小麦显性矮秆基因Rht3理想株高突变体的基因型检测

本研究采用4BS染色体携带Rht3基因的小麦显性矮源"矮苏3"(55～60 cm),经辐射与化学诱变,获得了一系列株高在70～85 cm、具小麦育种理想株高的突变体.采用形态标记、生化标记及分子标记对上述理想株高突变体进行了基因型检测.经成熟种子萌发试验的生化标记检测表明,理想株高突变体仍具有显性矮秆基因Rht3成熟种子α-淀粉酶活性低而抗穗萌的特性.经采用位于4BS染色体上的"易组太谷核不育基因MS2 (4BS)"作为形态标记基因来定位理想株高突变体携带的半显性矮秆基因,证实了理想株高突变体携带的半显性矮秆基因与MS2(4BS)连锁、因而与Rht3基因同位于普通小麦4B染色体上.基于通常认为Rht3与隐性矮秆基因Rht1同为4BS染色体上的复等位基因,经采用Ellis等开发的"perfect marker"SSR特异引物的分子标记检测,在矮苏3及其理想株高突变体上同时扩增出了与Rht-B1b相同的237 bp的特征带.以上3种类型的基因标记检测的结果,均有利于说明矮苏3的理想株高突变体携带Rht3突变衍生的复等位基因,因其具理想株高而又抗穗萌,可望作为半显性创新矮源用于高度集约化的小麦"分子设计育种",以克服小麦育种目前局限于使用隐性矮源的局面,实现自"绿色革命"以来小麦育种矮源的升级换代.     

四倍体小麦矮秆基因的赤霉素敏感性及对农艺性状的影响

为明确四倍体小麦矮秆基因Rht14、Rht16和Rht18的赤霉素敏感性及其对小麦农艺性状的影响,促进这些矮秆基因的合理利用。选用分别含有Rht14、Rht16和Rht18的四倍体小麦近等基因系ANW16D(Rht14)、ANW16F(Rht16)、ANW16G(Rht18)及其高秆轮回亲本LD222以及六倍体小麦中国春(Chinese spring),测量其不同浓度GA3处理下小麦的株高,计算赤霉素敏感系数(GRI)并推断3种矮秆小麦的赤霉素反应类型。在成熟期对LD222近等基因系小麦的农艺性状如株高、穗长、主穗穗下第一茎节(P-1)节间长、节间表皮细胞、种子表皮细胞及种子体积等进行测量,分析Rht14、Rht16、Rht18这3个矮秆基因对小麦这些农艺性状的效应。结果表明,ANW16D、ANW16F和ANW16G这3个矮秆小麦株高恢复到正常LD222株高的最适GA3浓度为10-4mol/L;3个矮秆品种均为赤霉素敏感型且敏感性大小为中国春ANW16GANW16FANW16DLD222;Rht14、Rht16、Rht18均是通过降低主穗穗下第一茎节(P-1)节间长度来使小麦株高降低,降低效应为Rht18Rht16Rht14;它们降低小麦株高的根本原因均是缩短了小麦节间表皮细胞长度且缩短效应与降低株高效应一致;3个矮秆基因均在降低小麦株高的同时不影响种子的体积。     

小麦显性矮秆基因Rht10“微突变”的发现

以4D染色体携带Rht10而极度矮化的小麦显性矮秆系“矮变1号”与中、高秆的现代小麦改良品种杂交，选育出了一批植株较矮变1号显著提升、以至达到小麦育种理想株高的半显性衍生矮秆系，已将其应用于杂交小麦及小麦常规育种。对半显性衍生矮秆系与起始矮秆系矮变1号矮秆主基因之间的同一性进行了研究。以此提出了小麦显性矮秆基     

小麦的矮秆基因及其研究方法

小麦的矮秆基因及其研究方法程治军,吕知敏(中国农业科学院作物所北京100081)普通小麦中已被命名的矮秆基因有20多个,它们大多由突变产生。小麦最终株高除决定于所带的矮秆基因外,还受矮秆基因所处的遗传背景和环境条件的影响。除显性、半显性的Rht3、R...     

