小麦矮秆突变体的鉴定及其突变性状的关联分析

矮秆突变体是小麦育种和株高遗传研究的重要基因资源。通过‘云麦53’成熟种子的EMS (Ethyl methyl sulfonate)诱变及诱变植株连续自交,获得了33个M3代候选突变体。通过诱变亲本与M2和M3代候选植株的株高差异分析,筛选到26个矮秆突变体,其株高变幅为(13.61±0.11)~(44.08±1.73) cm。基于8个矮秆基因的12个特异性标记检测发现, 26个矮秆突变体至少携带2个矮秆基因标记位点。除株高外, 26个矮秆突变体还携带穗长、小穗密度、节间数和平均节间长4个不同突变性状。26个矮秆突变体可聚为5个亚类,第1亚类的小穗数和小花数最少;第2亚类的株高最矮,穗长和平均节间长最短,小穗密度最高;第3亚类突变体的节间数最少。株高与平均节间长和节间数呈极显著相关,偏相关系数分别为0.94、0.58,但与穗长、小穗数、小花数和小穗密度4个性状无相关性。26个矮秆突变体的株高与平均节间长和节间数关联遗传,携带不同的突变基因组合,可用于小麦矮化育种,以及株高、穗长和小穗密度等性状的遗传机制研究。     

OsGA20ox2不同长度RNAi片段对水稻株高等农艺性状的遗传效应

利用OsGA20ox2基因序列构建不同长度的RNAi片段并导入水稻，获得不同高度的矮化植株。将这些矮化植株与野生型植株回交获得B₁F₂群体，卡方检测表明B₁F₂群体矮秆植株数和高秆植株数符合3∶1比例，表现为矮秆显性的遗传规律。对矮化植株的F₅和B₁F₂群体株高、各茎节间长度和一些主要农艺性状方差分析显示, OsGA20ox2基因的RNAi能显著缩短株高和各节间长度(P<0.05)，RNAi干扰片段越长，使植株株高和节间长度缩短程度越大，可使株高降低24~42 cm，矮化22%~39%。在同一长度的RNAi干扰片段下，倒一节节间长度平均缩短与倒二节节间长度平均缩短非常相近，倒三节和倒四节节间长度平均缩短非常相近，总的缩短程度是倒四节>倒三节>倒二节>倒一节。这种近基部节间长度缩短幅度和比例较大的特点，利于提高水稻的抗倒伏能力，同时上部节间缩短幅度和比例较小，有效地保持合理株高，不使生物产量明显降低，有利于水稻的稳产和高产。OsGA20ox2基因的RNAi不影响如千粒重、结实率、穗长等其他主要农艺性状或影响很小。     

Heterosis and combining ability for plant height and its components in hybrid wheat with Triticum timopheevi cytoplasm

The heterosis and combining ability for plant height and its components of hybrid wheat were investigated in an incomplete diallel experiment including 5 CMS lines and 4 restorer lines. The results showed that heterosis (HS) and heterobeltiosis (HBS) occurred in plant height (PH) and length of the first internode (LFI), second internode (LSI), third internode (LTI), basal internode (LBI) and the spike (LS) of hybrids, but their values varied among crosses and characters; the HS and HBS of LBI were larger than those of other characters, the HS and HBS of LSI and LTI contributed a lot to those of PH. There were significant relationships between internode lengths and PH for specific combining ability (SCA) and general combining ability (GCA), and among lengths of the adjacent internodes for SCA and/or GCA effects. However, the relationships of LS with the lengths of internodes and PH were insignificant for GCA, SCA, HS and HBS. The SCA effects were more important than GCA effects for LFI, the reverse was true for LSI, LTI, LS and PH, and the SCA effects was nearly equal to the GCA effects for LBI. So, LFI was mainly influenced by non-additive effect of genes, while LSI, LTI, LS and PH were mainly controlled by additive gene effects, LBI was controlled equally by additive and non-additive effects of genes. The genes that control the length of specific internode not only affect PH, but also the length of the adjacent internode. The genetic system in charge of lengths of internodes and plant height is independent of that for length of spike. Thus, it is possible to develop new wheat cultivars or hybrid combinations having long spike but dwarf plant height. This revised version was published online in July 2006 with corrections to the Cover Date.     

