Statistical discrimination between pollen tube growth and seed set in establishing self incompatibility in Gaura lindheimeri 1

The University of Minnesota Gaura breeding program is developing USDA Z3-4 winter-hardy genotypes via interspecific hybridization of G. lindheimeri (Z5-6) and G. coccinea (Z2-4). Prior to commencing interspecific hybridization, the reproductive barriers operating in both parental species need to be characterized. The objective of this research was to determine the type and stability of reproductive barriers operating in G. lindheimeri by statistical comparisons between pollen tube growth and seed set in a full-sib diallel. Slowed or aborted pollen tube growth in the style indicated the presence of a gametophytic self incompatibility (SI) system. A statistical method, female (FCC) and male (MCC) coefficients of crossability, was used to verify that a stable SI system was operating and that other reproductive barriers were present. Several genotypes also expressed stage-specific inbreeding depression and incongruity. The simple linear regression equation for FCC/MCC, using pollen tube growth, was Y = 0.0124 + 0.974X, which was much closer to the expected Y = 0.0 + 1.0X (indicating a stable SI system) than the equation for seed set, Y = 0.012 + 0.910X. Using pollen tube length, both general combining ability (GCA) and specific combining ability (SCA) values were highly significant for G. lindheimeri (P ≤ 0.001). Histograms were used to delineate cut-offs to identify intra-incompatible/inter-compatible classes and S allele groups. Four possible classes were identified, but further research is needed to verify S allele genotypes.Scientific Research Paper No. 031210120 of the Department of Horticultural Science. This research was supported by a grant from the Perennial Plant Association and, in part, by the Minnesota Agricultural Experiment Station     

水稻同源多倍体自交回复后代中二倍体的育种利用

[目的]利用水稻多倍体自交回复创制优良二倍体育种材料。[方法]同源多倍体自交回复后代中出现二倍体植株,在其分离后代中,通过系统选择,选择其中稳定的优良二倍体材料与三系、两系不育系进行广泛测交配组,对具有较强杂种优势的水稻进行考种。[结果]Y58S/10-C242、Y58S/10-C256、C815S/12-C156、C815S/13-C96的杂种一代具有一定的杂种优势。[结论]多倍体自交回复后代中的优良二倍体植株可为杂交稻选育提供优良亲本材料。     

梨自花及异花授粉对其花柱自发荧光的影响

 利用激光共聚焦显微技术研究了砂梨(Pyrus serotina Rehd．)品种‘丰水’ 自花授粉和异花(‘二十世纪’)授粉16 h后花柱自发荧光的分布规律。发现未授粉花柱整体的自发荧光比较弱。但从柱头端向子房端花柱自发荧光呈上升趋势;异花授粉和自花授粉后花柱整体的自发荧光都有所增加;授粉后自发荧光变化最大的部位在柱头区域; 自花授粉后,在柱头及距柱头0～400an范围内荧光值较高,其他区域的荧光值相近;而异花授粉后在花柱的中部(距柱头1500～2050an范围内)荧光值最低; 自花授粉后自发荧光除柱头以外主要分布在花柱的边缘区域;异花授粉后自发荧光在花柱上半部的分布情况与自花授粉类似,下半部分布相对均匀。关键词：中图分类号： 文     

Low diversity of vegetative compatibility types and mating type of Cryphonectria parasitica in the southern Balkans

The diversity of vegetative compatibility (vc) types and mating type was estimated in populations of the chestnut blight fungus, Cryphonectria parasitica , throughout Macedonia and from selected areas in Greece. Nearly all of the 786 isolates (94%) from Macedonia were in a single vc type, EU-12; all 379 isolates from Greece were EU-12. Only six of 20 populations in Macedonia had more than one vc type. The diversity of vc types in the most diverse populations of Macedonia was comparable with the least diverse populations found previously in Italy. All but six of the 313 isolates assayed had the same mating type, MAT-1 , and no perithecia of Cryphonectria parasitica were observed in any population. These results lead to the conclusion that sexual reproduction does not occur in these populations. The lack of vc type diversity may indicate a high potential for the spread of hypoviruses and successful biological control with transmissible hypovirulence. However, if sexual reproduction should occur in Macedonian populations, up to 32 vc types would be possible by recombination among vegetative incompatibility loci.     

