Occurrence of viable unreduced pollen in a <Emphasis Type="Italic">Begonia</Emphasis> collection

Polyploidy is widespread in plants and has played a major role in the evolution and diversification of the plant kingdom. Unreduced (2n) gametes are an interesting tool for polyploidisation and the creation of genetic variation in plant breeding. Especially in ornamentals, polyploidisation can broaden attractive features within a species. A Begonia collection was screened on the occurrence of 2n pollen with the aid of four different techniques: pollen size measurement, flow cytometric analysis of nuclei isolated from germinated and non germinated pollen, investigation of the microsporogenesis and analysis of progeny. In ten of the 70 screened genotypes (B. dregei, B. pearcei, B. ‘Anna Christina’, B. ‘Bubbles’, B. ‘Florence Rita’, B. ‘Orococo’, B. ‘Rubaiyat’, B. ‘Spatflacier’, B. ‘Tamo’ and B276), large pollen were observed with a rather spherical than normal ellipsoidal shape. Flow cytometric data proved that these aberrantly shaped pollen were associated with 2n ploidy levels, although they were not always viable. Meiotic aberrations in these large pollen producers resulted mainly in dyads although also monads, triads and polyads were observed. Successful crosses were obtained with B. dregei, B. ‘Orococo’, and B276 as pollinators; DNA content had increased in all or a part of the progeny. The results show that the occurrence of 2n pollen is not a rare phenomenon in Begonia.     

赤眼蜂寄生行为研究(Ⅰ)——过寄生与子代分配

寄生蜂的过寄生现象是经常发生的。Ullyett(1949)认为,一种有效的昆虫寄生蜂,往往以蜂卵在寄主上的分布这种方式来使其达到最高存活率。Smith(1916)指出,由于蜂卵在寄主上的分布不同,形成了过寄生。关于过寄生对寄生蜂种群繁殖率的影响,国     

白榆子代测验的十年结果

本文以河南省选出的白榆优树为材料,平行地进行的半同胞子代和无性系子代测验的结果,表明白榆优树半同胞子代间差异不显著,而且与对照也不显著,这可能是白榆生长条件复杂,选优准确性低和异花授粉又引起入选优树基因重组造成。同一批材料的无性系测验揭示优树的基因型间有极显著差异,因而对异花授粉树种进行无性系选择的育种效果要比现行的以混合选择为依据的种子园途径成本低,选种效率高。无性系测验的决选林龄也可以比家系选择提前。     

Progeny of Eucalyptus globulus Labill ssp. Globulus

The preliminary assessment of progeny test in a seed orchard of Eucalyptus globulus Labill.ssp.globulus at Yipinglang State Farm of Yunnan Province in China was conducted.The trial was composed of 21 replications,with 2 trees on each plot,15 plots in each incomplete block,and 18 incomplete blocks in each replication,laid out in a α-design of 270 open-pollinated families.The families were of three categories (natural populations,local land race and seed orchard).They were further subdivided into 11 regions.The data from an assessment of growth,stem form and other characteristics of the young trees after being planted 2 years were analyzed.Results are as follows:the different categories differed significantly in their growth,with the families from seed orchards being the best.Regions also differed significantly in their growth.The families from the regions of Westem Victoria,Eastern Victoria and all three seed orchards were better than others.The tamilies from Yunnan had the best frost tolerant and its survival was the highest.For growth,stem form and fungal tolerance,the families from Yunnan were similar to that from Southern Tasmania and Eastem Tasmania.Two-tree plots were strongly recommended over singletree plot designs for large-scale progeny trials.     

