Induzione Sperimentale Della Maschio-Sterilità in Triticum

Abstract

Experimental induction of male sterility in Triticum. — Prolonged artificial illumination (12-24 h. every 24 hours) and high temperature (20-25[ddot]C.) induce in « Denti de cani » plants (Meletti, 1955) the transformation of the stamens, which tend to take morphological characteristics of female organs (Meletti, 1960). The prolonged illumination induces, also at temperatures inferior to 20[ddot]C., a remarkable increase of the percentage of « Denti de cani » flowers which have reduced anthers without pollen grains.     

Synthesis and evaluation of Triticum durum — T. monococcum amphiploids

Summary Nine Triticum durum — T. monococcum amphiploids (AABBA^mA^m) were synthesized by chromosome doubling of sterile triploid F₁ hybrids involving nine T. durum (AABB) cultivars and a T. monococcum (A^mA^m) line. The triploid F₁ hybrids had a range of 4–7 bivalents and 7–13 univalents per PMC. The synthetic amphiploids, however, showed a high degree of preferential pairing of chromosomes of the A genomes of diploid and tetraploid wheats. The amphiploids were meiotically stable and fully fertile. Superiority of four amphiploids for tiller number per plant, 100-grain weight, protein content and resistance to Karnal bunt demonstrated that these could either be commercially exploited as such after overcoming certain inherent defects or used to introgress desirable genes into durum and bread wheat cultivars. Methods for improvement of these amphiploids are discussed.     

小麦(Triticum aestivum)雄核发育的细胞学研究

本工作对小麦花粉胚和愈伤组织的诱导条件和雄核发育的细胞学现象作了研究。结果如下:(1)N_6培养基诱导花粉愈伤组织的效果显著优于 MS 培养基。外源激素对于雄核发育的启动不是必需的,但对愈伤组织进一步的生长却是不可缺少的。(2)用花药整体制片法研究了雄核发育的各种途径,结果表明,不均等分裂和均等分裂的小孢子都能形成花粉胚,但前者占较大比例。(3)在部分多细胞花粉和白化苗中观察到染色体断片和微核,推测白化或畸形的花粉植株可能起源于具微核的花粉。(4)细胞的核内再复制和游离核的融合是产生二倍体和多倍体花粉植株的重要原因。     

α-amylase inhibitors in Triticum aestivum: Purification and physical-chemical properties

Two α-amylase inhibitors in aqueous extracts of wheat flour have been resolved by DEAE-Sephadex chromatography. α-Amylase inhibitor I, the major inhibitor, was homogeneous by disc gel electrophoresis. It had a MW of 20 000 daltons and an isoelectric point of 6·7. α-Amylase inhibitor II had two minor contaminants when analysed by electrophoresis. These inhibitors were classified as typical wheat albumin proteins. A third α-amylase inhibitor was discovered when it was observed that an albumin protein which is found only in Triticum aestivum varieties of wheat could also inhibit pancreatic α-amylase. All three of these inhibitors could be distinguished by their characteristic electrophoretic mobilities.     

以色列野生二粒小麦(Triticum dicoccoides)耐盐性鉴定

采用水培法对从以色列引进的分属8个自然群体的93份野生二粒小麦进行了耐盐性初步鉴定.结果表明:①供试材料中仅有高耐盐材料3份,耐盐材料7份 ,耐盐性较好的材料仅占参试材料总数的10.7%;②8个自然群体的野生二粒小麦的耐盐性存在较大差异,其中3号群体耐盐性明显高于其他群体,说明来自Tabigha地区的野生二粒小麦具有丰富的耐盐基因源;③将经过鉴定的耐盐性较好的野生二粒小麦与普通小麦中的耐盐品种进行比较研究发现,以色列耐盐性较好的野生二粒小麦的耐盐性不如普通小麦中的茶淀红和SW10两个耐盐品种.     

