Physical mapping of the blue-grained gene(s) from Thinopyrum ponticum by GISH and FISH in a set of translocation lines with different seed colors in wheat.

The original blue-grained wheat, Blue 58, was a substitution line derived from hybridization between common wheat (Triticum aestivum L., 2n=6x=42, ABD) and tall wheatgrass (Thinopyrum ponticum Liu & Wang=Agropyron elongatum, 2n=10x=70, StStEeEbEx), in which one pair of 4D chromosomes was replaced by a pair of alien 4Ag chromosomes (unknown group 4 chromosome from A. ponticum). Blue aleurone might be a useful cytological marker in chromosome engineering and wheat breeding. Cytogenetic analysis showed that blue aleurone was controlled by chromosome 4Ag. GISH analysis proved that the 4Ag was a recombination chromosome; its centromeric and pericentromeric regions were from an E-genome chromosome, but the distal regions of its two arms were from an St-genome chromosome. On its short arm, there was a major pAs1 hybridization band, which was very close to the centromere. GISH and FISH analysis in a set of translocation lines with different seed colors revealed that the gene(s) controlling the blue pigment was located on the long arm of 4Ag. It was physically mapped to the 0.71-0.80 regions (distance measured from the centromere of 4Ag). The blue color is a consequence of dosage of this small chromosome region derived from the St genome. We speculate that the blue-grained gene(s) could activate the anthocyanin biosynthetic pathway of wheat.     

Effects of an Agropyron chromosome on endosperm proteins in common wheat (Triticum aestivum L.)

An Agropyron chromosome having a gene conferring blue color on the aleurone layer of the kernel endosperm causes a 15% increase in total grain protein content when it is added to the common wheat (2n=42) complement. In contrast, there is no effect of this chromosome on total protein content if it replaced part of a wheat chromosome. Endosperm protein components of isolines having blue aleurone due to the Agropyron chromosome being added (2n=44) or translocated (2n=42) were compared to normal nonblue isoline counterparts. Gliadin proteins separated by aluminum lactate (pH 3.2) polyacrylamide gel electrophoresis (PAGE) in one or two dimensions showed greater staining intensity for the blue addition isolines (2n=44) than nonblue (2n=42) isolines. However, the 42-chromosome blue isoline did not show increased protein staining over the nonblue isoline, but at least five protein differences were detected between the lines. SDS-PAGE showed that blue and nonblue differences were expressed primarily in the gliadins, but also in the glutenin, globulin, and albumin proteins.This research was supported by a D. F. Jones Postdoctoral Fellowship to K. M. Soliman and by Western Regional Project W-132, Genotype-environment interactions related to end-product uses in small grains.     

Selection and identification of a spontaneous alien chromosome translocation in wheat

A wheat (Triticum aestivum L. emend Thell) disomic addition line (2n = 6x = 44), SH1–152–2, with a pair of Elytrigia pontica (Podp.) Holub 2n = 10x = 70 [syn. Agropyron elongatum (Host) P.B.] chromosomes controlling blue aleurone color was crossed with a short-statured spring wheat `Sonora 64' (T. aestivum). Isoline pairs of blue-disomic addition lines and nonblue euploid lines were produced by selecting plants segregating for blue aleurone for 12 generations. Nineteen of 20 blue aleurone lines were 2n = 44 addition lines, and one had 2n = 42 chromosomes. Several lines of evidence showed that this line had a spontaneous translocation in which the β arm of wheat chromosome 4A was replaced by an Elytrigia chromosome arm carrying the blue aleurone gene. The Elytrigia chromosome in SH1–152–2 appeared to be homologous with E. pontica chromosome 4el₁, which also carries the blue aleurone gene. It was concluded that the spontaneous translocation originated from simultaneous misdivision of univalents and subsequent reunion at the centromere of chromosome arm 4Aα with the Elytrigia chromosome arm.     

