Variation at storage protein loci in winter common wheat cultivars of the central forest-steppe of Ukraine

Genotypes at the gliadin loci Gli-A1, Gli-B1, Gli-D1 and the high-molecular-weight glutenin subunit loci Glu-A1, Glu-B1, Glu-D1 were identified in 77 winter common wheat cultivars developed in the Central Forest Steppe of Ukraine in different periods of time. The highest level of variation was observed at the Gli-A1 locus. Predominant alleles (one or two per locus) were revealed. The comparison of allele frequencies in groups of cultivars developed in different periods of time (before 1996 and in 1996–2007) has demonstrated appearance of new alleles and change of frequencies of existing alleles at the storage protein loci. The high frequency of cultivars with the wheat-rye 1BL/1RS translocation was detected (about 40%). The wheat rye 1AL/1RS translocation was identified in six cultivars developed in the last decade. Four gliadin alleles, Gli-A1w (a marker for the 1AL/1RS translocation), Gli-A1x, Gli-A1y and Gli-B1x, were proposed for cataloging. The article is published in the original.     

PCR analysis of the wheat varieties and near-isogenic wheat lines with the use of allele-specific primers for the <Emphasis Type="Italic">Gli-1</Emphasis> and <Emphasis Type="Italic">Glu-3</Emphasis> loci

The allelic characteristics of Gli-A1, Gli-B1, Gli-D1 and Glu-A3 loci of 14 bread wheat varieties and 6 near-isogenic wheat lines derived from the Bezosta 1 variety were found by the use of PCR. The conformity between molecular-genetic and storage protein electrophoretic data was revealed: the GliA1.2 allele corresponds to the Gli-A1o and Gli-A1m allelic variants of gliadin blocks; the GliA1.1 PCR allele corresponds to the Gli-A1f, Gli-A1b and Gli-A1c variants of gliadin blocks; the GliB1.1 allele corresponds to the Gli-B1b and Gli-B1d allelic variants; and the GliB1.2 allele corresponds to the Gli-B1e, Gli-B1g and Gli-B1c variants. A new PCR allele with primers for marker GliB1.1 at the Gli-B1 locus in the GLI-B1-12 line (with the gliadin Gli-Blo block), which was generated from crossing of Bezosta 1 and the variety Levent, was detected.     

黑麦碱基因（Sec–1）表达缺失的1RS／1BL易位系的鉴定

用改良的Giemsa C－带技术、DNA原位杂交和酸性聚丙烯酰胺凝胶电泳（A-PAGE）对来源于小麦品种绵阳11与不同黑麦自交系远缘杂交获得的高代株系（BC1F7）的染色体结构和醇溶蛋白进行了研究。结果发现,在鉴定的200个株系中,有45个株系经C-带和A-PAGE检测均一致地发现它们含有一对1RS /1BL易位染色体,而一个株系843-1-1,C-带鉴定、原位杂交结果均证明它含有一对1RS/1BL易位染色体,但A-PAGE醇溶蛋白图谱却不具有黑麦1RS染色体臂的黑麦碱特征带,而表达出既不同于黑麦碱又不同于亲本绵阳11的醇溶蛋白带型。这一结果表明,利用不同的黑麦亲本资源,可以获得黑麦碱基因Sec-1表达缺失的新的1RS/1BL易位系。这种新的1RS/1BL易位系缺失了影响小麦品质的黑麦碱蛋白,因此是进一步研究1RS/1BL 易位对小麦品质影响的珍贵材料。研究指出,在利用外源基因的植物育种中,外源种供体材料的遗传多样性是值得重视的基因资源。     

Cytogenetic characteristics of wheat lines with modified 1RS.1BL rye-wheat translocation

The higher frequency (almost 90%) of inheritance through pollen of heterozygous hybrids has been shown for the modified 1RS.1BL translocation compared with the 1BL telocentric, and, as a result, the segregations at the Gli-B1 and Glu-B1 loci strongly deviated from the expected values. The distance between the Glu-B1 locus and the centromere was 15.7–24.4 cM. Products of the 1RS_m.1BL translocation “misdivision” were observed at a frequency of 0.05%. Both the Pavon MA1 lines and the winter wheat line with the 1RS_m.1BL _al translocation have shown a significant decrease in the level of homologous chromosome pairing, causing aneuploidy. These lines did not contain any reciprocal translocations with respect to the Kuyal’nik cultivar. A “hybrid desynapsis” has been observed in F₁ hybrids (Kuyal’nik × Pavon MA1) in contrast to analogous hybrids from a winter line by the 1RS_m.1BL _al type. No single case of the 21_Closed ^II formation has been observed among the studied 693 pollen mother cells (PMCs), which would have indicated the presence of pairing between the short arms of the 1RS_m.1BL translocations and the intact chromosome 1B.     

