Evaluation of Pre-Harvest Sprouting(PHS)Resistance and Screening of High-Quality Varieties from Thirty-Seven Quinoa(Chenopodium quinoa Willd.)Resources in Chengdu Plain

Pre-harvest sprouting(PHS)will have a serious effect both on the yield and quality of quinoa(Chenopodium quinoaWilld.).It is crucial to select and breed quinoa varieties with PHS resistance and excellent agronomic traits for guidance production and utilization of quinoa.A comprehensive evaluation of the PHS resistance and agronomic traits of 37 species of quinoa resources was conducted in Chengdu Plain.The evaluation used various methods,including grain germination rate(GR),grain germination index(GI),total spike germination rate(SR),total grain germination index(SI),grey correlation analysis(GCA),cluster analysis and correlation analysis.Results showed significant differences in PHS resistance and agronomic traits amongst the 37 quinoa resources.CDU-23 was most resistant to PHS within 24 h,with a germination rate of 2.67%and 0%according to the GR and SR results,respectively.However,in the same time,CDU-31 showed the maximum susceptibility to PHS based on the SR of 31.07%,while CDU-34 was the most sensitive to PHS according to the GR of 100%.The comprehensive evaluation identified one and nine kinds of high resistance species for grain and whole spike germination,respectively.In both cases,the coefficients of variation(CV)for these parameters were 34.78%and 82.13%,respectively.GCA results showed that the magnitude of the association between each trait and yield in the thirty-seven quinoa resources was in the following order:thousand grain weight>seed length>seed area>seed width.Although the seed weight of CDU-18 reached 3.7010 g,the seed weight of CDU-5 was only 1.6030 g.However,the size of the seeds,their width and area did not correlate with their 1000-grain weight.There was a complex correlation between PHS resistance index and agronomic traits.Based on clustering analysis,thirty-seven quinoa resources were classified into three taxa.It was found that various taxa differed in PHS resistance and agronomic traits.Several comparisons of the aggregated data led to the selection of five varieties of quinoa,of which CDU-2 presented excellent agronomic qualities and strong PHS resistance.This study has provided a reference for breeding excellent quinoa varieties with PHS resistance.

Identification of KASP markers and putative genes for pre-harvest sprouting resistance in common wheat(Triticum aestivum L.)

Common wheat(Triticum aestivum L.)is the most important crop in the world and a typical allopolyploid with a large and complex genome.Pre-harvest sprouting(PHS)leads to a significant reduction in grain quality worldwide.PHS is a complex trait with related QTL located on different chromosomes.However,the study of markers and genes related to PHS resistance is limited especially for whitegrained wheat.Four pairs of near isogenic lines(NILs)from a white-grained wheat cross of Chara
DM5637B*8 targeting a major QTL for PHS resistance(Qphs.ccsu-3A.1)on wheat chromosme 3AL were genotyped using the 90K SNP Illumina iSelect array.Ten SNPs were identified,with a 75%-100%consistency between genotype and phenotype in the resistant or susceptible isolines.The 10 SNPs were converted to cost-effective kompetitive allele-specific PCR(KASP)markers.Screening of 48 wheat cultivars with different phenotypes of PHS identified four KASP markers with 81.3%-85.4%conformity between genotype and phenotype.Further investigation revealed that the four SNPs(BS00022245_51,Kukri_c49927_151,BS00022884_51 and BS00110550_51)corresponding to the four validated KASP markers are residing in three independent genes(TraesCS3A03G1072800,TraesCS3A03G1072400,TraesCS3A03G1071800)close to each other with a distance of 4.28-4.48 Mb to the targeted QTL.These three annotated genes have potential functions related to PHS resistance.Our study revealed that combined use of NILs and the 90K SNP chip is a powerful approach for developing KASP markers and mining functional genes in wheat.The KASP markers for PHS resistance on chromosome 3AL are useful for high-throughput evaluation and marker-assisted selection,and the three identified genes could lead to a better understanding of the genetic pathways controlling PHS.

