Identification of P-type plasma membrane H^(+)-ATPases in common wheat and characterization of TaHA7 associated with seed dormancy and germination

The P-type plasma membrane(PM)H^(+)-ATPases(HAs)are crucial for plant development,growth,and defense.The HAs have been thoroughly characterized in many different plants.However,despite their importance,the functions of HAs in germination and seed dormancy(SD)have not been validated in wheat.Here,we identified 28 TaHA genes(TaHA1-28)in common wheat,which were divided into five subfamilies.An examination of gene expression in strong-and weak-SD wheat varieties led to the discovery of six candidate genes(TaHA7/-12/-14/-16/-18/-20).Based on a single nucleotide polymorphism(SNP)mutation(C/T)in the TaHA7 coding region,a CAPS marker(HA7)was developed and validated in 168 wheat varieties and 171 Chinese mini-core collections that exhibit diverse germination and SD phenotypes.We further verified the roles of the two allelic variations of TaHA7 in germination and SD using wheat mutants mutagenized with ethyl methane sulphonate(EMS)in‘Jimai 22’and‘Jing 411’backgrounds,and in transgenic Arabidopsis lines.TaHA7 appears to regulate germination and SD by mediating gibberellic acid(GA)and abscisic acid(ABA)signaling,metabolism,and biosynthesis.The results presented here will enable future research regarding the TaHAs in wheat.

Optimization of sowing date and seeding rate for high winter wheat yield based on pre-winter plant development and soil water usage in the Loess Plateau,China

Sowing date and seeding rate are critical for productivity of winter wheat(Triticum aestivum L.).A three-year field experiment was conducted with three sowing dates(20 September(SD1),1 October(SD2),and 10 October(SD3)) and three seeding rates(SR67.5,SR90,and SR112.5) to determine suitable sowing date and seeding rate for high wheat yield.A large seasonal variation in accumulated temperature from sowing to winter dormancy was observed among three growing seasons.Suitable sowing dates for strong seedlings before winter varied with the seasons,that was SD2 in 2012–2013,SD3 in 2013–2014,and SD2 as well as SD1 in 2014–2015.Seasonal variation in precipitation during summer fallow also had substantial effects on soil water storage,and consequently influenced grain yield through soil water consumption from winter dormancy to maturity stages.Lower consumption of soil water from winter dormancy to booting stages could make more water available for productive growth from anthesis to maturity stages,leading to higher grain yield.SD2 combined with SR90 had the lowest soil water consumption from winter dormancy to booting stages in 2012–2013 and 2014–2015; while in 2013–2014,it was close to that with SR67.5 or SR112.5.For productive growth from anthesis to maturity stages,SD2 with SR90 had the highest soil water consumption in all three seasons.The highest water consumption in the productive growth period resulted in the best grain yield in both low and high rainfall years.Ear number largely contributed to the seasonal variation in grain yield,while grain number per ear and 1 000-grain weight also contributed to grain yield,especially when soil water storage was high.Our results indicate that sowing date and seeding rate affect grain yield through seedling development before winter and also affect soil water consumption in different growth periods.By selecting the suitable sowing date(1 October) in combination with the proper seeding rate of 90 kg ha–1,the best yield was achieved.Based on these results,we recommend that the current sowing date be delayed from 22 or 23 September to 1 October.

Differential Gene Expression Between Cross-Fertilized and Self-Fertilized Kernels During the Early Stages of Seed Development in Wheat

In order to understand molecular basis of cross-fertilized kernel advantage and heterosis, improved differential display of mRNA was used in this study to analyze alterations in gene expression between cross-fertilized and self-fertilized kernels at 2, 4, 6, 8, 10 and 12 days after pollination (DAP) by using 3 wheat hybrids with different level of heterosis. Four patterns of differential expression were observed: (i) bands observed in cross-fertilized kernels but not in self-fertilized kernels (BCnS); (ii) bands occurring in only self-fertilized kernels but not in cross-fertilized kernels (BSnC); (iii) cDNA over-expressed in cross-fertilized kernels compared to self-fertilized kernels (OEC); (iv) cDNA under-expressed in cross-fertilized kernels compared to self-fertilized kernels (UEC). Further analysis showed that BCnS is positively correlated with heterosis, but BSnC is negatively correlated with heterosis. Four differentially expressed cDNA fragments were verified by reverse-northern blot and sequence homology search in GenBank showed that one of them was new sequences; the other exhibited higher similarity to NBS-LRR type resistance protein, 1,6-bisphosphatase and photosystem Ⅱ chlorophyll a-binding protein psbB, respectively, which indicated diverse pathways may be involved in heterosis formation.

