播期对玉米早代自交系田间抗病性的影响

对1998－2000年4月中下旬（春播）和6月上旬（夏播）种植的1607份玉米早代系进行田间自然抗性鉴定表明：播期对玉米早代系田间抗病性具有很大的影响，玉米早代自交系大斑病和粗缩病以春播发生较重，而小斑病和茎基腐病以夏播发病较充分。因此，在鉴定玉米早代系田间抗性时应根据鉴定病害对象安排在不同播期进行。     

Development of B-Genome Chromosome Addition Lines of B. napus Using Different Interspecific Brassica Hybrids

By interspecific hybridization within the genus Brassica, trigenomic haploids were produced and back-crossed four times with B. napus, variety ‘Andor’. From this material, monosomic B-genome chromosome addition lines were selected with the extra chromosome derived from three different B-genome sources, i.e., B. nigra (BB), B. carinata (BBCC), and B. juncea (AABB). After selfing and/or microspore culture, disomic addition lines were obtained. Meiotic behavior was studied of the trigenomic hybrids, the pentaploid BC₁ plants, and the monosomic addition lines. The addition lines were shown to possess cytological stability and good fertility.     

不同施肥水平对油菜胞质雄性不育系07A和杂一代品种川油12育性影响研究

以甘蓝型油菜ｐｏｌｉｍａ细胞质雄性不育（ＣＭＳ）系０７Ａ和杂一代品种川油１２号为材料，连续两年采用四元二次回归正交旋转组合设计，研究了氮、磷、钾、硼不同施用量对上述材料育性的影响。结果表明：（１）不育系的不育度和杂一代的恢复度均受年度间气候变化的影响，同一材料在年度间有不同的表现，对各元素施用量的反映也不尽相同；（２）施用过多的氮肥会降低０７Ａ的不育度和杂一代的恢复度，而增施磷、钾、硼肥可提高不育     

Ⅱ优63及其亲本酯酶同工酶电泳分析

用聚丙烯酰胺凝胶电泳分析Ⅱ优63及其亲本Ⅱ-32A和Ⅱ-32B稻苗的酯酶同工酶表明:萌发生长10～18天的Ⅱ优63稻苗中具活性渐强的特征带17A(Rf=0.745),而其亲本均无此带。     

Application of Triticum monococcum for the improvement of triticale resistance to leaf rust (Puccinia triticina)

The aim of this work was to evaluate the leaf rust resistance introduced into introgressive triticale lines with Triticum monococcum genes, and to study the expression of these genes at the hexaploid level. The introgressive lines were developed by incorporating diploid wheat (T. monococcum s.s.) genes into hexaploid triticale LT 522/6 using the synthetic allotetraploid T. monococcum/Secale cereale (A^mA^mRR) as a bridging form. A group of 44 those lines, parental stocks and check cultivars were inoculated at the seedling stage (in a greenhouse) and at the adult‐plant stage (in the field) with four pathotypes of Puccinia triticina. At the seedling stage the assessment of infection type showed that four lines had resistance to all pathotypes as high as in the T. monococcum donor. Adult plant examinations showed some introgressive lines with complete resistance and also lines with partial resistance, expressed in area under the disease progress curve (AUDPC) calculations as slow rusting. Some lines comprise low AUDPC with complete resistance at seedling stage.     

Identification and Inheritance of Fertility Restorer Genes for 'tour' CMS in Rapeseed (Brassica napus L.)

Eighteen genotypes of Brassica napus were crossed to a cytoplasmic male sterile (CMS) line of B. napus BO 15 carrying B. tournefortii cytoplasm (‘tour’ cytoplasm). Fourteen genotypes were found to be stable maintainers of the ‘tour’ CMS. Of the remaining four genotypes, GSL-1 and ‘Asahi-natane’ were found to be heterozygous and ‘Mangun’ and ‘Yudal’ were homozygous for the restorer gene. Analysis of the F₁ and F₂ progenies of (CMS) BO 15 בMangun’ and (CMS) BO 15 בYudal’ showed that fertility restoration is controlled by a single dominant gene. The availability of a number of stable maintainer lines and the simple inheritance pattern of fertility restorer gene makes ‘tour’ CMS a useful system for hybrid seed production in rapeseed.     