蓝粒小麦花青素生物合成途径中的二氢黄酮醇4-还原酶基因的分子克隆

蓝色色素在蓝粒小麦种子糊粉层中的生物合成途径的分子生物学机制至今仍不清楚.应用RT-PCR和RACE方法从蓝粒小麦正在发育的种子中克隆到一个编码二氢黄酮醇4-还原酶的基因(DFR).推测其为花青素生物合成途径中的一个关键基因,且与蓝粒小麦中蓝色色素形成密切相关;其开放阅读框编码一个包含354个氨基酸残基的多肽,与一些从其他植物中已克隆到的DFR有很高的同源性:大麦(94%)、水稻(83%)、玉米(84%).从长穗偃麦草(2n=70)、蓝粒小麦、浅蓝粒小麦自交产生的白粒后代小麦以及中国春的基因组中分别分离到一个全长DFR序列.经聚类分析表明DFR cDNA核甘酸序列与从中国春基因组中克隆的DFR具有100%的同源性,且与长穗偃麦草、蓝粒小麦、白粒小麦基因组中分离的DFR均有很高的同源性.4个DFR基因组DNA均含有3个内含子,且它们之间的差异主要在内含子区,表明该基因在进化上很保守.经Southern杂交分析,DFR在小麦中至少有3～5个拷贝,不同小麦材料间未见明显差异,但与长穗偃麦草有明显差异,属于一个DFR超基因家族.Northern分析表明该DFR在蓝粒和白粒种子的不同发育时期的表达存在明显差异,都在开花后大约18 d表达最强,在同一时期的蓝白种子中,DFR在蓝粒种子中的表达量高于白粒.DFR转录本在小麦和长穗偃麦草的幼叶中积累多,但在芽鞘中的表达显著低于幼叶中;在小麦的根和长穗偃麦草的发育种子中均未检测到DFR的表达.推测蓝粒小麦中可能存在调控DFR在蓝粒小麦中表达的调控基因,类似于玉米花青素合成途径中的调节基因.     

蓝粒小麦花青素生物合成途径中的二氢黄酮醇4-还原酶基因的分子克隆

蓝色色素在蓝粒小麦种子糊粉层中的生物合成途径的分子生物学机制至今仍不清楚。应用RT—PCR和RACE方法从蓝粒小麦正在发育的种子中克隆到一个编码二氢黄酮醇4-还原酶的基因(DFR)。推测其为花青素生物合成途径中的一个关键基因,且与蓝粒小麦中蓝色色素形成密切相关;其开放阅读框编码一个包含354个氨基酸残基的多肽,与一些从其他植物中已克隆到的DFR有很高的同源性：大麦(94％)、水稻(83％)、玉米(84％)。从长穗偃麦草(2n=70)、蓝粒小麦、浅蓝粒小麦自交产生的白粒后代小麦以及中国春的基因组中分别分离到一个全长DFR序列。经聚类分析表明DFR cDNA核甘酸序列与从中国春基因组中克隆的DFR具有100％的同源性,且与长穗偃麦草、蓝粒小麦、白粒小麦基因组中分离的DFR均有很高的同源性。4个DFR基因组DNA均含有3个内含子,且它们之间的差异主要在内含子区,表明该基因在进化上很保守。经Southern杂交分析,DFR小麦中至少有3-5个拷贝,不同小麦材料间未见明显差异,但与长穗偃麦草有明显差异,属于一个DFR超基因家族。Northern分析表明该DFR在蓝粒和白粒种子的不同发育时期的表达存在明显差异,都在开花后大约18d表达最强,在同一时期的蓝白种子中,DFR蓝粒种子中的表达量高于白粒。DFR转录本在小麦和长穗偃麦草的幼叶中积累多,但在芽鞘中的表达显著低于幼叶中;在小麦的根和长穗偃麦草的发育种子中均未检测到DFR的表达。推测蓝粒小麦中可能存在调控DFR在蓝粒小麦中表达的调控基因,类似于玉米花青素合成途径中的调节基因。     