Development and QTL assessment of Triticum aestivum–Aegilops tauschii introgression lines

A set of 84 bread wheat lines, each containing a single homozygous introgression of the Aegilops tauschii genome was produced in the ‘Chinese Spring’ background via backcrossing of the D-genome chromosome substitution lines ‘Chinese Spring’/Sears’s ‘Synthetic 6x’ with the recurrent parent and subsequent selfing. The development of the lines was accompanied by microsatellite marker assisted selection. With the exception of three telomeric regions at chromosomes 1DL, 4DL and 7DS, and a region of less than 24 cM on the chromosome arm 3DL, the genome of Ae. tauschii is fully represented in these lines. The newly developed lines were used for the discovery of morphological and agronomical quantitative trait loci (QTLs) from the wild species. Fifty-two introgression lines were grown in the field and evaluated for six traits including flowering time, plant height, ear length, spikelet number, fertility and grain weight per ear. Seventeen significant QTLs were detected, Ae. tauschii contributed favourable alleles at nine loci influencing five traits. The whole set of 84 homozygous lines provides a tool for further testing the effects and stability of the detected QTLs and for the evaluation of new traits.     

Mapping of QTL for Fusarium head blight resistance and morphological and developmental traits in three backcross populations derived from Triticum dicoccum?×?Triticum durum

Breeding for resistance to Fusarium head blight (FHB) in durum wheat continues to be hindered by the lack of effective resistance sources. Only limited information is available on resistance QTL for FHB in tetraploid wheat. In this study, resistance to FHB of a Triticum dicoccum line in the background of three Austrian T. durum cultivars was genetically characterized. Three populations of BC₁F₄-derived RILs were developed from crosses between the resistant donor line T. dicoccum-161 and the Austrian T. durum recipient varieties DS-131621, Floradur and Helidur. About 130 BC₁F₄-derived lines per population were evaluated for FHB response using artificial spray inoculation in four field experiments during two seasons. Lines were genetically fingerprinted using SSR and AFLP markers. Genomic regions on chromosomes 3B, 4B, 6A, 6B and 7B were significantly associated with FHB severity. FHB resistance QTL on 6B and 7B were identified in two populations and a resistance QTL on 4B appeared in three populations. The alleles that enhanced FHB resistance were derived from the T. dicoccum parent, except for the QTL on chromosome 3B. All QTL except the QTL on 6A mapped to genomic regions where QTL for FHB have previously been reported in hexaploid wheat. QTL on 3B and 6B coincided with Fhb1 and Fhb2, respectively. This implies that tetraploid and hexaploid wheat share common genomic regions associated with FHB resistance. QTL for FHB resistance on 4B co-located with a major QTL for plant height and mapped at the position of the Rht-B1 gene, while QTL on 7B overlapped with QTL for flowering time.     

Genetic mapping of QTL for resistance to Fusarium head blight spread (type 2 resistance) in a Triticum dicoccoides × Triticum durum backcross-derived population

Improvement of resistance to Fusarium head blight (FHB) is a continuous challenge for durum wheat breeders, particularly due to the limited genetic variation within this crop species. We accordingly generated a backcross-derived mapping population using the type 2 FHB resistant Triticum dicoccoides line Mt. Gerizim #36 as donor and the modern Austrian T. durum cultivar Helidur as recipient; 103 BC₁F_6:7 lines were phenotyped for type 2 FHB resistance using single-spikelet inoculations and genotyped with 421 DNA markers (SSR and AFLP). QTL mapping revealed two highly significant QTL, mapping to chromosomes 3A and 6B, respectively. For both QTL the T. dicoccoides allele improved type 2 FHB resistance. Recombinant lines with both favorable alleles fixed conferred high resistance to FHB similar to that observed in the T. dicoccoides parent. The results appear directly applicable for durum wheat resistance breeding.     

