杂交早稻K优619高产制种技术

K优619系温州市农科院选育的籼粳型早杂新组合，制种易获高产，1998～1999年在遂昌县制种9.98 hm2，平均单产3.05 t/hm2，其中1.6 hm2连片制种单产达4.32 t/hm2。对其高产制种技术进行了总结。     

不同秧龄移栽对恢复系播始历期的影响

在制种实践中,恢复系402,298, 191的播始历期随秧龄的延长而延长.试验结果进一步表明,3～6叶期移栽,播始历期无明显变化;从7叶期开始,每推迟1叶移栽,播始历期延长2～3 d;当恢复系402,298移栽叶龄增至9叶,191增至10叶时,播始历期大幅缩短,且出现早穗.因此,在制种中父本移栽叶龄与父母本花期相遇的关系值得重视.     

Male fertility and cytology of triploid hybrids between tetraploidSolanum commersonii (2n=4x=48, 2EBN) and Phureja-Tuberosum haploid hybrids (2n=2x=24, 2EBN)

Summary Solanum commersonii Dun. is a diploid (2n=2x=24, 1EBN) wild species of potential value for potato breeding. It is a reproductively isolated species and cannot be crossed with Tuberosum haploids (2n=2x=24, 2EBN) or other diploid 2EBNSolanum species. In order to overcome the EBN barriers, triploid hybrids were produced between Phureja-Tuberosum haploid hybrids, which form 2n pollen grains by parallel spindles, and tetraploidS. commersonii. Microsporogenesis analysis of the triploids indicated a trend towards low values of chromosome distribution at Anaphase I; lagging chromosomes were often observed as well. Despite these abnormalities, the percentage of stainable pollen was very high, ranging from 5.0% to 74.3%. A high variation in pollen grain diameter was also evident. Parallel and tripolar orientation of spindles at Metaphase II of microsporogenesis was a common feature of all the triploids analyzed, but dyads and triads were observed at a very low frequency. Therefore, also the frequency of 2n pollen was very low; the different size of stainable pollen appears to represent the ploidy levels which are possible according to the distribution of chromosomes in Anaphase I. The results obtained also suggest thatS. commersonii could have minor genes acting at the end of meiosis in such a way that, despite the presence of parallel/tripolar spindles, dyads/triads are not formed.Contribution no. 124 from the Research Center for Vegetable Breeding.     

水稻内稃扭曲突变体palea distortion 1(pd1)的鉴定与基因定位

在对籼稻缙恢10进行EMS(ethyl methane sulfonate)处理后的群体中,发现一个花器官突变体,主要表现为内稃扭曲并呈现外稃化特征,浆片数目增加且呈现稃状特征,雄蕊数目减少至1～4个,部分雄蕊的花丝呈现浆片化特征,暂将其命名为水稻颖壳扭曲突变体palea distortion 1(pd1)。遗传分析表明该突变性状受一个隐形单基因控制。利用群体分离分析法(bulked segregation analysis,BSA),将PD1基因定位在第2染色体的RM13693和RM13936之间,遗传距离分别为3.25cM和3.90cM。该研究结果为PD1基因的图位克隆奠定了基础。     

Geographical variation of solanidane aglycone glycoalkaloids in the wild potato species Solanum chacoense Bitter

The Colorado Potato Beetle is a serious pest of the cultivated potato. Natural resistance has been found in a few wild species, including Solanum chacoense Bitter, in which the resistance is attributed to the presence of leptine glycoalkaloids. Production and accumulation of these compounds within S. chacoense varies widely and appears to be inherited in a quantitative fashion, but high leptine-producing clones occur rarely. In the present study, 15 different accessions from various locations and altitudes of origin within central to northern Argentina and Paraguay were analyzed for foliar glycoalkaloid (leptine, leptinine, solanine, chaconine) content. The objective was to infer the frequency of leptine production in ecogeographically distinct S. chacoense accessions, and to ascertain any possible association between leptine levels/concentrations and ecogeographical location. Leptines were detected in 8 of the 15 accessions, and the amounts within each accession varied widely. Most of the leptine-containing accessions originated from western Argentina except two in province Córdoba in central Argentina. There was no relationship between elevational level and leptine, but there was a negative trend with total glycoalkaloids (TGA) and elevation, due to solanine and chaconine levels which decreased with increasing elevation. In addition, nine unidentified, putative glycoalkaloids were detected, in very high proportions in some individuals and accessions. This study raises interesting questions about glycoalkaloid distribution, helps provide direction for new avenues of leptine and glycoalkaloid research, and proposes a systematic, ecogeographically based method for bioprospecting genes controlling rare plant secondary compounds.     

