牛体外受精卵5～10细胞期单一卵裂球染色体诊断

利用单一卵裂球的染色体诊断牛体外受精5－～10－细胞期胚胎的正常性。牛体外受精后5－～10-细胞期的胚胎用0．5％链霉蛋白酶处理分离单一卵裂球，然后用100ng/ml长春花碱处理10h，制作染色体标本。检查33枚不同发育期胚胎及卵裂球185个，有43．8％的可进行染色体分析（81／185）。结果表明，正常2倍体的发生率为46．9％，染色体异常的卵裂球中，单倍体的发生率为50．6％，显著高于多倍体（2．5％）的发生率（P＜0．001）。单倍体中含有X－性染色体和含有Y－性染色体的性比基本相同。引起单倍体发生的原因可能是由于卵母细胞的孤雌发育或受精过程中精子穿入未成熟卵后由雄性原核产生。     

Study on Chromosome Doubling for Haploid Produced by Wheat × Maize Crossing

There is no spontaneous chromosome doubling in haploid plants produced by wheat × maize crossing. In order to obtain doubled haploid, two chromosome doubling methods were used. Results showed that: After adding colchicine solution directly into a medium for young embryos that had been cultured 7 days,frequencies of embryo germination in colchicine concentrations of 50lng/L, 100mg/L and 200mg/L were 32.1%, 26.4% and 16.3%, respectively, and frequencies of chromosome doubling were 85.3%, 100% and 50.0%, respectively. But in the control without colchicine, the frequency of embryo germination was 67.4%and no seed was setting. As the time of colchicine treatment increased from 24 to 72 hours, the frequency of embryo germination was reduced, and 24 hours had better results. After soaking seeding crowns and roots with colchicine solution of 500mg/L, 750mg/L and 1 000mg/L for 5 hours, the frequencies of doubling were 89.6%, 76.0% and 73.3%, respectively. By soaking crowns and roots of strong seedings with 500mg/L colchicine solution, the frequency and efficiency of doubling were 98.2% and 93.2%, respectively.     

小麦×玉米诱导小麦单倍体高效系统的建立

为建立一套高效的小麦×玉米单倍体诱导系统用于构建小麦DH群体,采用杂交后剪穗进行人工控制环境条件的室内离体培养法和田间常规杂交法诱导小麦×玉米单倍体,研究了不同培养环境、离体培养时环境温度、常规杂交法时T>10℃有效积温对单倍体成胚率和成苗率的影响。结果表明:就平均成胚率而言,离体培养法(23.6%)>常规杂交法(18.1%),获得最高成胚率的环境温度为21℃~23℃,T>10℃有效积温为188℃;就平均成苗率而言,离体培养法(18.7%)高于常规杂交法(15.1%),获得最高成苗率的环境温度为23℃,T>10℃有效积温为188℃。并在此基础上建立了一套高效、可靠、重复性好的小麦×玉米单倍体诱导系统。实验还表明大田条件下,授粉后12~14d的培养时间不宜作为小麦×玉米单倍体剥胚的时间标准,而应以授粉后外界环境提供的T>10℃有效积温作为剥胚的时间标准可能更准确。     

玉米单倍体诱导及化学加倍方法的研究

【目的】玉米单倍体的诱导及加倍.【方法】以北方春玉米区高抗丝黑穗病自交系K88和高感丝黑穗病自交系G115的杂交F1代作为母本,以5个诱导系(JS6-11~JS6-15)作为父本,进行单倍体杂交诱导试验;以秋水仙素作为玉米单倍体人工染色体加倍药剂,采取4种(浸根法、浸芽法、滴心叶法、针刺生长点法)处理方法,每种方法设置3个浓度梯度(0.2、0.4和0.6 mg·m L-1),并分别以体积分数2%DMSO+5%甘油溶液作为辅助药剂,进行单倍体加倍试验.【结果和结论】花丝长短和授粉时间对单倍体诱导率有重要影响.延迟授粉(长花丝≥7cm)的平均单倍体诱导率为17.0%,约为正常授粉(短花丝≤4 cm)条件下的3.3倍;伏后授粉的诱导率平均为18.4%,约为伏期授粉的3.4倍,证明延迟授粉时间和较低的温度有利于提高单倍体诱导率.秋水仙素加倍试验表明,浸根法对植株伤害较严重,存活率低于50%;针刺生长点法(0.6 mg·m L-1)和滴心叶法(0.4 mg·m L-1)的散粉率较高(45.9%,28.9%),相应的结实率也较高(15.2%,11.1%),说明针刺生长点法处理效果最好,滴心叶法次之.     

