Detecting and estimating segregation distortion and linkage between glufosinate tolerance and blackleg resistance in Brassica napus L.

Summary The segregation and linkage between glufosinate (transgenes ‘Rf3’ and ‘T177’) and blackleg resistance genes in canola (Brassica napus L.) were assessed using F₁ microspore-derived doubled haploid (DH) populations from four crosses including reciprocals, two involving the transgene ‘Rf3’ and the other two involving the transgene ‘T177’. To relax the assumption of no segregation distortion required for the conventional analysis of segregation and linkage, we employed Bailey's analysis that allows detecting segregation distortion at linked loci. The significant departures from the 1:1 segregation were detected in the crosses involving the transgene ‘T177’ but not in the crosses involving the transgene ‘Rf3’. The apparent deficit of the herbicide tolerant DH lines in the crosses with the transgene ‘T177’ is likely due to differential selection against the gametes carrying ‘T177’ during microspore culture. The linkage was strong between blackleg resistance and the transgene ‘Rf3’ but weak or absent between blackleg resistance and the transgene ‘T177’, suggesting that the two transgenes are probably inserted into distant regions of the genome. The observed linkage offers an opportunity to develop new canola cultivars with both glufosinate tolerance conferred by transgene ‘Rf3’ and blackleg resistance.     

Development a Coil Compactor used in High Temperature

材料和方法 1.1试验材料 　　荔枝果实采自武鸣县府城镇大同村陶蓬德果场，品种为新丰黑叶，果实成熟度为 9成半；龙眼果实采自武鸣县城东镇大同村蒙桂辅果场，品种为石硖、储良，果实成熟度分别为 8成半和 8成。 1.2采前处理 　　荔枝采收前即 2000年 6月 15日和 6月 28日分别     

Performance and Variability of Local Barley Landraces in Near-Eastern Environments

Homozygous lines from six Syrian and two Jordanian landrace populations were tested under highly productive growing conditions in Tel Hadia (1982/83), under drought stress in Breda (1983/84), and under dryland salinity stress in Hegla (1982/83/84) in Syria. Mean grain yield levels ranged between 260 kg/ha and 4850 kg/ha. Under drought and salinity stress, the majority of the landrace lines out-yielded the best cheeks significantly. In Tel Hadia the check cultivars mostly outyielded the landrace lines, but not always significantly. In all environments the harvest index of the landrace lines was near the optimum for barley. They expressed intermediate plant height and time to flowering, high lodging susceptibility under favorable growing conditions, high protein content, and a wide range of yield component combinations. In the stress environments highly significant genetic variation among the landrace lines was found. The heritabilities for gram yield were high in these trials. The correlations between performance under stress and under favorable growing conditions were poor. Therefore, the largest gains for variety improvement for the Syrian steppe area are expected from direct selection under stress conditions. Unique responses in proline accumulation and germination patterns in saline solution indicated specific adaptation in this material. These landraces, thus, are a useful source of breeding material, which also widens the genetic base of the present breeding program.     

Analysis of Unbalanced Data by Mixed Linear Models Using the mixed Procedure of the SAS System

Unbalanced data are a common problem in plant research based on designed experiments. Such data are often conveniently analysed using linear mixed models. Recent developments in mixed model theory have been implemented in major packages. This paper describes the use of the mixed procedure of the SAS System for the analysis of designed experiments. Special emphasis is given to the specification of options as depending on the assumed mixed model and on the unbalancedness in the data. In addition, we consider a compact representation of multiple comparisons for unbalanced data (letter display). Two small data sets are used to exemplify the methods.     

高粱区域试验新杂交种的综合评价

采用模糊数学综合评判方法,综合评价了1989年山西省高粱新杂交种区域试验材料.结果表明,6个高粱新杂交种,其中晋杂871、21A×晋粱五号、FA×8643变3个组合以亩产量、丰产素质为主,包括抗病性、抗倒性、株高在内的综合性状明显优于对照晋杂四号,达到优良或较好的评价标准,其综合指标值分别比对照增加18.29%、11.28%和7.00%.晋杂871对不同环境的适应能力强,综合性状稳定性好;旱抗六、V_4A×87382-3两个杂交种综合特性与对照相当;旱抗五劣于对照,综合指标值比对照减少5.06%.模糊综合评判方法,客观地反映了品种的综合特性,克服了仅用产量指标评价品种优劣的不足,对新品种的审定、推广利用都具有实际意义.     

Effect of plant density on selection for seed yield in two population types of Phaseolus vulgaris L.

Summary Pedigree selection for seed yield, using early generation yield tests, was practiced from the F₂ to F₇ in two populations of common bean (Phaseolus vulgaris L.) in three plant densities: 66, 133, and 266 thousand plants ha^-1 at CIAT-Palmira, Colombia. The six highest yielding lines selected from each plant-density, along with 13 parents, were evaluated in a 7×7 lattice design with three replications at the three densities utilized for selection, and at 399,000 plants ha^-1 in 1988 and 1989.Based on the mean performance of selected lines and the mean of the parents, selection for seed yield was effective in all densities in both populations. However, none of the lines selected from the population within the race Mesoamerica (TC 4673) significantly outyielded their best parent under any plant density. The highest yielding lines selected from the interracial population (TR 4635) outyielded their best parent irrespective of the plant-density used for selection. The highest yielding line originated from the highest density used for selection. Low density was neither good for selection nor for evaluation and identification of high-yielding cultivars of common bean. There was no significant difference between the mean yield of lines selected at the intermediate and high population densities. The effects of plant density, year, and their interactions were significant for seed yield.     

Resistance in Cucumis sativus L. to Tetranychus urticae Koch. 2. Designing a reliable laboratory test for resistance based on aspects of the host-parasite relationship

Summary The relationship between the twospotted spider mite and cucumber has been studied on plants and on leaf disks of a number of varieties with different levels of resistance. Existing laboratory tests are critically discussed and it appears that they are only reliable if many factors are taken into account. A new, more efficient laboratory test for resistance, measuring acceptance and reproduction is described.     

Test Bench of Air Braking System for Vehicles

The stability of the brake system is a key factor for the vehicle safety.It is important for the air braking system's stability to shorten the time lag between the front brake and the rear brake,the reasonable disposal of the air pipeline and the optimization of the braking system design.A test bench is developed to test the performance of the air braking system,which is mainly made of pressure sensors,signal amplifiers,data acquisition system,computer,pressing air resource and so on.Based on this test bench,the reaction time of the system while braking and abandoning brake can be measured.Using this test bench,the performances of the air braking system of a certain commercial vehicle is detected.Compared with the actual road test,it can save the cost and the time for experiment largely.     

The Preliminary Study of the Automobile Steering-gear Performance Test Theory and Its Test System

This paper presents a new steering-gear performance test calculation formula,and set up a corresponding test system on this basis,and obtain a preliminary test result.     

Experimental Analysis of Vibration Behavior for Large-span Underground Structure

In this paper, a shaking table test for large-span underground structure is introduced. Based on the test, the frequency of inherent vibration, damping ratio and the dynamic response of the structure are studied. The response of the underground structure for vertical seismic excitation is studied as a key point. With the different imbedding depth, the influence of interaction of soil and structure on the earthquake-resistant capacity of the underground structure is discussed.