Changes in Root Hydraulic Conductivity During Wheat Evolution

A better understanding of the mechanisms of water uptake by plant roots should be vital for improving drought resistance and water use efficiency (WUE). In the present study, we have demonstrated correlations between root system hydraulic conductivity and root characteristics during evolution using six wheat evolution genotypes (solution culture) with different ploidy chromosome sets (Triticum boeoticum Bioss., T. monococcum L.: 2n = 2x = 14; T. dicoccides Koern., T. dicoccon (Schrank) Schuebl.: 2n = 4x = 28;T. vulgare Vill., T. aestivum L. cv. Xiaoyan No. 6: 2n = 6x = 42). The experimental results showed that significant correlations were found between root system hydraulic conductivity and root characteristics of the materials with the increase in ploidy chromosomes (2x→6x) during wheat evolution. Hydraulic conductivity of the wheat root system at the whole-plant level was increased with chromosome ploidy during evolution, which was positively correlated with hydraulic conductivity of single roots, whole plant biomass,root average diameter, and root growth (length, area), whereas the root/shoot ratio had an inverse correlation with the hydraulic conductivity of root system with increasing chromosome ploidy during wheat evolution. Therefore, it is concluded that that the water uptake ability of wheat roots was strengthened from wild to modern cultivated species during evolution, which will provide scientific evidence for genetic breeding to improve the WUE of wheat by genetic engineering.     

Uncovering the evolutionary origin of blue anthocyanins in cereal grains

Functional divergence after gene duplication plays a central role in plant evolution. Among cereals, only Hordeum vulgare (barley), Triticum aestivum (wheat) and Secale cereale (rye) accumulate delphinidin‐derived (blue) anthocyanins in the aleurone layer of grains, whereas Oryza sativa (rice), Zea mays (maize) and Sorghum bicolor (sorghum) do not. The underlying genetic basis for this natural occurrence remains elusive. Here, we mapped the barley Blx1 locus involved in blue aleurone to an approximately 1.13 Mb genetic interval on chromosome 4HL, thus identifying a trigenic cluster named MbHF35 (containing HvMYB4H, HvMYC4H and HvF35H). Sequence and expression data supported the role of these genes in conferring blue‐coloured (blue aleurone) grains. Synteny analyses across monocot species showed that MbHF35 has only evolved within distinct Triticeae lineages, as a result of dispersed gene duplication. Phylogeny analyses revealed a shared evolution pattern for MbHF35 in Triticeae, suggesting that these genes have co‐evolved together. We also identified a Pooideae‐specific flavonoid 3′,5′‐hydroxylase (F3′5′H) lineage, termed here Mo_F35H2, which has a higher amino acid similarity with eudicot F3′5′Hs, demonstrating a scenario of convergent evolution. Indeed, selection tests identified 13 amino acid residues in Mo_F35H2 that underwent positive selection, possibly driven by protein thermostablility selection. Furthermore, through the interrogation of barley germplasm there is evidence that HvMYB4H and HvMYC4H have undergone human selection. Collectively, our study favours blue aleurone as a recently evolved trait resulting from environmental adaptation. Our findings provide an evolutionary explanation for the absence of blue anthocyanins in other cereals and highlight the importance of gene functional divergence for plant diversity and environmental adaptation.     

Development,identification, and characterization of blue-grained wheat- Triticum boeoticum substitution lines

Diploid wild einkorn wheat, Triticum boeoticum Boiss (AbAb, 2n = 2x = 14), is a wheat-related species with a blue aleurone layer. In this study, six blue-grained wheat lines...     

