担子菌原生质体融合子的免疫学鉴定

TritonX一100提取香菇单核体L52~(-adc)“和金针菇单核体F_(v23)的菌体壁抗原,分别注射兔子制备抗血清。同样方法制备L52~(-adc)“和F_(v23)原生质体融合子F_(02),F_(03)的菌体壁抗原,琼脂糖双向扩散显示融合子F_(02)、F_(03)的菌体壁抗原能与所制备的亲本抗血清发生特异性沉淀反应。表明两个融合亲本的菌体壁抗原基因在融合子中得到表达。从而也进一步证实融合子确为两亲本的杂合子。     

提高鸡传染性支气管炎病毒血凝抗原滴度途径及抗原灭活

将７株传染性支气管炎病毒（ＩＢＶ）标准株（Ｍ４１、Ｈ１２０、Ｈｏｌｔｅ、Ｇｒａｙ、Ｃｏｎｎｅｃｔｉｃｕｔ、Ｉｏｗａ６０９和Ｔ株）和６株分离株（ＮＩＢＶ、ＧＩＢＶ、Ｍ、ＳＨ、Ｊ和Ｈ株）分别接种于鸡胚，收获尿囊液，经浓缩后，用魏氏梭菌培养液处理，制备血凝抗原。其中，Ｈ１２０株血凝滴度最高，Ｔ、Ｍ、Ｊ和Ｈ株无血凝性。应用含有不同滴度ＩＢＶ母源抗体的鸡胚增殖病毒制备抗原，效价与用ＳＰＦ鸡胚增殖病毒制备的抗原效价一致。尿囊液经反复冻融后再制备抗原会使血凝价降低。抗原分别用甲醛、高碘酸钠、硼氢化钾和ＳＤＳ灭活，其中甲醛灭活效果最理想。抗原对氯仿敏感，对乙醚稳定。适宜浓度的Ｎａ＋、Ｍｇ２＋可显著提高抗原的血凝性     

Some remarks on carrot breeding (Daucus carota sativus Hoffm.)

Carrot breeding in the past 150 years has resulted in varieties with high yield, a short growing period, and excellent root colour. Recently, hybrid varieties have demonstrated good uniformity of roots, a quality accepted by most consumers. By contrast, only a few resistant varieties (mainly open-pollinated varieties) are offered by seed companies, most being resistant to Alternaria. Hybrid breeding offers a chance of combining good uniformity and different sources of resistance. Efforts in future breeding should concentrate on the improvement of health and the development of genotypes suitable for cultivation in suboptimal climates and regions, as well as for special applications.     

Response to long-term selection in early maturing maize synthetic varieties

Long-term continuous selection is essential for germplasm improvement. However, choice of germplasm for long-term genetic improvement might limit the success of germplasm enhancement programs. The objective of this research was to report the response to long-term selection in early maturing North Dakota (ND) synthetic varieties. We wanted to determine whether the performance of three ND maize synthetic varieties was improved by long-term mass selection (M) and if the performance of one of them was improved by long-term modified ear-to-row (MER) selection. The evaluation of long-term selection response was performed at two plant densities. An experiment in a randomized complete block design with split-plot arrangement was used to evaluate NDSM(M), NDSAB(M), NDSCD(M), and NDSAB(MER) under 75,000 and 42,500 plants per hectare across seven environments. Long-term mass selection for grain yield and stalk lodging resistance in NDSM(M), NDSAB(M), and NDSCD(M) was not successful, since there were no significant changes in grain yield or stalk lodging in these populations at either low or high densities. On the other hand, long-term modified ear-to-row selection was effective for grain yield improvement in NDSAB(MER). Grain yield increased non-linearly from 3.9 Mg ha⁻¹ in cycle 0 to 5.0 Mg ha⁻¹ in cycle 12 at a rate of 2.5% per cycle. Interaction between plant density and genotype was not detected even though selection was performed at relatively low densities (20,000 plants ha⁻¹ for mass selection and 50,000 plants ha⁻¹ for ear-to-row selection). The confirmation of a lack of interaction between plant density and genotype suggests that selection at low plant densities might still be able to provide high-density stress resistance through density-independent genotypes, allowing progeny testing across multiple locations with better accuracy and fewer resources. Selection methods that emphasize both additive and dominance effects such as full-sib recurrent selection are recommended to maximize genetic improvement of advanced population cycles of early maturing synthetics.     