Negative Association between Seed Dormancy and Seed Longevity in Bread Wheat

Many organisms have dormant stages with an extension of their life span to increase longevity, and deeper dormancy is usually related to greater longevity. In cereal crops, seed dormancy is significantly associated with pre-harvest sprouting tolerance during seed development, as seed longevity is a valuable trait for seed banks and providing reliable crop seeds to farmers. In this study, we evaluated both seed dormancy and longevity in bread wheat based on germination and artificial aging tests. According to phenotypic clustering analysis, relative germination rate/potential and relative seedling vigor index were more effective to indicate seed longevity than relative electrical conductivity in wheat, while all the four investigated phenotypes of relative germination potential, relative germination rate, germination index and degree of seed dormancy fit well as a reflex of wheat seed dormancy. In the correlation analysis, the germination level of newly harvested grain negatively reflected its degree of seed dormancy, while the germination ability of grain after artificial aging reflected its seed longevity. However, in contrast to the current opinion in plant, seed dormancy was significantly negatively correlated to seed longevity in our study, and it was not an accidental phenomenon, for that the majority of accessions with high degree of seed dormancy had short seed longevity. To our knowledge, this is the first to report the negative association between seed dormancy and longevity in cereal crops. It would lead to further concerns about how to breed wheat with both prolonged seed longevity and deep dormancy to avoid pre-harvest sprouting.

TaSRO1 interacts with TaVP1 to modulate seed dormancy and pre-harvest sprouting resistance in wheat

Dormancy is an adaptive trait which prevents seeds from germinating under unfavorable environmental conditions.Seeds with weak dormancy undergo pre-harvest sprouting(PHS)which decreases grain yield and quality.Understanding the genetic mechanisms that regulate seed dormancy and resistance to PHS is crucial for ensuring global food security.In this study,we illustrated the function and molecular mechanism of TaSRO1 in the regulation of seed dormancy and PHS resistance by suppressing TaVP1.The tasro1 mutants exhibited strong seed dormancy and enhanced resistance to PHS,whereas the mutants of tavp1 displayed weak dormancy.Genetic evidence has shown that TaVP1 is epistatic to TaSRO1.Biochemical evidence has shown that TaSRO1 interacts with TaVP1 and represses the transcriptional activation of the PHS resistance genes TaPHS1 and TaSdr.Furthermore,TaSRO1 undermines the synergistic activation of TaVP1 and TaABI5 in PHS resistance genes.Finally,we highlight the great potential of tasro1 alleles for breeding elite wheat cultivars that are resistant to PHS.

The GATA transcription factor TaGATA1 recruits demethylase TaELF6-A1 and enhances seed dormancy in wheat by directly regulating TaABI5

Seed dormancy is an important agronomic trait in crops, and plants with low dormancy are prone to preharvest sprouting(PHS) under high-temperature and humid conditions. In this study,we report that the GATA transcription factor TaGATA1 is a positive regulator of seed dormancy by regulating TaABI5 expression in wheat.Our results demonstrate that TaGATA1 overexpression significantly enhances seed dormancy and increases resistance to PHS in wheat. Gene expression patterns, abscisic acid(ABA) response assay, and transcriptome analysis all indicate that TaGATA1 functions through the ABA signaling pathway. The transcript abundance of TaABI5, an essential regulator in the ABA signaling pathway,is significantly elevated in plants overexpressing TaGATA1. Chromatin immunoprecipitation assay(ChIP) and transient expression analysis showed that TaGATA1 binds to the GATA motifs at the promoter of TaABI5 and induces its expression.We also demonstrate that TaGATA1 physically interacts with the putative demethylase TaELF6-A1, the wheat orthologue of Arabidopsis ELF6.ChIP–qPCR analysis showed that H3K27me3 levels significantly decline at the TaABI5 promoter in the TaGATA1-overexpression wheat line and that transient expression of TaELF6-A1 reduces methylation levels at the TaABI5 promoter, increasing TaABI5 expression. These findings reveal a new transcription module, including TaGATA1–TaELF6-A1–TaABI5, which contributes to seed dormancy through the ABA signaling pathway and epigenetic reprogramming at the target site. TaGATA1 could be a candidate gene for improving PHS resistance.