小偃6号背景下黑麦遗传物质的荧光原位杂交分析

利用普通小麦(Triticum aestivum L.)“小偃6号”与黑麦(Secale cereale L.)品种“德国白粒”杂交,选育出“小偃6号”类型带有黑麦性状的种质材料。应用总基因组原位杂交(GISH)进行检测,在8份材料中探测到黑麦染色质的存在,其中附加系3个,代换系1个,易位系4个;进一步用荧光绿标记探针pSc119.2及荧光红标记探针pAs1的双色荧光原位杂交(FISH)技术,对其中部分品系的染色体组成进行分析鉴定,结果表明:易位系BC116-1是1RS/1BL小麦/黑麦易位系,BC152-1是涉及一条1B染色体的1RS/1BL易位系, 代换系BC97-2是2R(2D)二体代换系;附加系BC122-3附加了一条6R黑麦染色体,一条6B染色体的长臂缺失。同时,对连续的总基因组原位杂交和双色荧光原位杂交技术在小麦育种中的应用进行了讨论。     

Analysis of common wheat varieties and near-isogenic lines by PCR with allele-specific primers for Gli-1 and Glu-3 loci

The allelic characteristics of the Gli-A1, Gli-B1, Gli-D1 and Glu-A3 loci of 14 bread wheat varieties and 6 near-isogenic lines derived from Bezostaya 1 have been detected by PCR analysis. The conformity of molecular-genetic data and electrophoresis of storage proteins has been determined: the allelic variants of gliadins Gli-A1o and Gi-A1m correspond to the PCR-allele GliA1.2, the gliadin variants Gli-A1f, Gli-A1b, Gli-A1c correspond to the PCR-allele GliA 1.1, the allelic variants Gli-B1b, Gli-B1d--to the PCR-allele GliB1.1 and the variants Gli-B1e, Gli-B1g, Gli-B1c-to the PCR-allele GliB1.2. A new PCR-allele at the GliB) locus in the line Gli-B1-12 (with the gliadin block Gli-B1o from Levent) was identified.     

Identification of SNPs and development of allele-specific PCR markers for γ-gliadin alleles in Triticum aestivum

The coding regions of 28 entries of hexaploid wheat gamma-gliadin genes, gene fragments or pseudogenes in GenBank were used for nucleotide alignment. These sequences could be divided into nine subgroups based on nucleotide variation. The chromosomal locations of five of the seven unassigned subgroups were identified through subgroup-specific polymerase chain reactions (PCR) using Chinese Spring group-1 nulli-tetrasomic lines. Multiple single nucleotide polymorphisms (SNPs) and small insertions/deletions were identified in each subgroup. With further mining from wheat expressed sequence tag databases and targeted DNA sequencing, two SNPs were confirmed and one SNP was discovered for genes at the Gli-A1, Gli-B1 and Gli-D1 loci. A modified allele-specific PCR procedure for assaying SNPs was used to generate dominant DNA markers based on these three SNPs. For each of these three SNPs, two allele-specific primer sets were used to test Chinese Spring and 52 commercial Australian wheat varieties representing a range of low-molecular-weight (LMW) alleles. PCR results indicated that all were positive with one of the primer sets and negative with the other, with the exception of three varieties containing the 1BL/1RS chromosomal translocation that were negative for both. Furthermore, markers GliA1.1, GliB1.1 and GliD1.1 were found to be correlated with Glu-A3 a, b or c, Glu-B3 b, c, d or e and Glu-D3 a, b or e LMW glutenin alleles, respectively. Markers GliA1.2, GliB1.2 and GliD1.2 were found to be correlated with the Glu-A3 d or e, Glu-B3 a, g or h and Glu-D3 c alleles, respectively. These results indicated that the gamma-gliadin SNP markers could be used for detecting linked LMW glutenin subunit alleles that are important in determining the quality attributes of wheat products.     