Nucleolus organizer competition in Triticum aestivum — Aegilops umbellulata chromosome addition lines

Summary The nucleolar organizer activity of wheat (Triticum aestivum, AABBDD) and Aegilops umbellulata (UU) chromosomes have been analyzed in the complete set of the chromosome addition lines by using a highly reproducible silver-staining procedure. Chromosomes 1U and 5U produce the partial inactivation of wheat nucleolar organizer chromosomes 6B, 1B and 5D. The chromosomes D and G from Ae. umbellulata, which are not SAT-chromosomes, seem to specifically influence the activity of wheat NORs. The predominant status of the U genome with respect to nucleolar competition in the Triticeae is confirmed.     

A self-fertile trigeneric hybrid,Triticum aestivum ×Agropyron michnoi ×Secale cereale

Trigeneric hybrids between the (Triticum aestivum ×Agropyron michnoi) F₁ (CM, 2n=5x=35; ABDPP) and two winter rye (Secale cereale L., 2n=2x=14; RR) cultivars, Wugong 774 and AR-132, were synthesized. Such trigeneric hybrids could be used to transfer resistance genes for powdery mildew from rye to CM and subsequently to common wheat and to identify (1) the effects of the P genome ofAgropyron on the self-fertility of the hybrids and (2) the differences in genetic background between rye cultivars with marked differences in pollinating habit. The trigeneric hybrids varied widely in morphology and showed a high level of resistance to such diseases as barley yellow dwarf virus (BYDV), stripe rust, leaf rust, stem rust, and powdery mildew. Selfed and many backcross derivatives were obtained from the trigeneric hybrids. The results indicated that rye cvs Wugong 774 and AR132 arose from different gene pools and that the P genome ofAgropyron carries gene(s) responsible for chromosome segregation, leading to functional gamete formation and self-fertility of the hybrids. The F₂ and BC₁ plants could be obtained in two ways — fusion of the unreduced gametes and the assumed apomixis of unreduced female gametes in the trigeneric hybrid plant II-4 — which indicates that this trigeneric hybrid may be a special genetic stock. Chromosome pairing in the trigeneric hybrids and ways of producing wheat/rye and wheat/Agropyron translocations are discussed.     

Chromosomal Behavior during Meiosis in the Progeny of Triticum timopheevii × Hexaploid Wild Oat

The meiotic behavior of pollen mother cells (PMCs) of the F₂ and F₃ progeny from Triticum timopheevii × hexaploid wild oat was investigated by cytological analysis and sequential C-banding-genomic in situ hybridization (GISH) in the present study. A cytological analysis showed that the chromosome numbers of the F₂ and F₃ progeny ranged from 28 to 41. A large number of univalents, lagging chromosomes, chromosome bridges and micronuclei were found at the metaphase I, anaphase I, anaphase II and tetrad stages in the F₂ and F₃ progeny. The averages of univalents were 3.50 and 2.73 per cell, and those of lagging chromosomes were 3.37 and 1.87 in the F₂ and F₃ progeny, respectively. The PMC meiotic indices of the F₂ and F₃ progeny were 12.22 and 20.34, respectively, indicating considerable genetic instability. A sequential C-banding-GISH analysis revealed that some chromosomes and fragments from the hexaploid wild oat were detected at metaphase I and anaphase I in the progeny, showing that the progeny were of true intergeneric hybrid origin. The alien chromosomes 6A, 7A, 3C and 2D were lost during transmission from F₂ to F₃. In addition, partial T. timopheevii chromosomes appeared in the form of univalents or lagging chromosomes, which might result from large genome differences between the parents, and the wild oat chromosome introgression interfered with the wheat homologues’ normally pairing.     