QTL mapping revealed TaVp-1A conferred pre-harvest sprouting resistance in wheat population Yanda 1817×Beinong 6

Pre-harvest sprouting （PHS） occurs frequently in most of the wheat cultivation area worldwide, which severely reduces yield and end-use quality, resulting in substantial economic loss. In this study, quantitative trait loci （QTL） for PHS resistance were mapped using an available high-density single nucleotide polymorphism （SNP） and simple sequence repeat （SSR） genetic linkage map developed from a 269 recombinant inbred lines （RILs） population of Yanda 1817xBeinong 6. Using phenotypic data on two locations （Beijing and Shijiazhuang, China） in two years （2012 and 2013 harvesting seasons）, five QTLs, designated as QPhs.cau-3A. 1, QPhs.cau-3A.2, QPhs.cau-5B, QPhs.cau-4A, and QPhs.cau-6A, for PHS （GP） were detected by inclusive composite interval mapping （ICIM） （LOD≥2.5）. Two major QTLs, QPhs.cau-3A.2 and QPhs.cau-5B, were mapped on 3AL and 5BS chromosome arms, explaining 6.29-21.65% and 4.36-5.94% of the phenotypic variance, respectively. Precise mapping and comparative genomic analysis revealed that the TaVp-1A flanking region on 3AL is responsible for QPhs.cau-3A.2. SNP markers flanking QPhs.cau-3A.2 genomic region were developed and could be used for introgression of PHS tolerance into high yielding wheat varieties through marker-assisted selection （MAS）.

QTL mapping for pre-harvest sprouting in a recombinant inbred line population of elite wheat varieties Zhongmai 578 and Jimai 22

Pre-harvest sprouting(PHS)is one of the serious global issues in wheat production.Identification of quantitative trait loci(QTL)and closely-linked markers is greatly helpful for wheat improvement.In the present study,a recombinant inbred line(RIL)population derived from the cross of Zhongmai 578(ZM578)/Jimai 22(JM22)and parents were phenotyped in five environments and genotyped by the wheat 50 K single-nucleotide polymorphism(SNP)array.Two QTL of germination index(GI),QGI.caas-3A and QGI.caas-5A,were detected,explaining 4.33%–5.58%and 4.43%–8.02%of the phenotypic variances,respectively.The resistant effect of QGI.caas-3A was contributed by JM22,whereas that of QGI.caas.5A was from ZM578.The two QTL did not correspond to any previously identified genes or genetic loci for PHSrelated traits according to their locations in the Chinese Spring reference genome,indicating that they are likely to be new loci for PHS resistance.Four kompetitive allele-specific PCR(KASP)markers K_AX-109605367and K_AX-179559687 flanking QGI.caas-3A,and K_AX-111258240 and K_AX-109402944flanking QGI.caas-5A,were developed and validated in a natural population of 100 wheat cultivars.The distribution frequency of resistance alleles at Qphs.caas-3A and Qphs.caas-5A loci were 82.7%and57.1%,respectively,in the natural population.These findings provide new QTL and tightly linked KASP markers for improvement of PHS resistance in wheat.

The association between the allelic state of <i>Vp</i>-1<i>B</i>and pre-harvest sprouting tolerance in red-seeded hexaploid triticale

The core collection of red-seeded winter hexaploid triticale with different pre-harvest sprouting (PHS) resistance has been evaluated for the allelic structure of the gene VIVIPAROUS-1B (Vp-1B) with STS molecular marker. The discovered structure of the collection was as follows: 50.0% and 41.7% of the collection carries Vp-1Bа and Vp-1Bc alleles, respectively, while 8,3% possesses both of them. As a result of the seed color estimation, the collection has been divided into two groups: with dark red seeds and light red seeds. The allele Vp-1Bc has appeared to be associated with PHS resistance while Vp-1Ba with PHS susceptibility in the triticale accessions with light red seeds only. The influence of the seed color and allelic state of Vp-1B on PHS resistance in triticale is discussed.