Rht8、Rht10和Rht12矮秆基因对产量构成因子的影响

利用携带不同矮秆基因的近等基因系,通过两年、两地的试验研究证明,Rht8半矮秆基因虽然其总小穗数显著低于其他系,但其籽粒产量、小花结实率较Rht10和Rht12显著高.Rht10的降秆作用最强,千粒重显著高于Rht8,但其分蘖成穗率、结实率及小区籽粒产量显著低于其他,表现对环境条件特敏感.Rht12矮秆基因的降秆程度显著高于Rht8,但由于生物产量太低、成熟太晚,造成籽粒产量显著降低,在小麦育种中单独利用价值较低.     

小麦矮杆基因的分子检测及遗传效应研究

利用矮秆基因Rht-B1b、Rht-D1b和Rht8的特异性分子标记对202份普通小麦材料进行了分子检测,连续两年观测了供试材料的重要农艺特性,分析了不同矮秆基因的遗传效应。结果表明:在202份供试材料中,22份供试材料含有基因Rht-B1b,分布频率为10.89%;基因Rht-D1b、Rht8和不含3种矮秆基因的材料分布频率分别为73.76%、65.84%和6.93%,其中有12份材料含基因Rht-B1b+Rht8,有104份材料含Rht-D1b+Rht8,分布频率分别为5.94%和51.43%。矮秆基因对农艺特性的影响不同。3个矮秆基因均可以显著地降低株高,其降秆效应分别为Rht-D1bRht-B1bRht8,就基因组合而言,降秆效应则是Rht-D1b+Rht8Rht-D1bRht-B1b+Rht8Rht-B1bRht8,说明矮秆基因具有累加效应,同时含有2个矮秆基因要比只含有其中1个矮秆基因株高更低。矮秆基因在有效分蘖、穗长、小穗数和穗粒数等方面不存在显著差异,但矮秆基因对有效分蘖有一定的负效应,有利于穗长和穗粒数的增加。基因Rht8可以显著提高千粒重,而Rht-B1b和Rht-D1b对千粒重存在一定的负效应。试验中含有基因Rht-D1b和Rht8的部分材料在农艺性状中表现良好,应进一步加以利用。     

Rht12导入八倍体小黑麦及其对小黑麦株高、单株分禁数和种子饱满度的影响

Rht12是位于5A染色体上的显性矮秆基因。用带有该基因的普通小麦Bezostaya1, Mercia作矮源与八倍体小黑麦杂交、回交,经自交和染色体数镜检及田间、室内选择,将Rht12基因导入八倍体小黑麦,获得了染色体数56的矮秆八倍体小黑麦株。在八倍体小黑麦遗传背景下,基因型纯合(Rht12 Rht12)时降秆能力约为41.2%,杂合(Rht12rht12)     

矮败小麦的遗传研究

矮败小麦是具有矮秆基因标记的显性核不育材料,显性雄性不育基因Ms2与显性矮秆基因Rht10连锁十分紧密,其连锁交换值仅为0.18,而紧密连锁基因Ms2和Rht10与着丝点间的遗传距离为31.17个交换单位。     

黄淮南片麦区新育成品种（系）中3个矮秆基因分子标记检测及其与农艺性状的关系

利用矮秆基因RhtB1-b、RhtD1-b和Rht8特异分子标记对郑麦583和2015-2016年度参加河南省区域试验、河南省品种比较试验、国家黄淮南片区域试验及国家黄淮麦区品种比较试验的共630份小麦材料的基因型进行检测。结果表明,供试材料中检测到549份材料含有RhtB1-b基因;592份材料含有RhtD1-b基因;513份材料含有Rht8基因;422份材料同时含有3个矮秆基因,169份材料仅含有2个矮秆基因,说明3个主要的矮秆基因在河南小麦育种过程中被聚合使用。此外,分析发现,矮秆基因Rht8与株高和每公顷穗数,以及千粒重具有显著相关性。郑麦583等小麦品种聚合了这3个矮秆基因,具有优良的丰产性,通过选择和利用矮秆基因对于培育具有丰产性优点的小麦品种具有一定价值。     