云南小麦(Triticum aestivum ssp yunnanense King)的抗旱性鉴定研究初报

云南小麦(Triticum aestivum ssp yunnanense King)产于云南省澜沧江、怒江下游,为云南省所特有,具有护颖坚硬、极难脱粒、穗轴受压力易折断等原始特性,又有耐瘠薄、抗旱、抗穗发芽、抗鸟害等多种优点.本文研究了云南小麦的苗期和成株期抗旱性.结果表明云南小麦的苗期抗旱性在不同品种间存在较大差异,但均不及云南普通小麦地方品种油榨地光头麦;而澜沧铁壳麦和永德铁壳麦的苗期抗旱性强于育成品种云麦42.云南小麦具有较强的成株期抗干旱能力,不同品种间差异不明显,其中云县铁壳麦超过油榨地光头麦,其它品种与育成品种云麦42接近.     

小麦(Triticum aestivum L.)野生资源的发掘、利用研究进展

小麦是世界主要的粮食作物,其生产面积居谷类作物之首。由于长期的定向选择,小麦遗传多样性不断降低,品种间杂交难以选育出抗性和综合性状优良的突破性品种。然而小麦近缘种如黑麦(Secale)、簇毛麦(Haynaldia)和偃麦草(Elytrigia)等包含很多优异基因,并且与小麦基因组间具有很好的互补性。可见远缘杂交在世界小麦育种实践中发挥了重要的作用。综述了小麦近缘野生资源的多样性、近缘野生种的利用方法和存在问题等的研究进展,讨论了小麦野生资源在小麦遗传改良的重要性和发展方向,以期为小麦优良品种培育及其遗传研究提供参考。     

东方小麦(Triticum turanicum Jakubz.) 醇溶蛋白遗传多样性分析

为了进一步利用东方小麦(Triticum turanicum Jakubz.)遗传资源,对来自埃塞俄比亚、伊拉克、伊朗、阿塞拜疆、阿富汗、摩洛哥等国家共87份东方小麦醇溶蛋白位点的遗传多样性进行了分析.结果发现,供试材料存在丰富的遗传变异,87份材料共产生72种谱带类型,分离出33条带纹,每份材料可电泳11～22条带,平均16条;在α、β、γ和ω四个区均差异较大,分别有16、11、20和20种谱带变异类型.聚类分析发现,醇溶蛋白揭示的材料间遗传多样性与其地理来源有一定关系.     

云南小麦（Triticum aestivum ssp yunnanense King）的抗旱性鉴定研究初报

云南小麦(丁riticum aestivum ssp yunnanense King)产于云南省澜沧江、怒江下游，为云南省所特有，具有护颖坚硬、极难脱粒、穗轴受压力易折断等原始特性，又有耐瘠薄、抗旱、抗穗发芽、抗鸟害等多种优点。本文研究了云南小麦的苗期和成株期抗旱性。结果表明云南小麦的苗期抗旱性在不同品种间存在较大差异，但均不及云南普通小麦地方品种油榨地光头麦；而澜沧铁壳麦和永德铁壳麦的苗期抗旱性强于育成品种云麦42。云南小麦具有较强的成株期抗干旱能力，不同品种间差异不明显，其中云县铁壳麦超过油榨地光头麦，其它品种与育成品种云麦42接近。     

影响小麦(Triticum vulgare)花粉植株诱导频率的几种因素

在离体培养条件下,对影响小麦花粉愈伤组织的诱导和分化的某些因素进行了对比试验;对部分组合的愈伤组织进行了染色体观察,其结果:1.做为碳源和调节渗透压的蔗糖,10%的浓度最适宜;2.酪蛋白水解物对花粉愈伤组织的形成,器官分化及细胞染色体的自然加倍有明显效果;3.花药接种前在3—5℃下处理48小时,对提高诱导频率有明显作用;4.较高的温度对愈伤组织的诱导及其分化能力有促进作用;5.遗传型的差异,对花粉植株的成功率起着一定作用。     