Isolation and Functional Characterization of a B3 Transcription Factor Gene <i>FUSCA3</i>Involved in Pre-Harvest Sprouting Resistance in Wheat

Pre-harvest sprouting (PHS) reduces yields and grain quality, resulting in seriously economic losses in wheat. It has been showed that PHS is significantly correlated to seed dormancy levels. FUSCA3 (FUS3) gene is considered to be the key regulator of seed dormancy. However, little information is available about the function of FUS3 gene (TaFUS3) in wheat. In this study, three homologous genes were identified in wheat grain, and their functions were investigated by gene silencing. Three full-length DNA (3477, 3534 and 3501 bp) and cDNA (1015, 1012 and 1015 bp) sequences encoding a B3 transcription factor, designated TaFUS3-3A, TaFUS3-3B and TaFUS3-3D, were first isolated from common wheat. The transcription of three TaFUS3 genes in seed development and germination process was detected. TaFUS3-3B and TaFUS3-3D had similar expression profiles, and high levels of gene transcripts were detected in seeds at 25 DAP (days after pollination) and after 24 h of imbibition. However, the transcription of TaFUS3-3A was not detected. Silencing of TaFUS3 in common wheat spikes resulted in increased seed germination and PHS. Compared with wild-type, the TaFUS3-silenced plants showed increased expression of genes related to GA biosynthesis and ABA metabolism, and decreased expression of genes associated with ABA biosynthesis. Moreover, silencing of TaFUS3 in wheat plants led to a decrease in embryo sensitivity to ABA and changed the expression of genes involved in ABA signal transduction. The results of gene silencing indicated that TaFUS3 plays a positive role in wheat seed dormancy and PHS-resistance, which might be associated with ABA, GA level and signal transduction.

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.

水的总硬度和pH值对绿豆种子萌发及其绿豆芽品质的影响

研究13种水的pH值和6种水的总硬度对绿豆种子萌发及其芽苗菜品质的影响,结果显示:水的硬度值为26度,pH值为6.0的处理液处理绿豆种子,其发芽率、发芽势、发芽指数、芽苗菜平均株高和生物产量均较高;不同处理液浸种后的种子,其相对吸水量差异并不明显;pH值3.0-6.5处理液处理的芽苗菜随着酸性增强其可溶性糖含量逐渐增加,碱性条件下差异不显著;其蛋白质含量在pH值为3.0-7.5无显著差异,但pH值7.5-11有明显上升的趋势.

pH对松柳芽苗菜生长的影响

[目的]探明pH对松柳芽苗菜生长的影响规律,为松柳芽苗菜的培育提供改进建议。[方法]采用20℃育苗盘恒温水培栽植方法,通过改变不同培养液pH,检测相应松柳苗出芽率及成熟期松柳的整株重量和根重,分析其对酸碱的耐受性。[结果]强酸和强碱条件均会对松柳的生长产生较强的抑制作用,而在弱酸和弱碱环境下,松柳有较强的耐受性。[结论]在松柳发芽的早期阶段,弱酸条件可提高松柳的出芽率;后期生长阶段,弱碱条件可提高松柳的生长速度。