Seedling emergence,coleoptile length,and plant height relationships in crosses of dwarf and standard-height wheats

Summary Seedling emergence was closely correlated with coleoptile length and plant height among parents, F₂ and F₃, populations of crosses involving dwarf wheats Olesen Dwarf (CI 14497), Norin 10 derivative D6301, Tom Thumb derivative D6899, and the standard-height varieties Ramona 50 and Nainari 60. Genetic mechanisms that governed plant height also influenced coleoptile length, but the relative effects of genes showing dominant or epistatic effects appeared to be different. With respect to the two parents involved in each of 15 crosses, mean F₂ coleoptile lengths were consistently closer to the low parent value than were corresponding mean F₂ plant heights. A slight curvilinear relationship was also found between coleoptile length and plant height of F₃ lines. The results suggest that selection of semidwarf wheats with long coleoptiles and improved emergence properties from crosses involving the dwarf wheats of this study would be unlikely.     

陆地棉矮化突变体Ari1327的矮化机理研究

 Ari1327是从美国引进的陆地棉种质Ari971经⁶⁰Coγ射线照射后得到的一个新型矮化突变体。Ari1327在萌发期和子叶期就表现出矮化性状。在现蕾期,突变体的株高、节间数和节间平均长度均小于野生型,差异达到极显著水平,节间平均长度的缩短导致了突变体株高的降低。突变体主茎节间纵向细胞的长度要显著小于野生型,横向细胞的直径与野生型差异不显著,节间细胞伸长受抑制导致了突变体节间平均长度的缩短。突变体中IAA、GA₃和ABA 含量高于野生型,外施GA₃能使其株高恢复至野生型水平,外施BR和IAA不能使其株高恢复到正常水平,较低浓度的IAA对突变体的株高和节间长度就开始产生抑制作用。突变可能导致了IAA合成相关基因的过量表达,突变体内源IAA含量急剧升高而抑制了植株生长,使株高降低。     

Genetic dissection of plant height by molecular markers using a population of recombinant inbred lines in maize

Plant height is an important trait for maize breeding because it is related to planting density and lodging resistance. It is influenced by many qualitative genes and quantitative trait loci (QTL). In this study, the genetic basis of plant height and its related traits were dissected, using simple sequence repeat (SSR) markers with a maize population of 294 recombinant inbred lines (RIL). Correlation results showed that plant height had a significant positive correlation with leaf number, average internode length and internode number. Increased plant height was affected most by average internode length. Six QTL for plant height were detected, which were consistent with those reported in previous studies. Moreover, eight QTL for leaf number, seven for internode number and six for average internode length were identified. Four of six QTL detected for average internode length were located on the same chromosomal region as the QTL affecting plant height and shared common molecular markers. This latter result strongly suggests that average internode length was the main contributor to plant height in maize.     

Genetic analysis of mesocotyl length and its relationship with other agronomic characters in rice (Oryza sativa L.)

Summary Mesocotyl length is an important character in promoting seedling emergence of direct-seeded rice. Genetic analysis of rice mesocotyl length was conducted using a six parent diallel cross. Generation mean analysis was carried out on parents (P), F1, F2 and backcrosses (B) of three crosses to complement the genetic information from the diallel analysis. Both analyses demonstrated the presence of significant additive and dominance effects. Duplicate type of non-allelic interaction was detected by the generation mean analysis and two crosses showed significant negative dominance gene effect. Dominance was partial and the narrow sense heritability estimate for mesocotyl length was high, indicating the preponderance of the additive effects.Mesocotyl length was negatively but weakly correlated with the coleoptile length and length of the second internode L2. There was no correlation between mesocotyl length and other mature plant characters such as plant height and internode lengths L₁, (L₁ being the peduncle with subsequent internodes to the base of the plant). Selection for mesocotyl length can therefore be carried out independent of these plant characters and semidwarf rice varieties with long mesocotyl can be developed.     