小麦几个“矮源”品种矮秆基因的遗传分析

本研究选用矮变1号、冬协2号为主要矮源,通过株高的常规遗传分析、单体分析和赤霉酸(GA_3)鉴定,分析了矮源品种矮秆基因的遗传特点。结果表明:矮变1号受一对不完全显性矮杆基因控制,其株高和胚乳皆对 GA_3不敏感。蚰包的衍生系冬协2号、CA8333和农林10号的衍生系 G-230携带有相同的一对隐性矮秆基因 Rht2,且位于4D 染色体上,     

四川省小麦品种(系)穗发芽抗性评价

穗发芽严重影响小麦产量和品质，受到生长环境、种皮颜色和遗传基因的共同控制。由于四川地区在小麦收获季节容易出现高温高湿的气候条件，是小麦穗发芽的常发和重发区。依据材料的穗发芽抗性，有目的性地配制杂交组合选育抗性品种是控制小麦穗发芽的重要策略，而系统鉴定分析各优良品种及品系的穗发芽抗性是亲本选配的重要依据。本研究调查分析了242份2000年来四川省审定小麦品种及即将成为未来几年新品种的2017—2018 年四川省区试品系的田间穗发芽情况，发现分别有23(9.5%)和67 (27.7%)份材料具有强（穗发芽率低于5%）和高（穗发芽率介于5%~15%）的穗发芽抗性。这为穗发芽抗性育种亲本的选择提供了参考；并且发现穗发芽抗性在不同类型材料中存在差异：2000 年来审定品种＜区试普通小麦品系＜区试早播早熟小麦品系＜区试特殊用途小麦品系，穗发芽抗性在未来几年品种中将有所增强；种皮颜色对穗发芽抗性具有强烈影响，随着种皮颜色加深，穗发芽抗性越强，但仍发现3 份（‘川育26’、‘川辐9 号’、‘川辐17 号’）白皮小麦材料具有强的穗发芽抗性，为白皮小麦抗穗发芽育种提供参考。其次发现在四川环境下，早播可能会提高小麦品种的穗发芽抗性。     

Methods for characterization of preharvest sprouting resistance in a wheat breeding program

Preharvest sprouting (PHS) can be a serious problem in western Canada resulting in economically important yield and grade losses for wheat producers. Improved PHS resistance is an important breeding objective and wheat breeders require effective and reliable methods to select for PHS resistance. The objective of this study was to evaluate whether differences exist between field and artificial weathering in the evaluation of PHS resistance in breeding lines and to determine whether sprouting scores are a good estimator of PHS resistance when compared to Hagberg falling numbers. Results suggest that both field and artificial weathering can be effectively used to screen for PHS resistance in wheat breeding lines. Although in this study, field weathering resulted in greater sprouting damage than artificial weathering, the ability to control conditions may make artificial weathering the more reliable test for PHS resistance in a breeding program. Mean sprouting scores greater than 7.5 consistently identified lines with low PHS resistance; hence, sprouting scores can be used to discard the most sprouting susceptible lines. However, falling numbers appear to be more reliable to evaluate the PHS resistance of advanced lines. This revised version was published online in August 2006 with corrections to the Cover Date.     

抗穗发芽2D/2H小大麦易位系的鉴定和应用研究

大麦2H染色体长臂上的Isa-H基因控制α-淀粉酶抑制蛋白的合成，减轻高α-淀粉酶活性对小麦穗发芽的不利影响。为了检测小大麦杂交后代中有无大麦Isa-H基因导入，利用染色体C-分带和原位杂交技术相结合对所创制的2H小大麦异附加系WBA9812和易位系WBT371进行了鉴定，以完整麦穗吸水保湿发芽法测定穗发芽的抗性，结合农艺性状观测，选育出具有抗穗发芽等优异特性的小大麦新种质。分析结果表明：WBT371是2D／2H易位系，抗小麦穗发芽。WBT371为进一步培育抗穗发芽小麦新品种创造了宝贵的种质资源。     