Mating Behaviour and Vegetative Compatibility in Spanish Populations of Botryotinia fuckeliana

Mating behaviour and vegetative compatibility were studied in Spanish populations of Botryotinia fuckeliana. Fifty-seven isolates out of the 61 tested were sexually fertile with one or more of the reference strains of known mating type (MAT1-1 or MAT1-2). Thirty-nine isolates were heterothallic, giving fertile crosses when mated with the MAT1-1 (24 isolates) or the MAT1-2 (15 isolates) reference strain. Eighteen isolates crossed successfully with both MAT1-1 and MAT1-2 reference strains, and were referred to as homothallic or MAT1-1/2. Both mating types were widespread, being represented in isolates from two regions, from the same and different greenhouses, from different hosts, and from different years of isolation. Isolates were paired on Malt Extract Agar + NaCl to evaluate vegetative compatibility. Most of the paired isolates were unable to fuse and showed a different reaction of incompatibility. Nitrate-non-utilising (nit) mutants were selected by growth on a medium amended with 30–50gl^–1 potassium chlorate. Over 600 chlorate-resistant sectors were recovered from 40 isolates at a mean frequency of 0.15–2.39 sectors per colony, but only 11% were identified as nit mutants by their thin growth with no aerial mycelium on minimal medium. However, most of these nit mutants reverted to wild type during six months of storage on chlorate-amended medium. Genetic complementation between nit mutants occurred only in two cases between mutants from the same isolate.     

Microtubule dynamics in compatible and incompatible interactions of soybean hypocotyl cells with Phytophthora sojae

The arrangement of microtubules in soybean ( Glycine max ) cells was examined during compatible and incompatible interactions of hypocotyls of soybean cv. Harosoy (susceptible) and cv. Haro 1272 (resistant) with race 1 of the soybean-specific pathogen Phytophthora sojae . Both reaction types were similar during the first 3 h after zoospore inoculation in terms of the number of cells penetrated, and depth penetrated into the cortex. By 3 h postinoculation, clear differences had developed between the two interaction types: incompatible interactions were characterized by a hypersensitive response that was confined to single penetrated cells; while compatibly responding cells appeared unchanged. Both types of response were characterized by autofluorescence of cell walls or cytoplasm and, at 6 h after inoculation, complete disorganization of cell cytoplasm. Reorientation and loss of microtubules was seen in the early stages of the incompatible interaction in association with cellular hypersensitivity, but not in compatible responses. In cells adjacent to those that reacted hypersensitively, there was little evidence of change in microtubule orientation. Treatment of hypocotyls with the microtubule depolymerizer oryzalin prior to inoculation did not alter the compatible response, but led to breakdown of the incompatible response. Changes in microtubule orientation and state are thus among the first structural changes that are visible within cells during incompatibility in this system.     

Production of diploid and triploid interspecific hybrids between Lilium concolor and L. longiflorum by in vitro ovary slice culture

Successful hybridization between Lilium concolor and Lilium longiflorum has not been reported but ovary slice culture technique, after cut-style pollination has now been used to produce diploid and triploid interspecific hybrids between these species. Reciprocal crosses between diploid cultivars (2n= 2x= 24) were conducted. 5, 10, 15, 20, 25, 30, 35, 40, and 45 days after pollination (DAP), ovaries were sliced and cultured on a modified Murashige and Skoog (MS) medium without growth regulators and NH₄NO₃, supplemented with 6% sucrose, 50 mg/1 yeast extract and 0.25% gelrite at pH 6.3. For the L. concolor × L. longiflorum cross, embryo germination was found to be best at 20 DAP, while for the L. longiflorum × L. concolor at 25 DAP. After transfer to a MS (half-strength) medium supplemented with 1.5% sucrose, 0.25% gelrite and 0.2% active charcoal at pH 5.8, diploid and triploid hybrid plants were developed. All regenerated plants were identified as hybrids on the basis of karyotype and isozyme analyses. Ovary slice culture technique as a method of producing polyploids is discussed.     

黑木耳白色品种的选育

将收集到的黑木耳(Auricularia heimuer)白色变异菌株进行分离、纯化和栽培,选择性状理想的纯白色菌株,收集孢子,经自交纯合,获得稳定遗传的纯白色黑木耳菌株JAUH-W-591。通过形态学观察,结合分子生物学分析方法对该菌株进行鉴定,确定其为黑木耳的白色变种。实验表明,JAUH-W-591菌丝生长的最适碳源为乳糖,最适氮源为酵母浸粉,最适培养温度为25~28 ℃,最适pH为6.5。生产实验结果表明:新品种JAUH-W-591的平均产量为每袋干重53.5 g,较对照平均增产7.1%,具有较明显的商品优势和栽培价值。     

论电荷自能的总和大于电荷之间的互能

在静电学中提出了电场能等于带电体系的自能与互能之和,但并未对自能的总和永远大于互能作更进一步的论证。本文从特殊情况出发,论证了这个问题。这对于深刻理解电场能的本质,具有重要的意义。