三结合育种方法在小麦优异种质创育中的应用

为创建新型的小麦基因体系,并为性状改良和新品种选育提供丰富的种质资源,利用远缘杂交、多倍体育种和电离辐射三结合的育种方法,进行了37 a的小麦超亲遗传及新种质创育工作。结果表明,三结合育种后代品系的染色体数量变异和结构变异幅度大,趋向双亲性状类型的分离较少而超亲遗传突出,后代种质分离持续时间长,不少具有较好的综合性状,籽粒产量和品质较常规育种后代显著提高。研究证明,三结合育种方法既克服了单纯的远缘杂交、多倍体育种或辐射育种方法的缺点,又综合了它们的优点,为丰富小麦种质资源和提高小麦育种效率开辟了一条新途径。     

盐胁迫对小麦代换系幼苗叶片保护酶活性影响及染色体效应

为研究盐胁迫对小麦代换系酶活性的影响,以中国春-Synthetic 6x 染色体代换系及其亲本为材料,通过测定在盐处理条件下幼苗抗氧化酶SOD、POD活性和丙二醛（ MDA）含量变化,并对其相关耐盐特性的基因进行染色体定位。采用霍格兰营养液水培法,设置对照（0 mmol/L NaCl）和盐处理（150 mmol/L NaCl）,在幼苗两叶一心时进行处理,四叶一心时取样,分别测定对照和盐处理条件下幼苗的SOD和POD活性以及MDA含量。在盐胁迫条件下,小麦代换系幼苗SOD和POD活性显著升高,丙二醛含量降低。其中,1A、5A、6A、1B、5B、6B、7B和5D代换系的SOD活性显著或极显著高于母本中国春,2A、1B、2B、3B、5B、6B、5D和6D代换系的相对SOD 活性显著或极显著高于母本中国春;3A、4A、5A、6A、7A、6B和7D代换系的POD 活性显著或极显著高于中国春,4A、5A、6B、1D和7D 代换系的相对POD活性显著或极显著高于中国春。由于保护酶的作用,在盐胁迫条件下,多数代换系MDA含量明显减少,2A、3A、4A、6A、1B、3B、4B、5B、6B、7B、1D、5D和7D代换系的MDA含量显著或极显著低于母本中国春,2A、6A、6B、1D和2D代换系的相对MDA含量显著或极显著低于母本中国春。 Synthetic 6x 的1B、5B、6B 和5D 染色体上可能存在诱导幼苗SOD活性增强的基因,4A、5A、6B和7D染色体上可能存在诱导幼苗POD 活性增强的基因,抑制幼苗MDA含量增高的基因可能存在于2A、6A、6B和1D染色体上。     

大赖草染色体对小麦光合特性和产量性状的效应

大赖草是改良小麦的重要近缘植物,目前已育成多个小麦-大赖草二体附加系和代换系,然而对大赖草染色体的光合效应和对产量性状的效应却研究较少。因此,了解大赖草染色体的效应,对进一步利用大赖草外源基因具有指导作用。通过光合仪测定和产量性状调查,对小麦-大赖草二体附加系、代换系和亲本中国春进行了鉴定,结果表明,10个异染色体系的净光合速率均低于对照普通小麦中国春,但多数差异不显著。大赖草E染色体具有增加水分利用效率的正向效应。大赖草E、J染色体能够提高小麦单穗粒重和千粒重,对提高小麦产量具有正效应。     

Genetic diversity of the Mexican Lidia bovine breed and its divergence from the Spanish population

Lidia bovine breed exists since the XIV century in the Iberian Peninsula. These animals were initially produced for meat but some, showing an aggressive behaviour which difficulted their management, were used to participate in popular traditional and social events. A specialization of the breed giving rise to the original Lidia population is documented in Spain since mid-XVIII century. Following the same tradition than in the Spanish population, Mexico used aggressive animals at the beginning of the XX century until two families of breeders started importing Lidia breed bovines from Spain with the aim of specializing their production. Each family (Llaguno and González) followed different breeding managements, and currently, most of the Lidia Mexican population derives from the Llaguno line. Although genetic structure and diversity of the Spanish population have been studied (using autosomal microsatellite markers, Y chromosome DNA markers and mitochondrial DNA sequences), the Mexican population is not analysed. The aim of the study was to assess both the genetic structure and diversity of the Mexican Lidia breed and its relationship with the original Spanish population using the same molecular tools. A total of 306 animals belonging to 20 breeders issued from both existing Mexican families were genotyped, and the genetic information was compared to the previously existing Spanish information. Slightly higher levels of genetic diversity in Mexican population were found when comparing to the Spanish population, and the variability among populations accounted for differences within them showing mean values of 0.18 and 0.12, respectively. Animals from the Mexican breeders, belonging to each of the two families, clustered together, and there was little evidence of admixture with the Spanish population. The analysis of Y chromosome diversity showed a high frequency of the H6 haplotype in the Mexican population, whereas this haplotype is rare in the Spanish, which is only found in the Miura (100%) and Casta Navarra (38%) lineages. Mitochondrial DNA revealed similar haplotypic pattern in both Spanish and Mexican populations, which is in accordance with most of the Mediterranean bovine breeds. In conclusion, as the Mexican Lidia population had initially a small number of founders and its current population has been reared isolated from their Spanish ancestors since a long time, these bottleneck effects and a combination of mixed cattle origin are the factors that might erase any trace of the Spanish origin of this population.     

