Correlation of ribonuclease zymograms and incompatibility genotypes in almond

Proteins were extracted from styles of 29 self-incompatible cultivars of almond and separated using non-equilibrium pH gradient electro-focusing, and the gels were stained for ribonuclease activity. Mutually incompatible cultivars had similar banding patterns and, for the 24 cultivars already genotyped in France or California, the bands correlated well with the reported alleles. The band corresponding to S₁ of the French labelling system was indistinguishable from that corresponding to S_b of the Californian labelling system, and a controlled cross confirmed that these alleles are identical. The band corresponding to the Californian S_a was distinct from the bands corresponding to French alleles and, to harmonise the allele labels, it was redesignated S₅. The genotypes of five uncharacterised self-incompatible cultivars were inferred from zymograms as follows: ‘Desmayo Largueta’ and ‘Glorieta’, S₁S₅, ‘Masbovera’, S₁S₉, ‘Tarragones’, S₂S₉, and ‘Tokyo’, S₆S₇. The alleles designated S₆ and S₉ have not previously been reported. Nine self-compatible cultivars or selections were analysed, and each showed a band corresponding to an incompatibility allele as well as a common band; however, the correspondence of this common band to S_f, the allele for self-compatibility, is unproven. This revised version was published online in July 2006 with corrections to the Cover Date.     

农村籍学生在研究生阶段面临的教育公平问题

主要从研究生入学机会、学习过程、毕业后走向三个方面来描述并分析了农村籍学生在研究生阶段所面临的教育公平问题。     

加入世贸山西小麦生产发展的战略构想

根据山西粮食安全及经济发展的需要 ,在入世的大背景之下 ,研究了山西小麦的生产问题。通过省内外、国内外市场的调研、预测与分析 ,明确了入世后山西小麦面临的挑战与机遇 ;首次提出并论证了占领省内市场 ,实现自给平衡的可行性 ,构筑了未来发展的大体框架 ;提出了小麦生产“三大支撑体系”的概念 ,并以此为切入点 ,深刻分析了山西小麦生产存在的深层次问题 ;建立起加入世贸山西小麦自给平衡的战略体系 (战略方针 +战略对策 ) ,为入世后政府的小麦生产决策提供了依据。     

羊草自交不亲和性初步研究

在自然条件下进行羊草自交、异交结实性实验。采用FDA染色法检测羊草小孢子活力，观测雌、雄蕊发育的时空特点。结果表明，在草原上羊草异交结实率远大于其自交结实率。在成熟花药中有生活力的花粉平均达95．2％以上。在发育时间顺序和空间结构上，雌、雄蕊并不妨碍自体授粉。另外，利用禾本科植物自交不亲和性（SI）有关的硫氧还蛋白h基因设计的引物在羊草DNA中检测到预期片断。因此，笔者认为，羊草自交不结实或结实率低的主要原因可能在于基因控制下的自交不亲和反应机制，硫氧还蛋白h基因可能与羊草的自交不亲和性有关。这仅为初步结论，仍需在细胞学和分子生物学方面取得更多的依据。     

利用蛋白激酶抑制剂和激活剂调控甘蓝自交不亲和性

 利用蛋白激酶抑制剂( 槲皮素) 和蛋白激酶激活剂( 佛波酯) 分别对甘蓝自交不亲和系与自交亲和系花蕾进行田间处理。结果表明, 槲皮素处理后的自交不亲和系的自交亲和指数与对照相比有所提高, 甚至转变为自交亲和系; 而佛波酯处理后的自交亲和系的自交亲和指数与对照相比有所降低, 甚至转变为自交不亲和系。差异显著性测验结果表明处理与对照之间在结荚率和自交亲和指数上均有显著差异。这为化学调控自交不亲和性提供了新方法。     

人工合成甘蓝型油菜的繁育特性与试管繁殖

通过甘蓝品种(2n=18，CC)与白菜品种(2n=20，AA)杂交并借助胚珠培养和染色体加倍，获得一系列人工甘蓝型油菜新品系。对18个人工合成甘蓝型油菜新品系的花粉育性、自交结实性、异交结实性等研究表明，人工油菜品系花期自交不结实或结实率很低。蕾期自交一朵花平均获3．6粒种子，平均结角率为19．7％。但是，人工甘蓝型油菜无论作父本还是作母本与天然甘蓝型油菜杂交的结实率都较高。以人工油菜作父本与天然油菜杂交。42个组合平均杂交一朵花获得10．3粒杂交种子；以人工油菜作母本与天然油菜杂交，15个组合平均杂交一朵花获得8．5粒杂交种子。分析结果表明。本试验的人工油菜品系具有很强的自交不亲和性，蕾期自交结实率也较低，但对异交结实影响不大，因此可以直接用于杂种生产。试验对自交结实特别困难的5个人工甘蓝型油菜新品系进行了试管繁殖，采取子叶、下胚轴和茎尖联合培养方式。22株无菌苗经过2个月快繁，获得260株苗。平均繁殖系数为12．4。不同基因型繁殖系数差异较大。变幅为3．3～21．0。     

