木薯有性四倍体遗传稳定性分析

木薯作为中国重要的经济作物,其优良品种的选育一直是木薯科研工作的重点,而多倍体的巨型性特点为其育种提供了新的思路,目前多倍体研究大多是体细胞加倍,有性多倍化研究起步较晚,而本课题组通过2n配子有性活体杂交,成功获得了首例木薯有性四倍体植株。为了研究木薯有性四倍体的遗传稳定性,本研究分别采用:田间的农艺性状观测(生长稳定期)、流式细胞术、叶片染色体计数、蛋白质含量测定/蛋白质聚丙烯酰胺凝胶电泳以及淀粉含量测定等方法进行鉴定。结果显示:木薯有性四倍体各株系农艺性状均保持了母株器官巨型性的多倍体特征;流式细胞仪分析显示,木薯有性四倍体各株系叶片DNA含量均为二倍体亲本(SC5)的两倍,相对应的叶片染色体数目也为二倍体亲本(SC5)的两倍,且视野中四倍体细胞所占比例均在90%以上;各株系蛋白质含量均小于二倍体对照组,且有性多倍体株系电泳谱带基本相似;在淀粉含量测定中,其各株系淀粉含量均小于对照组,且各株系之间含量波动较小。本研究结果表明木薯有性四倍体植株具有较好的遗传稳定性,对木薯多倍体品种的选育具有重要意义。     

Comparison of selection methods among and within full-sibling progenies in Urochloa humidicola

Hybridization in the Urochloa humidicola breeding programme allowed to explore the genetic variability of the apomictic sources and, thus, to obtain new sexual and apomictic parents with compatible ploidy and/or superior progenies. However, given the high variability arising from crosses, there is a need to adopt efficient selection strategies among and within progenies. The aim of this study was to compare the selection methods among U. humidicola progenies with (t-BLUP) and without (BLUP) the weighting based on prediction error and subsequent selection within progenies by individual simulated (BLUP_IS) or optimal individual BLUP. We evaluated seventy-one U. humidicola full-sib progenies from biparental crosses between nine sexual and ten apomictic parents. The experiment was set up in an incomplete block design with 64 blocks of 15 plots each, consisting of individual plants. Seven consecutive cuts were made and the traits total dry-matter, leaf dry-matter and regrowth scores were measured. Genetic variance was expressive for all traits. The selection procedure among progenies of U. humidicula based on t-BLUP proved to be more advantageous regarding the use of BLUP not weighted by the prediction error, resulting in higher selection gains, taking as reference the optimal procedure of the individual BLUP. Furthermore, the use of BLUP_IS allowed an optimized selection of hybrids, allowing the breeder to explore with variable selection intensity the genetic variability within the selected full-sib progenies based on relative genetic merit.     

四倍体及二倍体毛泡桐截干再生特性研究

为掌握人工诱导四倍体毛泡桐保持多倍体特性情况及毛泡桐截干再生特性,笔者以5a生四倍体及二倍体毛泡桐截干再生苗为材料,对截干再生苗的倍性、出芽数、生长速率、叶片特性、叶绿素含量及光合特性等进行研究.结果表明:四倍体毛泡桐截干再生苗能很好地保持其多倍体倍性,相对于二倍体来说,出芽数较少,生长较缓慢;气孔增大,气孔密度降低;...     

离体培养条件下金鱼草多倍体诱导研究

在离体培养条件下 ,研究了秋水仙素不同浓度、不同处理时间对金鱼草实生苗的诱变效果。结果表明 ,金鱼草多倍体诱导容易成功 ,0 1%～ 0 2 %秋水仙素处理 12～ 36h均能成功地诱导出金鱼草多倍体。以二倍体金鱼草为对照 ,对四倍体金鱼草形态特征和光合作用特性进行了初步研究。结果表明四倍体金鱼草叶色浓绿、叶片肥厚 ,特别是花形巨大 ,花瓣厚而挺 ,花色艳丽 ,气孔和花粉粒比二倍体显著增大。且四倍体金鱼草的净光合速率、蒸腾速率及气孔导度均比二倍体高。另外 ,还进行了四倍体与二倍体的杂交试验 ,获得了三倍体金鱼草。     

Cross Breeding of Populus and Its Hybrids for Cold Resistance

Populus tomento a was crossed with P. tremuloidis, P grandiden ata, P. lba × P. grandidentata and P. alba × Ulmus s . ta pumila in order to maintain its rapid growth and high wood quality and improve its resistance to cold. Two methods were used to increase the germination rate from 1.5% to 41.1% and the remaining rate from 1.7% to 44.2%. Forty crossing combinations were conducted and 2 744 hybrid seedlings were obtained. MX. t4 × P grandiden ata (G-1-58), MX3 × P. tremuloidis (T-44-60), MX2 × P. tremuloidis (l-13-87-37) and MX2 × (P. alba × P. grandidentata) were regarded as superior combinations after analysis and selection. Thirty seedlings of these combinations and 11 triploid seedlings identified by counting their chromosomes were selected as super plants.     