人工合成小麦和地方品种穗发芽抗性育种利用效率

【目的】小麦穗发芽是影响小麦产量和品质的重要限制因子。具有抗穗发芽特性的人工合成小麦和地方品种是改良栽培小麦穗发芽抗性的重要基因资源,通过分子标记辅助选择转育人工合成小麦和地方品种穗发芽抗性位点,评价人工合成小麦和地方品种导入系抗穗发芽育种利用效率,筛选抗穗发芽小麦新材料,为小麦穗发芽抗性育种提供数据和材料支撑。【方法】以抗穗发芽的人工合成小麦SYN792和四川地方品种涪陵须须麦为母本,以穗发芽敏感品种川麦45为轮回亲本,构建2个BC1F7群体。2017年,通过整穗发芽鉴定法对2个BC1F7群体的1796个株系进行穗发芽表型初筛,然后利用与人工合成小麦PHS-3D和地方品种PHS-A1穗发芽抗性位点连锁的SSR标记进行分子标记选择,筛选出整穗发芽率(SGR)小于35%且携带PHS-3D和PHS-A1抗性位点的导入系;2018和2019年,连续2年对初筛选出的PHS-3D和PHS-A1导入系进行整穗发芽率、籽粒发芽指数(GI)和产量相关性状鉴定,其中,籽粒发芽鉴定试验设置25℃(18GI)和32℃(19GI)2个发芽温度。通过不同环境下穗发芽抗性和产量数据,分析人工合成小麦和地方品种导入系抗穗发芽育种利用效率,筛选抗穗发芽且综合性状好的优异导入系。【结果】经整穗发芽鉴定初筛,从1796个衍生系中筛选出SGR值小于35%的株系537个;进一步对筛选出的537个株系进行分子标记检测,发现332个株系导入了人工合成小麦PHS-3D和地方品种PHS-A1穗发芽抗性位点,包括人工合成小麦导入系73个、地方品种导入系259个;地方品种PHS-A1导入系的频率显著高于人工合成小麦PHS-3D导入系。2018和2019年通过对332个穗发芽抗性位点导入系穗发芽鉴定发现,不同年份穗发芽指标间均呈极显著正相关,穗发芽指标SGR和GI表现出相对稳定的趋势;人工合成小麦和地方品种导入系的3个穗发芽指标平均值(18GI、18SGR和19SGR)均低于23%,差异不显著。不同发芽温度导入系的GI值差异较大,发芽温度32℃时,人工合成小麦PHS-3D导入系的GI值显著低于地方品种PHS-A1导入系。筛选出的73个人工合成小麦导入系中,红粒系穗发芽指标值均低于白粒系;其中,11个人工合成小麦白粒导入系表现中抗及以上抗性水平,14个红粒导入系在不同发芽温度时GI值均低于35%。2年产量相关性状分析表明,人工合成小麦PHS-3D导入系的千粒重显著高于地方品种PHS-A1导入系,而穗粒数显著小于地方品种PHS-A1导入系。根据产量性状和穗发芽抗性表现,筛选出23个穗发芽抗性和综合性状均较好的优异导入系,包括7个人工合成小麦PHS-3D导入系、16个地方品种PHS-A1导入系;人工合成小麦优异导入系中有2个白粒导入系穗发芽抗性中抗以上,2个红粒导入系不同发芽温度的GI值均低于25%,表现出稳定的穗发芽抗性。【结论】人工合成小麦和地方品种均可用于改良现代栽培小麦穗发芽抗性,利用地方品种进行穗发芽抗性育种改良效率优于人工合成小麦;但人工合成小麦导入系的穗发芽抗性的稳定性优于地方品种导入系。筛选出的23个人工合成小麦和地方品种导入系是小麦穗发芽抗性和产量性状改良的重要基因资源;特别是人工合成小麦白粒导入系(编号5201)和红粒导入系(编号5497和5505)是非常有育种利用价值的穗发芽抗性育种亲本材料。

