滴灌模式下矮秆基因对小麦部分农艺性状的效应

为探明滴灌模式下矮秆基因对小麦农艺性状的影响,对不同麦区的271份小麦品种(系)所含的矮秆基因Rht-B1b、Rht-D1b和Rht8进行检测,并对其在滴灌栽培模式下的株高、穗长、小穗数、穗粒数和单株产量进行分析。结果表明,参试的271份小麦品种(系)中有177份含矮秆基因Rht-D1b,占65.31%;110份含Rht-B1b,占40.59%;58份含有Rht8,占21.40%;27份材料不含有所检测的3个矮秆基因。34.68%的品种(系)含有2个或3个矮秆基因。根据所含矮秆基因的类型可将271份材料分为8类。3个矮秆基因都能显著降低滴灌栽培模式下小麦的株高,其中Rht-B1b还显著降低了穗长、小穗数和单株产量,对穗粒数的影响不显著;Rht8对穗长、小穗数、穗粒数和单株产量均产生了负效应,但影响不显著;Rht-D1b对株高的影响最大,并对穗长、穗粒数和单株产量具有正效应,在育种中应加强利用。     

黄淮麦区小麦品种矮秆基因Rht-B1b、Rht-D1b和Rht8的检测及其对农艺性状的影响

为了解黄淮麦区小麦品种主要矮秆基因的分布和利用状况及其与主要农艺性状的关系,利用分子标记结合系谱分析对黄淮麦区20世纪及近年来新育成的129份小麦品种所含矮秆基因Rht-B1b、Rht-D1b和Rht8进行检测,并结合田间株高、基部茎秆直径和壁厚、小穗数、穗粒数、千粒重及不同播期条件下的株高差等农艺性状的调查结果,分析比较了不同矮秆基因对农艺性状的影响。结果表明,129份小麦品种中,含Rht-B1b基因的品种有37份,含Rht-D1b基因的品种有73份,含Rht8基因的品种有89份,不含这3个矮秆基因的品种有6份,所占比例分别为28.68%、56.59%、68.99%和4.65%。其中,同时含Rht-B1b和Rht-D1b的品种有1份,同时含Rht-B1b和Rht8的品种有29份,同时含Rht-D1b和Rht8的品种有44份,同时含Rht-B1b、Rht-D1b和Rht8的品种有1份。不同矮秆基因及其组合的品种,在小穗数、基部茎秆直径及基部茎秆壁厚等性状上无显著差异,但仅含Rht8基因的品种的千粒重、基部茎秆直径及壁厚均大于其他基因型,并且能够显著增加穗粒数。不同矮秆基因的降秆作用强度依次为Rht-D1bRht-B1bRht8,并具有累加效应。在不同播期条件下,除不含矮秆基因材料外仅含Rht8的品种的株高稳定性最佳,仅含Rht-B1b的品种株高稳定性最差。仅含Rht-B1b的品种小穗数最高,但千粒重却最低,并显著低于不含这3个矮秆基因的品种。以上结果表明,虽然矮秆基因Rht8的降秆作用较弱,但其对农艺性状的有利贡献较多,且在不同播期环境条件下株高稳定性较好,因此在未来小麦育种中应注重矮秆基因Rht8的利用。     

黄淮麦区小麦种质资源矮秆基因分布及其与农艺性状的关系

为了进一步阐明多个矮秆基因的分布及其与小麦农艺性状的关系,运用分子标记对来自我国黄淮麦区的246份小麦种质资源中6个矮秆基因位点(Rht1、Rht2、Rht4、Rht8、Rht9及Rht12)分别进行了检测,同时连续3年调查参试材料株高、穗长、穗下节长、小穗数、旗叶长、旗叶宽、穗粒数、粒长、粒宽和千粒重共10个农艺性状,分析了不同矮秆基因位点对小麦农艺性状的影响。结果表明,6个矮秆基因在黄淮麦区小麦中均具有广泛分布,其中含有Rht1和Rht2基因的小麦品种分布最广。分析矮秆基因位点对小麦农艺性状的影响发现,在Rht1位点,Rht1-B1a和Rht1-B1b两种基因型间的株高没有显著差异;在Rht2位点,拥有Rht2-D1b类型的小麦品种所有年份间的株高和穗下节长较低,但千粒重较高,为相对优良的基因型。排除Rht1和Rht2基因效应后,Rht4、Rht8、Rht9和Rht12位点对黄淮麦区小麦品种不同农艺性状均具有重要影响,其中,Rht4基因位点主要对小麦株高和千粒重具有重要影响,且Rht4-B1b类型为相对优良的基因型;Rht8基因位点主要对小麦穗下节长、穗长和千粒重具有重要影响,且Rht8-D1b类型为相对优良的基因型;Rht9基因位点主要对小麦株高和千粒重具有重要影响,且Rht9-A1a类型为相对优良的基因型;Rht12基因位点主要对小麦千粒重和穗长具有重要影响,且Rht12-A1a类型为相对优良的基因型。进一步分析发现,6个位点中对株高影响最大的是Rht2基因,其次是Rht4基因;有4个位点(Rht1、Rht2、Rht8、Rht12)对千粒重有显著影响,其中Rht2基因的影响最大。分析除Rht1外其他5个位点优良基因型在不同时期小麦品种中的分布发现,从早期历史品种、近期历史品种到现代品种,不同位点优良基因型分布比例总体呈现上升趋势,表明优良矮秆基因型在黄淮麦区小麦品种选育中的利用逐渐增加,尤其是82.9%的现代小麦品种已含有Rht2-D1b类型。     

