Gibberellin-sensitive Rht alleles confer tolerance to heat and drought stresses in wheat at booting stage

The present study compared six near-isogenic lines from different backgrounds, varying in Rht (reduced height) alleles for gibberellin (GA) response, for heat and drought tolerance. Various temperature (day/night: 20/12 °C to 39/31 °C), and irrigation (100% field capacity and no irrigation) treatments were imposed at booting stage. Results depicted a 50% reduction in grain yield at 36.7 °C with irrigation and at 31.2 °C without irrigation. Number of grains per spike was severely reduced over 26 °C for water-stressed plants while irrigated plants did not show any significant reduction up to 34 °C. Ear numbers per pot and spikelets per spike were unaffected by irrigation till 33 °C. In Mercia, grain nitrogen, sulphur, and Hagberg falling number (HFN) were significantly higher for severe dwarfs (Rht-D1c and Rht-12), however, in Maris Widgeon, rht (tall) recorded higher nitrogen and sulphur concentration while Rht-B1b presented the maximum sedimentation of sodium dodecyl sulphate (SDS). The SDS was higher in Maris Widgeon while HFN were superior in Mercia. Conclusively, the present study demonstrated that heat and drought stresses severely reduced the grain yield while improved grain quality traits. The GA-insensitive semi dwarf Rht-B1b was the most promising genotype for grain yield and HFN under combined drought and heat stresses.     

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。     

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。     

67份美国小麦品种矮秆基因的分子标记检测

为了明确矮秆基因在美国小麦品种中的分布特点并发掘较少利用的矮秆基因,本研究利用8个小麦矮秆基因的特异分子标记对67份美国小麦品种中的矮秆基因进行了检测。结果表明,67份美国小麦品种中,超过80%的品种（56个）含有矮秆基因,其中 Rht-B1b和 Rht8基因频率较高,分别占62.7%和43.3%。仅有5个品种含有 Rht-D1b基因,同时发现3个品种含有 Rht5基因,2个品种含有 Rht12基因,未发现含有 Rht4、 Rht9和 Rht13基因的品种。在含有矮秆基因的品种中,35.8%的品种含有2个或2个以上的矮秆基因。其中有1个品种同时含有3个矮秆基因,有20个品种同时含有 Rht-B1b和 Rht8基因,有3个品种同时含有 Rht-D1b和 Rht8基因,有1个品种同时含有 Rht-D1b和 Rht12基因,其余32个品种各含有1个矮秆基因。本研究未发现同时含有 Rht-B1b、 Rht-D1b、 Rht8以及同时含有 Rht-B1b、 Rht-D1b的品种。     

Genotypic increases in coleoptile length improves stand establishment,vigour and grain yield of deep-sown wheat

Timely sowing is critical for achieving high grain yields in winter cereals. However, inadequate seed-zone moisture for germination commonly delays sowing to reduce biomass and subsequent yield in semi-arid environments. Sowing deep to reach soil moisture is often avoided by growers of Rht-B1b and Rht-D1b semi-dwarf wheat as these wheat show poor emergence when sown deep. Their reduced cell elongation associated with insensitivity to endogenous gibberellins, results in shorter coleoptiles and smaller early leaf area. Alternative dwarfing genes responsive to endogenous gibberellins (e.g. Rht8) are available for use in wheat breeding. These reduce plant height without affecting coleoptile length and offer potential to select longer coleoptile wheat for deep sowing. Nine semidwarf (Rht8, Rht-B1b, and Rht-D1b) and seven tall (rht) wheat genotypes were sown at depths of 50, 80 and 110 mm at three locations in 2 or 3 years. Coleoptile lengths measured in a growth cabinet at four temperatures (11, 15, 19 and 23 °C) were strongly correlated with coleoptile length (r_p = 0.77–0.79^**) and plant number (r_p = 0.49^*–0.79^**) in deep-sown plots in the field. Furthermore, differences in coleoptile length were genetically correlated with greater numbers of emerged seedlings (r_g = 0.97^**), shallower crown depth (−0.58^**), greater seedling leaf area (0.59^**) and seedling biomass (0.44^*). Wheat containing the Rht-B1b or Rht-D1b dwarfing genes produced significantly (P < 0.01) shorter coleoptiles (97 mm) than both Rht8 (118 mm) and tall (117 mm) wheat. In turn, compared with emergence from 50 mm depth, the Rht-B1b and Rht-D1b wheat produced significantly fewer seedlings at 110 mm sowing depth (−62%) than either Rht8 (−41%) or tall (−37%) wheat. Effects of deep sowing early in the season were maintained with reductions in spike number and biomass at both anthesis and maturity. Kernel number was also reduced with deep sowing leading to reductions in grain yield. Over all entries, genotypic increases in plant number were associated with increases in fertile spike (r_g = 0.61^**) and kernel number (0.21^*), total biomass (0.26^*) and grain yield (0.28^*). Reduction in spike number and grain yield with deep sowing was smallest for the Rht8 (−18 and −10%) and rht (−15 and −7%) wheat, and largest for the Rht-B1b/D1b (−39 and −16%) wheat. Plant height and coleoptile length were independent among Rht8 and tall wheat genotypes. This study demonstrates the importance of good seedling emergence in achieving high wheat yields, and the potential use of alternative dwarfing genes such as Rht8 in development of long coleoptile, reduced height wheat suitable for deep sowing.     