水稻中胚轴伸长特性的遗传分析

以长中胚轴/短中胚轴杂交组合的两个亲本、F₁、B₁、B₂和F₂为试验材料，在小型人工气候箱黑暗条件下培养幼苗，对水稻中胚轴伸长特性的遗传规律进行了研究。结果表明，中胚轴伸长特性受两对隐性基因控制。F₂群体中长、短中胚轴植株在节间长度、穗长、株高和剑叶长等性状上均存在较明显的差异，而中胚轴伸长特性与节间粗、剑叶宽、单株穗数、每穗总粒数、结实率、千粒重和单株产量等性状关系不明显。还对水稻中胚轴伸长特性的遗传改良以及长中胚轴材料在直播稻育种上的利用进行了探讨。     

水稻矮秆鞘包穗突变体茎的形态解剖学研究

以T-DNA标记的水稻矮秆、鞘包穗突变体A846及其野生型为材料,用解剖学方法对比研究茎的外部形态和显微结构。结果表明：突变体A846平均株高38.64cm,大于野生型株高的一半,为半矮秆类型;其矮生性在拔节期显著表现;主茎茎秆各节间收缩比例不一,穗下第一节间显著缩短,与sh-型突变体类似;茎秆各节间居间分生组织细胞分化正常,由居间分生组织分化的细胞延伸受到不同程度的阻碍;各节间基本组织细胞纵向长度相应缩短,穗下第一节间缩短比例最大,其平均值小于野生型的一半;主茎节间数目与旗叶的叶鞘长类似于野生型。     

基于SSSL群体的玉米穗下节间长QTL分析

穗下节间长决定着玉米的穗位高和株高, 而株高和穗位高与产量、抗倒伏性等重要农艺性状密切相关。玉米穗下第7、第8、第9节间长对穗位高具有决定作用, 与其他农艺性状相比, 对穗下节间长的遗传基础了解甚少。因此, 研究玉米穗下节间长的遗传基础, 对玉米育种有重要意义。本研究以lx9801为受体亲本, 昌7-2为供体亲本通过连续回交和自交所构建的一套包含260份染色体单片段代换系的群体为研究对象, 通过两年两环境的表型鉴定, 并结合基因型数据对第7、第8、第9节间长和穗位高的QTL进行定位。共检测到18个第7节间长QTL, 23个第8节间长QTL和17个第9节间长QTL, 其中8个QTL是为第7、第8、第9节间长所共有。穗位高定位到的20个QTL中, 有12个(60%)与第7、第8、第9节间长QTL共定位。说明第7、第8、第9节间长与穗位高有着共同的遗传基础, 节间长也是穗位高的重要构成因子, 决定着玉米的株高和穗位高。     

DCPTA与CCC复配对寒地春玉米茎秆抗倒伏特性及光合作用的影响

为了研究新型植物生长复配剂对寒地春玉米抗倒伏特性及光合作用的影响,试验选择3种化控剂进行试验,其中2种为已用于大田生产的化控剂,分别为玉黄金(YHJ)和吨田宝(DTB),第三种为实验室自行配置的以DCPTA（2-(3,4-二氯苯氧基)-乙基-二乙胺）和CCC（氯化氯代胆碱）为主要成分的复配剂(FPJ)。结果表明,复配剂(FPJ)和玉黄金(YHJ)处理后玉米株高及穗位高降低,基部节间长度降低,基部节间直径增加。吨田宝(DTB)处理则增加了株高、穗位高和节间长度。以抽雄后10天为例,经过复配剂(FPJ)处理后的1、3、5节间长度分别比对照降低12.62%、9.49%、6.51%,而节间直径比对照增加了13.70%、12.37%、12.69%。复配剂处理能增加玉米茎叶干物质积累,部分处理差异显著。经复配剂处理后的叶面积指数与对照差异不显著。经复配剂处理后叶绿素荧光参数Fo（初始荧光）及qN（非光化学淬灭系数）数值下降,Fv/Fm（可变荧光/最大荧光）及qP（光化学淬灭系数）数值增加,这说明复配剂喷施处理不但对降低株高,增加抗倒伏性状有作用,也促进了玉米叶片光合作用,为玉米最终获得高产奠定基础。     