半矮杆基因Rht1和Rht2对小麦加倍单倍体品系产量的影响

为了评价半矮秆基因Rht1和Rht2对农艺性状的影响,应用了以携带对赤霉素不敏感的半矮秆基因Rht1和Rht2的F_1杂种诱导出的30个小麦加倍单倍体品系。这两个基因对降低株高起累加效应。携带Rht1或Rht2基因的半矮秆品系产生同用人工支撑防止倒伏下高秆品系一样多的产量。携带这两个基因的矮秆品系籽粒产量显著减少。在杂种基因型重组的遗传背景下改良了株高和籽粒产量,但是并不产生超过半矮杆基因效应的变异。     

四川小麦主要矮秆基因的分子鉴定

为系统研究四川小麦品种主要矮秆基因的组成,应用Rht-B1b和Rht-D1b基因的STS标记及Rht8基因的连锁SSR标记,对262个小麦品种(系)进行了检测。结果表明,四川小麦品种(系)具有Rht8基因连锁标记的频率为54.6%,Rht-D1b基因的频率为37.4%,Rht-B1b基因的频率为15.3%。与前人的研究比较发现,四川小麦Rht8连锁标记的频率高于全国平均值,而Rht-B1b和Rht-D1b的频率都低于全国平均值。这3种矮秆基因一共构成了8种组合类型。为分析不同基因组合对株高的影响,对连续种植3年的125份材料进行了测定。这些材料中,不含3种基因的类型占12.8%,仅含有Rht8的类型最多(33.6%),其次为仅含有Rht-D1b基因的类型(20%);同时含有Rht8基因和Rht-D1b基因的类型占17.6%;含有Rht-B1b基因的组合类型所占比例较少(都低于10%)。矮秆基因的降秆强度表现为:Rht-D1bRht-B1bRht8。同时具有3种矮秆基因的材料,其降秆强度最大,其次为含有2种矮秆基因的组合类型。     

小麦显性矮源对主要农艺性状的影响

利用 5个普通小麦品种与 5个不同显性矮源回交 6代以上 ,产生的 5套近等基因系 ,研究显性矮源对株高、穗长、小穗数、穗下节间长、旗叶长和生物产量等主要农艺性状的影响。结果表明 ,显性矮源的近等基因系对回交父本的主要农艺性状有显著影响 ,回交父本的遗传背景对显性矮源近等基因系有一定的修饰作用。所有显性矮源近等基因系都极显著降低回交父本的株高、穗下节间长和生物产量。西农 0 2和矮苏 3矮源近等基因系对回交父本的穗长没有影响 ;奥尔森矮源近等基因系对回交父本的小穗数没有影响 ,对旗叶长影响比较小 ;矮变 1号矮源近等基因系对回交父本的所有主要农艺性状有极显著降低作用。携带 Rht10突变基因的西农 0 2和矮变 1号矮源近等基因系的主要农艺性状之间存在明显差异 ,表明西农 0 2矮源不同于矮变 1号矮源。此外 ,本文对如何降低显性矮源的负效应也进行了探讨     

47份外引小麦种质中矮秆基因的检测及其降秆效应分析

为有效利用外引小麦种质资源,明确矮秆基因的组成分布和降秆效应,利用8个矮秆基因(Rht-B1b、Rht-D1b、Rht4、Rht5、Rht8、Rht9、Rht12、Rht13)的特异性分子标记分别对47份外引种质矮秆基因进行分子检测.结果表明,有46份种质含有矮秆基因,其中,Rht-B1b、Rht4和Rht12基因的频...     