抗穗发芽小麦品系的初步鉴定

为了选育优质、高产、抗病,且抗穗发芽的小麦新品种,我们用模拟人工降雨的方法对56份品系（种）进行了抗穗发芽的鉴定,其中红兴隆科研所后备材料48份,从国外引进的材料8份,以目前黑龙江省主栽品种龙麦26为对照,鉴定出综合性状好、抗穗发芽的品系提升下一级试验,同时为亲本圃提供抗穗发芽的育种基础材料。     

Heritabilities and genetic variation for preharvest sprouting in progenies of Clark's Cream white winter wheat

Summary Preharvest sprouting resistance is a major breeding criterion in many regions where white wheat (Triticum aestivum L.) is produced. Availability of genetic sources of sprouting resistance should significantly advance this goal. Objectives of the present investigation were to determine heritabilities and genetic variation of sprouting resistance in progeny of six susceptible genotypes and Clark's Cream, a cultivar with excellent sprouting resistance. Sixty-five randomly selected F₂:F₃ lines from the six parental combinations were evaluated in blocks-within-replication designs at two locations during 1984–85. Falling number, -amylase activity, and sprouting percentage in simulated rain were usually more favorable in F₂:F₄ grain than in grain of the susceptible parents and frequently equalled levels in grain of the resistant parent. Broad sense heritability estimates were moderate to high for falling number and -amylase activity, low to moderate for visual sprouting, and inconsistent for embryo germination in ABA. Phenotypic correlations with sprouting were significant most often for falling number and least often for the agronomic traits, days to heading and kernel weight. We concluded that increased preharvest sprouting resistance is an attainable objective when genetic sources of strong resistance and appropriate selection criteria, such as sprouting after simulated rain, are used.     

Genetic analysis of pre-harvest sprouting in a durum wheat cross

Pre-harvest sprouting of durum wheat (Triticum turgidum L. var durum) reduces commercial grade, although the actual effects on processing quality are controversial. Little is known about the genetics of the dormancy component of pre-harvest sprouting resistance in durum. We studied the segregation of dormancy in 98 recombinant inbred lines from a cross of a relatively non-dormant line, CI13102, with a moderately dormant line, Kyle. The lines and parents were grown in field tests over three years, 1996, 1997 and 1998. Spikes were collected at approximately 20% moisture and stored at −23 ∘C. Hand-threshed grain of the lines was germinated, and number of seeds germinated was counted each day. A germination resistance index was calculated to characterize dormancy. Dormancy appeared to be complexly inherited in this cross. Lines were observed that were significantly (P < 0.05) more dormant than the parents. The lines transgressive for dormancy expressed in different combinations of the three environments, indicating an environmental interaction. DNA of lines and parents was tested with simple sequence repeat primers and AFLPs that were used in quantitative trait loci (QTL) analysis of dormancy. Significant QTLs for dormancy were found, with the most notable being on chromosome 1A, where other QTLs for pre-harvest sprouting resistance have been reported in common wheat.     

Dormancy breaking procedures and the breeding of white-grained wheat with resistance to pre-harvest sprouting

Summary Gibberellic acid, cold (4°C) and a combination of these two treatments were tested for use in breaking dormancy in 27 lines of white-grained wheat with varying levels of resistance to pre-harvest sprouting. Germination increased in all lines treated with gibberellic acid. Dormancy could be broken with 1 M gibberellic acid. Response to cold varied. A combination of gibberellic acid and cold treatment was the most effective. This technique has been found useful in treating seed in a breeding program aimed at producing wheats with resistance to pre-harvest sprouting.     

