陕西省玉米杂交种种质基础分析

对1984年～1993年陕西省种植面积在0.67万hm~2以上的玉米杂交种种质基础进行了分析,结果表明:陕西省玉米杂交种的生产已基本达到单交种化;生产上使用的杂交种比较集中,省外系和国外系组成的杂交种面积较大;玉米杂交种亲本系利用更趋集中,种质基础狭窄;玉米自交系主要采用以窄基为主的选育方式;种质杂交模式主要是美国的瑞德黄马牙、兰卡斯特分别和中国的唐山四平头、旅大红骨的杂交形式。     

盐胁迫对不同玉米品种幼苗渗透调节物质的影响

以辽宁玉米主栽品种丹玉103、京科301、丹玉99、丹玉201、金刚35、郑单958、瑞盛512、丹玉603、辽单145为试验材料,测定不同浓度盐溶液胁迫对各玉米品种幼苗脯氨酸、可溶性糖以及可溶性蛋白含量的影响。试验结果表明:随着盐胁迫浓度的增加,所有玉米品种幼苗的脯氨酸、可溶性糖含量均有所增加,可溶性蛋白含量均有所降低;上述9个玉米品种中,丹玉103、京科301、丹玉99属强耐盐品种;丹玉603、辽单145属中度耐盐品种;丹玉201、金刚35、郑单958、瑞盛512属弱耐盐品种。     

两种基因型玉米苞叶水势比较研究

以郑单958和农大364两个玉米品种为研究材料,对大田条件下玉米苞叶水势的变化规律进行了比较研究,并探讨了苞叶水势和饱和亏缺之间的关系.结果表明:两种基因型玉米苞叶水势日变化趋势基本一致,呈抛物线型;郑单958的苞叶水势日均值和日变幅高于农大364;苞叶水势和相对水分含量均随着玉米生育期推进呈现不断降低的趋势,饱和亏缺变化趋势与之相反;郑单958的苞叶饱和亏缺数值低于农大364,相对水分含量高于后者;苞叶水势和饱和亏缺之间呈线性关系:Y=A BX.郑单958常数项值比农大364大,表明在正常水分条件下郑单958饱和亏缺值较低,相对含水量较高,因此抗旱性强于农大364.     

利用RIL群体创造抗黄曲霉兼抗青枯病的高油花生新种质

协同提高抗青枯病花生品种的黄曲霉抗性及含油量是我国花生育种的重要目标之一。利用远杂9102×中花5号杂交后代衍生的重组近交系群体(RIL),通过黄曲霉抗性、青枯病抗性鉴定及含油量测试,表明黄曲霉抗性受2对连锁并具累加作用主基因+加性多基因控制,含油量受2对具抑制作用主基因+加性多基因控制,RIL群体的黄曲霉抗性和含油量变异远远超过双亲的差异,表明它们均具有通过互补产生超亲性状的潜力。获得了抗黄曲霉或抗青枯病的高油后代家系18份,其中抗黄曲霉兼抗青枯病高油新种质1份(J091)。农艺性状和SSR分析结果表明,18份后代材料具丰富的遗传多样性,农艺性状优良,具有重要育种价值。     

高温老化对两个玉米品种种子活力发芽指标影响的研究

以玉米太谷1号、泽玉2号两个品种为材料,采用人工高温处理加速老化的方法,研究了种子在老化过程中,发芽指标、种子活力、电导率的变化。结果表明:高温(45±1℃),高湿(100%相对湿度)密闭条件下,随着老化处理时间的延长,两个品种种子的发芽率、发芽势、发芽指数、活力指数、种子活力等逐渐下降,短时间的高温老化对玉米的多项发芽指标和种子活力影响不大,长时间高温老化种子活力和各项发芽指标迅速下降;随着老化处理时间的延长,两个玉米品种的电导率均逐渐上升。两个玉米品种种子在老化处理过程中,种子的多项发芽指标的高低与种子活力的强弱存在显著的正相关关系,而与种子的相对电导率呈极显著的负相关关系。     

优质蛋白玉米发展回顾与前景展望

优质蛋白玉米(QPM)是过去植物育种领域中取得最意想不到的成就之一,它的赖氨酸和色氨酸含量比普通玉米高,从而改善玉米蛋白质品质,因此其营养价值优于普通玉米。文章回顾了优质蛋白玉米的发展历史以及中国优质蛋白玉米研究的发展历程,提出政府支持,重视科技投入,加强研究力度,实施多学科合作尤其是现代生物技术的引进利用,加强种质资源创新与利用研究,把普通玉米自交系和杂种优势群转育为优质蛋白玉米资源,挖掘新的种质源,探索新的检测方法和应用领域,形成科研——种植——加工业——养殖业产业链联合开发是中国优质蛋白玉米研究的发展方向。     