小麦穗发芽抗性机制及抗性育种研究

穗发芽是禾本科作物籽粒在收获前于高湿环境下的穗上发芽现象,严重影响小麦的产量与品质。种子休眠水平是影响小麦穗发芽抗性的主要因素,而往往驯化作物的籽粒休眠水平低,导致栽培小麦普遍比其野生祖先种更易发生穗发芽。小麦穗发芽主要受外源环境(温度、湿度等)和内源植物激素(GAs、ABA、IAA、MeJA、ET、BR)的调控。已鉴定出一批抗穗发芽材料,并克隆了一系列调控穗发芽抗性的关键基因,如PM19、MFT、MKK3、Myb10-3D、Vp1等。通过分子标记辅助选择、人工合成小麦和CRISPR/Cas9基因编辑技术,已成功创制了抗穗发芽小麦新材料。本文综述了小麦穗发芽抗性的遗传机制及抗性育种研究的最新进展,未来仍需继续挖掘关键穗发芽抗性基因,以生物育种的方法培育抗穗发芽小麦新品种。

山东省小麦育种现状与建议

山东省作为我国小麦主产省份之一,其小麦产业的高质量发展对保障国家粮食安全具有重要意义。选育和推广优良品种是促进小麦产业发展的基础。本文回顾了山东省近年来小麦育种发展现状,分析了存在的问题和挑战,并提出了推进山东省小麦育种可持续发展的建议,为实现山东省小麦产业高质量发展,确保山东省乃至全国粮食安全提供参考。

不同播种方式对冬小麦产量构成和旗叶光合特性的影响

探究不同播种方式对冬小麦光合特性以及籽粒产量的影响,为进一步提高冬小麦产量提供理论依据。以‘济麦44’为试验材料,于2018—2019年和2019—2020年在潍坊市农业科学院昌邑试验农场和山东省泰安市岱岳区岳洋专业合作社进行,在大田条件下设置了4种播种方式:冬小麦精播半精播(PS)、冬小麦宽幅精播(WPS)、冬小麦苗带少耕播种(LTS)和冬小麦耙压一体单粒匀播(SUS)。分别于小麦苗期、返青期、拔节期、灌浆期和成熟期测定不同播种方式下冬小麦分蘖成穗率、叶片SPAD值、叶面积指数、净光合速率、有效光强辐射以及产量,并分析不同播种方式下,冬小麦种群结构和生理特性之间的差异。试验表明,2年2点SUS平均分蘖成穗率相较于PS、WPS和LTS分别提高了14.94%、29.37%和15.03%;旗叶叶绿素含量于扬花期和灌浆中期分别提高了7.54%、7.06%、5.79%和8.30%、8.15%、5.50%;叶面积指数于扬花期分别提高了13.8%、8.88%和6.32%;旗叶净光合速率于扬花期分别提高了13.15%、11.50%和12.23%;冠层光合有效辐射量于扬花期分别提高了17.10%、18.96%和10.73%;产量方面,SUS相较于其他3种播种方式,2年2点穗数、千粒重和产量分别增加了5.17%~8.93%、5.33%~9.52%和6.11%~14.86%。综合来看,SUS相较于PS、WPS和LTS可显著提升小麦的分蘖成穗率和旗叶光合特性,并最终通过穗数和千粒重的增加,实现了籽粒产量的增加。冬小麦耙压一体单粒匀播方式(SUS)可显著改善冬小麦的光合能力,增加冠层截获的有效光辐射量,是实现冬小麦高产较合理的播种模式。

Influences of wide-narrow seeding on soil properties and winter wheat yields under conservation tillage in North China Plain