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.     

Development of simple and co-dominant PCR markers to genotype puroindoline a and b alleles for grain hardness in bread wheat (Triticum aestivum L.)

Grain hardness is one of the most important quality characteristics of cultivated bread wheat (Triticum aestivum L.). A large deletion in the puroindoline a (Pina) gene or single nucleotide polymorphisms (SNPs) in the puroindoline b (Pinb) gene results in hard grain texture. So far, nine Pina alleles (Pina-D1a–Pina-D1b, Pina-D1k–Pina-D1q) and seventeen Pinb alleles (Pinb-D1a–Pinb-D1g, Pinb-D1p–Pinb-D1ab) have been identified in bread wheat. The major Pina and Pinb alleles identified in hard wheat cultivars are Pina-D1b, Pinb-D1b, Pinb-D1c and Pinb-D1d. In this study, a three-primer PCR system was employed to develop nine co-dominant STS markers for genotyping Pina-D1a and Pina-D1b, whereas temperature-switch (TS) PCR was used to develop six co-dominant SNP markers for genotyping the Pinb-D1a, Pinb-D1b, Pinb-D1c and Pinb-D1d alleles. These STS and TS-PCR markers were used to verify the grain hardness genotype of 100 wheat cultivars. The reliability and genotyping accuracy of TS-PCR markers were confirmed through sequencing of PCR products and a comparison with previously published results. Therefore, STS and TS-PCR markers offer a simple, cost-effective and reliable method for high-throughput genotyping Pina and Pinb alleles to select grain hardness in wheat quality breeding programs and for wheat market classification.     

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...     

The role of sensitivity to abscisic acid and gibberellin in pre-maturity α-amylase formation in wheat grains

To study the role of abscisic acid (ABA) and gibberellin (GA) sensitivity in regulating pre-maturity α-amylase (PMA) in wheat grains, plants were grown in a glasshouse under cold-shock and ambient conditions. α-amylase activity in response to applied ABA and GA was measured in detached-grains with the embryo removed (in vitro) and in intact-grains attached to the plant (in situ). The in vitro experiment was conducted using Spark (low PMA-susceptible genotype) and Rialto (highly PMA-susceptible genotype), with the aim of defining the time point for GA-sensitivity. The results showed an increase in GA-sensitivity at about 640 degree days after anthesis (DAA) in Rialto. There was no evidence for a change in ABA-sensitivity in either variety. The in situ experiments were conducted using genotypes from a Spark × Rialto doubled haploid population segregating for the Rht-D1a (tall) or Rht-D1b allele and for the presence or absence of 1BS/1RS. For Rht-D1a (tall) or Rht-D1b genotypes with or without 1BS/1RS, the cold-shock significantly increased GA-sensitivity, whereas there was no significant change in ABA-sensitivity. These results show PMA is related to an increase in GA-sensitivity that occurs in the aleurone at around 640 degree DAA, and can be enhanced by environmental factors (e.g. cold-shock).     

