大麦穗长和株高QTL的鉴定

为挖掘大麦穗长和株高的QTL位点,以1个大麦重组自交系（recombinant inbred line,RIL）群体（以J36528和BMJ89为亲本,包含125个F₁₀代）为材料,基于本课题组前期利用DArT标记构建的连锁图谱,结合4年2点共6个不同生态环境测得的穗长和株高表型数据,鉴定大麦穗长和株高QTL。结果表明,共鉴定到3个穗长QTL和2个株高QTL,分别分布在2H、3H、6H和7H染色体上,其中,穗长位点 Qsl.sicau-JB-2H在2个环境中被检测到,能够解释11.38%~14.66%的表型变异; Qsl.sicau-JB-7H在6个环境中均被检测到,能够解释35.10%~46.34%的表型变异;而 Qph.sicau-JB-6H仅在1个环境中被检测到,可解释17.99%的表型变异。株高位点 Qph.sicau-JB-6H在5个环境中均被检测到,能够解释16.36%~21.18%的表型变异;而 Qph.sicau-JB-3H仅在1个环境中被检测到,可解释15.40%的表型变异。本研究为解析大麦植株形态和产量性状遗传机制以及分子辅助育种奠定了基础。     

大麦旗叶长和宽的QTL分析

为解析调控大麦旗叶大小的遗传机制,以1个大麦重组自交系(RIL)群体(由J36528和BMJ89为亲本构建,包含125个F10代)为材料,利用447个DArT和8个SSR标记绘制遗传连锁图谱,结合4年2点共6个生态环境下测得的旗叶长和宽表型数据,鉴定旗叶长和宽相关的QTL。结果表明,所构建的遗传图谱包含7个连锁群,总长1 034.96 cM,平均每条染色体147.85 cM,标记密度为2.27 cM。共检测到7个旗叶长QTL和5个旗叶宽QTL,分布在2H、4H、5H、6H和7H染色体上。其中,有2个旗叶长主效位点 QFll.sicau-JB-5H.2和 QFll.sicau-JB-6H.1,能够在多环境下稳定表达,表型变异解释率范围分别为12.02%~  19.95%和16.69%~16.99%;二者累加对旗叶长具有增加效应,聚合这2个位点对大麦旗叶长的调控和产量提升具有潜在价值。另外,有1个旗叶宽主效位点 QFlw.sicau-JB-4H在多环境下能够稳定表达,表型变异解释率为15.03%~23.99%。将主效QTL锚定到大麦参考基因组后比对发现, QFll.sicau-JB-6H.1可能为新位点,而 QFll.sicau-JB-5H.2可能与小麦第五部分同源群检测到的旗叶长位点具有同源性。本研究鉴定获得的与旗叶长和宽相关的稳定表达的主效QTL对大麦不同旗叶形态基因的精细定位和分子辅助育种提供了依据。     

四倍体小麦株高和穗长性状的QTL定位及其遗传效应分析

株高和穗长是影响小麦高产稳产的重要农艺性状。为进一步发掘控制株高和穗长的主效QTL,以硬粒小麦矮兰麦和野生二粒小麦LM001构建的F₈代重组自交系（RIL）群体为材料,基于小麦55K SNP芯片构建的遗传连锁图谱,并结合5年8个生态环境的株高和穗长表型数据,进行QTL定位和遗传解析。结果表明,在RIL群体中,株高和穗长均呈现正态分布,符合数量性状遗传特征。共检测到24个QTL,其中7个与株高相关,分布在2A、2B、4B、5A、6A和7A染色体上,可解释7.46%~20.03%的表型变异;17个与穗长相关,分布在2A、2B、3A、4A、4B、5A和6B染色体上,可解释6.52%~17.10%的表型变异。控制株高的 QPh.sicau-AM-4B和 QPh.sicau-AM-7A以及控制穗长的 QSl.sicau-AM-2B.2和 QSl.sicau-AM-4B.4能够同时在单环境和多环境分析中检测到,为稳定的主效QTL,分别解释了9.17%~20.03%、10.44%~ 14.48%、10.41%~16.29%和7.54%~11.70%的表型变异。此外,在RIL群体子代中存在超亲分离现象,进一步的QTL聚合效应分析表明,株高位点 QPh.sicau-AM-4B和 QPh.sicau-AM-7A的聚合或者穗长位点 QSl.sicau-AM-2B.2和 QSl.sicau-AM-4B.4的聚合均能极显著地提高株高和穗长表型,表明鉴定到的控制株高和穗长的QTL位点具有累加效应。     