干旱胁迫下冬小麦(Triticum aestivum)高光谱特征和生理生态响应

2006年于冬小麦(Triticum aestivum)孕穗期、开花期和灌浆期,采用ASD Fieldspec HH光谱仪测定了不同水分胁迫下冬小麦高光谱反射率、红边参数和对应的冬小麦生理生态参数叶绿素a(Chla)、叶绿素b(Chlb)、叶绿素a b(Chla b),叶片水分含量(LWC),叶面积指数(LAI).结果表明,冬小麦生理生态参数随生长发育呈现先上升后下降趋势,Chla、Chlb和Chla b开花期达最大值;LWC和LAI孕穗期达最大值.随干旱胁迫程度增加,Chla、Chlb和Chla b、LWC和LAI减少.不同水分处理下冬小麦高光谱反射率具有绿色植物特征.用红边一阶微分光谱特征参数分析,冬小麦孕穗期和开花期红边(λred)位于728～730nm,灌浆期红边(λred)移到734nm.Chla、Chlb和Chla b与Dλ730:Dλ702、Dλ730:Dλ718,LWC与Dλred、Dλ718以及LAI与Dλ718、Dλred、Sred均呈正相关,相关系数大于0.5(p<0.05).经回归分析,Chl与Dλ730:Dλ702、LWC与Dλred呈线性关系(R2=0.87),LAI与Sred呈二次关系(R2=0.68).因此,用冬小麦高光谱特征及红边参数能判断冬小麦生育后期长势和农田水分胁迫程度.     

小麦品种Triticum spelta album中抗条锈病基因Yr5的RAPD标记

共用520个10碱基随机引物对小麦抗条锈基因Yr5的近等基因系进行了RAPD分析,发现了3个特异性DNA片段S1496、S14181950与Yr5基因连锁,其中S1496761与Yr5基因紧密连锁,遗传距离为2．7cM。经对特异性DNA片段S1496 761进行克隆,测序,设计了PCR扩增用专化引物SC－S1496 761a和SC－S149676b,用该引物可扩增出与原RAPD引物扩增出的相似的特异DNA片段,由于该引物还可扩增出迁移率极为相近的另1条非特异带,在琼脂糖凝胶上难以分辨,需用聚丙烯酰胺凝胶电泳结合银染进行检测,经用F2分离群体及部分相关品种材料检测,已证明该标记的可靠性。     

Tolerance to high concentrations of boron for the amphiploid of Triticum aestivum × Agropyron elongatum

The response to high concentrations of B in soil was compared for Triticum aestivum L. (vars. Chinese Spring and Halberd) and the amphiploid of Chinese Spring × Agropyron elongatum (Host). The tolerance of the three genotypes, with respect to yield at the high B treatments, was amphipolid>Halberd>Chinese Spring. The concentration of B in whole shoots was similar for the amphiploid and Halberd and significantly higher for Chinese Spring. The mechanism for tolerance to B appears to be the same for the amphiploid and wheat and is related to reduced accumulation of B in shoots.     

Microspore culture in wheat (Triticum aestivum) – doubled haploid production via induced embryogenesis

The inherent potential to produce plants from microspores or immature pollen exists naturally in many plant species. Some genotypes in hexaploid wheat (Triticum aestivum L.) also exhibit the trait for androgenesis. Under most circumstances, however, an artificial manipulation, in the form of physical, physiological and/or chemical treatment, need to be employed to switch microspores from gametophytic development to a sporophytic pathway. Induced embryogenic microspores, characterized by unique morphological features, undergo organized cell divisions and differentiation that lead to a direct formation of embryoids. Embryoids `germinate' to give rise to haploid or doubled haploid plants. The switch from terminal differentiation of pollen grain formation to sporophytic development of embryoid production involves a treatment that halts gametogenesis and initiates sporogenesis showing predictable cellular and molecular events. In principle, the inductive treatments may act to release microspores from cell cycle control that ensures mature pollen formation hence overcome a developmental block to embryogenesis. Isolated microspore culture, genetic analyses, and studies of cellular and molecular mechanisms related to microspore embryogenesis have yielded useful information for both understanding androgenesis and improving the efficiency of doubled haploid production. The precise mechanisms for microspore embryogenesis, however, must await more research.