黄淮麦区部分骨干品种重要基因等位类型分析及全基因组优异位点挖掘

为了从分子水平上了解黄淮麦区部分骨干品种(尤其是西农系列品种)的春化和光周期特性、矮秆基因、抗赤霉病基因类型及全基因组优异位点的分布,以西农979、西农511等近年黄淮麦区主栽小麦品种(共64份)为材料,采用分子标记及小麦35K芯片对供试品种进行检测。结果表明,13份材料含有显性春化基因 Vrn-D1(20.3%),3份材料含有显性基因 Vrn-B1(4.7%),未检测到显性基因 Vrn-A1和 Vrn-B3;除中国春和宁春45外,其余62份材料均含光周期不敏感基因 Ppd-D1a;9份材料携带矮秆基因 Rht-B1b,28份材料携带矮秆基因 Rht-D1b,35份材料携带矮秆基因 Rht8;15份材料同时含有 Rht-D1b和 Rht8;苏麦3号和兰考198含抗赤霉病基因位点 Fhb1。芯片检测结果发现,西农系列品种亲缘关系较近,共含有1 049个特异SNP,集中在2A和6B染色体上,这些位点可能是决定西农系列品种区别于其他品种的重要遗传位点;所有参试材料共含有1445个相同的SNP位点,集中在2D和3B染色体上。     

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。     

小麦矮秆基因 Rht-B1b和 Rht-D1b的检测及其验证

为研究矮秆基因 Rht-B1b、 Rht-D1b在小麦品种中的分布及其对株高的影响,以3个小麦群体（中国冬麦区白粒小麦品种、中国小麦历史品种、春小麦育种材料）共321份小麦品种为材料,检测矮秆基因 Rht-B1b和 Rht-D1b的分布频率,并分析比较它们对春小麦育种材料株高的影响。结果表明,在检测的321份材料中,共有193份材料含有 Rht-B1b矮秆基因,分布频率为60.1%,其中,中国冬麦区白粒小麦品种、中国小麦历史品种、春小麦育种材料中含有 Rht-B1b矮秆基因的材料分别有29、77和87份,分布频率分别为 34.5%、72.6%和66.4%;共有135份材料含有 Rht-D1b矮秆基因,分布频率为42.1%,其中,中国冬麦区白粒小麦品种、中国小麦历史品种、春小麦育种材料中含有 Rht-D1b 矮秆基因的材料分别有41、21和73份,分布频率分别为48.8%、19.8%和55.7%;共有78份材料同时含有 Rht-B1b和 Rht-D1b矮秆基因,分布频率为 24.3%,其中,中国冬麦区白粒小麦品种、中国小麦历史品种、春小麦育种材料中同时含有 Rht-B1b和 Rht-D1b矮秆基因的材料分别有15、17和46份,分布频率分别为17.6%、15.9%和35.1%。对已被鉴定株高表型的91份春小麦育种材料进一步分析发现,同时携带 Rht-B1b和 Rht-D1b矮秆基因的材料株高较低。     

小麦株高QTL的定位及对重要农艺性状的多效性分析

株高作为小麦育种的重要指标,对产量具有较大的影响。为进一步挖掘小麦株高的数量性状位点（quantitative trait loci,QTL）,本研究以扬麦12和偃展1号杂交得到的包含205个家系的重组自交系（recombinant inbred lines,RIL）群体为材料,利用小麦55K SNP芯片构建高密度遗传图谱,结合 3年共6个环境的表型数据对株高性状进行QTL定位分析。结果表明,在染色体2B（1）、4B（1）、4D（1）、5A（1）、5B（1）和7D（2）上共检测到7个与株高相关的QTL。QPh.yaas-4B、QPh.yaas-5A和QPh.yaas-7D.1的矮秆效应来源于扬麦12,其余4个QTL的矮秆效应来源于偃展1号。在6个环境下都能检测到的位点是QPh.yaas-4B和QPh.yaas-4D,对株高的贡献率分别14.50%~24.09%和19.01%~29.80%,经过比对发现,这2个QTL分别是Rht1和Rht2。QPh.yaas-5A在5个环境下被检测到,对株高的贡献率为3.29%~5.36%;QPh.yaas-2D和QPh.yaas-7D.2在4个环境中均被检测到,对株高的贡献率分别为3.45%~6.14%和3.16%~4.10%;QPh.yaas-5B和QPh.yaas-7D.1分别在2个和3个环境中被检测到,对株高的贡献率分别是2.27%~5.09%和2.72%~4.82%。QTL比较分析后发现,QPh.yaas-7D.1和QPh.yaas-7D.2可能是新的株高位点。研究Rht-B1和Rht-D1对千粒重、穗长和穗粒数的效应,发现Rht-B1位点对这些农艺性状无显著效应,Rht-D1位点仅对千粒重有显著效应,其株高增效等位变异可显著增加千粒重。在自然群体中验证Rht-B1和Rht-D1的效应结果与RIL群体结果一致。     

Development of STS markers and establishment of multiplex PCR for Glu-A3 alleles in common wheat (Triticum aestivum L.)