小麦旗叶大小及穗部相关性状的QTL定位

为了发掘更多控制小麦旗叶大小及穗部相关性状的QTL,以兰考906和小偃81创制的133个F6~F7重组自交系为试验材料,在6个环境下利用SSR标记对旗叶大小及穗部相关性状进行QTL定位。结果表明,有202对SSR标记被用于构建遗传连锁图谱,图谱覆盖小麦21条染色体,全长1 678.93cM,标记间平均距离8.30cM。采用完备区间作图法共检测到30个QTL,分布在1B、2A、3D、4A、4B、4D、5D、6A、6B、6D和7D染色体上。其中,旗叶宽QTL有7个,穗长QTL有9个,小穗数QTL有5个,穗粒数QTL有5个,小穗着生密度QTL有4个,不同环境下单个QTL可解释的表型变异率为4.94%~23.14%,有14个QTL的表型贡献率大于10%,有8个QTL可在2个或2个以上环境中被检测到。其中,Qflw-4A在3个环境中被检测到,贡献率为10.13%~20.77%,是控制旗叶宽的稳定主效QTL;Qsl-4D.2在4个环境中被检测到,贡献率为12.58%~23.14%,是控制穗长的稳定主效QTL;Qker-5D在2个环境中被检测到,贡献率为11.44%~14.32%,是控制穗粒数的稳定主效QTL。这3个稳定主效QTL可作为改良叶宽和增加穗粒数的功能QTL作进一步研究。     

利用90K基因芯片进行小麦旗叶相关性状的QTL定位

为了发掘影响小麦旗叶相关性状的QTL,以小麦骨干亲本周8425B与优良品种小偃81构建的包含102个家系的重组自交系(Recombinant inbred line,RIL)为材料,采用小麦90KSNP基因芯片技术和SSR标记对其进行分子标记检测,构建含有全基因组SNP和SSR标记的高密度遗传图谱,并在4个环境下对小麦旗叶相关性状QTL进行检测。结果表明,所构建图谱含有6 949对多态性标记,其中,SNP标记6 910对,SSR标记39对,覆盖染色体总长度4 839.9cM,标记间平均距离0.7cM;A、B和D染色体组分别有2 085、4 677和187对标记,分别占总标记数的30.0%、67.5%和2.7%,标记间平均距离分别为1.0、0.6和0.8cM。采用完备复合区间作图法共检测到22个旗叶性状加性效应QTL,10个旗叶长QTL分布于2A、3B、4B、5A、6B和7B染色体上,解释表型变异7.900%~24.098%,除Qfll2A-1能在2个环境中检测到外,其余均为单环境QTL;4个旗叶宽QTL分布于2A、3A和5B染色体上,解释表型变异9.080%~16.540%,其中,Qflw2A-1在3个环境中均能检测到,解释表型变异12.483%~16.540%,为1个稳定的主效QTL;8个旗叶面积QTL分布于2A、3B、4B、5A、6B和7A染色体上,解释表型变异9.310%~30.498%,其中,3个QTL位于5A染色体上。此外,鉴定出3个分布于2A、5A和6B染色体上的QTL富集区段。     