A fertile amphiploid between durum wheat (Triticum turgidum) and the x Agroticum amphiploid (Agropyron cristatum x T. tauschii)

Agropyron (Gaertn) is a genus of Triticeae which includes the crested wheatgrass complex, i.e. A. cristatum (L.) as representative species containing the P genome. This species is an important source for increase the genetic variability of both durum and bread wheat. Among the possible interesting features to be introgressed into wheat are resistance to wheat streak mosaic virus, rust diseases, and tolerance to drought, cold and moderate salinity. By crossing tetraploid wheat (Triticum turgidum conv durum, 2n = 4x = 28; AABB) with a fertile allotetraploid (2n = 4x = 28; DDPP) between diploid wheat (T. tauschii) and crested wheatgrass (A. cristatum L.), amphiploid plants were obtained. Fluorescence in situ hybridization (FISH) using both genomic DNA from A. cristatum and the repetitive probe pAs1, proved that the plants were true amphiploids with a chromosome number 2n = 8x = 56 and genomic constitution AABBDDPP. Using total genomic in situ hybridization (GISH) to study meiotic metaphase I, data on allosyndetic and autosyndetic chromosome pairing were obtained. The amphiploids were perennial like the male parent but their morphology was close to that of the wheat parent. They were resistant to wheat leaf rust and powdery mildew under field conditions.     

Changes in Root Hydraulic Conductivity During Wheat Evolution

A better understanding of the mechanisms of water uptake by plant roots should be vital for improving drought resistance and water use efficiency (WUE). In the present study, we have demonstrated correlations between root system hydraulic conductivity and root characteristics during evolution using six wheat evolution genotypes (solution culture) with different ploidy chromosome sets (Triticum boeoticum Bioss., T. monococcum L.: 2n=2x=14;T. dicoccides Koern., T. dicoccon (Schrank) Schuebl.:2n=4x=28;T. vulgare Vill., T. aestivum L. cv. Xiaoyan No. 6:2n=6x=42). The experimental results showed that significant correlations were found between root system hydraulic conductivity and root characteristics of the materials with the increase in ploidy chromosomes (2x→6x) during wheat evolution. Hydraulic conductivity of the wheat root system at the whole-plant level was increased with chromosome ploidy during evolution, which was positively correlated with hydraulic conductivity of single roots, whole plant biomass,root average diameter, and root growth (length, area), whereas the root/shoot ratio had an inverse correlation with the hydraulic conductivity of root system with increasing chromosome ploidy during wheat evolution. Therefore, it is concluded that that the water uptake ability of wheat roots was strengthened from wild to modern cultivated species during evolution, which will provide scientific evidence for genetic breeding to improve the WUE of wheat by genetic engineering.     

The transfer and characterization of resistance to common root rot from Thinopyrum ponticum to wheat.

Common root rot, caused by Cochliobolus sativus (Ito and Kurib) Drechs. ex Dastur, is a major soil-borne disease of spring and winter wheat (Triticum aestivum L. em Thell.) on the Canadian prairies. Resistance to common root rot from Thinopyrum ponticum (Podp.) Liu and Wang was transferred into wheat via crossing with Agrotana, a resistant wheat - Th. ponticum partial amphiploid line. Evaluation of common root rot reactions showed that selected advanced lines with blue kernel color derived from a wheat x Agrotana cross expressed more resistance than the susceptible T. aestivum 'Chinese Spring' parent and other susceptible wheat check cultivars. Cytological examination revealed 41 to 44 chromosomes in the advanced lines. Genomic in situ hybridization, using total genomic DNA from Pseudoroegneria strigosa (M. Bieb) A. L?ve (St genome) as a probe, demonstrated that the blue kernel plants had two pairs of spontaneously translocated J-Js and Js-J chromosomes derived from the J and Js genome of Th. ponticum. The presence of these translocated chromosomes was associated with increased resistance of wheat to common root rot. The lines with blue aleurone color always had a subcentromeric Js-J translocated chromosome. The subtelocentric J-Js translocated chromosome was not responsible for the blue kernel color. The genomic in situ hybridization analysis on meiosis revealed that the two spontaneous translocations were not reciprocal translocations.     

