maize landraces cv. Xiaoyumi and Xiao Huangmaya. The highest haploid plant producing frequency (6.95 %) was obtained in the TG14 × Xiaoyumi.     

Fertilization and Embryo Development in Wheat x Maize Crosses

The fertilization and embryo development in crosses of hexaploid wheat “Kangxuan 9” X maize “SS 7700” were studied. Of 180 florets fi,ced after pollination 34(18.9%) had embryo and endosperm, 46(25.6%) had only embryo and 12(6.7%) had only endosperm. Percentages of single or double fertilization were higher than that in control (“Chinese Spring” X maize). The hybrid embryos and endosperms obtained were karyotypically unstable and characterized by rapid elimination of the maize chromosomes to produce haploid wheat embryos. The potentials for wheat haploid production and transfer of DNA segments, including transposable elements, from maize to wheat is discussed.     

Induction of Haploid Durum Wheat Plants Through Pollination of Maize Pollen

When tetraploid wheat (Triticum durum Desf. ) variety DR147 was crossed with maize (Zea mays L. ) variety suppersweet ss 7700, pollen readily germinated on the stigma and one or more pollen tubes reached the embryo sac in 83.4% of wheat florets. The frequency of fertilization and embryo formation was 44.5% and 42. 6% respectively. The hybrids were karyotypically unstable and the maize chromosomes were eliminated early in the development. Thus haploid wheat embryos were form. Although the double fertilization frequency of durum wheat X maize was high (32.7%) to form embryos and endosperms, yet the endosperms were highly abnormal. It was very difficult to produce viable mature seeds from the mother durum wheat plants. The survival of hybrid embryos produced by durum wheat X maize could be improved or prolonged by treatment with 100 ppm 2, 4-D (either by dipping inflorescences in solution or injecting 0.3 to 0.5 mL 2, 4-D solution into the uppermost internodes of the wheat stem). 9 to 13 days after pollination, caryopsis were excised from the pollinated spikes and surface sterilized for peeling of the embryos in different developing stages. The embryos were plated on MS solid medium containing 3% sucrose, 200 mg/L casein hydrolysate for embryo rescue. The experimental results revealed that the well developed embryos (larger than 0. 5 mm with scutellum structure) were easy to produce calli by callus induction or produce haploid wheat plants by embryo rescue, whereas the poorly developed embryos (globular, pear or torpedo-shaped embryos smaller than 0.3 mm) responsed very poorly. The germination frequencies of well and poorly developed embryos were 83.3 % and 12.5 %, respectively. Chromosome counts of root tip cells of the rescued plants proved their haploid nature (2n= 2x= 14).     

小麦与玉米杂交及单倍体的产生

应用普通小麦不同品种(品系)与苏玉4号杂交,喷洒100ppm的2,4—D一至二次,授粉后子房膨大,其膨大率因品种不同而异。在部分膨大子房中剥取到发育幼胚,经组织培养后,获得单倍体小麦植株,植株未结实。     

Fertilization and Embryo Development in Hybridization Between Wheat and Leymus

Observations were made of the fertilization and embryo development in intergeneric cross between Triticum aestivum L. cv. Chinese Spring and Leyrnus secalinus Tzrel. The pollen germination of Leymus secalinus appeared normal on the stigma of Triticum aestivum and the pollen tubes grew into the style and entered the embryo sacs. Double and simple fertilization were observed in the pollinated florets. Of the 319 ovaries examed 62 (19.44%) had double fertilization and had embryo and endosperm, but endosperm development was slower than that of the embryos, 49 (15.36%) had only embryo and 7 (2.19%) had only endosperm. The total percentage of fertilization was as high as 36.99%. However, only I seed was obtained from 150 wheat ftorets pollinated with Leymus secalinus. This was obviously due to the absence or poor development of the endosperm. It may be suggested that the potential of increasing the frequency of hybrid plant obtainment was great in the cross between wheat and leymus, if embryo culture technique is employed at the early stage of hybrid embryo development.     