不同种植密度下玉米Lancaster群改良系的杂种优势及配合力

为耐密植玉米新品种的选育提供参考,以玉米Lancaster群5个改良自交系为父本,Reid群和Dom群5个骨干自交系为母本,按NCⅡ设计组配25个玉米杂交组合,研究5.5万株/hm~2、7万株/hm~2和9万株/hm~2种植密度对各杂交组合及亲本单株产量杂种优势及配合力的影响。结果表明:在3种种植密度下,25个玉米杂交组合单株产量的杂种优势分别为137.12%、134.90%和127.86%,且杂种优势随种植密度的增加而降低;但PH4CV改良自交系父本所配杂交组合在高密度种植条件下的杂种优势较高。在5.5万株/hm~2种植密度下,一般配合力以自交系PH5AD最高,为7.02;在7万株/hm~2和9万株/hm~2种植密度下,以自交系PH4CV最高,分别为20.73和18.24。以PH5AD为父本所配杂交组合适宜稀植,以PH4CV为父本所配杂交组合在高密植条件下易获高产;以PH4CV为父本所配杂交组合较耐密植,以J1577为父本所配杂交组合宜稀植。     

Evaluating eddy covariance method by large-scale weighing lysimeter in a maize field of northwest China

Accurate determination of evapotranspiration (ET) is useful to develop precise irrigation scheduling. Although eddy covariance (EC) is a direct method which is widely used to measure ET, its performance in arid region of northwest China is not clear. In this study, ET measured by EC (ET_EC) was compared with that by large-scale weighing lysimeter (ET_L) during the whole growing season of maize in 2009. Energy balance ratio was 0.84 for daytime fluxes, indicating that lack of energy balance closure occurred, so daytime ET_EC was adjusted by Bowen-ratio forced closure method. Compared to the corresponding ET_L, half-hourly daytime ET_EC was underestimated by 21.8% without the adjustment and 4.8% with the adjustment. Furthermore, nighttime ET_EC was adjusted using filtering/interpolation method. Mean error between half-hourly nighttime ET_EC and ET_L decreased from 30.2% without the adjustment to 10.3% with the adjustment. After such adjustment of day and night measurements, daily ET_EC was underestimated by 6.2% compared to ET_L. These results indicated that the adjusted ET_EC well matched with the ET_L. Moreover, the discrepancy of adjusted total ET_EC and ET_L was decreased to 3.2% after subtracting the overestimated ET by lysimeter resulting from irrigation and heavy rainfall events. Thus, after appropriate adjustments of observations, eddy covariance method is accurate in estimating maize ET in the arid region of northwest China.     

Yield and quality components of silage maize in killed and live cover crop sods

In sloping areas with high precipitation, planting maize into live winter cover crop sods may help to alleviate the environmental problems associated with clean-tillage production systems of maize. The present study evaluates the performance of silage maize (Zea mays L.) under several cultivation methods: CC (conventional cropping system, i.e., maize was sown into the bare, autumn-ploughed soil); LGS/CK (maize was planted into a living Italian ryegrass (Lolium multiflorum Lam.) sod which was subsequently herbicidally killed); and LGS/MR (similar to LGS/CK, but the ryegrass was mechanically regulated). The research was conducted in the midlands of Switzerland on a fertile sandy loam under humid conditions during three cropping seasons. With 110 kg N ha⁻¹ (fertilizer nitrogen plus mineral nitrogen of the soil at maize planting), the CC system was much more productive than were the LGS/CK and LGS/MR systems in terms of dry matter and nitrogen yields of maize. Increasing the nitrogen supply to 250 kg N ha⁻¹ considerably reduced the yield advantage of CC over the LGS/CK and LGS/MR systems, indicating that nitrogen was the most limiting factor for maize yield in the mulch seeding systems. With 250 kg N ha⁻¹, the LGS/CK and LGS/MR systems produced greater total yields of digestible organic matter (maize plus ryegrass) than did the CC system, whereas the total nitrogen yield was similar for all cropping systems. The whole-shoot concentrations of nitrogen were highest under CC, irrespective of the level of nitrogen supply. With 110 kg N ha⁻¹, concentrations of phosphorus and magnesium were clearly higher for the mulch seeding systems. There were only minor differences among the cropping methods in the concentrations of potassium and calcium in the whole shoot. When 250 kg N ha⁻¹ were applied, there were no significant variations among the cropping systems in the concentrations of minerals. Changes in the botanical composition of the cover crop sod and in the time and method of cover crop control may help to reduce the competition for nitrogen between maize and the living mulch.     

Isolation, identification and characterization of disomic and translocated barley chromosome addition lines of common wheat

Two disomic barley chromosome addition lines and five translocated chromosome addition lines of common wheat cultivar Shinchunaga were isolated. They were derived from a hybrid plant between Shinchunaga and cultivated barley Nyugoruden (New Golden) by backcrossing with wheat and self pollination. Barley chromosomes added to chromosome arms involved in the translocated chromosomes were identified by C-banding method and by crossing these lines with Chinese Spring/Betzes addition lines. Two disomic addition lines were identified to have chromosome 6 and 7 of barley, respectively. Two of the five translocated chromosome addition lines were clarified to have same chromosome constitution, 42 wheat chromosomes and a pair of translocated chromosomes constituted with a long arm of chromosome 5B of wheat and a short arm of chromosome 7 of barley. The other three lines could not be identified due to chromosome rearrangement. Performances of these seven lines on agronomic characters were examined. Addition of barley chromosome 7 induced early heading, and chromosome 6 showed lated heading. Almost all of the lines except that of chromosome 6 showed short culm length and all showed reduced number of tillers, spikelets and grains per ear, and low seed fertility. These lines would be useful for genetic analyses in wheat and barley and for induction of useful genes of barley into wheat. This revised version was published online in July 2006 with corrections to the Cover Date.