Chromosome elimination and in vivo haploid production induced by Stock 6-derived inducer line in maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.)

In vivo haploid production induced by inducer lines derived from Stock 6 is widely used in breeding program of maize (Zea mays L.), but the mechanisms behind have not yet been fully understood. In this study, average frequency of haploid induction in four inbred lines by Stock 6-derived inducer line HZI1 was above 10%. About 0.2% kernels from the cross Hua24 x HZI1 had mosaic endosperm showing yellow shrunken parts from Hua24 to normal parts with purple aleurone from HZI1. Individual lagged chromosomes and micronuclei were observed in mitotic cells of ovules pollinated by HZI1. Above 56.4% of the radicles from the kernels with purple aleurone and colorless embryos were mixoploid (2n = 9-21), and more than 45.22% cells were haploid cells (2n = 10) in three crosses. More than 62.5% of the radicles from the kernels with purple aleurone and purple embryos were mixoploid (2n = 9-21) having 54.27% cells with 2n = 20. SSR analysis showed that all haploids from the cross Hua24 x HZI1 shared the same genomic compositions as Hua24 except for plants Nos. 862 and 857 with some polymorphic DNA bands. The results revealed that chromosome elimination after fertilization caused the haploid production in maize.     

Identification of variation in adaptively important traits and genome-wide analysis of trait-marker associations in Triticum monococcum

Einkorn wheat Triticum monococcum (2n=2x=14, A(m)A(m)) is one of the earliest domesticated crops. However, it was abandoned for cultivation before the Bronze Age and has infrequently been used in wheat breeding. Little is known about the genetic variation in adaptively important biological traits in T. monococcum. A collection of 30 accessions of diverse geographic origins were characterized for phenotypic variation in various agro-morphological traits including grain storage proteins and endosperm texture, nucleotide-binding site (NBS) domain profiles of resistance (R) genes and resistance gene analogues (RGAs), and germination under salt and drought stresses. Forty-six SSR (single sequence repeat) markers from bread wheat (T. aestivum, 2n=6x=42, AABBDD) A genome were used to establish trait-marker associations using linear mixed models. Multiple significant associations were identified, some of which were on chromosomal regions containing previously known genetic loci. It is concluded that T. monococcum possesses large genetic diversity in multiple traits. The findings also indicate that the efficiency of association mapping is much higher in T. monococcum than in other plant species. The use of T. monococcum as a reference species for wheat functional genomics is discussed.     

长穗偃麦草优异基因的染色体定位及应用

长穗偃麦草比较公认的有2个种,即二倍体长穗偃麦草(Thinopyrum elongatum,2n=2X)和十倍体长穗偃麦草(Thinopyrum ponticum,2n=10X),是重要的小麦近缘种,具有抗病、抗寒、抗旱、耐盐碱等优良性状。因其基因组中蕴含许多对小麦品种改良极为有用的基因,且易与小麦杂交等优势,多年来长穗偃麦草一直作为小麦遗传改良的优良种质资源而备受关注。本文对长穗偃麦草的基因组研究及其在小麦的抗逆、抗病和提高光合能力、产量及高分子量谷蛋白(HMW-GS)含量等方面的应用做了综述,为其基因组中优异基因的进一步开发和利用提供了理论依据。     

Synthesis and cytological characterization of trigeneric hybrids of durum wheat with and without Ph1.