大穗材料高麦1号/ 密小穗F2群体穗长性状的QTL初步定

为了解小麦穗长性状的遗传特性,并将其应用于分子标记辅助育种,以大穗材料高麦1号/密小穗的292个植株的F2群体为材料,利用SSR标记对穗长进行了QTL定位分析.结果表明,选用500对SSR引物对高麦1号和密小穗两个亲本进行多态性检测,共获得180对在双亲问有多态性的引物,多态性引物检出率为36.0％.利用这180对引物进一步进行F2群体筛选,有96对引物在群体中表现出多态性,占多态性标记的53.3％.利用QTL_IciMapping软件构建出小麦染色体组的8个连锁群图谱,并将96对SSR引物定位到遗传连锁图谱上.图谱全长1 383.29 cM,标记间的平均遗传距离15.37 cM.平均每个连锁群有11.25个标记,含有标记最多的是4A和6B染色体,各有17个标记,其次是3A和7B染色体,含有9～14个标记,1B和5D染色体含有的标记最少,只有5～7个.共检测出7个与穗长相关的QTL位点,包括6个加性QTL和1个加性+显性QTL.7个QTL的加性效应值均为正值,单个QTL的贡献率为2.04％～15.26％.其中3A染色体上的QTL位点距离其最近标记只有0.58 cM,为连锁最紧密的一个位点,并且其加性效应值最大,可解释表型变异的15.26％.因此,3A染色体上存在控制穗长的主效基因.     

扬麦17/ 宁麦18的F2群体穗部性状QTL定位

小麦穗部性状特别是穗顶部、基部结实性对穗粒数的建成及产量具有重要影响。为给QTL精细定位、基因克隆及穗部性状分子标记的开发和辅助选择奠定基础,本研究以扬麦17与宁麦18杂交获得的310个F₂群体及其衍生的F_2:3家系为材料,构建了一个由215个SSR标记组成的全长为1 717 cM的遗传连锁图谱,共覆盖19条染色体（1D和6A未涉及）,标记间平均距离为7.99 cM,并对6个穗部性状进行QTL定位。利用复合区间作图法共检测出22个QTL,分布在1A、1B、2B、2D、3B、3D、4B、5A、5B和7A染色体上。其中,穗顶部结实粒数QTL有7个,穗基部结实粒数QTL有2个,穗长QTL有5个,总小穗数QTL有3个,不育小穗数QTL有2个,穗粒数QTL有3个,表型贡献率为2.56%～13.66%。控制穗顶部和基部结实粒数QTL的增效基因来源于宁麦18,表明该品种可作为具有高产潜力的小麦育种材料加以利用。     

玉米雄穗相关性状QTL分析

以掖478和齐319构建染色体片段代换系群体（CSSLs），分析石家庄、新乡、昌平、顺义4个地点的雄穗主轴长（TL）和雄穗分枝数（TBN）的表型鉴定数据。结果表明，在2个以上环境中共检测到27个雄穗主轴长QTL，分布在1、2、3、4、5、7、8、9和10号染色体上，其中，1号染色体上雄穗主轴长QTL位点最多；共检测到23个雄穗分枝数QTL，分别位于1、2、4、6、7、8和10号染色体，其中，1号染色体上雄穗分枝数QTL位点最多。验证了北方春玉米环境稳定的3个雄穗主轴长QTL和10个雄穗分枝数QTL，发掘到黄淮海环境特异的5个雄穗主轴长QTL和3个雄穗分枝数QTL。在4个环境下均能检测到5个雄穗主轴长QTL（qTL1-3、qTL1-4、qTL2-1、qTL3和qTL4-2）和1个雄穗分枝数QTL（qTBN1-7），可为控制雄穗主要性状的基因克隆和机理解析提供参考。     