Complement Titres of Naturally and Artificially Raised Piglets II. Comparison with the Results of Electrophoretic Examinations

Serial serum samples from piglets in one naturally-raised and three artificially-raised litters, 19 animals, were examined by cellulose acetate electrophoresis. The electropherograms of all day-old suckling and colostrum deprived piglets showed five definite bands, the first, third, fourth and fifth corresponding in position to the albumin, alpha-, beta- and gamma-globulin regions for adult pig serum. The second, well-defined band was located between the albumin and main alpha-globulin bands. This component, considered to be alpha₁-globulin or fetuin, was no longer visible as a distinct band in the electrophoretic pattern for sera of three-week old suckling piglets or of five-week old artificially-raised piglets. No consistent relationship was observed between the rate of increase in haemolytic complement titre and the proportional changes in the various categories of serum globulins.     

Day-blindness in three dogs: clinical and electroretinographic findings

A 6-month-old Rhodesian ridgeback-cross, a 6-year-old Chihuahua and a 12-month-old Australian cattle dog were presented to the authors with a history of colliding with obstacles in daylight. Ophthalmic examination was normal and all three dogs successfully negotiated obstacle courses in dim light. In daylight the dogs became suddenly blind and repeatedly collided with obstacles. Elecroretinography (ERG) revealed no retinal activity to high frequency (30 Hz), bright intensity blue light retinal stimulation by any dog, confirming cone dysfunction. Achromatopsia has previously been recorded in Alaskan malamutes and miniature poodles. This clinical case series illustrates the characteristic behavioral presentation and the electroretinographic findings of severe day-blindness and demonstrates that this condition may exist in other breeds of dogs.     

Genetic diversity and pathogenic variability among isolates of colletotrichum species from strawberry

ABSTRACT Ninety-five isolates of Colletotrichum including 81 isolates of C. acutatum (62 from strawberry) and 14 isolates of C. gloeosporioides (13 from strawberry) were characterized by various molecular methods and pathogenicity tests. Results based on random amplified polymorphic DNA (RAPD) polymorphism and internal transcribed spacer (ITS) 2 sequence data provided clear genetic evidence of two subgroups in C. acutatum. The first subgroup, characterized as CA-clonal, included only isolates from strawberry and exhibited identical RAPD patterns and nearly identical ITS2 sequence analysis. A larger genetic group, CA-variable, included isolates from various hosts and exhibited variable RAPD patterns and divergent ITS2 sequence analysis. Within the C. acutatum population isolated from strawberry, the CA-clonal group is prevalent in Europe (54 isolates of 62). A subset of European C. acutatum isolates isolated from strawberry and representing the CA-clonal and CA-variable groups was assigned to two pathogenicity groups. No correlation could be drawn between genetic and pathogenicity groups. On the basis of molecular data, it is proposed that the CA-clonal subgroup contains closely related, highly virulent C. acutatum isolates that may have developed host specialization to strawberry. C. gloeosporioides isolates from Europe, which were rarely observed were either slightly or nonpathogenic on strawberry. The absence of correlation between genetic polymorphism and geographical origin in Colletotrichum spp. suggests a worldwide dissemination of isolates, probably through international plant exchanges.     

Antimicrobial susceptibilities of canine Clostridium difficile and Clostridium perfringens isolates to commonly utilized antimicrobial drugs

Clostridium difficile and Clostridium perfringens are anaerobic, Gram-positive bacilli that are common causes of enteritis and enterotoxemias in both domestic animals and humans. Both organisms have been associated with acute and chronic large and small bowel diarrhea, and acute hemorrhagic diarrheal syndrome in the dog. The objective of this study was to determine the in vitro antimicrobial susceptibilities of canine C. difficile and C. perfringens isolates in an effort to optimize antimicrobial therapy for dogs with clostridial-associated diarrhea. The minimum inhibitory concentrations (MIC) of antibiotics recommended for treating C. difficile (metronidazole, vancomycin) and C. perfringens-associated diarrhea in the dog (ampicillin, erythromycin, metronidazole, tetracycline, tylosin) were determined for 70 canine fecal C. difficile isolates and 131 C. perfringens isolates. All C. difficile isolates tested had an MIC of or=256 microg/ml for both erythromycin and tylosin. A third C. perfringens isolate had an MIC of 32 microg/ml for metronidazole. Based on the results of this study, ampicillin, erythromycin, metronidazole, and tylosin appear to be effective antibiotics for the treatment of C. perfringens-associated diarrhea, although resistant strains do exist. However, because there is limited information regarding breakpoints for veterinary anaerobes, and because intestinal concentrations are not known, in vitro results should be interpreted with caution.