Wild grasses in the tribe Triticeae, some in the primary or secondary gene pool of wheat, are excellent reservoirs of genes for superior agronomic traits, including resistance to various diseases. Thus, the diploid wheatgrasses Thinopyrum bessarabicum (Savul. and Rayss) A. Love (2n = 2x = 14; JJ genome) and Lophopyrum elongatum (Host) A. Love (2n = 2x = 14; EE genome) are important sources of genes for disease resistance, e.g., Fusarium head blight resistance that may be transferred to wheat. By crossing fertile amphidiploids (2n = 4x = 28; JJEE) developed from F1 hybrids of the 2 diploid species with appropriate genetic stocks of durum wheat, we synthesized trigeneric hybrids (2n = 4x = 28; ABJE) incorporating both the J and E genomes of the grass species with the durum genomes A and B. Trigeneric hybrids with and without the homoeologous-pairing suppressor gene, Ph1, were produced. In the absence of Ph1, the chances of genetic recombination between chromosomes of the 2 useful grass genomes (JE) and those of the durum genomes (AB) would be enhanced. Meiotic chromosome pairing was studied using both conventional staining and fluorescent genomic in situ hybridization (fl-GISH). As expected, the Ph1-intergeneric hybrids showed low chromosome pairing (23.86% of the complement), whereas the trigenerics with ph1b (49.49%) and those with their chromosome 5B replaced by 5D (49.09%) showed much higher pairing. The absence of Ph1 allowed pairing and, hence, genetic recombination between homoeologous chromosomes. Fl-GISH analysis afforded an excellent tool for studying the specificity of chromosome pairing: wheat with grass, wheat with wheat, or grass with grass. In the trigeneric hybrids that lacked chromosome 5B, and hence lacked the Ph1 gene, the wheat-grass pairing was elevated, i.e., 2.6 chiasmata per cell, a welcome feature from the breeding standpoint. Using Langdon 5D(5B) disomic substitution for making trigeneric hybrids should promote homoeologous pairing between durum and grass chromosomes and hence accelerate alien gene transfer into the durum genomes.     

EST derived SSR markers for comparative mapping in wheat and rice

Structural and functional relationships between the genomes of hexaploid wheat (Triticum aestivum L.) (2n=6x=42) and rice (Oryza sativa L.) (2n=2x=24) were evaluated using linkage maps supplemented with simple sequence repeat (SSR) loci obtained from publicly available expressed sequence tags (ESTs). EST-SSR markers were developed using two main strategies to design primers for each gene: (1) primer design for multiple species based on supercluster analysis, and (2) species-specific primer design. Amplification was more consistent using the species-specific primer design for each gene. Forty-four percent of the primers designed specifically for wheat sequences were successful in amplifying DNA from both species. Existing genetic linkage maps were enhanced for the wheat and rice genomes using orthologous loci amplified with 58 EST-SSR markers obtained from both wheat and rice ESTs. The PCR-based anchor loci identified by these EST-SSR markers support previous patterns of conservation between wheat and rice genomes; however, there was a high frequency of interrupted colinearity. In addition, multiple loci amplified by these primers made the comparative analysis more difficult. Enhanced comparative maps of wheat and rice provide a useful tool for interpreting and transferring molecular, genetic, and breeding information between these two important species. These EST-SSR markers are particularly useful for constructing comparative framework maps for different species, because they amplify closely related genes to provide anchor points across species.Communicated by R. Hagemann     

蓝粒小麦易位系的荧光原位杂交鉴定

普通小麦（Triticum aestivum L.)和长穗偃麦草（Agropyron elongatum (Host)Beauv=Elytriga elongatum(Host)Nevski=Thinopyrum ponticum (Host)Barkworth and Dewey,2n=10x=70)杂交后选育出的蓝粒小麦异代换系（蓝５８）,２n=42其中９９０６中被易位蓝粒片段的相对长度约占易位小麦染色体短臂的１／３,而９９０２中被易位蓝粒片段的相对长度约占易位小麦染色体长臂的１／２,并将９９０２的蓝粒易位片段定位在小麦Ｄ组染色体上;（２）９９１５易位附加和９９０４易位－易位附加,其体细胞染色体数均为４４,其中９９１５的体细胞染色体只有一对发生了易位,另外队了两条长穗偃麦草染色体;而９９０４有两对染色体发生了易位,并易位系中控制蓝粒性状的长穗偃麦草染色体片段的定位和蓝粒小麦易位系的应用进行了讨论。     