Rht12矮秆基因在不育系繁殖中的应用研究

为了解决小麦矮秆不育系的繁殖问题，使半矮秆杂种小麦尽快投入生产应用，利用中国农业大学从德国引入的Rht12矮秆系与江苏省小麦推广品种杂交和回交，育成了适合江苏省南部种植的Rht12矮秆系及其T型细胞质雄性不育系。由同一品种转育的Rht12矮秆系，其株高变动于50～90cm之间；不同株高的Rht12矮秆系可以配制出不同株高的杂种F1。在拔节期至穗期喷施50～100mg/kg的赤霉酸溶液，可以使Rht12矮秆系的株高显著增加。在不育系种子繁殖区内，喷施50mg/kg的赤霉酸溶液，保持系株高由65cm增加到90cm，不育系植株的异交结实率由对照的20.2%增加到60.4%，从而显著地提高了不育系种子产量。株高的差异也能在收获时防止保持系种子混入不育系中，从而可以确保不育系种子的纯度。本文还讨论了如何解决Rht12矮秆系所存在的晚熟性和早枯等不良性状问题。     

籼稻矮秆等基因系分析

 以11个籼稻矮秆品种（系）高秆籼稻棉花条和南京6号为轮回亲本，连续回交5代，育成两套籼稻矮秆等基因系。比较分析了有关株高、叶片配置和产量等22种性状的变异。结果表明：株高、地上部节间长、穗长、上部3叶片的长宽、剑叶和倒二叶的夹角等14个性状明显受矮秆基因多效性的影响。sd-1和非等位基因间存在差别。等基因系与原品种（系）之间，株高和地上部节间长多数性状有显著差别。讨论了非基因多效性引起的变异的遗传原因。     

甘肃冬小麦品种(系)主要矮秆基因型及其育种利用进展

适当降低株高,增强品种抗旱性,提高品种丰产性是甘肃旱地冬小麦育种新策略。为了明确近20年甘肃冬小麦品种(系)中矮秆基因的分布以及株高变化情况,本研究利用6个主要矮秆基因的特异性分子标记对92份冬小麦品种(系)进行基因型检测,并对矮秆基因的利用情况进行分析。结果表明,供试品种(系)中均含有Rht-D1b基因,其次是Rht8、Rht13和Rht5(分布频率分别为59.8%、29.3%和10.9%),但并未检测到Rht-B1b和Rht12。Rht5和Rht13基因主要分布在陇南(天水市和陇南市)的山旱地品种(系)中,频率分别为16.7%和36.7%,Rht8主要分布在陇南川区品种(系)中,频率为77.4%。同时含有2个矮秆基因的材料有39份,分布频率为42.4%,其中Rht-D1b+Rht8的分布频率最高(33.7%);同时含有3个矮秆基因的材料有25份,分布频率为27.2%,其中Rht-D1b+Rht8+Rht13的分布频率最高(19.6%);同时含有4个矮秆基因Rht-D1b+Rht5+Rht8+Rht13的材料只有1份,分布频率为1.1%。含多矮秆基因组合的品种(系)在陇南川区的分布频...     

Physiological and Agronomic Consequences of Rht Genes in Wheat

Summary

Yield of wheat has risen dramatically and world-wide in the last two decades, in part because of the widespread introduction of Rht genes that reduce the length of tillers of wheat. We review the physiological consequences of incorporating reduced height genes into wheat. The Rht₁ or Rht₂ genes modulate the morphology and physiology of wheat in a manner that involves compensation among several physiological processes. For instance, Rht genes decrease leaf area, but photosynthesis per unit area increases, so biomass accumulation is rarely altered. Although Rht genes increase leaf permeability to water vapor, plant water status changes in compensation to minimize differences in water use efficiency. Perhaps due to less competition for carbohydrate during stem elongation, semidwarf wheat has greater harvest index than tall wheat at maturity. Although tall wheat has a greater weight per kernel at maturity, this does not completely compensate for greater grain number per spike in semidwarf wheat. The compensation that leads to greater yield in semidwarf wheat appears to fail in Rht₁Rht₂ or Rht₃ dwarf wheat. Either specific photosynthesis does not completely compensate for decreased area per leaf, or the reduction in plant height retards canopy closure and efficient interception of solar radiation, resulting in lower biomass and yield of dwarf wheat. Drought stress reduces yield and harvest index of dwarf wheat more than tall wheat. Rht genes have insignificant effects on rate of development or winter hardiness. The effects of Rht genes on physiology appear to be similar in winter, spring and durum wheat.     