不同倍性小麦和玉米不同群体杂交诱导小麦单倍体的研究

自从Ｚｅｎｋｔｅｌｅｒ等［１］首先报道了小麦×玉米受精现象以来,许多学者对六倍体普通小麦与玉米杂交进行了广泛的研究,获得单倍体的普通小麦,并筛选到一些杂交亲和性较高的亲本材料［２］。但四倍体小麦与玉米杂交研究报道较少。ＯＤｏｎｏｕｇｈｕｅ等用四倍体小麦与玉米杂交获得单倍体胚［３］。随后,Ａｍｒａｎｉ等［４］和孙敬三等［５］利用这一方法相继获得四倍体小麦的单倍体苗。本文报道了不同倍性的小麦基因型与玉米不同群体杂交对诱导小麦单倍体的影响１　材料和方法１．１　亲本材料用作母本的二倍体小麦有一粒小麦（…     

由小麦×玉米获得的普通小麦加倍单倍体后代的RFLP变异

用小麦（Ｔｒｉｔｉｃｕｍ　ａｅｓｔｉｖｕｍＬ．）的ｒＤＮＡ克隆ｐＴａ７１和与小麦基因组有部分同源性的玉米（ＺｅａｍａｙｓＬ．）ＤＮＡ克隆作探针,对由小麦ｘ玉米获得的普通小麦加倍单倍体（ＤＨ）后代群体进行ＲＦＬＰ分析。结果发现,不但用ｐＴａ７１在这些ＤＨ后代中检测到ｒＤＮＡ所发生的明显的减少和扩增及非转录间隔区的限制性片段长度的变化,而且用与小麦基因组部分同源的玉米克隆ＭＲ１３和ＭＲ５０在一些ＤＨ后代中检测到缺失变异,特别是用ＭＲ１３在普通小麦ＤＨ系的１８号株的基因组中检测到大幅度的限制性片段长度的变化,即原来的４．３ｋｂ的强信号带消失,取而代之的是４０．０ｋｂ、２．５ｋｂ和２．０ｋｂ三条杂交带。这可能与小麦基因组ＤＮＡ较大的重排事件有关,也可能是由外源的玉米ＤＮＡ插入造成的。     

玉米花药培养和单倍体育种的研究新进展

利用花药培养获得单倍体,从而加速育种进程,是一顶新兴的生物技术,目前在玉米育种中广泛应用,本文综合近几年来国内外玉米的花药培养、单位体育种以及基因工程等方面的研究进展,重点对影响玉米花药培养效率的诸多因素进行了详细论述,并讨论了利用单7保体植株进行基因转导的潜力。     

玉米孤雌生殖单倍体诱导及加倍机理研究新进展

玉米单倍体技术的应用可以大大缩短自交系选育年限,加快育种进程,提高选育效率,尤其是孤雌生殖单倍体技术的广泛应用,能够在高效加倍的基础上快速选育稳定的纯系。本文较全面地综述了近年来关于玉米孤雌生殖诱导产生单倍体的机理及单倍体染色体加倍分子机制的研究新进展,旨在为单倍体技术更广泛的应用提供一定的理论依据。     

Haploid Plant Regeneration from Protoplast Cultures of Durum Wheat (Triticum durum Desf.)

Haploid suspension callus cultures from embryos of durum wheat (Triticum durum Desf. ) × maize (Zea mays L. ) crosses were used for protoplast isolation. Experimental results from enzyme digestion showed large numbers of viable protoplasts released from both suspension culture and solid culture of callus cut into small pieces of 1 mm in size prior to incubation in an enzyme solution containing 2.0% cellulase RS and 0.5 % pectolyase Y-23. Division frequency of protoplasts isolated from suspension cultured callus was quite different from that of solid cultured callus, however, the former being 5.20%, and the latter less than 1.0% when cultured on KM8p medium containing 1.0 mg/L 2, 4-D using LMP (low melting point) agarose embedding method. Embryogenic ealli could be selected out from protoplast-derived microcalli after 2 to 3 subcultures. Plants could be regenerated from protoplast-derived embryogenic calli after 20 days of culture on differentiation medium I (MS basal medium supplemented with 0.2 mg/L 2, 4-D, 1.0 mg/L BAP, 0. I mg/L NAA, 3 %/4 su- crose, 200 mg/L casein hydrolysate, 146 mg/L glutamine, 300 mg/L aspartic acid) and (components were the same as I without 2, 4-D) respectively. The plant regeneration frequency was about 20%. Chromosome count of root tip cells of 4 plants of the 22 protoplast- derived plants sampled at random revealed haploid in nature (2n= 2x= 14).     