Low-molecular-weight glutenin subunits (LMW-GS) play a key role in determining the processing quality of the end-use products of common wheat. The objectives of this study were to identify genes at Glu-A3 locus, develop the STS markers, and establish multiplex PCR with the STS markers for Glu-A3 alleles. Gene-specific PCR primers were designed to amplify six near-isogenic lines (NILs) and Glenlea with different Glu-A3 alleles (a, b, c, d, e, f and g) defined by the protein electrophoretic mobility. Three Glu-A3 genes with complete coding sequence were cloned, designated as GluA3-1, GluA3-2 and GluA3-3, respectively. Seven dominant allele-specific STS (sequence tagged sites) markers were designed based on the SNPs (single nucleotide polymorphisms) among different allelic variants for the discrimination of the Glu-A3 protein alleles a, b, c, d, e, f and g. Four multiplex PCRs were established including Glu-A3b + Glu-A3f, Glu-A3d + Glu-A3f, Glu-A3d + Glu-A3g, and Glu-A3b + Glu-A3e. These markers and multiplex-PCR systems were validated on 141 CIMMYT wheat varieties and advanced lines with different Glu-A3 alleles, confirming that they can be efficiently used in marker-assisted breeding.     

Late-maturity α-amylase: Low falling number in wheat in the absence of preharvest sprouting

Late maturity α-amylase (LMA), or prematurity α-amylase (PMAA) as it has been termed in the UK, in wheat involves the untimely synthesis of high pI α-amylase during the middle to later stages of grain development and ripening. The enzyme activity is retained in the grain at harvest ripeness, resulting in low falling number and failure to meet receival standards and customer specifications. This phenomenon, which is restricted to specific genotypes, appears to be controlled by 1 or 2 recessive genes acting alone or in combination and in most cases appears to be triggered by a temperature shock. This shock is only effective if it occurs during a window of sensitivity around 25–30 days postanthesis. Expression of LMA is reduced in the presence of dwarfing genes such as Rht1, Rht2 and Rht3 that confer insensitivity to gibberellin. Screening technologies, including molecular markers and high pI-specific ELISA, have been developed to assist wheat breeders and will be required to meet new challenges posed by novel germplasm such as primary synthetic wheats.     

利用KASP标记检测青海和西藏小麦品种中光周期基因分布

为了解青海和西藏小麦品种中光周期基因的分布情况,采用KASP标记对青海和西藏249份小麦品种光周期基因 Ppd-D1、 Ppd-B1和 Ppd-A1等位变异组成进行检测。结果显示,在 Ppd-B1位点上,237个品种携带光周期不敏感型等位变异 Ppd-B1a(95.18%),12个品种携带光周期敏感型等位变异 Ppd-B1b(4.82%);在 Ppd-A1位点上,233个品种携带光周期不敏感型等位变异 Ppd-A1a(93.57%),16个品种携带光周期敏感型等位变异 Ppd-A1b(6.43%);在 Ppd-D1位点上,221个品种携带光周期不敏感型等位变异 Ppd-D1a(88.76%),28个品种携带光周期敏感型等位变异 Ppd-D1b(11.24%)。光周期不敏感型等位变异 Ppd-B1a和 Ppd-A1a分别在青海和西藏小麦品种光周期反应中占主导地位。西藏和青海小麦品种中共存在6种等位变异组合类型,其中青海小麦品种中存在5种等位变异组合类型,不存在 Ppd-D1a/Ppd-B1b/Ppd-A1a类型,西藏农家品种中存在4种等位变异组合类型,不存在含光周期敏感型等位变异 Ppd-A1b的类型。等位变异组合 Ppd-D1a/Ppd-B1a/Ppd-A1a在青海和西藏小麦品种中分布最广。     

The role of sensitivity to abscisic acid and gibberellin in pre-maturity α-amylase formation in wheat grains