New strategies for increasing heterozygosity in crops: Vicia faba mating system as a study case

Our research assesses the feasibility of using artificial selection on pre-mating floral traits to modify the mating system of faba bean (Vicia faba). This analysis considered two synthetic populations, which were derived from different genetic pools and had undergone five years of multiplication. For these populations, we identified floral and inflorescence traits that influence outcrossing per plant and examined the relative importance of these traits in governing yield. Codominant isozyme loci and the mixed-mating model were used to estimate the multilocus female outcrossing rate. A maternal half-sib design was used to evaluate the additive genetic component of floral and inflorescence traits, yield and yield components. Multiple regression was used to assess the effects of floral and inflorescence traits on outcrossing and yield and components of yield. The two populations exhibited mixing mating. Self-fertilization appears to result from the action of pollinating bees, so that its incidence could be modified by selection on floral and inflorescence traits that affect pollination. Floral and inflorescence traits affected individual differences in outcrossing unequally, with most variation being associated with the numbers of displayed flowers and inflorescences. Variation among plants in reward traits and in shape, although statistically significant, had limited and inconsistent influences on individual differences in outcrossing. Yield and its components varied strongly with aspects of floral display and, to a lesser extent, floral design, except for seed weight. Overall, our results imply that both outcrossing and yield could be enhanced by selection for plants that produce more inflorescences, each with relatively few flowers.     

Applicability of Aegilops tauschii drought tolerance traits to breeding of hexaploid wheat

Few genes are available to develop drought-tolerant bread wheat (Triticum aestivum L.) cultivars. One way to enhance bread wheat’s genetic diversity would be to take advantage of the diversity of wild species by creating synthetic hexaploid wheat (SW) with the genomic constitution of bread wheat. In this study, we compared the expression of traits encoded at different ploidy levels and evaluated the applicability of Aegilops tauschii drought-related traits using 33 Ae. tauschii accessions along with their corresponding SW lines under well-watered and drought conditions. We found wide variation in Ae. tauschii, and even wider variation in the SW lines. Some SW lines were more drought-tolerant than the standard cultivar Cham 6. Aegilops tauschii from some regions gave better performing SW lines. The traits of Ae. tauschii were not significantly correlated with their corresponding SW lines, indicating that the traits expressed in wild diploid relatives of wheat may not predict the traits that will be expressed in SW lines derived from them. We suggest that, regardless of the adaptability and performance of the Ae. tauschii under drought, production of SW could probably result in genotypes with enhanced trait expression due to gene interactions, and that the traits of the synthetic should be evaluated in hexaploid level.     

Applying hybrid dynamic substructure synthetic method to dynamic analysis for tower crane

This paper presents a dynamic hybrid substructure synthetic method for tower crane dynamic analysis. This method employs the transfer matrix method and the flexibility degree method respectively to formulate the vibration mathematical models of the tower body and tower top system substructures in the hoisting luffing plane. Based on the motion of the substructures in the interface and the dynamic harmonize condition, the frequency equations are established. Then the program is designed according to the mathematical models and firstly applied to the dynamic analysis of the QTZ63 tower crane in the construction site and the parameter identification of attached device and tower body. The test results show that the value calculated by the above method is quite approximate to the instrument measured value, which can meet the engineering requirements. Further study has found that , for the flexible long-distance attached tower crane, the method that introduces dynamic load coefficient for statics analysis of tower cranes is unprecise enough since there exist errors.This paper suggests to conduct site test and identification of the rigidity coefficient of attached device of the tower crane for the accident prevention of tower crane collapse by timely take measures.     

多种病虫综合危害小麦产量损失率及综合防治指标的研究

通过田间开放式小区试验研究，明确了小麦穗期多病虫同时危害与产量损失的关系：建立了小麦穗期受麦蚜Ｘ１、白粉病Ｘ２和叶锈病Ｘ３同时危害与产量损失的相关模式。设立了麦蚜Ｘ１、白粉病Ｘ２的经济阈值模型。并提出了稳期病虫的综合防治指标。     

水稻对田间多种病虫害综合抗性的评价初探

 通过对柳江县近年引进、推广的中优663等13个主要水稻品种（组合）进行田间小区试验,采用[0,1]多目标决策法进行综合评价,按对稻飞虱、稻纵卷叶螟、三化螟及稻纹枯病等多种病虫害的综合抗性的强弱排序为：优Ⅰ602＞金优602＞灵优6602＞丰两优1号＞金两优2号＞优Ⅰ402＞T优259＞金优463＞中优71＞中优663＞中优207＞金优207＞金优616。前五个品种（组合）均为中抗,其余品种（组合）均为中感。无高抗品种（组合）,说明水稻对多种病虫害的综合抗性的选育工作任重而道远。通过亲缘关系分析发现,亲缘关系相近的水稻品种（组合）具有相近的综合抗性;分析五个中抗品种（组合）的抗性构成,为不同生态环境的品种布局提供依据。