大穗材料高麦1号/密小穗F_2群体穗长性状的QTL初步定位

为了解小麦穗长性状的遗传特性,并将其应用于分子标记辅助育种,以大穗材料高麦1号/密小穗的292个植株的F2群体为材料,利用SSR标记对穗长进行了QTL定位分析。结果表明,选用500对SSR引物对高麦1号和密小穗两个亲本进行多态性检测,共获得180对在双亲间有多态性的引物,多态性引物检出率为36.0%。利用这180对引物进一步进行F2群体筛选,有96对引物在群体中表现出多态性,占多态性标记的53.3%。利用QTL_IciMapping软件构建出小麦染色体组的8个连锁群图谱,并将96对SSR引物定位到遗传连锁图谱上。图谱全长1 383.29cM,标记间的平均遗传距离15.37cM。平均每个连锁群有11.25个标记,含有标记最多的是4A和6B染色体,各有17个标记,其次是3A和7B染色体,含有9~14个标记,1B和5D染色体含有的标记最少,只有5~7个。共检测出7个与穗长相关的QTL位点,包括6个加性QTL和1个加性+显性QTL。7个QTL的加性效应值均为正值,单个QTL的贡献率为2.04%~15.26%。其中3A染色体上的QTL位点距离其最近标记只有0.58cM,为连锁最紧密的一个位点,并且其加性效应值最大,可解释表型变异的15.26%。因此,3A染色体上存在控制穗长的主效基因。     

基于温热BC1群体的农艺性状QTL定位

利用昌7-2与热带自交系CML451构建的BC₁群体开花期、株高以及产量相关性状进行QTL定位分析。通过复合区间作图方法共检测到与散粉期、抽丝期、株高、穗位高、穗长、穗粗、穗轴粗、穗行数8个性状相关联的QTL 26个。控制散粉期的qDTP5被定位于第5染色体上的umc1523-bnlg1660标记区间,其解释了16%表型变异;控制株高的qPH3被定位于第3染色体上的bnlg1798-bnlg1852标记区间,解释了19.9%表型变异;控制穗位高的qEH10-2被定位于第10染色体上的umc1911-bnlg594标记区间,解释了13.4%表型变异;控制穗长的qEL10-2被定位于第10染色体的bnlg1250-bnlg594区间,解释了13%表型变异;控制穗粗的qED5、控制穗轴粗的qCD5、控制穗行数的qER5均被定位于第5染色体上的bnlg1660-bnlg1208区间,分别解释了18.1%、11.3%与21.8%表型变异;qED7定位于第7染色体上的umc1154-umc1799区间,与穗粗相关,解释了21.9%表型变异。     

安徽省小麦赤霉病菌群体遗传多样性AFLP分析

为了解安徽省小麦赤霉病菌的群体分化和遗传变异规律,利用AFLP技术对安徽省4个地理群体的68个供试菌株进行了群体遗传多样性分析。结果表明,8对引物共扩增出245条带,供试菌株间的遗传距离为0.014~0.021。4个小麦赤霉病菌群体之间的遗传距离与地理分布没有明显的相关性。4个赤霉病菌群体的Shannon信息指数I为0.321,基因多样性指数H为0.193,表明具有一定的遗传多样性。方差分析表明,被测小麦赤霉病菌群体的遗传变异主要存在于群体内(99.80%),群体间的遗传变异仅占0.20%。4个赤霉病菌群体间存在较低的遗传分化(Gst=0.049)和频繁的基因交流(Nm=9.648)。相比较而言,北部群体和中部群体亲缘关系较近,而南部群体和中、北部群体亲缘关系较远。     

Production of above-ground seed tubers on stem cuttings from eight potato cultivars

Summary The formation of above-ground tubers on stem cuttings of eight potato cultivars was studied over three seasons. To promote tuber formation in the leaf axils, stems grown from single node cuttings were exposed to short day conditions. Tuber formation underground was reduced by covering the soil with a plastic sheet and by using single node cuttings planted with the leaf axils several centimetres above the soil surface. With all cultivars except Alpha, which produced mis-shapen tubers in all experiments, an average of 11 (maximum 40) tubers per cutting were harvested. Significant cultivar × year interactions were observed.     

Influence of early haulm killing of seed crops on subsequent sprouting,physiological ageing and tuber yield

Summary The production of healthy and high yielding seed potatoes is closely related to the control of virus diseases and to other cultural practices, like those modifying the physiological age of tubers. Seed crops from cv. Bonaerense La Ballenera MAA, were defoliated early in 3 seasons, 1983/84, 84/85 and 85/86. After harvest, the seed tubers were stored in heaps in the field and, later, their sprouting capacity and physiological age, and their tuber yield were evaluated. Results showed that early haulm killing did not affect these variables nor diminish the quality of the seed potatoes obtained.     