棉花地上部生长的功能-结构模型研究

利用2008-2010年棉花密度试验, 分析棉株器官生物量-形态间异速生长关系, 改进COTGROW模型中的发育和形态发生模块, 构建了棉花地上部器官形态建成模型; 基于COTGROW模型模拟数据,与GroIMP可视化开发平台的数据链接, 实现了棉花生长过程的可视化; 利用建立的功能-结构模型对不同密度棉花冠层的光截获量进行了模拟。利用2010年的试验数据检验模型, 结果表明, 棉花株高、主茎节数、果枝数、各果枝果节数、节间长度、节间直径、叶片长度、叶片宽度、叶柄长度、叶柄直径、棉铃长度以及铃直径测定值与模拟值间的均方根误差分别为3.85、0.64、0.52、0.66、1.00、0.15、1.58、2.39、2.54、0.05、0.13和0.10 cm, 模型效果较好; 构建的棉花地上部功能-结构模型可以较好地模拟棉花的形态特征, 并较逼真地显示棉花器官、植株的三维动态生长过程, 可以反映出不同环境条件、不同密度处理下棉花植株的三维形态, 在可视化的基础上模拟棉花冠层空间的光截获量。为虚拟棉作研究提供了技术基础。     

20对大麦株高近等基因系农艺与产量性状差异及相关性分析

为培育高产优质啤酒大麦提供理论依据,以20对二棱啤酒大麦株高近等基因系为试材,通过测定其农艺性状和产量性状,探讨近等基因系中半矮秆基因uzu对株高、穗长、地上部干质量、单穗粒数、单株粒重和千粒质量等的影响,并进行20个高秆基因系之间、20个矮秆基因系之间的性状差异比较及相关分析。结果表明:除地上部干质量和单穗粒数性状外,高秆基因系(无半矮秆基因uzu)其他性状均显著或极显著高于矮秆基因系(含半矮秆基因uzu),即半矮秆基因对较多的农艺性状和产量性状能够产生降低作用。相关分析表明:20个高秆基因系中,千粒质量之间的差异最为显著,说明千粒质量对于产量的提升潜力较大;株高与穗下节间长度、穗长呈极显著正相关,与产量性状均呈负相关,但无显著相关性。在20个矮秆基因系中,千粒质量同样差异最为显著;株高与其他性状均无显著相关性,但与千粒质量、单穗粒数呈负相关,与单株粒重呈正相关。     

不结球白菜单株产量与主要农艺性状的灰色关联度分析

为揭示不结球白菜单株产量与主要农艺性状间的关系，利用灰色关联度分析法，对18个不结球白菜品系的单株产量和8个主要农艺性状间的关联度进行分析。结果表明，不结球白菜各农艺性状与单株产量性状间的关联度排序为株幅＞最大叶叶宽＞最大叶叶柄宽＞最大叶叶柄厚＞叶片数＞最大叶叶长＞株高＞最大叶叶柄长。株幅、最大叶叶宽、最大叶叶柄宽对不结球白菜单株产量影响最大。在不结球白菜育种过程中，注重株幅、最大叶叶宽、最大叶叶柄宽性状的选择，同时兼顾其他性状的选择，可以获得单株产量较高的不结球白菜新品种。     

水稻第5节间长度与出穗促进率的相关性

出穗促进率和株高变化是反映水稻品种光温生态响应的重要指标。能否在育种阶段采用相对容易识别的性状来判断水稻品种的生态响应能力,对广适性品种的选育具有重要意义。本文从12个水稻亲本聚合杂交后代选出的36个高代稳定自交系及其亲本共48份材料,在湖北荆州作中稻以及在广州作早稻和晚稻,研究不同生态条件下株高及各组成成分变化与出穗促进率的变化规律。结果表明,第5节间长度是株高成分中最容易受环境影响的部分,其在不同季节的变化与出穗促进率呈现极显著的正相关性,在早稻和中稻、中稻和晚稻、早稻和晚稻3种情况下,第5节间长度变化和出穗促进率之间的相关系数分别为0.37、0.52和0.49,均达到了极显著水平,偏相关系数分别为0.42、0.43和0.36,也都达到了极显著水平。说明第五节间长度容易受光温条件的影响,是生态响应变化的重要指标,越是敏感的材料响应越大,适应性越差。因此,不同环境条件下第五节间长度可用作判断水稻品种对光温条件的响应指标。     

