粳稻不育系繁殖产量及其构成因素之间的关系*

 通过对滇Ⅰ型杂交粳稻不育系合系42A和榆密15A繁殖产量及其构成因素的分析,结果表明：繁殖产量与结实率、有效穗、穗实粒数及千粒重之间呈极显著或显著正相关关系,合理调控它们之间的相互关系,可以大幅度提高繁殖产量。在生产应用过程中,必须充分掌握不育系的特征特性,根据各个不育系的经济性状进行合理的群体结构调控,才能有效地发掘其增产潜力。     

河套地区2次暴雨天气过程对比分析

利用MICAPS常规资料和自动站资料,对2008年7月30～31日和8月15～17日发生在河套地区的2次局部暴雨天气过程进行对比分析,结果表明：2次暴雨天气过程的影响系统不同,7月30日是700hPa暖式切变线、台风外围西南急流、地面倒槽,而8月15～17日是高空中小尺度的暖式切变线和地面中低压;台风“凤凰”登陆后,与副高脊之间形成1支超地转的东南低空急流并在其左侧形成1支西南急流,2支水汽源源不断地输送到河套地区是造成7月30日暴雨的重要原因;环境风场的垂直切变特征对强对流的发生发展有重要影响：0℃层高度与-20℃层高度差在2—3km、850hPa与300hPa的温差〉40℃、K指数大于32℃、CAPE〉1200J／kg都是强对流天气发生的重要指标：高低层散度的数值大小以及在空间上的配置与暴雨的发生有较好的指示作用。     

30个水稻杂交组合在四川南部农艺性状差异研究

运用6个水稻三系不育系与5个恢复系通过不完全双列杂交配得30个杂交组合,次年种植,成熟后取样、测产,所得的穗长、有效穗、结实率、千粒质量、小区产量、播抽期和株高7个性状以不育系为基础进行分析．结果显示每个不育系所配品种的农艺性状平衡程度都有差异,只是某方面表现较好,其他方面的表现却一般或较差．而宜香1A所配品种穗子最长,植株最高,其他性状居中;中浙A所配品种有效穗最多,结实率高,但穗子偏短,千粒质量和小区产量最低,播抽期最短,植株最矮;II-32A所配品种的结实率最高,除千粒质量和株高居中外,其他性状数值都较大,小区产量也最高;德香074A所配的品种的千粒质量最高,结实率最低,其他性状一般或偏好;蓉18A和Q3A所配品种的农艺性状数值偏低或一般．总的说来,就这7个性状而言,II-32A所配品种的每个性状表现得比较均衡,其次是宜香1A所配品种的性状,再其次是德香074A所配的品种．本研究认为协调好品种每个农艺性状之间的平衡是确保杂交水稻高产、稳产的前提;千粒质量和播抽期是每个不育系所配品种间差异最显著的2个农艺性状;在土壤肥力水平较高的四川南部,适宜推广生育期较长、植株较高的重穗型杂交水稻新品种     

自走式小麦联合收割机电气控制线路优化

为提升自走式小麦联合收割机的收割效率,在收割机结构组成与工作原理的基础上,对收割机的电气控制系统及相关线路展开优化分析。通过分析行走系统与收割装置等关键部件的工作特性,得出其传递函数及实现双闭环控制与调节的条件;采取行进速度智能精确控制,加入PID核心算法控制、辅助电气线路改进与控制、加入实时监测与准确报警装备等措施,实现整机的控制线路优化并通过试验进行验证。结果表明:经优化后的收割机主要性能指标均得到明显改善,尤其收割效率较优化前提高13%左右。电气控制线路优化具有一定的可行性,能够为小麦联合收割机的其他结构优化与改善提供参考。     

Development and characterization of chromosome segment substitution lines derived from backcross between japonica donor rice cultivar Yukihikari and japonica recipient cultivar Kirara397

Grain yield-related traits and grain quality-related traits are important for rice cultivars. The quantitative trait loci (QTLs) involved in controlling the natural variation in these traits among closely related cultivars are still unclear. The present study describes the development of a novel chromosome segment substitution line (CSSL) population derived from a cross between the temperate japonica cultivars Yukihikari and Kirara397, which are grown in Hokkaido, the northernmost limit for rice cultivation. Days to heading, culm length, panicle length, panicle number, brown grain weight per plant, thousand brown grain weight, brown grain length, brown grain width, brown grain thickness, apparent amylose content, and protein content were evaluated. Panicle length, brown grain length and amylose content differed significantly in the parental cultivars. Thirty-five significant changes in the evaluated traits were identified in the CSSLs. A total of 28 QTLs were located on chromosomes 1, 2, 3, 4, 5, 6, 8, 9, 10, 11 and 12. These findings could be useful for breeding rice cultivars in the northernmost limit for rice cultivation.     