小麦显性矮源对株粒重及产量构成因素的影响

利用8个普通小麦品种与5个不同显性矮源进行回交产生的8套近等基因系，进行了株粒重及产量构成因素的研究，结果表明，显性矮源对有效穗数没有显著影响，对株粒重、穗粒数和千粒重都有显著的降低作用，降幅最小的是具有奥尔森矮源的近等基因系，分别降低19．6％、26．9％和10．5％；降幅最大的是具有矮变1号矮源的近等基因系，分别降低68．9％、66．7％和24．7％。携带Rht10基因的西农02和矮变1号矮源转育的近等基因系之间的株粒重、穗粒数和千粒重的差异都显著或极显著，说明它们对普通小麦品种的影响不一致。具有显性矮源的近等基因系株粒重偏低的主要原因是穗粒数减少和千粒重降低。具有显性矮源近等基因系的株粒重与株高的回归分析表明，适当提高显性矮源的株高可以提高株粒重。     

Growth and development in tall and dwarf isogenic lines of spring wheat

The objective of the experiments reported here was to analyse the nature of the effects of the Rht dwarfing genes on yield potential in spring wheats, using near-isogenic lines of Yaqui 50 and Ciano 67 grown controlled environments. Although tall and dwarf lines had similar relative growth rates at all stages, the taller plants were consistently larger throughout due to faster and more uniform germination. Stem weight at anthesis-whether total or residual-was reduced by the Rht genes in proportion to height. Leaf length and area were much less affected by the Rht genes than was stem length, and later-formed leaves of dwarf plants could even be larger than in their tall counterparts at cool temperatures. Peak photosynthetic rates were similar in talls and dwarfs, the small differences usually reflecting differences in leaf size or specific leaf weight. Root weight was initially heavier in the taller lines, but after the stage of rapid stem elongation it tended to be heavier in the dwarfs. Tillering could be greater or less in the dwarfs depending on environmental conditions, stage, and genotype.Inflorescence initiation was somewhat earlier in the dwarf lines and their inflorescences were therefore initially heavier, and remained so up to anthesis under low irradiance and warm temperatures. But under high irradiance and/or cool temperatures, after an initially slower start the inflorescences of the taller lines eventually became the heavier. Ear weight at anthesis was closely correlated with grain number per ear at maturity and with grain yield per ear in Yaqui 50, but less closely in Ciano 67 lines, in which grain set was reduced at lower temperature when additional Rht genes were present. No evidence was found for a specific effect of the Rht genes in raising grain number. Ear weight at anthesis was relatively less affected than stem weight by adverse conditions, especially in the shorter lines. Nevertheless, across all conditions there was a close relation between stem and ear weights at anthesis, which differed between lines of different height but which closely fitted one regression when ear weight was related to the weight per unit length of stem. Under low irradiance and high temperature the greater stem growth of the taller lines was associated with smaller ears, but at high irradiance and cool temperatures both ears and stems were heavier in the taller lines.Treatments with GA₃ or CCC, to which only the tall lines responded, showed that ear weight at anthesis did not vary with large increase or decreases in stem weight, but grain set and kernel weight could be changed substantially.The yield-determining effects of the Rht genes thus varied with stage of development and environmental conditions, and with genetic background, which may have to be adjusted in order to optimise the effects of the Rht genes on yield potential, suggesting that comparisons of isogenic lines may not always provide a satisfactory indication of the potential value of major genes in breeding programs.     

The Rht13 dwarfing gene reduces peduncle length and plant height to increase grain number and yield of wheat

The green-revolution Rht-B1b and Rht-D1b dwarfing alleles are usually associated with increased wheat yields but are linked to reduced early growth and poor emergence if sowing conditions are unfavourable. Other dwarfing genes are available but not used in commercial breeding. The Rht13 bread wheat donor, Magnif M1, produces uniquely short peduncle and penultimate internodes to reduce plant height. A set of near-isogenic (NILs) and recombinant inbred (RILs) lines varying for height were developed from the cross of Magnif M1 and the Rht8c-containing Chuan-mai 18, and evaluated for a range of agronomic characteristics across favourable environments. Reductions in plant height were associated with increased grain number (r² = 0.35**) and harvest index (r² = 0.62**) in the NILs. Reduced-height RILs containing the Rht13-linked, Xgwm577_M microsatellite marker were significantly shorter, produced greater biomass, yield and harvest index, and increased spike and grain number than lines without the marker. Approximately 74 and 7% of the total phenotypic variance in plant height was accounted for by allelic differences in Xgwm577 and Rht8 loci, respectively. The peduncle and penultimate peduncle internodes of Rht13-containing lines were proportionately shorter than Rht8c-containing sibs and lines containing the Rht-B1b dwarfing allele. The unique height-reducing phenotype, increased grain number and yield associated with Rht13 indicate considerable potential for use of this dwarfing allele for improving wheat performance.     