RFLP Variations of Common Wheat Doubled Haploid Progenies from Wheat×Maize Crosses

Wheat ( Triticum aestivum L. ) and maize ( Zea mays L. ) crosses (the chromosome elimination system) can be used to produce frequently a large number of doubled haploid (DH) wheat lines by embryo rescue and doubling treatment. The resulting DH lines are genetically homogeneous. Significant RFLP variations were detected in common wheat DH progenies from wheat and maize crosses by using wheat rDNA clone pta71 and two maize DNA clones (MR13 and MRSO) homologous to wheat genome as probes. The results revealed that the copy number and restriction fragment length of rDNA in some wheat DH progenies was changed, and also that deletion was detected in several DH plants when probed with MR13 and MR5O. In particular, the RFLP pattern of DH line No. 18 was greatly changed using MR13 as a probe. In this line, three new bands, 40.0 kb, 2.5 kb and 2.0 kb emerged while a 4.3 kb intense band from the parental common wheat genome disappeared. This change may be related to a quite large DNA rearrangement within the wheat genomic DNA or an insertion by alien maize DNA fragment.     

莜麦与玉米的远缘杂交

莜麦（Ａｖｅｎａ ｎｕｄａ Ｌ．）和玉米（Ｚｅａ ｍ ａｙｓＬ．）杂交有一定的受精率和成胚率。人工传粉后玉米花粉能很快在莜麦柱头上萌发并长入莜麦花柱中,在６８％ 的莜麦花柱中可观察到不只一条玉米花粉管。对授粉后的１６３ 个莜麦子房进行制片观察,发现受精率可达１１．０４％ ,其中只形成胚而无胚乳的卵细胞单受精占３．０７％ ,只形成胚乳而无胚的中央细胞单受精占１．８４％ ,既形成胚又形成胚乳的双受精占６．１３％ 。从授过玉米花粉的大约２２００ 朵莜麦小花中收获１８ 粒种子,对１２ 株实生苗根尖染色体计数表明,其中９ 株为单倍体（２ｎ＝ ２１）,３ 株为二倍体（２ｎ＝ ４２）。结果证明,通过莜麦和玉米杂交后玉米染色体的消除可以获得莜麦单倍体     

Efficient production of haploid wheat (Triticum aestivum) through crosses between Japanese wheat and maize (Zea mays)

Summary Four Japanese wheat varieties, three crossable and one non-crossable with Hordeum bulbosum, were pollinated with maize pollen of 5 genotypes. By the application of 2,4-dichlorophenoxyacetic acid after pollination, embryos kept developing on wheat plants until 14 days after pollination. The frequency of embryo formation was significantly different among the maize genotypes, varying from 18.0% to 31.9%, but not among the wheat varieties. By bagging spikes with flag leaves the frequency of embryo formation was increased by about 7%. Ten- to twelve-day-old embryos gave higher frequencies of plant formation (83.6%) than 14-day-old embryos(50.0%). All 6 regenerated plants investigated cytologically were found to be haploid. Twelve of the 14 colchicine-treated plants produced florets setting seeds. The overall efficiency of our procedure is considered to be higher than that reported by Laurie and Bennett (1988).     

从小麦雄性不育系的未授粉子房诱导单倍体植株

采用N₆培养基为基本培养基,附加不同水平的生长素,培养普通小麦、小麦雄性不育系及其保持系共10个材料的未授粉子房,所用的材料都能诱导出愈伤组织,出愈率在4.2-38.1%。经分化培养分别从T型不育系和太谷核不育材料获得了单倍体植株。供试材料的基因型、培养基中的生长素的种类及用量,对诱导愈伤组织及分化绿苗有重要的作用。 The unpollinated ovaries of male sterile lines and its manitainers of wheat, as well as common wheat, were cultured on N6 medium in vitro,when the pollen of the same panicle were at uninucleate stage. Callus were obtained from all of the materials, haploid plantlets were regenerated from the unpollinated ovaries of timopheevi cytoplasm male sterile line (T75-3369A) and Taigu nucleus male sterile line (Tal x C⁶⁸⁴₁).     

玉米花粉单倍体植株染色体上异染色质的变异

我们用Giemsa BSG C-带技术检查了玉米花药培养获得的花粉单倍体植株根尖细胞染色体上异染色质的变异,观察结果表明,有的植株所显示的C-带数目是与供体植株的相一致,有的植株所显示的C-带数目则发生了显著变化,其中有的增加,有的减少。并讨论了异染色质发生变异的可能原因。还相应地观察到间期核中染色中心的变化是与中期染色体上C-带数目的变化相一致。     