Enhancing the identification of genetic loci and transgressive segregants for preharvest sprouting resistance in a durum wheat population

Preharvest sprouting reduces grain quality and lowers grade. Characterization of preharvest sprouting resistance is important in selection in breeding for transgressive segregation and understanding the genetics of the trait for identifying QTL. Methods of measuring dormancy and other factors contributing to preharvest sprouting resistance are varied. The objective of this study was to demonstrate the requirement of multiple methods of measurement over multiple durations of germination to maximize understanding of transgressive segregation and QTL for preharvest sprouting resistance within a segregating durum wheat population grown in multiple environments. Ninety-eight durum wheat (Triticum turgidum L. var. durum) recombinant inbred lines (RIL) from a cross of a minimally dormant line, Sentry, by a moderately dormant line, Kyle, and controls were grown in replicated field tests in 1996, 1997 and 1998 and in a growth chamber trial in 1998. Preharvest sprouting was measured from intact spikes as sprouting index or from hand threshed grain as germination index (GI), germination resistance (GR), and percent germination (PG). The threshed grain measures were evaluated using counts at 7, 14 and 21 days intervals from the start of germination. Correlations performed on the measure type and duration using lines within the RIL population showed some discontinuity across environments, type of measure and duration of measure, with counts at extended intervals for PG producing the lowest correlations. The number of transgressive segregant lines varied with environment, duration and type of measure. Different QTL were identified by different types of measures and duration of counts. GI calculated for 7, 14 and 21 days germination count intervals and GR calculated for 21 days identified a highly significant QTL on chromosome1A (QPhsd.spa.-1A.1). GR calculated for 7 days identified a highly significant QTL on 2A (QPhsd.spa.-2A.1) in two different environments, and GI calculated for 21 days and PG at 7 days identified the same highly significant QTL on chromosome 7B (QPhsd.spa.-7B.1). The results indicated that multiple measures and durations of measure intervals must be applied to results collected across different environments to maximize the identification of QTL and transgressive segregants of the population segregating for preharvest sprouting resistance.     

小麦穗发芽抗性分子标记的有效性检测与验证

小麦收获前穗发芽严重影响加工品质,来年种用价值以及产量.本研究利用万县白麦子/京411穗发芽重组自交系群体对已报道的第3染色体上有关穗发芽抗性分子标记XBarc321、XBarc310和XBarc57以及第4染色体上Xbarc170、Xgwm397和Xgwm269进行有效性检测,并在穗发芽抗性不同的40份地方品种以及推广品种中进一步验证,结果表明,小麦第3染色体上的分子标记XBarc321、XBarc310和XBarc57在穗发芽群体以及穗发芽抗性不同的品种中选择效应较大,尤其是XBarc321和XBarc310,证实该标记与穗发芽抗性紧密相关,而第4染色体上的分子标记在该群体中并没有显示与穗发芽相关.本研究结果为定位控制该群体中穗发芽抗性的QTL位点提供了重要信息.     

Three classes of loci controlling preharvest sprouting in rye (Secale cereale L.) discerned by means of bidirectional selective genotyping (BSG)

Bidirectional selective genotyping (BSG) carried out on recombinant inbred lines (RILs) derived from the 541 × Ot1-3 intercross revealed three classes of selection responsive loci underlying preharvest sprouting (PHS) in rye. Ten PHS directional loci (PHSD) located on chromosomes 1RL (3), 3RS (2), 3RL (2), 5RL (2), and 7RS (1) responded significantly to both directions of the disruptive selection and were epistatic to the remaining two classes. Nine PHS resistance loci (PHSR) mapped on chromosomes 1RS, 1RL, 2RS, 3RS, 4RS, 5RS, 5RL, and 6RL (2) responded only to selection for sprouting resistance, being neutral for selection carried out in opposite direction. Eight PHS enhancing loci mapped on chromosomes 2RL, 3RL, 4RL, 5RL, 6RS, and 7RS (3) were affected by selection for sprouting susceptibility and did not respond to selection for sprouting resistance. Map positions of the selection responsive loci coincided with QTLs for PHS and alpha-amylase activity (AA) detected earlier, but BSG coupled with molecular mapping increased precision of PHS dissection in rye. Efficient strategy of marker assisted selection for preharvest sprouting resistance in rye should be based on PHSD and PHSR loci.