甘薯近缘野生种Ipomoea trifida(4x) GISH分析

以甘薯近缘野生种I. trifida (2x)为探针, 与I. trifida (4x) 2个株系“695104”和“697288”的体细胞染色体进行基因组荧光原位杂交, 结果显示, 2株系都与I. trifida (2x)有很近的亲缘关系, 但2株系的信号存在差异。“695104”几乎所有染色体整条都有均匀明亮的信号, 应为I. trifida (2x)基因组直接加倍而来;而 “697288”与“695104”不同, 虽然各条染色体也均有杂交信号, 但信号的区域与亮度有差异, 较为复杂, 可分为三种情况。第1种是整条染色体有均匀明亮的信号, 亮度与分布区域同“695104” , 有41条;第2种是几乎整条染色体有信号, 但亮度较第一种暗, 有14条;第3种为染色体部分区域有信号, 亮度较前二者更暗, 有5条。推测 “697288”是在加倍同时或之后又发生了基因组重组与部分变异。     

Creation of a New Resistant Germplasm to Verticillium Wilt by Distant Hybridization in Upland Cotton

To create new germplasm lines resistant to Verticillium wilt in upland cotton, 65 distant hybridization germplasm lines (DHGLs) in upland cotton genetic background were cultivated by interspecific hybridization between Gossypium hirsutum and wild species including G. anomalum, G. armourianum, G. aridum, G. raimondii, G. mustelinum, interspecific F₁ backcrossing with G. hirsutum for four generations, and selfing for four generations, followed by a conventional breeding program. The results of agronomic trait identification during 2011-2012 indicated that average plant heights of DHGLs were closely similar to commercial cultivars of upland cotton, while average fruit branches, fruit nodes, bolls of DHGLs individual plant were lower than those in commercial cultivars of upland cotton. Average single boll weight and lint percentage of DHGLs were lower than commercial cultivars of upland cotton. Fiber length, strength, fineness and maturity of DHGLs were reasonably collocated. Fiber of most lines was suitable for spinning extra high count yarn, but the main fiber quality indices of commercial cultivars of upland cotton were not well coordinated. Identification of resistance to Verticillium wilt in defoliation disease nursery during 2012-2013 indicated that five DHGLs resistant to Verticillium wilt . Suyuan 040, Suyuan 045 and Suyuan 061 were highly resistant to Verticillium wilt with a disease index of 8.33, 4.35 and 7.79, respectively. Suyuan 030 and Suyuan 034 were resistant to Verticillium wilt with a disease index of 12.35 and 13.70, respectively. The genetic relationship of new germplasm lines resistant to Verticillium wilt were traced and showed that Suyuan 040 and Suyuan 045 were DHGLs of G. raimondii, Suyuan 061 was DHGL of G.mustelinum, Suyuan 030 and Suyuan 034 were DHGLs of G. aridum.     

Occurrence of 2n gametes in the F1 hybrids of Oriental × Asiatic lilies (Lilium): Relevance to intergenomic recombination and backcrossing

Cytological modes of the origin of 2n gametes were investigated in six different genotypes of F₁ hybrids between Oriental and Asiatic (OA) lilies (Lilium, 2n = 2x = 24). Chromosome pairing between the parental genomes was very low, the average frequency range from 0.3 to 1.2 bivalents per cell among the genotypes. Within a genotype the frequency of bivalents varied from 0 to 6 in some cases. The normally occurring haploid pollen grains were totally sterile. In contrast, in different genotypes, variable percentages of 2n pollen were found and shown to be fertile as estimated from pollen germination. A cytological analysis of Metaphase I and subsequent stages of meiosis using genomic in situ hybridization (GISH) revealed that there was intergenomic recombination between the alien genomes. Following Metaphase I stage, three different types of abnormal cytological events led to the formation of 2n pollen: (i) Post-Metaphase I division (PMI), (ii) Post-Metaphase II division (PMII) and (iii) Asymmetric Cytokinesis of the pollen mother cell followed by chromosome division. All three cytological events led to first division restitution (FDR) gametes. Based on in vitro pollen germination it was proved for two genotypes that 2n pollen was viable only during the first day of anthesis. It was possible to use 2n pollen successfully for backcrossing. Implications of 2n pollen for intergenomic recombination in BC₁ progenies are discussed.     