云南松天然优良林分自由授粉混合种子子代测定

１９８８年在腾冲县古永林场采用完全随机区组设计开展试验。通过７年的观测,试验已显示出天然优良林分子代具有干型通直、木纹理扭转度小、生长量大的特点,其树高、胸径、材积和木纹理扭转度的实际增益分别达到３７４９％、６５６０％、２１９８４％和２６９５７％,遗传增益分别为２０１４％、４０４６％、１０７１１％和５９７９％,目前已远远超过云南松天然优良林分子代遗传增益３％的攻关考核指标。通过试验反馈表明了所制定的“云南松天然优良林分选择方法及标准（滇西）”具有科学性和可靠性。     

马尾松优树子代测定及速生优良家系选择的研究

１９８２年在福建省马尾松优良种源区１６个县天然林中选择２１１株优树,从广西、广东等省（区）引进１８株优树的单株球果,共计２２９个家系。１９８４年在生态上具有代表性的闽北邵武卫闽、闽东南仙游溪口、闽中大田桃源林场营造优树子代测定试验林。逐年调查树高、胸径、病虫害等１０个性状。对多年多点调查数据进行变量分析、相关分析,计算各性状各家系的遗传力、遗传方差、环境方差;进行基因型稳定性分析;运用遗传距离指数理论、聚类分析对参试家系进行综合评价。从中评选出高产稳定型速生优良家系１９个,其材积平均遗传增益为２８．３０％,可在全省马尾松产区推广;１３个适宜闽西北的高产优良家系,材积增益为２１．０７％;１７个适宜闽东南的优良家系,材积增益为２５．５１％。     

白芥和甘蓝型油菜属间杂种后代种子结构比较

白芥具有很多优良的农艺性状,从白芥和甘蓝型油菜属间体细胞杂种后代中筛选出多个具有黄籽或趋向黄籽性状的株系,利用光学显微镜和电子显微镜技术观察它们种子的结构。回交后代种皮解剖结构与甘蓝型油菜相似,而与白芥相差较远。种皮色素主要分布在栅栏层,甘蓝型油菜和部分后代株系中有色素分布,而白芥和部分黄籽后代株系中没有色素分布。栅栏层在甘蓝型油菜中最厚,在白芥中最薄,而后代介于两者之间。回交后代和甘蓝型油菜种皮表面纹饰为网-穴状,白芥为沟槽状或水疱状。胚子叶细胞面积以白芥最小,甘蓝型油菜最大,后代介于两者之间;而蛋白体面积指数以白芥最大,甘蓝型油菜最小,后代介于两者之间。超微结构观察表明,亲本和后代蛋白体均为球状晶体蛋白体,油体有大、小两种,其大小在亲本和后代间有差异。上述结果表明,回交后代株系种子解剖结构与甘蓝型油菜相近,种皮颜色、色泽深浅和栅栏层厚度,以及胚子叶细胞大小、油体和蛋白体等受亲本白芥的影响而发生变化。     

非洲破布木子代测试

非洲破布木是埃塞俄比亚的本土商业木材树种,在自然种群中,存在着巨大的品种变异。由于当地苗圃优良种质资源匮乏,筛选优良母树建立种子园非常必要。该研究从其不同的自然种群中,采集了大量的供试种子样品,对其种子外部特征和在苗圃中发芽率和种苗生长表现,进行了观察;方差分析显示,在所有的研究属性中,不同种源显示出较大的属性差异性,同时初步筛选出适合种子园所需的优树。     

樟子松不同种源对子代林生长的影响

[目的]选择生产力高、适应性强的樟子松种源,提高林地生产力。[方法]从1991年开始选取7个樟子松不同种源进行种源对比试验,造林后分别于1992、2010、2011年对樟子松不同种源子代林生长因子进行调查。[结果]长春净月潭樟子松种源及付家林场母树林种源非常适合付家地区生长,内蒙古红花尔基樟子松种源不适合在该地区生长。[结论]在今后的造林育种过程中应选择长春净月潭樟子松种源和当地母树林种源。     

超甜玉米细胞和组织培养及其后代育种

利用高培养力基因型与甜玉米杂交，其Ｆ１代进行花药培养具有较高的培养力，花粉胚的诱导频率可达２６％．甜玉米基因型通过幼胚培养，建立起２个可长期继代培养，大量再生绿苗的体细胞克隆，并获得了自交结实后代，同工酶分析表明，同一克隆再生植株可产生基因突变．常规高培养力材料与甜玉米杂交后代进行二环系培养，可以筛选出高配合力的超甜玉米自交系。