低氮胁迫下大麦苗期株高和根长的遗传特性

为指导大麦耐低氮育种,以耐低氮大麦材料BI-04与低氮敏感材料BI-45衍生的F3群体为供试材料,利用主基因十多基因混合遗传模型,对低氮胁迫下大麦苗期的株高和根长性状进行了遗传分析.结果表明,低氮胁迫下,F3群体株高表现为13-4遗传模型,即2对主基因的等加性遗传模型,遗传率为30.99％,说明选育株高性状可以在相对较早的世代进行.F3群体根长则表现为A-0遗传模型,即无主基因遗传模型,说明选育根长性状需要在较晚世代进行.     

Effect of weight of potato minitubers on sprout growth,emergence and plant characteristics at emergence

Summary The behaviour of minitubers in five weight classes, having mid-point values between 0.19 and 3.00 g, was studied during sprouting and emergence under controlled conditions. Lighter tubers took longer to produce sprouts of 2 mm, and their sprouts grew more slowly between 2 and 4 mm and 4 and 6 mm. As sprouts lengthened their rate of growth increased. The influence of tuber weight was less for heavier tubers and also decreased as the sprouts grew longer. When tubers with sprouts of the same length were planted in pots, sprouts from lighter tubers took longer to emerge. Emergence was later and differences between weight classes were larger when tubers were planted deeper (6 or 9 cm) or when they had shorter sprouts at planting (2 or 4 mm). At emergence, plants from lighter tubers had thinner stems and lower stem and root weights, but higher stem weights proportional to tuber weights and higher shoot:root ratios.     

A joint influence of the distributions of fiber length and fineness on the strength efficiency of the fibers in yarn

The length and fineness of fibers are critical to the strength of yarns. Much research has been conducted on the issue in the past decades. Zeidman and Sawhney introduced a new parameter called strength efficiency (SE) of fibers in a yarn using an elaborate probabilistic method. Their final formula, a non-dimensional measure, describes the influence of the fiber length distribution on the strength of yarn. The result, however, is based on the assumption that the fibers are identical in all respects including their cross-sectional area. The influence of fiber fineness can not be seen in their formula. In fact the joint influence of fiber length and fineness is rarely studied. We derive a new strength efficiency of the joint influence of fiber length and fineness on the basis of Zeidman’s result. The conclusion is helpful to the understanding of the comprehensive influence of fiber length and fineness on the strength of yarn. Furthermore, we give a plausible method to estimate the critical length defined by Zeidman. The result can be applied to the research of the properties between fibers and yarns.     

The influence of fiber length distribution on the accelerated points in drafting: A new perspective on drafting process

The distribution of the accelerated points of fibers in roller drafting is the key to the evenness of the drafted slivers. The fiber length distribution is believed to affect the accelerated points. This approach is trying to give a quantitative expression of the influence. A parabolic density function is introduced for the expression of density functions and a generalized method is presented. The experiment shows that the parabolic-type density function is a better explanation for the distribution of the accelerated points in the drafting zone in terms of the consequent yarn unevenness. The statistical test verifies the distribution type. The analysis helps to understand the mechanism of the roller drafting and can be used in the optimization of the parameters in roller drafting.     

The effect of temperature and light during storage of young seed potatoes on initial plant development at early plantings

Summary Young seed tubers of several cultivars were exposed to storage temperatures of 4–24°C in light and dark intended to optimise their growth vigour following early plantings. In five experiments during four autumn and winter periods, the effects of storage conditions on subsequent initial plant development in the glasshouse were studied. Storage of seed potatoes for 2 months at temperatures of 12°C or higher greatly increased early plant development of five cultivars following early plantings. Light during storage had a favourable effect, but desprouting before planting was greatly disadvantageous.