Interspecific hybridization between Coffea arabica L. and tetraploid C. canephora P. Ex Fr. II. Meiosis in F1 hybrids and back crosses to C. Arabica

Summary Melosis was studied in Coffea arabica, in induced tetraploid C. canephora, in their F₁ hybrid (arabusta hybrid) and in backcross generations of the hybrid with C. arabica as recurrent parent. Irregularities were observed, consisting of univalents (especially in the arabusta hybrid), multivalents (especially in tetraploid C. canephora) and uneven distribution of chromosomes at first anaphase. Chromosome distribution was improved by backcrossing. Meiotic irregularities wer negatively correlated with pollen fertility.     

几种化学物质和温度处理对高羊茅种子发芽的影响

用高羊茅(Festuca arundinacea)种子为试验材料,置入光照培养箱培养,研究化学物质和温度处理对其发芽的影响.结果表明:0.2%的次氯酸钠(NaClO)处理促进高羊茅种子的发芽,浓度梯度设置在0.5%～1.5%时均抑制其发芽,且浓度与发芽率和发芽势均成负相关.不同浓度的硝酸钾(KNO3)处理均促进其发芽,且浓度为2.0%时,发芽率最高,发芽势是先降低后升高.高羊茅最适播种温度为20℃,高于或低于20℃,对种子的发芽均有不同程度的抑制作用.     

Effect of Induced Autotetraploidy on Response to Sclerotinia Clover Rot in Trifolium pratense L.

The effect of induced autotetraploidy on the response of red clover to Sclerotinia clover rot (SCR) was studied under laboratory, glasshouse and field conditions. To assess the response in the laboratory, the detached leaf technique was employed, whereas in the glasshouse and in the field, 6—14 weeks old seedlings and adult plants, respectively, were artificially inoculated with the pathogen grain inoculum. The results of the studies showed that great genotypic variability occurs within diploid (2×)and tetraploid (4×)red clover in response to that disease. Generally, tetraploid red clover, in comparison to diploid, is more resistant to SCR. The laboratory, glasshouse and field experiments showed that the effect of induced autotetraploidy on SCR resistance is positive. The hardening of plant with light and temperature enlarged the differences in reponse to SCR between ploidy levels, family pairs and individual strains with every testing method. Other factors, like plant age and flowering time, influencing red clover response to SCR are also discussed.     

Improved doubled haploid production protocol for Brassica napus using microspore colchicine treatment in vitro and ploidy determination by flow cytometry

A rapid and efficient microspore culture protocol was applied to produce homozygous progeny of crosses between low erucic canola and high erucic resynthesized rapeseed (Brassica napus L.). Microspores of Canadian cultivars ‘Excel’ and ‘Profit’ as well as three F₁ hybrids with the resynthetic line ‘RS239’ were treated with colchicine immediately after isolation. Flow cytometry was applied for early identification of doubled haploid (DH) regenerants. The diploidization rate was subsequently verified by scoring flower morphology. In vitro colchicine treatment had a positive effect on induced diploidization, and was associated with the frequency of preliminary spontaneous diploidization which was, however, determined by the genotype. In addition, the effects of colchicine treatment on embryoid formation and regeneration have been evaluated. The method presented is feasible for commercial large‐scale production of DHs in rapeseed as the genotype‐specific diploidization can be efficiently balanced by in vitro colchicine treatment. In addition, the use of flow cytometry immediately after in vitro culture allows efficient selection for DHs, thus saving labour and cost and in the laboratory and subsequent greenhouse phase.     

植物低温诱导蛋白和诱导基因研究新进展

本文就近年来植物低温诱导蛋白和低温诱导基因的研究进展进行了概述，同时探讨了低温诱导蛋白和低温诱导基因与植物抗寒能力之间的关系。     

Pollen Characteristics and Genetics of Induced and Spontaneous Genetic Male-Sterile Mutants in Rice

Pollen characteristics, inheritance and allelism of 23 genetic male-sterile (ms) mutants of rice (Oryza sativa L.) were investigated. Ten of the mutants were induced by ethyl methane sulfonate, one induced by ethyleneimine, seven induced by gamma rays, one induced by streptomycin, one derived from tissue culture and three were spontaneous mutants found in the field. Four pollen abortion types were observed among these ms mutants: 3 no-pollen (NP) type, 6 complete pollen abortion (CPA) type, 13 partial pollen abortion (PPA) type, and 1 stainable pollen abortion (SPA) type. Progeny tests over two years indicated that each of the mutants was inherited as a monogenic recessive. A partial diallel cross among the 23 ms mutants indicated that mutant E2 was allelic to G4, E5 was allelic to E9, N2 was allelic to N3, and that three other mutants, E3, G6 and T1, shared the same ms locus. Gene symbols ms-46 (t) through ms-63 (t) were assigned to these mutants.     

Doubled haploid production of sunflower (Helianthus annuus L.) through irradiated pollen-induced parthenogenesis

Induced parthenogenesis as a possible method of haploidization in sunflower (H. annuus L.) was tested in previous investigations (Todorova et al., 1994) and conditions for reproducible regeneration of gynogenic doubled haploids were established by the present work. Forty eight treatments were studied, involving four pollen donors and four recipient hybrids. Pollen was irradiated with doses of 300 Gy, 600 Gy and 900 Gy. In total, 2279 embryos were cultivated in vitro of which 1107 plants were obtained and 582 of them produced seeds after selfing. The ploidy level of the regenerants was evaluated at the two – three leaf stage and 296 of the plantlets obtained were haploids. Some of them underwent spontaneous diploidization, the others were treated with colchicine solution for chromosome doubling. The diploid plantlets were checked for their gynogenic origin by genetical and biochemical methods. The effectiveness of the method expressed as the number of agronomically useful DH lines to the number obtained that were fertile and resistant to downy mildew, branched and unbranched plants was 8,6% on average. This revised version was published online in July 2006 with corrections to the Cover Date.     

水稻压致变异后代主要农艺性状的研究

用高压诱变法处理高收获指数型水稻品种粤香占 ,培育出变异材料粤压 1号、2号和 3号。通过对其主要农艺性状比较研究发现 ,3个变异材料与粤香占在生育期、株高、分蘖数、有效穗数、穗部性状、外观米质、抗病性和抗寒性等方面存在明显差异 ,表明高压诱变可能成为一种新的育种方法。     

CO_2浓度、氮素和水分对春小麦碳素固定的影响

试验设350μmolmol-1和700μmolmol-12种CO2浓度水平,湿润、干旱2种水分处理和施N0、50、100、150和200mgkg-15个水平。结果表明,CO2浓度增加,春小麦地上部碳固定量和碳固定总量均增加,但与氮肥施用水平有关。在中氮和高氮时,CO2浓度增高,地上部碳固定量和碳固定总量明显增加,而不施氮肥和低氮时,增加则不明显。不同水分处理地上部碳固定量和碳固定总量也没有明显差别,这表明,CO2浓度升高对氮素和水分胁迫及对春小麦碳固定并没有补偿作用。