In order to promote the winter wheat yield and guarantee seeding quality in double-cropping system,no-tillage or reduced tillage planting modes with different row spacing have been implemented to result in different levels of yield.A three-year(2012-2015)field experiment was conducted on the experimental farm at Zhuozhou of Hebei Province in North China Plain to compare winter wheat yield from the two planting modes:wide-narrow row space planting mode(WN)and uniform row space planting mode(UR)Both planting modes were performed under reduced tillage conditions with straw mulching.The results showed that in North China Plain WN had positive impacts on crop yield,yield components,leaf area index(LAI)and intercepted photosynthetically active radiation(IPAR)index.Comparing with the UR,IPAR and LAI index for WN were enhanced by 4.8%and 5.2%,respectively.The average yield for WN was 7.2%,significantly greater than that of UR under the same quantity and density.In addition,for WN mode,machinery could pass through with less blocking under large amount of straw mulching,which largely improved tillage efficiency and potentially popularized the conservation tillage technology in North China plain.It is therefore recommended that wide-narrow row space planting mode(WN)combined with reduced tillage and straw mulching be more suitable for conservation tillage in double-cropping pattern areas in North China Plain.

不同播期和密度对小麦新品种航宇19产量及其构成要素的影响

为确定航天诱变小麦新品种航宇19高产高效栽培措施,采用二因素互作裂区试验设计,研究不同播期和密度对其产量及构成要素的影响,以明确该品种在豫中北部生态条件下的最优栽培措施。结果表明,播期、密度和播期×密度互作对航宇19产量及其构成要素均具有显著影响,且播期效应大于密度效应。播期对航宇19穗粒数的影响不明显,播期延迟后,单位面积成穗数和千粒重显著降低。密度增加后,成穗数相应增加,但穗粒数和千粒重降低。本试验条件下,航宇19的适宜播期为10月20日前后,且150~195 kg/hm2的播种密度可使航宇19达到更高的产量水平。说明通过调整播期与密度,可使该品种的单位面积成穗数和穗粒数显著响应,进而达到提高产量的目的。

Proteomics of Wheat Endosperm:a Tool to Find Genes Involved in Kernel Composition and Quality

The composition of the wheat kernel is the result of the expression of thousands of genes translated in enzymes involved in all the biochemical pathways that are needed for endosperm cell functions and also for the ac-

播期和播量对冬小麦生长发育和产量的影响

为解决鲁西南地区因播期推迟影响小麦产量的实际问题。采用双因素裂区试验设计,以播期为主区,播量为副区,2018—2019年播期设10月18日(S_(1))、10月23日(S_(2))、10月28日(S_(3))3个水平;播量设2.70×10^(6)株/hm^(2)(D1)、3.75×10^(6)株/hm^(2)(D_(2))2个水平;2019—2020播期设10月22日(S_(4))、10月27(S_(5))、11月1日(S_(6))、11月6日(S_(7))、11月11日(S_(8))5个水平;播量设2.25×10^(6)株/hm^(2)(D_(3))、3.375×10^(6)株/hm^(2)(D_(4))、4.50×10^(6)株/hm^(2)(D_(5))3个水平,研究播期、播量对小麦冬前分蘖、叶龄、春季分蘖、叶龄、株高、穗长及产量三因素的影响。结果表明,同一播量,随播期推迟,小麦的冬前叶龄、冬前分蘖,春季叶龄及次生根条数逐渐减少,春季分蘖逐渐增加;同一播期,随播量的增加,冬前叶龄、冬前分蘖,春季叶龄及次生根条数、春季分蘖均在减少。播期、播量显著影响了小麦株高、穗长、有效穗数、穗粒数、产量。播期对基部第二节间影响显著,播量对千粒重影响极显著。两者互作对有效穗数和产量影响显著。本试验条件下,鲁西南地区‘山农28’适期晚播时间为10月18日—22日,播量为3.75×10^(6)株/hm^(2)为宜,播期在11月左右,播量在4.50×10^(6)株/hm^(2)以上,可以获得较高的产量。