杂交水稻不同穗萌程度种子质量差异与穗萌分级研究

研究不同穗萌程度种子质量,对科学划分穗萌级别,优化穗萌指标计算方法至关重要。本试验以钱优0508(Qianyou 0508, QY0508)、Y两优689 (Y Liangyou 689, YLY689)两个籼型杂交水稻品种为材料,测定穗上不同穗萌程度种子的发芽指标,以及可溶性糖、可溶性蛋白含量等生理指标,以此评估不同穗萌程度水稻种子的发芽质量。同时,采用自然晾干和38℃烘干2种方式干燥穗萌种子,并将种子在低温和水淹2种逆境条件下发芽,探究实际生产中不同干燥处理对已穗萌种子质量的影响,及不同穗萌程度种子萌发抗逆能力的差异。此外,由于水稻种子通常在蜡熟末期至完熟初期为最佳收获期,期间均可能遭遇不良气候条件导致种子穗萌,因此本研究对不同成熟时期的穗萌种子质量也进行了探讨。通过鉴定穗上不同萌动程度的种子质量,提出了新的水稻穗萌分级方法,即完整饱满未萌动种子为0级,胚根凸起但稃壳未开裂的种子为1级,胚根露出且可见长度不足2mm的种子为2级,胚根可见长度大于2 mm的种子为3级。与0级种子相比,1~3级穗萌种子的发芽率均显著下降,不正常幼苗率显著增加,在低温、水淹逆境下,该现象更明显。相对而言, 38℃烘干方式对种子质量的影响较自然晾干小,而授粉后35 d (35 DAP)成熟度高的种子发生穗萌后对种子质量影响较授粉后25 d (25 DAP)成熟度低的种子小。本研究经过对不同穗萌程度种子质量的研究,提出了新的穗萌分级方法,对准确评估田间水稻穗萌水平有重要价值。

小麦穗发芽研究进展

小麦穗发芽是世界性的自然灾害,主要受外部环境和自身遗传因素影响,是小麦产量和品质的重要限制因子。从小麦穗发芽影响因素、相关数量性状位点和基因、防控方法等方面对前期研究进行了梳理,认为种子的休眠性和对脱落酸与赤霉素的敏感性是决定穗发芽抗性的关键因素,培育抗性品种是解决小麦穗发芽问题的根本途径,并对今后重点研究方向进行了展望。对于解决小麦穗发芽问题、提高产量和品质、保障国家粮食安全具有借鉴意义。

Sdr4 dominates pre-harvest sprouting and facilitates adaptation to local climatic condition in Asian cultivated rice

Pre-harvest sprouting(PHS),which reduces grain yield and quality,is controlled by seed dormancy genes.Because few dormancy-related genes have been cloned,the genetic basis of seed dormancy in rice(Oryza sativa L.)remains unclear.Here,we performed a genome-wide association study and linkage mapping to dissect the genetic basis of seed dormancy in rice.Our findings suggest that Seed Dormancy4(Sdr4),a central modulator of seed dormancy,integrates the abscisic acid and gibberellic acid signaling pathways at the transcriptional level.Haplotype analysis revealed that three Sdr4 alleles in rice cultivars already existed in ancestral Oryza rufipogon accessions.Furthermore,like the semi-dwarf 1(SD1)and Rc loci,Sdr4 underwent selection during the domestication and improvement of Asian cultivated rice.The distribution frequency of the Sdr4-n allele in different locations in Asia is negatively associated with local annual temperature and precipitation.Finally,we developed functional molecular markers for Sdr4,SD1,and Rc for use in molecular breeding.Our results provide clues about the molecular basis of Sdr4-regulated seed dormancy.Moreover,these findings provide guidance for utilizing the favorable alleles of Sdr4 and Rc to synergistically boost PHS resistance,yield,and quality in modern rice varieties.

Breeding for pre-harvest sprouting resistance in bread wheat under rainfed conditions

Pre-harvest sprouting in wheat is the germination of seeds within the spikes when rains occur after or during grain ripening, which occurs commonly in the barani tract of Pakistan. Therefore, 10 cultivars and five advanced lines of spring bread wheat were evaluated for pre-harvest sprouting resistance. After natural rainfall,seeds were immediately collected from the wet spikes and tested for germinating ability. Three different germination tests were applied to hand-threshed seed:(1) spikes threshed on the day of sampling and germination tested immediately,(2) spikes threshed on the day of sampling and germination tested 1 week later, and(3) spikes threshed 1 week after sampling and germination test immediately after threshing. Seeds and spikes kept for 1 week were place on blotting paper at room temperature.Cultivars BARS-09, 09 FJ17, Doukkala-12, NARC-09 and Ouassou-20 exhibited higher sprouting resistance while other genotypes were susceptible to pre-harvest sprouting in each of the three tests. A diallel crossing was conducted with six susceptible and two resistant genotypes to assess the genetic behavior of pre-harvest sprouting resistance.The combining ability(CA) demonstrated a higher proportion of additive genetic effects for sprouting resistance, because of higher variance of general and specific CA for both parameters under study. Doukkala-12 and BARS-09 showed increased pre-harvest sprouting resistance in their F1 descendants.