Genetic and Geographic Patterns of Duplicate DPL Genes Causing Genetic Incompatibility Within Rice: Implications for Multiple Domestication Events in Rice

Strong genetic incompatibilities exist between two primary rice subspecies,indica and japonica.However,the wild ancestors of rice,O.nivara Sharma et Shastry and O.rufipogon Griff.,are genetically compatible.How this genetic incompatibility became established has not been clearly elucidated.To provide insights into the process,we analyzed a pair of hybrid sterility genes in rice,DOPPELGANGER 1(DPL1)and DOPPELGANGER 2(DPL2).Either of the two loci can have one defective allele(DPL1-and DPL2-).Hybrid pollen carrying both DPL1-and DPL2-alleles is sterile.To explore the origination of DPL1-and DPL2-,we sequenced the DPL1 and DPL2 genes of 811 individual plants,including Oryza sativa(132),O.nivara(296)and O.rufipogon(383).We then obtained 20 DPL1 and 34 DPL2 sequences of O.sativa from online databases.Using these sequences,we analyzed the genetic and geographic distribution patterns of DPL genes in modern rice and its wild ancestors.Compared with the ancestral populations,DPL1-and DPL2-showed reduced diversity but increased frequency in modern rice.We speculated that the diversity reduction was due to a historic genetic bottleneck,and the frequency had likely increased because the defective alleles were preferred following this artificial selection.Such results indicated that standing variances in ancestral lines can lead to severe incompatibilities among descendants.Haplotype analysis indicated that the DPL1-haplotype of rice emerged from an O.nivara population in India,whereas the DPL2-haplotype emerged from O.rufipogon in South China.Hence,the evolutionary history of DPLs conforms to the presumed multiple domestication events of modern rice.     

Horizontal transmission of hypoviruses between vegetative compatibility types of <Emphasis Type="Italic">Cryphonectria parasitica</Emphasis> in Macedonia

Biological control of chestnut blight with hypovirulence depends on the successful transmission of hypoviruses between individuals of the chestnut blight fungus, Cryphonectria parasitica. Vegetative incompatibility inhibits horizontal virus transmission, but not completely. In an effort to assess the potential for the spread of hypoviruses in the Republic of Macedonia, we studied the transmission of Cryphonectria hypovirus 1 (CHV-1) among the five observed vegetative compatibility (vc) types of C. parasitica. One fungal isolate of each vc type was infected with CHV-1 and was paired in vitro with isolates of all other vc types for a total of 20 combinations of virus donors and recipients, and 250 replicate trials per combination. Virus transmission was scored after 7 days as successful if the recipient isolate took on an unpigmented culture phenotype typical of virus infection. Transmission occurred at high frequencies between some pairs of vc types, but in <1% of the trials for 10 of the 20 combinations of donors and recipients. Asymmetric transmission was observed between some vc types that had different alleles at vegetative incompatibility loci vic1 or vic7; i.e., transmission occurred at high frequencies in one direction, but very low frequencies between the same pair of isolates in the opposite direction. The expected virus transmission, calculated as the average transmission predicted for any two randomly chosen individuals from a population, was highly negatively correlated to vc type diversity. Results for isolates of C. parasitica from Macedonia were similar to those from Italy, but less transmission was generally observed. Differences in genetic background effects on transmission may vary among different populations even when isolates differ by the same vic alleles.     

SFB‐based S‐haplotyping of apricot (Prunus armeniaca) with DHPLC

Most cultivars that belong to the Rosaceae are self‐incompatible and depend on cross‐pollination. The pollen donor and pollen recipient have to flower synchronously and must be genetically compatible. Genetic compatibility is governed by the S‐locus, which holds the S‐RNase and S‐haplotype‐specific F‐Box (SFB) genes. Thus, the S‐genotype of cultivars is an important feature and is characterized molecularly by the S‐RNase and SFB alleles which are distinctive for each S‐haplotype. Here, we report the usage of DNA chromatography (denaturing high‐performance liquid chromatography – DHPLC) for identifying the S‐genotypes of European apricots on the basis of their SFB alleles. DHPLC is amenable to high‐throughput automation, and therefore is valuable for breeding and for high‐quality plant typing in the nursery.