Gliadain, a gibberellin-inducible cysteine proteinase occurring in germinating seeds of wheat, Triticum aestivum L., specifically digests gliadin and is regulated by intrinsic cystatins

We cloned a new cysteine proteinase of wheat seed origin, which hydrolyzed the storage protein gliadin almost specifically, and was named gliadain. Gliadain mRNA was expressed 1 day after the start of seed imbibition, and showed a gradual increase thereafter. Gliadain expression was suppressed when uniconazol, a gibberellin synthesis inhibitor, was added to germinating seeds. Histochemical detection with anti-gliadain serum indicated that gliadain was present in the aleurone layer and also that its expression intensity increased in sites nearer the embryo. The enzymological characteristics of gliadain were investigated using recombinant glutathione S-transferase (GST)-progliadain fusion protein produced in Escherichia coli. The GST-progliadain almost specifically digested gliadin into low molecular mass peptides. These results indicate that gliadain is produced via gibberellin-mediated gene activation in aleurone cells and secreted into the endosperm to digest its storage proteins. Enzymologically, the GST-progliadain hydrolyzed benzyloxycarbonyl-Phe-Arg-7-amino-4-methylcoumarin (Z-Phe-Arg-NH(2)-Mec) at K(m) = 9.5 microm, which is equivalent to the K(m) value for hydrolysis of this substrate by cathepsin L. Hydrolysis was inhibited by two wheat cystatins, WC1 and WC4, with IC(50) values of 1.7 x 10(-8) and 5.0 x 10(-8) m, respectively. These values are comparable with those found for GST-progliadain inhibition by E-64 and egg-white cystatin, and are consistent with the possibility that, in germinating wheat seeds, gliadain is under the control of intrinsic cystatins.     

Identification of Blue-grained Wheat Translocation Lines Using Fluorescence in Situ Hybridization

The blue-grained wheat substitution line (blue 58) originated from wild hybridization between Triticum aestivum L. and Agropyron elongatum (Host) Beauv= Elytrigia elongatum (Host) Nevski= Thinopyrum ponticum (Host) Barkworth and Dewey (2n=10x=70) was irradiated and four translocation lines were screened by fluorescence in situ hybridization from the offsprings. The results obtained include the following: (1) both the two translocation lines, 9906 and 9902, have 42 chromosomes. The length of the translocated blue-grained segment was approximately one-third of the short-arm and one-half of the long-arm of the translocated wheat chromosome in 9906 and 9902, respectively, and the blue-grained translocated segment in 9902 was located on D genome; (2) both 9915 and 9904 have 44 chromosomes. One pair of chromosomes was translocated and two chromosomes from Th. ponticum were added in 9903, while two pairs of chromosomes were translocated in 9904 by blue-grained wheat segment. The location and application of blue-grained wheat translocation lines were discussed.     

Features of recombination of nuclear genome in back crossed offspring of barley-wheat hybrids Hordeum vulgare L. (2n=14) x Triticum aestivum L. (2n+42) with the use of SSR-analysis

The backcross progenies of the barley-wheat hybrids Hordeum vulgare L. (2n = 14) x Triticum aestivum L. (2n = 42) and two alloplasmic lines derived from them were studied using microsatellite markers of barley and wheat. The F1 hybrids and first backcross plants BC1 contained the genetic material of both cultivated barley and the cultivars of common wheat involved in developing of these hybrid genotypes. The genomes of BC3, BC4, and alloplasmic lines contained no microsatellite markers of the cultivated barley, whereas chromosomes of each homeologous group of common wheat were identified. In chromosomes of backcross progenies BC3, BC4, and alloplasmic lines yielded by backcrosses of hybrids and various common wheat cultivars, microsatellite markers of the parental wheat cultivars were shown to undergo recombination.