First feeding of diploid and triploid yellowtail tetra Astyanax altiparanae: An initial stage for application in laboratory studies

In this study, the aim was to establish a protocol for first feeding of diploid and triploid yellowtail tetra Astyanax altiparanae in laboratory conditions. The fry were fed with five different diets: (i) Artemia franciscana nauplii, (ii) plankton, (iii) dry food, (iv) Artemia franciscana nauplii + plankton, and (v) Artemia nauplii + plankton + dry food. Additionally, the growth and survival rates of diploid and triploid individuals were also evaluated. On day 10, the length of the fish between the treatments differed significantly (p = .0001) and ranged from 4.07 ± 0.06 mm (dry food) to 8.50 ± 0.64 mm (plankton + Artemia). The sizes of the fish increased with time, except for the fish fed with dry food. The survival rates were similar for the fish fed with the four diets and ranged from 80.7 ± 5.4% (dry food + plankton + Artemia to 92.0 ± 1.6% (plankton + Artemia), but differed from the fish fed with dry food (17.7 ± 5.8%, p = .0017). Diploids and triploids did not present differences on day 0 (p = .2252) and on day 10 (p = .4844) when the fish presented 6.77 ± 0.25 mm and 6.54 ± 0.15 mm respectively. Survival of diploids (87.3 ± 5.13%) and triploids (74.67 ± 2.30%) were also similar (p = .0285). These data are innovative and useful for establishing protocols for this species in both academic and applied sciences.     

基于体细胞胚发生的细叶百合和兰州百合多倍体诱导及鉴定

以细叶百合（Lilium pumilum DC. Fisch.）和兰州百合（Lilium davidii var. unicolor）的鳞片和胚性愈伤组织作为诱导材料,用不同浓度秋水仙素以浸泡和混培两种处理方式进行多倍体诱导。以形态学观测、根尖染色体计数、气孔观测对多倍体植株进行倍性鉴定,分别获得了19株细叶百合四倍体植株和6株兰州百合四倍体植株,最佳处理方式为0.1%秋水仙素浸泡胚性愈伤组织24 h。使用ISSR对经体细胞胚发生的二倍体和多倍体再生植株进行遗传分析,发现两种百合二倍体植株遗传较稳定,而多倍体植株均发生遗传变异,其中细叶百合和兰州百合遗传变异率分别为15.48%和9.75%。     

连翘多倍体诱导与鉴定

以连翘籽苗为材料,采用秋水仙素溶液处理生长点的诱变,茎尖细胞染色体计数检测及流式细胞仪倍性鉴定等方法,研究了不同浓度秋水仙素对连翘的诱变效果.结果表明:02%的秋水仙素溶液处理连翘籽苗生长点72 h变异株率最高,达到583%,诱导效果最佳.经秋水仙素诱导后形成的多倍体植株叶片变宽变大,叶色变深,茎变粗且节距变大,气孔增...     

西瓜多倍体育种研究进展

综述西瓜多倍体的产生途径、特性特征、鉴定方法及育种的应用与研究新方向。     

生物入侵种喜旱莲子草的染色体核型特征

对外来人侵植物喜旱莲子草(Atlernanthera philoxeroides)的染色体核型进行了分析.结果表明,该入侵种的染色体数为2n=96,属六倍体物种,各染色体间形态差异不明显,均为中着丝粒或近中着丝粒染色体,最长与最短染色体相对长度比为2.10,全套染色体未见随体,核型公式为2n=96=60 m+36 sm,核型类型为进化程度较高的2B型.喜旱莲子草的多倍性特征及2B核型为其生物入侵性提供了重要的细胞学证据,文中同时提出不改变基因组DNA序列结构的表观遗传变异可能是喜旱莲子草成功入侵的重要机制.