影响不同种皮颜色小麦种子休眠的生理原因

为了解小麦种皮颜色和休眠性的关系,分别选取红皮和白皮小麦品种各15个,测定其种皮颜色和休眠水平,对影响不同种皮颜色小麦种子休眠差异的生理原因进行分析。结果表明,基于数码相机图片提取的RGB数值推导出的指标色调(H)、饱和度(S)和强度(I)均可反映小麦种皮颜色的深浅度。R、H、S和I值与种子休眠性呈显著负相关,R/(R+G+B)与籽粒休眠性呈显著正相关,即籽粒种皮颜色越深,其休眠性越强(P<0.05)。红皮与白皮品种中均存在休眠差异性显著的材料。选取白皮小麦敏感性品种华成麦1688(W1)和抗性品种安农0711(W15)及红皮小麦敏感性品种白湖麦1号(R1)和抗性品种扬麦27(R15),进行生理性状分析发现,在种子萌发过程中,敏感性品种W1和R1的种子吸水率、含水量及α-淀粉酶、β-淀粉酶和酸性磷酸酶活性高;同时种子内部可溶性糖含量和蛋白质含量高;赤霉素(GA_(3))含量逐渐上升,而脱落酸(ABA)含量逐渐下降。反之,抗性品种W15和R15种子的淀粉酶活性及可溶性糖、可溶性蛋白和GA_(3)含量在休眠解除过程中低,ABA含量高。相同敏感性材料中,白皮小麦品种吸水速率和含水量均高于红皮小麦品种,整体趋势表现为W1>R1>W15>R15趋势。种子内部可溶性糖含量、蛋白质消耗量和GA_(3)含量表现出相同趋势;而ABA含量恰好相反,表现为R15>W15>R1>W1。在育种过程中,R、H、S、I值可以用来快速鉴别红皮和白皮小麦,间接辅助筛选出抗穗发芽品种,含水量、α-淀粉酶活性、β-淀粉酶活性、酸性磷酸酶活性、可溶性糖含量和ABA含量可作为穗发芽抗性鉴定的生理参考指标。

Characters of Cysteine Endopeptidases in Wheat Endosperm during Seed Germination and Subsequent Seedling Growth

The endopeptidases （EPs） in wheat endosperm during seed germination and subsequent seedling growth were characterized by gradient-polyacrylamide gel electrophoresis with gelatin copolymerized into the gel. Four cysteine EPs （EP1, EP2, EP3 and EP4） were detected in wheat endosperm during the 7 d growth after seed imbibition. The results also showed that the activities of all of these EPs increased continuously, and EP2 first appeared and had the highest proteolytic activity among the four EPs in this experimental process. The optimum pH and temperature of all four EPs were 4.0 and 40.0 ~C. All EPs were completely inhibited by 25 μmol/L E-64 and had no good thermal stabilities, especially EP1. In addition, these EPs had different substrate specificities to albumins, globulins, gliadins and glutenins; the main storage proteins of mature wheat endosperm. Among them, EP2 had the highest proteolytic activities on globulins, gliadins and glutenins, and might be the most important and specific EP with potential to be tightly correlated with seedling development.

临沂市冬小麦规范化播种技术

为进一步规范临沂市冬小麦播种技术,提升播种质量,打好小麦丰产基础,经过多年试验研究与生产实践,从科学选用良种、精细整地、规范化播种等方面总结出临沂市冬小麦播种关键技术,将耕、耙和镇压3个因素配套应用,培育冬前壮苗,为临沂市冬小麦节本增效、抗逆减灾和稳产高产提供技术支撑。

氮肥运筹方式对孕穗期受渍冬小麦穗部结实特性与产量的影响

以小麦品种皖麦54为试验材料,连续两个生长季进行了氮肥运筹方式对孕穗期渍水冬小麦不同小穗位、粒位的结实粒数和粒重影响的观测。结果表明,不同氮肥运筹方式显著影响穗部结实特性,主茎穗结实特性优于分蘖穗。全部基施的氮肥运筹方式较基肥50%+拔节肥50%和基肥30%+拔节肥50%+孕穗肥20%的运筹方式显著增加了不孕小穗数,降低结实小穗数和结实粒数,2008—2010两年度全部基肥运筹方式较基肥30%+拔节肥50%+孕穗肥20%氮肥运筹方式处理不孕小穗数分别增加25.5%和29.8%,结实小穗数均降低5.7%。孕穗期渍水逆境对分蘖穗结实特性影响大于主茎穗,渍水逆境显著增加不孕小穗数,较对照处理,2008—2010两年度,不孕小穗数分别增加10.6%和4.6%;结实小穗数分别降低2.8%和1.4%。孕穗期渍水降低主茎穗结实4粒的小穗数比例和分蘖穗结实3、4粒小穗数的比例及第3、第4粒位籽粒粒重和第3、第4粒位粒重对单穗粒重的贡献率。氮肥后移运筹方式显著提高孕穗期受渍小麦主茎、分蘖穗结实小穗数和粒重,增加主茎和分蘖穗结实3、4粒小穗的比例和结实小穗第3、4粒位的粒重,提高第3、4粒位粒重对单穗粒重的贡献率,减少不孕小穗数,进而较氮肥前移处理显著提高经济产量。氮肥后移运筹方式有利于减轻孕穗期渍害对小麦穗部结实特性的影响。