棉花半配合材料VSg在遗传育种中的应用

以VSg作母本与其它材料杂交可以培育父性单倍体,但不同材料作父本与VSg杂文F₁所产生的父姓单倍体的比率不同.以海岛棉或海岛棉品种间杂交F₁作父本时较高(2.5%),海陆种间杂交F₁作父本时次之(1.3%),陆地棉或陆地棉品种间杂交F₁作父本时较低(0.7%).用秋水仙素水溶液处理父性单倍体植株后获得13个加倍单倍体株系.以VSg单倍体植株作母本与正常异源四倍体棉花杂交可以获得非整倍体.     

牛体外受精时老化卵对受精率与染色体异常发生的影响

通过延长体外培养时间得到牛老化卵，对其体外受精率与染色体的异常发生进行了研究，体外受精48h后的受精率，46h培养组与22h和34h培养组之间差异显著（P＜0．05），随着老化时间的延长，受精率及胚胎发育速度明显降低。染色体分析结果表明，46h组的受精卵的染色体异常发生率为61．6％，22h组44．6％，2组之间差异显著（P＜0．05），单倍体（n=31)的发生率也随着老化时间的延长而增加，这些单倍体的性染色体的构成表明，含有X－性染色体的胚的出现率显著高于含有Y－染色体的胚的出现率（P＜0．05）。单倍体的发生是由卵的老化而引起单一配子的孤雌发生，体外培养时间的延长对正常的2倍体的性别无明显影响。     

Comparison of Anther Culture and Hordeum bulbosum Method for the Production of Doubled Haploid in Winter Barley I. Production of Green Plants

The relative response to two-major techniques of producing haploids in barley – anther culture and the Hordeum bulbosyum method – were compared using seven F₁ hybrids from a winter barley breeding programme. Both techniques were Applied to the same plants with the same number of replications. 358 viable green plants were obtained from 420 spikes ot donor plants used: 147 through anther culture and 211 through the H. bulbosum method. From the data analysis we found that the response to the two techniques was not significantly different, genotype effect and genotype × technique interaction were highly significant. The possibility of combining the two techniques in a doubled haploid production programme is discussed.     

An Evaluation of Hordeum vulgare L. ×Psathyrostachys fragilis (Boiss.) Nevski Crosses for Doubled Haploid Barley Production

Investigations were carried out to assess the suitability of the intergeneric cross Hordeum vulgare×Psathyrostachys fragilis for haploid barley production. H. vulgare cvs. ‘Emir’ and ‘Vada’ were each pollinated with P. fragilis P.I. 343192 and plants regenerated from embryos cultured on a modified B5 medium. Seed sets on ‘Vada’ were significantly lower than on ‘Emir’, and all the planes from ‘Vada’×P. fragile remained hybrid. Several of these flowered but there was little pairing between the parental chromosomes. Most of the plants from ‘Emir’×P. fragilis died, as seedlings but 3 plants developed into haploid barley. Because of the practical limitations of pollen availability from P. fragilis and the inconsistencies in haploid plant formation, it is unlikely that the cross will prove as valuable as that between H. vulgare×H. bulbosum for a doubled haploid barley programme.     

Comparison of Anther Culture and the Hordeum bulbosum Method for the Production of Doubled Haploids in Winter Barley

The comparison, between the efficiency of anther culture and the Hordeum bulbosum method in barley was extended to the chromosome number distributions of all planes derived from the two techniques and the proportions of fertile doubled haploid plants which survived until maturity. The frequencies of haploid and spontaneously doubled haploid plants which were useful for practical breeding purposes were found to be around 90 % for both techniques. The remainder consisted of polyploid, mixoploid and aneuploid variants in the case of microspore-derived plants and diploid interspecific hybrids in the progeny of the H. bulbosum method. The ploidy level distributions of the microspore- and H. bulbosum-derived plants appeared to be independent of the genotype of the donor. There were no significant differences between techniques regarding the proportions, of plants which survived a severe winter and the production of fertile doubled haploid plants. Both techniques can therefore complement each other in a breeding programme and their relative merits are discussed. Possible ways of improving doubled haploid production in barley are suggested for increasing its use in breeding schemes.