Oligonucleotide fingerprinting of tomato DNA

Hinfl -digested DNA samples of wild and cultivated species of tomato were hybridized in gel to different oligonucleotide probes complementary to simple-sequence repeats. All motifs tested i.e. (GATA)₄, (GGAT)₄, (CA)₈. (CAG)₅, (GTG)₅, (GAAGTGGG)₂ and (CCTA)₄, produced multilocus fingerprints in all tomato species and cultivars. The extent of inter- and intraspecific polymorphism of the banding patterns varied considerably between different probes, with (GGAT)₄, (CCTA)₄, (GATA)₄ and (CA)₈ showing a much higher discriminatory potential than the other probes. Cluster analysis of band-sharing data yielded dendrograms which were consistent with the known history of tomato cultivation. (GATA)₄ was also successfully used for purity testing of breeding lines, as well as for analysing an F₁ progeny of a cross between two lines.     

Rht1(B. dw), an alternative allelic variant for breeding semi-dwarf wheat varieties

The vast majority of the world's acreage of semi-dwarf wheat varieties is at present cultivated with varieties carrying one of two genetically similar dwarfing genes, Rht1 and Rht2, derived from the Japanese variety ‘Norin 10’. Near-isogenic lines have been developed and tested to determine the breeding potential of an allelic variant of Rht1, designated Rht1(B. dw). Following its introduction into four varietal backgrounds, Rht1 (B. dw) was seen to reduce height by around 25%, to increase the number of grains setting in spikelets and ears by around 20%, to reduce grain weight by 10%, and to increase yields of plants grown under spaced or drilled conditions by about 8%. When compared to the commercially utilized Rht1 allele, as near isogenic lines in a ‘Mercia’ varietal background, Rht1 (B. dw) gives a significantly greater reduction in plant height, a greater increase in spikelet and ear fertilities, slightly less reduction in 1000-grain weight, and significantly higher spikelet, ear and plot yields. If these results are repeatable in other varietal backgrounds, over seasons, and under differing environmental conditions, Rht1 (B. dw) should have considerable commercial potential as an alternative allele for producing shorter-than-average, high-yielding, semi-dwarf wheat varieties.     

Wide mapping of a T-DNA insertion site in oilseed rape using bulk segregant analysis and comparative mapping

Doubled haploid oilseed rape lines segregating for a transgene inducing herbicide resistance (bar gene) were investigated for the wide mapping of the T-DNA insertion site. Bulk segregant analysis using presence/absence and intensity polymorphisms between the bulks, as well as comparative mapping with a linkage group deriving from another cross, led to the identification of 11 random amplified polymorphic DNA (RAPD) markers tightly or loosely linked to the bar gene. Ten RAPD loci out of 11 were located on the same side of the bar locus, strongly suggesting that the T-DNA integrated in a telomeric or subtelomeric position. The eleventh RAPD marker exhibited a strong segregation distortion, which could be the result of a heteroduplex formation. Comparison of the linkage groups obtained from the two crosses showed different recombination rates between markers, possibly reflecting differences in parental genetic backgrounds. Consequences and potential applications in transgene dispersal safety assessment studies are discussed.     

Heterosis in Primary Hexaploid Triticale with Heterozygous Wheat or Rye Genome*)

Twelve primary hexaploid triticale (X Triticosecale Wittmack), synthesized from, three lines of tetraploid wheat (Triticum durum L., T. turgidum L.) and four inbred lines of rye (Secale cereale L.), were used to produce 18 crosses with homozygous wheat and heterozygous rye genome and 12 crosses with heterozygous wheat and homozygous rye genome. Parents and crosses of triticale, wheat, and rye were tested for two years (rye for one year only) in two-replicate block designs with 1 m²-plots. Data were assessed for plant height, grain yield and for yield-related traits. Performance of triticale crosses was considerably lower than that of the wheat and rye crosses. The amount of heterosis varied greatly between years. Positive and mainly significant heterosis was revealed in triticale generations F₁ and F₂. The average values were closer to those in wheat than to those in rye. For most characters a high level of heterosis was retained in tnucalt1 generation F₂. Heterozygosity of the wheat and rye genome both contributed to heterosis in triticale. However, gene action of the rye genome strongly depended on the homozygous wheat background: one wheat line almost completely suppressed and another greatly stimulated the heterotic effect of the rye genome. In the later case, the amount of heterosis was related to that in rye per se. Information from hybrid rye breeding may therefore be used when establishing gene pools for hybrid breeding in triticale.