秋播冬麦区矮秆基因 RhtB1b、 RhtD1b和 Rht8的分布频率及其与产量性状的关系

为给小麦株高和产量的遗传改良提供参考依据,利用 Rht-B1b、 Rht-D1b基因的STS分子标记BF/MR1和BF/WR1、DF1/MR2和DF2/WR2,以及 Rht8基因的微卫星标记Xgwm261,对237份不同生态区秋播小麦材料进行分子标记检测,并分析 Rht-B1b、 Rht-D1b和 Rht8对株高及产量相关性状的影响。结果表明：（1）在分布频率方面, Rht-B1b、 Rht-D1b和 Rht8在秋播冬小麦中的频率较高,其中携带 Rht-B1b、 Rht-D1b和 Rht8的小麦材料分别占比16.5%、47.9%和44.1%;聚合两个矮秆基因（ Rht-D1b+Rht8、 Rht-B1b+Rht8和 Rht-B1b+ Rht-D1b）的小麦材料占比25.4%;聚合三个矮秆基因（Rht-B1b+Rht-D1b+Rht8）的小麦材料占比2.1%;（2）在分布特点方面,不同冬麦区存在一定偏好性：北部冬麦区、黄淮冬麦区、长江中下游冬麦区均以 Rht-D1b、 Rht8和 Rht-D1b+Rht8为主;西南冬麦区以 Rht-B1b、 Rht-D1b和 Rht8为主,西南冬麦区以 Rht-B1b、Rht-D1b和Rht8为主;（3）在降秆效应方面,降秆效果从强到弱依次为（ Rht-B1b+Rht-D1b+Rht8）>（ Rht-D1b+Rht8）> （ Rht-B1b+Rht8）> Rht-D1b> Rht-B1b> Rht8;(4)在产量结构特点方面, 携带 Rht-D1b和 Rht8的材料总体上具有较高的千粒重和单位面积穗数,携带 Rht-B1b的材料具有较高的穗粒数,但矮秆基因本身与产量因子间无显著的遗传相关性。     

部分印度小麦品种矮秆基因的检测及其对部分性状的影响

为了解印度小麦品种中矮秆基因的分布特点,明确矮秆基因对株高和胚芽鞘长度的影响,本研究利用8个小麦矮秆基因的特异分子标记结合赤霉素处理,检测21份印度小麦品种中的矮秆基因,并结合田间株高调查和室内胚芽鞘长度测量评价了该批材料中各种矮秆基因对株高和胚芽鞘长度的影响。结果表明,21份印度小麦品种中均检测到了相关矮秆基因,且均含有两个及其以上矮秆基因,其中含有3个矮秆基因的材料有13份,含有4个矮秆基因的材料有3份。该批材料中矮秆基因Rht8和Rht4的分布频率较高,分别占66.7%和61.9%;含有Rht5和Rht-B1b的材料也较多,分别占57.1%和52.4%;未检测到含有Rht12和Rht13基因的材料。赤霉素处理结果表明,该批材料中对赤霉素敏感的有4份。胚芽鞘长度调查结果表明,大部分材料的胚芽鞘长度比中国春的长,其中13份材料的胚芽鞘显著长于中国春。田间株高调查结果显示,该批材料株高均显著低于中国春。以上结果表明,这21份印度小麦品种中的矮秆基因降低株高的效应较强,且对幼苗胚芽鞘无不利影响,适于旱地矮秆小麦改良利用。     

多小穗小麦综合性状轮回选择改良研究

为进一步改良多小穗小麦的综合性状,利用太谷核不育材料(含显性Ms2基因),导入多小穗基因和中矮秆Rht10基因进行轮回选择育种.结果表明,轮回选择使多小穗基因与Ms2基因和Rht10基因相结合,使群体主茎小穗数达到24～27个,植株高度从100 cm降至65～70 cm,抽穗期和成熟期提前;选择出具有30个小穗的中矮秆多小穗基因型株系;获得了Ms2基因、Rht10基因、多小穗基因和早熟基因有机地结合为一体的多小穗小麦综合改良群体.