To study the role of abscisic acid (ABA) and gibberellin (GA) sensitivity in regulating pre-maturity α-amylase (PMA) in wheat grains, plants were grown in a glasshouse under cold-shock and ambient conditions. α-amylase activity in response to applied ABA and GA was measured in detached-grains with the embryo removed (in vitro) and in intact-grains attached to the plant (in situ). The in vitro experiment was conducted using Spark (low PMA-susceptible genotype) and Rialto (highly PMA-susceptible genotype), with the aim of defining the time point for GA-sensitivity. The results showed an increase in GA-sensitivity at about 640 degree days after anthesis (DAA) in Rialto. There was no evidence for a change in ABA-sensitivity in either variety. The in situ experiments were conducted using genotypes from a Spark × Rialto doubled haploid population segregating for the Rht-D1a (tall) or Rht-D1b allele and for the presence or absence of 1BS/1RS. For Rht-D1a (tall) or Rht-D1b genotypes with or without 1BS/1RS, the cold-shock significantly increased GA-sensitivity, whereas there was no significant change in ABA-sensitivity. These results show PMA is related to an increase in GA-sensitivity that occurs in the aleurone at around 640 degree DAA, and can be enhanced by environmental factors (e.g. cold-shock).     

株高、粒重及抗病相关基因在不同国家小麦品种中的分布

利用分子标记对来自21个国家的745份小麦品种的株高（Rht-B1b和Rht-D1b）、粒重相关基因（TaCwi-A1a和Hap-6A-A）和Lr34/Yr18/Pm38基因进行检测。结果表明：（1）在745份品种中,42.1%和28.7%的材料分别携带Rht-B1b和Rht-D1b等位变异,分布频率在不同国家差异很大。一般来说,来自同一个国家的材料主要携带矮秆基因Rht-B1b或Rht-D1b之一,只有意大利和澳大利亚这两种矮秆基因的频率均较高,而高纬度地区如加拿大和俄罗斯等对株高要求不严,矮秆基因分布频率很低;（2）78.4%的材料携带TaCwi-A1a等位变异,除日本（50.0%）、德国（45.3%）和智利（48.8%）外,其他国家材料中TaCwi-A1a分布频率均很高。29.3%的材料在TaGW2-6A位点携带Hap-6A-A等位变异,主要分布在春性和弱冬性小麦品种中,而冬性和强冬性品种中Hap-6A-G分布较为广泛;（3）22.1%的材料携带Lr34/Yr18/Pm38,美国（18.5%）、乌克兰（28.6%）、俄罗斯（26.1%）、伊朗（20.0%）、土耳其（34.8%）、匈牙利（50.0%）、保加利亚（38.9%）、罗马尼亚（87.0%）、日本（80.0%）、加拿大（34.6%）和澳大利亚（44.6%）分布频率较高;（4）TaCwi-A1的分子标记CWI21和CWI22能很好区分等位变异TaCwi-A1a和TaCwi-A1b,TaGW2-6A的CAPS标记能很好区分Hap-6A-A和Hap-6A-G,准确性高、重复性好,可作为千粒重选择的有效标记。     

Segregation analysis indicates that Puroindoline b-2 variants 2 and 3 are allelic in Triticum aestivum and that a revision to Puroindoline b-2 gene symbolization is indicated

Genetic and kernel texture relationships between Puroindoline b-2 variants 2 and 3 have not been fully established in wheat (Triticum aestivum L.). Here, 480 F₂ plants, derived from three hard spring wheat populations were used to test the segregation of Puroindoline b-2 (Pinb-2) variants 2 and 3. Chi-square analysis indicated that Pinb-2 variants 2 and 3 in all three F₂ populations segregated as a single bi-allelic locus, with segregation ratios fitting a 1:2:1 ratio. Using 448 of the 480 plants derived from these three F₂ populations, the average SKCS hardness index of plants homozygous for Pinb-2 variant 2 vs. those homozygous for variant 3 was not significantly different (67.5 vs. 67.9). Results indicated that plants with Pina-D1b/Pinb-D1a were on average 10.0 Single Kernel Characterization System (SKCS) hardness index units harder than those carrying the Pina-D1a/Pinb-D1b haplotype. In conclusion, Pinb-2 variants 2 and 3 are allelic and exert little effect on kernel texture in hard-kernel T. aestivum germplasm. Further, the designation of Pinb-2v2 and Pinb-2v3 should be changed to Pinb-B2a and Pinb-B2b, respectively. We propose that Pinb-2 variants 1 and 4 of Chinese Spring be designated Pinb-D2a and Pinb-A2a, respectively.