Production of hybrids between Cajanus acutifolius and C. cajan

There are many wild species of pigeonpea which are endemic to Australia. These wild species are cross incompatible with cultivated species of Indian origin. Cajanus acutifolius is one such species which does not easily cross with cultivated pigeonpea. Interspecific pollinations lead to hybrid seeds which were semi-shrivelled. Very few seeds germinated to give rise to F1 plants. Backcrossing the hybrid plants to C. cajan, the male parent, gave rise to aborting seeds which did not germinate in vivo hence BC1 plants are obtained after saving the aborting embryos in vitro. BC₁ plants showed normal meiotic pairing, but had low pollen fertility. The reasons for embryo abortion and low pollen fertility in spite of normal meiosis could be due to the effect of wild species cytoplasm. This revised version was published online in August 2006 with corrections to the Cover Date.     

中国荷斯坦牛部分乳房结构特性对泌乳性能的影响

本研究对规模化场奶牛乳房结构部分性状进行评价和测定,旨在分析其影响因素及其与泌乳性能的关系。现场评价和测定我国北方6个规模化奶牛场荷斯坦牛的乳房均衡(2 030条)、乳头长度(1 551条)和乳头位置评分(分前、后乳头,2 839条),使用SAS 9.2 GLM过程采用固定效应模型分析影响上述3个乳房性状的因素,同时分析3个单项性状对校正日产奶量和体细胞评分的影响。结果表明:场和胎次对3个乳房性状影响极显著(P0.01);前、后乳头位置和后乳头长度对校正日产奶量有显著影响(P0.05),校正日产奶量与前乳头位置评分值呈正比,与后乳头位置评分值呈反比;前乳头位置和长度对体细胞评分有显著影响(P0.05),体细胞评分随前乳头位置评分的增大而减小;5~5.5 cm的乳头长度对于校正日产奶量和体细胞评分都最佳。本研究结果为通过乳房性状选择、淘汰并提高奶牛的生产性能、乳房健康提供了参考。     

RNA可视化原位杂交技术对感染细胞中猪瘟病毒RNA定位与分布

【目的】为研究CSFV RNA在体外感染细胞中的分布及定位,建立了一种准确、敏感的RNA可视化原位杂交技术。【方法】本研究通过比对GenBank公布的CSFV、BVDV和BDV全序列,避开BVDV和BDV的同源区,设计了CSFV RNA及内参基因β-actin的特异探针。以CSFV中等致病力毒株（HeBHH1/95）为参考毒株,在PK15细胞中培养病毒,加入RNA可视化原位杂交特异探针和相应试剂,采用荧光共聚焦显微镜进行成像观察。通过综合分析观测结果、荧光强度、重复性等因素,采用正交试验优化了对原位杂交过程中具有重要影响的蛋白酶K浓度和甲醛固定时间,建立了CSFV RNA可视化原位杂交技术,并与FAT方法比较该技术灵敏度;用我国目前流行的CSFV 1.1、2.1、2.2、2.3基因亚型及BVDV、PPV、PRV和PCV-2病毒进行特异性试验。最终,以CSFV强致病力毒株（SM）接种PK15细胞,病毒感染后0.5、1、3、6、8、10、14、18、24、36、48、72、96h(hours post inoculation,hpi)取样,每个时间点2个重复,采用CSFV RNA可视化原位杂交技术进行检测。为佐证病毒蛋白在细胞中的定位及分布,同时采用FAT方法对SM株E2蛋白在PK15细胞中的表达情况进行动态研究。【结果】采用该技术在荧光共聚焦显微镜下可观察到CSFV RNA在细胞中的定位;当蛋白酶K浓度为1:1 000、甲醛固定时间为30min时为最优反应条件;灵敏度试验表明该技术对病毒的检测极限为10-8/200μL,比FAT高3.5个数量级;特异性试验结果显示该探针能与CSFV 1.1、2.1、2.2、2.3亚型结合,与BVDV、PPV、PCV-2、PRV无交叉反应。采用该技术对CSFV RNA感染后在靶细胞中的定位与分布研究结果显示:0.5hpi在胞核和胞浆均能检测到RNA,0.5-6hpi RNA主要分布于胞核内并在核内富集;10hpi胞浆内RNA逐渐增多,胞核内RNA逐渐减少,24hpi RNA主要集中在胞浆内细胞核周围;36hpi核外RNA大量聚集增多,72hpi达到峰值;96hpi RNA总量有所下降。而FAT结果显示：8hpi在少数细胞的胞浆内检测到病毒E2蛋白,10-24hpi蛋白表达数量一直较少;36hpi蛋白表达量不断增多,72hpi到最大值;96hpi荧光信号由强变弱。病毒蛋白在细胞浆内的聚集数量与细胞浆中RNA含量成正相关。【结论】首次建立了CSFV RNA可视化原位杂交检测技术,并对CSFV强致病力毒株在细胞中的RNA定位分布进行了研究,发现病毒RNA吸附和进入靶细胞的时间早于0.5hpi,观察到CSFV RNA有在细胞核内的生活史。     