喷洒微酸性电解水对荞麦芽菜生长的影响

针对荞麦(F.tatarium)芽菜生产过程中微生物污染造成的烂种、烂苗和食品安全问题,该文利用微酸性电解水在荞麦芽菜浸种和发芽过程中进行喷洒,考察微酸性电解水对荞麦种子发芽特性、种子表面微生物和芽菜品质的影响。试验结果表明:荞麦种子浸种宜采用有效氯浓度(available chlorine concentration,ACC)为40mg/L、pH值为5.0的微酸性电解水,发芽过程喷洒ACC为50mg/L的微酸性电解水能有效控制荞麦芽菜表面细菌和真菌数量,增加芽菜的苗高以及还原糖、芦丁含量,对芽菜产量和干质量无影响。

小麦种子颜色测定的色差计法和目测法及对穗发芽抗性的鉴定效果

为了解种子颜色目测法和色差计法对小麦穗发芽抗性的鉴定效果,利用这两种方法对1018份小麦材料种子颜色进行测定,并分析了色差计量指标L^(*)、a^(*)、b^(*)及a^(*)/b^(*)、b^(*)/a^(*)、a^(*)/L^(*)、b^(*)/L^(*)值与种子颜色和穗发芽抗性的关系。结果表明:(1)红粒小麦a^(*)、a^(*)/b^(*)和a^(*)/L^(*)的均值均显著高于白粒小麦,其他指标均值显著低于白粒小麦;(2)a^(*)/b^(*)和b^(*)/a^(*)值与种子颜色相关性强,相关系数分别为-0.934和0.941,其线性回归方程可用于判断小麦种子颜色;(3)红粒小麦的穗发芽抗性显著高于白粒小麦,但不同红粒品种之间穗发芽抗性差异很大,变异系数为122.36%;(4)种子颜色及a^(*)/b^(*)和b^(*)/a^(*)值与穗发芽抗性相关性强,相关系数分别为0.854、-0.831和0.835;其次是a^(*)/L^(*)值与穗发芽抗性的相关性,其相关系数为-0.735;(5)目测法获得的种子颜色可解释穗发芽抗性72.9%的变异,色差计参数可解释穗发芽抗性72.5%的变异,但在单独分析时,色差计参数对红粒和白粒小麦穗发芽抗性分别仅能解释11.4%和8.7%的变异。总之,色差计法测量种子颜色,可以作为目测法判别小麦种子颜色的补充方法,用于种子颜色定性和定量比较分析。尽管红粒小麦比白粒小麦抗穗发芽,但鉴于红粒小麦品种(系)间穗发芽抗性差异很大,仍需进行穗发芽抗性鉴定。

普通小麦穗发芽抗性相关分子标记在RIL群体中的验证与评价

为了鉴定我国西南冬麦区普通小麦品种的穗发芽抗性,筛选能鉴定穗发芽抗性的相关分子标记,利用小麦品种川农17和新品系R146构建的重组自交系（F7：8）共135个家系作为研究材料,通过测定种子的发芽指数和降落值来共同鉴定小麦的穗发芽抗性。选择7个已发表的与穗发芽抗性相关的分子标记（Xgwm46、Xgwm269、Xgwm282、Xgwm328、Xgwm397、Xwmc468和Xgwm518）对这些材料进行PCR扩增,分析扩增片段与发芽指数和降落值的相关性。结果表明,在135份重组自交系材料中,发芽指数小于0.4的材料有21份,介于0.4～0.8的材料有86份,高于0.8的材料有28份;降落值小于250的材料有20份,大于400的有16份。标记扩增片段与发芽指数和降落值相关分析表明,7个标记中有3个标记（Xgwm397、Xgwm282和Xwmc468）与穗发芽抗性相关,标记Xgwm397和Xwmc468可作为穗发芽抗性选择的分子标记在育种中加以利用;另外三个标记Xgwm269、Xgwm328、Xgwm518与穗发芽抗性不相关;标记Xgwm46只与发芽指数相关,与降落值相关不显著,能否用作穗发芽筛选标记需进一步验证。