基因组原位杂交鉴定玉米的外源染色体片段

利用基因组原位杂交技术,在稳定遗传的纯系５４０及其与玉米（ＺｅａｍａｙｓＬ．）自交系杂交后代Ｆ１即遗单６号中,成功地鉴定了渗入其中的二倍体多年生类玉米（ＺｅａｄｉｐｌｏｐｅｒｅｎｎｉｓＤｏｅｂｌｅｙ,ＤＰ）的染色体片段,采用ＤＡＢ（Ｄｉａｍｉｎｏｂｅｎｚｉｄｉｎｅｔｅｔｒａｈｙｄｒｏｃｈｌｏｒｉｄｅ）和荧光检出系统,二者获得了一致的结果,在纯系５４０的第１,２,５和８号两条同源染色体长臂上均检出杂     

不同处理对小麦×玉米产生小麦单倍体胚频率的影响

在田间条件下,选用3个小麦材料与不同玉米品种进行杂交,用含不同体积分数二甲基亚砜（DMSO）的100 mg/L 2,4-D溶液和3%DMSO与2,4-D配比处理两种方法诱导小麦×玉米产生单倍体.结果表明,在不同DMSO处理中,2%体积分数的DMSO最佳处理平均得胚率最高为15.8%,3%处理最低（7.1%）,二者差异显著;在激素配比试验中,以授粉后48 h采用小花滴注100 mg/L 2,4-D溶液、授粉后72 h再次采用小花滴注并穗下茎节注射3%DMSO的100 mg/L 2,4-D溶液的处理得胚率最高（14.1%）,但与3%DMSO的2,4-D 1次处理（13.4%）2、,4-D 1次处理（12.7%）、2,4-D 2次处理（10.6%）和3%DMSO的2,4-D 2次处理（12.6%）之间无显著差异,而这5种处理的得胚率均与对照和未授粉只进行3%DMSO的2,4-D 1次处理存在极显著差异.     

小麦Kr基因在小麦与玉米或鸭茅状摩擦禾杂交中的失活

用３７个小麦（Ｔｒｉｔｉｃｕｍａｅｓｔｉｖｕｍ）品种（系）为母本,分别与黑麦（Ｓｅｃａｌｅｃｅｒｅａｌｅ）、球茎大麦（Ｈｏｒｄｅｕｍｂｕｌｂｏｓｕｍ）、玉米（Ｚｅａｍａｙｓ）和鸭茅状摩擦禾（Ｔｒｉｐｓａｃｕｍｄａｃｔｙｌｏｉｄｅｓ）杂交,比较其亲和性,小麦和玉米或鸭茅状摩擦禾杂交比小麦与黑麦或球茎大麦杂交的亲和性显著提高。携带着显性Ｋｒ１和Ｋｒ２基因的小麦品种Ｈｏｐｅ与黑麦杂交,不能形成胚,而与玉米及鸭茅状摩擦禾杂交时,成胚率分别达１６．００％和３２．５０％。表明控制小麦与黑麦及球茎大麦杂交亲和性的Ｋｒ基因系统在小麦与玉米及小麦与鸭茅状摩擦禾属间杂交中失活。讨论了还存在有其它控制小麦属间杂交亲和性的遗传调控系统的可能性。     

小麦,玉米接种耐氨固氮菌试验初步分析

１９８９—１９９２年,在广东省部分县市进行了小麦、王米施用耐氨固氮菌大田对比试验,小麦接种耐氨固氮菌后,接菌区小麦的穗氏、有效穗、每穗粒数均比不接菌区明显增加,株高、成穗率、千粒重比对照略有增加,平均每亩比对照增产１６．７ｋｇ干麦,平均增产率为８．１％。玉米接种耐氨固氮菌后,接菌区玉米的茎粗、收获时的青叶片数、单苞重均比对照区明显增加,秃顶度比对照区明显减小,晒干率：出米率略有增加,平均每亩比对照增产５２．８ｋｇ玉米,平均增产率为１１．８９％。     

药物诱导玉米孤雌生殖植株的倍性变异

实验结果表明,孤雌生殖植株根尖体细胞以二倍体细胞最多,占６８．９％,其次为非整倍体细胞,占２８．７％,其他异倍体和单倍体细胞极少（２．４％）。Ｐａ１植株可分为二倍体和混倍体两类,以二倍体细胞占绝对多数的混倍体植株最多,为８３．５％,这些植株生长发育和结实均正常。在花粉母细胞中正常二倍体频率比根尖体细胞明显提高,提高频率为３５．３一５９．６％,不同材料之间趋势一致。讨论了体细胞染色体变异的来源及其能否延续到生殖细胞。