植物染色体制片中疑难问题的解析

用传统和改进的染色体制片技术,以油菜、水稻和芝麻的根尖为材料,分析了染色体数目多、形态小和细胞质较浓植物的染色体制片过程中存在的常见疑难问题,如中期分裂相少、染色体不易着色等,并提出了解决方案。     

药用植物刺五加根尖压片技术研究

[目的]研究药用植物刺五加根尖的压片技术。[方法]以刺五加幼苗根尖为试材,通过压片试验研究取材时间、预处理液浓度、预处理时间、固定和保存、解离时间和染色条件对根尖压片效果的影响。[结果]最佳取材时间为9：30～10：30和13：30～14：30;用0．10％秋水仙素处理2．5和3．0h的材料的中期和前中期细胞增多;固定根尖2．0～4．0h对后续操作没有显著影响;60℃下解离10min以上根尖的细胞膜破裂较多,解离8min以下的根尖的细胞壁没有破碎,镜下观察细胞呈方形,无膨胀。室温下解离15min以上和12min以下的解离效果都不理想。室温下用1mol／L盐酸解离根尖15rain,然后用改良的石炭酸品红染液进行染色,通常染色10min左右即可达到较好的染色效果。[结论]该研究为刺五加的染色体核型分析提供了技术支持。     

早熟禾族3种基因型草坪草的染色体核型分析

通过对禾本科早熟禾族(Poeae)匍匐翦股颖(帕特putter)和多年生黑麦草(首相premier、焦点focus)3种草坪草染色体核型进行分析,结果显示,3种基因型材料的染色体均以中部着丝点和近中部着丝点染色体为主,都具有随体。匍匐翦股颖帕特体细胞染色体数目为30条,核型公式是2n=30=22m(2SAT)+2sm,核型不对称系数(AS.K%)55.2%,分类标准属于“2C”型;多年生黑麦草2个品种草坪草体细胞染色体数目均为14条,其中首相核型公式是2n=14=12m(2SAT)+2st,核型不对称系数58.0%,核型分类标准属于“2C”型;焦点核型公式是2n=14=6m(2SAT)+8sm,核型不对称系数63.05%,属于“2B”型。     

水对蚕豆根尖细胞有丝分裂的影响

[目的]为饮用水的处理提供依据。[方法]以蚕豆根尖细胞为材料,采用微核试验方法,以蒸馏水处理为对照,研究凉开水及分别放置0、12、24、36、48h的自来水对蚕豆根尖细胞微核千分率和染色体畸变率的影响。[结果]随着自来水放置时间的延长,蚕豆根尖细胞的微核千分率和染色体畸变率逐渐降低,放置0、12、24h的自来水诱发蚕豆根尖细胞的微核千分率和染色体畸变率均明显高于对照和放置36和48h的自来水处理。不同放置时间自来水处理后,蚕豆根尖细胞产生多种类型畸变,如间期微核、前期微核、染色体断片等。[结论]凉开水对染色体的损伤小于自来水,放置0h的自来水对蚕豆根尖细胞的遗传毒性较大。     

Variation in kernel characteristics and protein molecular weight distribution of Langdon durum-wild emmer wheat chromosome substitution lines

Triticum turgidum L. var. dicoccoides (DIC) provides a useful source of genes to improve agronomic and quality characteristics of durum wheat. Research was performed to identify DIC chromosomes that carry useful genes for quality improvement. Langdon-T. dicoccoides substitution lines consisting of 13 lines based on DIC accession PI 481521, 10 lines on PI 478742, and 2 lines on Israel A were evaluated for kernel characteristics and protein molecular weight distribution. DIC chromosomes 3A from PI 481521, and 1A and 7A from PI 478742 increased kernel hardness. Chromosome 2A from PI 481521 increased kernel weight, which resulted in increased semolina yield. Some substituted DIC chromosomes also affected grain protein concentration and protein molecular weight distribution. For example, chromosomes 2A, 5B, and 7B from PI 481521, and 6B from Israel A increased total protein concentration, which was primarily attributed to an increase of SDS soluble gliadins. Chromosome 6B from PI 478742 was unique in that it led to an increase in SDS insoluble high molecular weight polymeric proteins, which contributed to increased dough mixing strength. Results from this research indicated that chromosome 6B from PI 478742 is a potential gene source to improve dough characteristics of durum wheat by increasing insoluble high molecular weight polymeric protein concentration.     

用基因组原位杂交方法分析甘蔗-斑茅杂种及回交后代的染色体组成

斑茅(Erianthus arundinaceus Retz)是甘蔗的近缘属植物,具有多种优良特性,是甘蔗育种的重要种质资源之一。本实验使用基因组原位杂交(GISH)技术分析了甘蔗-斑茅杂种及回交后代F1、BC1和BC2的染色体构成与传递行为。结果表明:在F1代,来自斑茅HN92-77的染色体数目介于28～30条,来自热带种Badila的染色体数目介于38～40条,体细胞染色体数为2n=68～70,基本符合n+n的染色体传递方式;在BC1和BC2代,来自斑茅的染色体数分别为22～28条和13～15条,来自甘蔗的染色体数分别是87～94条和98～101条,其体细胞染色体数2n分别为110～121条和112～115条,基本上分别符合2n+n和n+n的染色体传递方式。在所观察的渐渗系中,均存在有染色体丢失的现象,但未观察到染色体发生交换与重组。