RAPD在油用向日葵自交系鉴定和遗传分析中的应用

利用RAPD标记对8个油用向日葵自交系进行了鉴定和遗传分析。从40个UBC引物中筛选出12个能产生稳定遗传多态性的引物，利用其中3个引物提供的RAPD标记可将8个自交系逐一加以鉴别。12个引物对8个自交系共扩增出41条带，其中39条（占95．1％J）具有多态性，每个引物可扩增出1－7条带，平均为3．4条带，不同自交系之间的RAPD遗传距离在0．13－0．85之间，平均为0．42。按UPGMA方法可将8个自交系聚为2大类、4个亚类。     

水稻两用核不育系C815S的配合力及利用价值

以C815S等5个不育系为母本,与7个优良父本配组,采用p×q不完全双列杂交(NCⅡ)设计,对F1代9个农艺性状的配合力进行分析.结果表明,与两用核不育系龙S、7光S052、培矮64S和三系不育系Ⅱ-32A相比,C815S的一般配合力表现最好.C815S在有效穗数、每穗总粒数、着粒密度、单株产量和经济系数5个性状上的一般配合力分别为6.656、6.342、7.236、16.669、6.705,在5个不育系中最大;结实率和千粒重一般配合力分别为0.329和2.353,排第2位;株高的一般配合力为-2.197,排名第4.C815S有效穗数和单株产量的特殊配合力方差较大.C815S在有效穗、着粒密度、千粒重、单株产量、经济系数5个性状上分为Ⅰ类,在每穗总粒数、结实率2个性状上分为Ⅱ类,株高、穗长为Ⅳ类.     

广西主要玉米自交系氮利用效率评价

[目的]对低氮胁迫和正常施氮条件下玉米植株的生理指标、产量性状与耐低氮的关系进行研究,为玉米自交系氮利用效率进行有效评价提供参考.[方法]以96份广西主要玉米自交系为材料,通过两年一点两个水平的田间试验,鉴定玉米自交系在低氮和正常氮水平下的产量、吐丝期穗位叶SPAD值、低氮农学利用效率(LNAE)、株高、穗粒数、百粒重和ASI值等性状指标,分析它们之间的相关关系,计算遗传力等,对玉米自交系氮利用效率进行有效评价.[结果]在低氮和正常施氮条件下,各性状遗传变异较大;铁7922、9046、金黄55、P1201-1-1-6、89-1、D黄212、Su137-3P798-1-3-1-3、M017和越F1-1等玉米自交系氮利用效率较高,应充分利用.低氮条件下,各遗传力较高,正常氮下则较低;穗粒数与产量相关性最高,达0.76.[结论]低氮条件下选育自交系的效率更高;低氮农学效率(LNAE)可作为玉米自交系氮利用效率评价指标;选择与产量相关性较高的性状,能提高选择材料效率.     

Comparison of Vernalization Requirements and Frost Resistance of Winter Rape Lines Derived from Double Haploids

Vernalization requirements and cold resistance of 13 lines of winter rape derived from doubled haploids obtained by androgenesis were investigated. The degree of vernalization requirements was examined in two parallel experiments. In the first experiment seedlings aged 2 weeks were vernalized during 63 and 35 days under controlled conditions, at 5 °C. In the second experiment the natural conditions of vernalization were differentiated by sowing the plants at four different dates in spring: March 15th, April 15th, May 15th, and at the latest date excluding vernalization, June 5th. The lines examined revealed differentiation of vernalization requirements that were similar in both experiments; all the lines required a period of exposure to cold before flowering. Cold resistance of lines was estimated in two successive series at −15 °C and −17 °C. Before testing the plants were kept in natural field conditions from the beginning of September until the middle of November. Testing of cold resistance was preceded by hardening under controlled conditions. Considerable differences in cold resistance was found in the forms investigated.
The results obtained do not show any relation between frost resistance and the degree of vernalization requirements, as the line characterized by the strongest winter habit of growth showed low cold resistance, whereas the lines which were closer to spring growth habit showed the highest level of cold resistance; the lines with the least vernalization requirements revealed the highest level of cold resistance. This conclusion can be confirmed by the significance of the correlation coefficients between the various indices defining the frost resistance and the indices of vernalization requirements.     

HOW THE MACH PHENOMENON AND SHAPE AFFECT THE RADIOGRAPHIC APPEARANCE OF SKELETAL STRUCTURES

The shape of skeletal structures and their position relative to the x-ray beam have a considerable effect on their radiographic appearance. Depending on the thickness of the cortical or subchondral bone, skeletal structures display the characteristics of either homogeneous or compound lamellar structures. Convex homogeneous structures are associated with a negative Mach line, and concave homogeneous structures are associated with a positive Mach line. Convex compound lamellar structures are associated with a negative Mach band and visualization of the lamina (subchondral or cortical bone) is reduced. Concave compound lamellar structures are associated with a positive Mach band and visualization of the lamina is enhanced. The combined effect of Mach phenomenon, shape, and thickness enhances visualization of some skeletal surfaces and make others imperceptible. These principles are very useful to correctly identify complex skeletal structures and avoid misinterpretations.