关于贝类遗传改良几个问题的讨论

贝类大多为雌雄异体,少数种类是雌雄同体,在雌雄异体的种类也有部分个体表现为雌雄同体,而且雌雄异体型贝类还常有性转变现象。养殖贝类大多行体外受精并具有配子量大、子裔数量多等特点。野生型贝类表型方差大,遗传变异水平高。可见,贝类是一群比较独特的动物,其生殖方面的某些特性与作物的共同点甚至超过与高等动物的共同点。因此仅依靠脊椎动物或植物的育种方法,难以解决好贝类的种质改良问题。     

麦类作物DNA原位杂交及其在远缘杂种染色体分析中的应用

 应用生物素标记的物种基因组DNA探针和克隆的专化性探针，对六倍体小黑麦双二倍体及其杂种和八倍体小麦簇毛麦双二倍体及其杂种进行了染色体DNA原位杂交。结果表明，应用这两种探针均可以准确地检测出小麦远缘杂种中的异源染色体和染色体片段。先后对二个六倍体小黑麦双二倍体（Badger、M#-2A）、一个八倍体小簇麦双二倍体、三个小黑麦易位系（宁麦8026、Amigo、Apollo）、一个小黑麦代换系（84056）和二个小簇麦附加系（94009-5-4、94009-5-9）进行原位杂交和异源染色体的检测，均获得较好的结果。此外，还讨论了应用生物素标记的探针进行原位杂交可能出现的一些技术问题。     

湿地松与加勒比松杂交制种技术

广东省林业科学研究院系统开展湿地松（Pinus elliottii Engelmann）与加勒比松（P．caribaea Morelet）杂交育种的工作始于20世纪90年代。文章在以往杂交育种研究和实践的基础上,总结了一套加勒比松花粉的收集、处理、保存、人工控制授粉和球果与种子的收集、处理、贮藏等技术方法。该技术可为其它针叶树种的人工制种提供技术和方法上的参考。     

西门塔尔牛改良延边本地黄牛效果分析

为了研究西门塔尔牛对本地黄牛的改良效果。利用西门塔尔牛冻精为本地黄母牛人工授精,测定了3日龄、6月龄和12月龄西本F1公、母牛的体尺、体重、并与相应年龄性别的本地黄牛进行比较。结果发现：西本F1公、母牛各项指标均显著或极显著地高于本地黄牛,表明利用西门塔尔牛冻精杂交改良本地延边黄牛是切实可行的。