渭北旱塬不同施肥与覆盖栽培对冬小麦产量形成及土壤水分利用的影响

【目的】研究不同施肥和覆盖栽培模式对渭北旱塬旱地冬小麦产量和水分利用的影响。【方法】通过田间试验,研究测土推荐施氮、顶凌追肥、垄覆沟播、秸秆还田覆盖等措施对冬小麦产量、生物量、收获指数、水分利用效率及土壤水分周年变化的影响。【结果】旱地早春追肥使冬小麦增产6%—14%,水分利用效率提高7%—10%,达到12.2—13.6 kg.hm-2.mm-1;"减氮+垄覆沟播"增产达15%—41%,水分利用率提高10%—30%,达到12.2—16.5 kg.hm-2.mm-1。主要原因是,通过测土优化氮肥用量,采用基肥﹕追肥(3﹕1)方式,并与起垄覆膜栽培措施相结合可促进冬小麦利用深层土壤水分,提高冬小麦抽穗开花期植株含水量和成熟期的生物量及收获指数;虽然生育期耗水增加,但水分利用效率也提高。而单纯减少氮肥用量,不利于水分利用效率的提高;夏季垄上覆膜沟内覆盖作物秸秆可提高休闲效率,利于土壤水分恢复,实现土壤水分周年平衡和旱地小麦可持续增产。【结论】优化施氮结合垄覆沟播是黄土高原渭北旱地小麦增产增效的栽培模式。

种子休眠的研究进展

种子休眠是植物在长期系统发育进程中获得的一种适应环境变化的特性。这种特性能够确保物种在恶劣的环境中存活,减少同一物种中个体之间的竞争,以及防止种子在不适宜的季节萌发。该文综述了种子休眠的类型、种子休眠的发育与连续群、种子休眠的调节、与休眠诱导、维持和释放有关的蛋白以及种子休眠的进化,并提出了今后种子休眠研究的主要问题。

10.4%吡虫啉·烯唑醇悬浮种衣剂对小麦蚜虫和纹枯病的防治效果

为了解10.4%吡虫啉·烯唑醇悬浮种衣剂对小麦纹枯病、蚜虫的防治效果及最佳用药量,采用室内和田间小区试验相结合的方法,以郑麦366为试验品种,以600g.L-1吡虫啉和12.5%烯唑醇为对照药剂,设置3种不同药种质量比(1∶50、1∶60、1∶70)处理,研究不同剂量的10.4%吡虫啉.烯唑醇悬浮种衣剂对小麦蚜虫和纹枯病的防治效果。结果表明,10.4%吡虫啉.烯唑醇悬浮种衣剂包衣对小麦发芽、出苗和生长无不良影响,用药剂量越大,对小麦蚜虫和纹枯病的防治效果越好。在防治蚜虫方面,该种衣剂在药种比为1∶50和1∶60时防效分别为85.61%～97.71%和80.15%～93.38%,与对照药剂600g.L-1吡虫啉FS1∶300包衣效果差异不显著;药种比为1∶70时,在蚜虫发生前期和中后期防效分别为91.32%～94.91%和74.88%～83.27%,其中中后期防效显著低于药种比1∶50、1∶60和对照药剂处理。在防治纹枯病和枯白穗方面,该种衣剂在药种比为1∶50时防效分别为76.91%～86.64%和78.29%,与对照药剂12.5%烯唑醇WP 1∶1500拌种处理差异不显著;药种比为1∶60时的防效分别为69.14%～80.87%和72.68%,显著低于药种比1∶50包衣处理,与对照药剂差异不显著;药种比为1∶70时防效分别为60.75%～78.35%和64.43%,显著低于药种比1∶50、1∶60和对照药剂。以上结果说明,10.4%吡虫啉·烯唑醇悬浮种衣剂对小麦蚜虫和纹枯病具有良好防治效果,最佳使用剂量为药种比1∶50～1∶60。