多酚氧化酶活性与小麦抗穗发芽的关系及抗穗发芽新品种秦麦3号的选育

为更好地选育抗穗发芽小麦新品种,解决小麦生产中的穗发芽损失问题,以18个穗发芽抗性不同的小麦品种(系)为试材,以微喷人工降雨法诱导穗发芽,测定了发芽和未发芽籽粒的多酚氧化酶(PPO)活性、酚含量和吸水率,并分析了他们与穗发芽抗性之间的关系。结果表明,PPO活性、吸水率均与穗发芽率呈显著正相关,即PPO活性、吸水率越低,穗发芽抗性越强;而酚含量与穗发芽率无相关性。同时,以PPO活性为抗穗发芽能力的筛选指标,从“昌农921×东方红3号”的杂交后代中培育出了高抗穗发芽的小麦新品种秦麦3号。

白粒小麦品种(系)穗发芽抗性机制分析

为了解小麦穗发芽抗性机制,应用与抗穗发芽有关的功能标记Vp1B3、Vp1-b2和Dorm-1并结合整穗发芽、籽粒发芽、籽粒+芒、籽粒+穗轴、籽粒+颖壳和籽粒+芒+穗轴+颖壳共6种发芽试验处理,分析了11个小麦品种(系)的穗发芽抗性机制。结果表明,红粒抗穗发芽对照京9428和京冬8号的抗性受粒色、Vp-1Bc、颖壳或颖壳抑制物控制;9个白粒品种(系)穗发芽抗性均不同程度的受芒和颖壳或它们的抑制物控制;强抗穗发芽品系CA0431的抗性与Vp1B3、Dorm-1和粒色无关,而与其他遗传因素有关;强抗穗发芽品系山东046432属于由Vp-1Bc和Dorm-1控制的基因型;中抗穗发芽品种矮抗58的抗性与穗轴有关;Vp-1Bb基因对CA9550-2的穗发芽作用有待进一步证实;芒和颖壳或它们的抑制物对白粒中感穗发芽品系CA9640、CA0459、CA0493和白粒高感穗发芽品系山东928802和CA0306的穗发芽均有一定的抑制作用,但Vp-1Bb基因型与山东928802和Vp-1Bc基因型与CA0306的穗发芽并无相关。

穗发芽率和发芽指数及STS标记Vp1B3在小麦抗穗发芽基因型鉴定中的应用

为了筛选抗穗发芽品种(系)并了解其抗性机制,应用整穗发芽法和发芽指数鉴定了33份小麦新品系的穗发芽抗性,以红粒品种京冬8号和京9428作为抗穗发芽对照,以白粒品种京411和中优9507作为感穗发芽对照,并结合共显性STS标记Vp1B3对其基因型进行检测。结果表明,穗发芽率(SGR)低于抗性对照京冬8号和京9428平均值(12.7%)的品系有7份,其中2份为白粒,5份为红粒。只有一份红粒品系CA0489的发芽指数(GI)低于抗性对照平均值(13.2%)。应用STS标记Vp1B3共扩增出849 bp、569 bp和652 bp三种片段,分别属于抗穗发芽基因型Vp1Bb和Vp1Bc及感穗发芽基因型Vp1Ba,其频率分别为3%、18%和79%。红粒抗穗发芽品系CA0489属于Vp1Bb基因型和红色种皮休眠型,CA0481属于Vp1Bc抗穗发芽基因型,另外三份红粒抗穗发芽品系的抗性机理还需要进一步研究;白粒抗穗发芽品系CA0509和CA0459的抗性为非Vp1B3类型,其抗性可能与穗部性状和颖壳抑制物有关。