春播谷子成熟期抗倒伏性研究

试验以长谷4号、长生13和晋谷21为材料,在成熟期（乳熟期、蜡熟期和完熟期）测定7个性状指标,分析其与倒伏性的关系。结果表明,3个品种的倒伏指数均以黄熟期最大,乳熟期最小;从基部第2节间~第6节间,倒伏指数依次增加,抗倒伏性依次降低。相关性分析表明,基部第2节间倒伏指数与重心高度和单株穗鲜重呈显著正相关,与株高、单株鲜重和基部第2节间长度呈正相关,与基部第2节间直径和基部第2节间机械强度呈负相关,但都未达到显著水平。通径分析结果表明,各性状对倒伏指数的直接影响从大到小排序为：基部第2节间机械强度、单株鲜重、重心高度、株高、基部第2节间直径、基部第2节间长度和单株穗鲜重。由研究结果可见,基部第2节间机械强度和重心高度可作为评价谷子成熟期抗倒伏性的通用指标,对选育抗倒伏谷子新品种具有重要指导意义。     

化控剂-乙烯利对玉米植株主要性状和产量的影响

为了防止玉米倒伏,实现高产稳产,采用化控剂-乙烯利处理,研究其对玉米主要性状的影响。结果表明：经化控剂-乙烯利处理棒三叶长、基部节间长、株高、穗位、穗长和单株平均产量均低于对照,其中对棒三叶长、基部节间长的抑制效应前期>中期>后期,同一时期,随着处理剂量的增加棒三叶长、株高、穗位、穗长、单株产量逐渐减小,而基部节间长差异不明显。随着处理时期的推迟,穗位高表现高—低—高的变化趋势;株高逐渐下降;穗长变化不明显;除乙烯利使‘金丰50’减产幅度呈现低—高—低的变化外,采用烯施美处理‘金丰50’和AH2067,或采用乙烯利处理AH2067,减产幅度均呈现高—低—高的变化趋势。化控剂-乙烯利对籽行数和秃尖长影响不明显。     

Culture selected somaclonal variation in five Triticum aestivum L. genotypes

Somaclones (R₃ and R₄ generations) regenerated from five winter wheat (Triticum aestivum L.) genotypes were evaluated for variation in agronomic and morphological characters. Immature embryos were used as initial explant material. Comparisons for plant height, top internode length, spike length, number of seeds per spike and 100 seed weight were made between the somaclones and their parents. Some morphological variations of stem and spike characteristics were registered which demonstrate that plant height and spike length can be changed by using immature embryo culture. The results obtained may be considered a biotechnological contribution to wheat plant improvement. This revised version was published online in August 2006 with corrections to the Cover Date.     

Genome-wide association study of differences in 14 agronomic traits under low- and high-density planting models based on the 660k SNP array for common wheat

One hundred and ninety-seven wheat accessions from Yellow and Huai Winter Wheat Region (YHW) were evaluated for differences of 14 agronomic traits under low- and high-density plantings. Compared with the high-density plantings, plant height, neck length, uppermost internode length, flag leaf angle and number of sterile spikelets under the low-density plantings reduced, while heading date, flowering date, flag leaf length and width, spike length, number of fertile spikelets, grain number per spike, thousand-kernel weight and grain weight per spike increased. A total of 1,118 markers were detected based on GWAS, and seven QTLs were confirmed. One QTL on chromosomes 5BL and two other QTLs on 5Dl were all tightly associated with flowering date difference. Bioinformatics analysis revealed that two haploblocks in 5Dl were involved, and the Vrn-D1 locus was located in this interval. A region on chromosome 5B at around 531.5 Mb was significantly associated with plant height difference. Two QTLs including AX-94840438 (7BL) and AX-94563647 (7DS) were responsible for neck length or uppermost internode length difference.     

水稻矮秆脆性突变体dbc1的鉴定与基因定位

利用EMS诱变籼型水稻恢复系缙恢10号,获得一个稳定遗传的矮化脆性突变体dbc1,苗期即表现矮化、叶片变脆,一直保持到成熟。与原始亲本相比,突变体的各节间均显著缩短,株高仅58.93 cm,略有包穗,属于dn型矮化变异,对赤霉素的敏感性显著下降,有效穗、千粒重和结实率无明显变化,穗长、穗粒数和实粒数则极显著下降。进一步分析发现,dbc1的茎秆和叶片的载荷强度极显著下降,纤维素含量无变化,木质素含量则略有下降,差异达显著水平。遗传分析表明该性状受1对隐性核基因调控,利用886株西农1A/dbc1的F₂变异单株,最终把DBC1基因定位在第2染色体SSR标记RM13943和RM13952之间,物理距离仅197 kb,含有52个注释基因。这为下一步调控基因的克隆和dbc1材料的育种应用奠定了基础。