Polymorphism of omega-gliadins in durum wheat as revealed by the two-step APAGE/SDS-PAGE technique

Polymorphism of omega-gliadins was studied in 243 durum wheats from 27 countries using the two-step one-dimensional APAGE/SDS-PAGE technique. A total of 12 bands of different mobility were observed, and four of them were found to be different from those previously detected by Khelifi et al. (1992) in bread wheat. Fifteen alleles, six coded by the Gli-A1 locus and nine coded by the Gli-B1 locus, were identified, accounting for 19 different electrophoretic patterns. Seven new alleles were detected: two at the Gli-A1 locus and five at the Gli-B1 locus. The polymorphism found at the Gli-A1 and Gli-B1 loci was slightly greater than that found in bread wheat. Allelic differences between both species were higher at the Gli-B1 locus. A comparison of the frequencies of alleles in both species was carried out. The null allele, Gli-A1e, was more common in durum wheat than in bread wheat. The Gli-B1b allele, present in 60% of the bread wheats, was found in only 2% of the durum wheats and Gli-B1e, very common in durum wheat (45%), was rare in bread wheat (4%). The Gli-B1IV allele, common in durum wheat (28%), was not detected in bread wheat.     

Transmission-Ratio Distortion through F(1) Females at Chromosome 11 Loci Linked to Om in the Mouse Ddk Syndrome

We determined the genotypes of >200 offspring that are survivors of matings between female reciprocal F(1) hybrids (between the DDK and C57BL/6J inbred mouse strains) and C57BL/6J males at markers linked to the Ovum mutant (Om) locus on chromosome 11. In contrast to the expectations of our previous genetic model to explain the ``DDK syndrome,' the genotypes of these offspring do not reflect preferential survival of individuals that receive C57BL/6J alleles from the F(1) females in the region of chromosome 11 to which the Om locus has been mapped. In fact, we observe significant transmission-ratio distortion in favor of DDK alleles in this region. These results are also in contrast to the expectations of Wakasugi's genetic model for the inheritance of Om, in which he proposed equal transmission of DDK and non-DDK alleles from F(1) females. We propose that the results of these experiments may be explained by reduced expression of the maternal DDK Om allele or expression of the maternal DDK Om allele in only a portion of the ova of F(1) females.     

Conjugation of the 1BL/1RS translocation with qualitative and quantitative traits in the common wheat T.aestivum

The review considers the effect of the rye 1BL/1RS translocation in the common wheat genome on qualitative and quantitative traits: grain quality, resistance to diseases, productivity and adaptivity, parthenogenesis, regeneration in anther culture, frequency of chromosome aberrations and frequency of cross-pollination. Data on special features of transmission of the 1BL/1RS translocation through male and female gametes are presented.     

Development of a wheat genotype combining the recessive crossability alleles kr1kr1kr2kr2 and the 1BL.1RS translocation, for the rapid enrichment of 1RS with new allelic variation

The main objective of the present work was to develop a wheat genotype containing both the recessive crossability alleles (kr1kr1kr2kr2), allowing high crossability between 6x wheat and diploid rye, and the 1BL.1RS wheat/rye translocation chromosome. This wheat genotype could be used as a recipient partner in wheat–rye crosses for the efficient introduction of new allelic variation into 1RS in translocation wheats. After crossing the wheat cultivars ‘Mv Magdaléna’ and ‘Mv Béres’, which carry the 1BL.1RS translocation involving the 1RS chromosome arm from ‘Petkus’, with the line ‘Mv9 kr1’, 117 F₂ plants were analysed for crossability, ten of which had higher than 50% seed set with rye and thus presumably carried the kr1kr1kr2kr2 alleles. Four of the ten plants contained the 1BL.1RS translocation in the disomic condition as detected by genomic in situ hybridization (GISH). The wheat × rye F₁ hybrids produced between these lines and the rye cultivar ‘Kriszta’ were analysed in meiosis using GISH. 1BL.1RS/1R chromosome pairing was detected in 62.4% of the pollen mother cells. The use of fluorescent in situ hybridization (FISH) with the repetitive DNA probes pSc119.2, Afa family and pTa71 allowed the 1R and 1BL.1RS chromosomes to be identified. The presence of the 1RS arm from ‘Kriszta’ besides that of ‘Petkus’ was demonstrated in the F₁ hybrids using the rye SSR markers RMS13 and SCM9. In four of the 22 BC₁ progenies analysed, only ‘Kriszta’-specific bands were observed with these markers, though the presence of the 1BL.1RS translocation was detected using GISH. It can be concluded that recombination occurred between the ‘Petkus’ and ‘Kriszta’ 1RS chromosome arms in the translocated chromosome in these plants.     

Recombination frequency in the locus Gli-D1 of common wheat T. aestivum L

The recombination frequency at the gliadin locus Gli-D1 of common wheat was determined by the maximum likelihood method. Recombination was observed between the gene encoding the fastest omega-component of the allele Gli-D1j, and the genes encoding the other omega-gliadins of this allele. The frequency of recombination was 0.65 +/- 0.18% for the cross between the near-isogenic lines of winter common wheat with respect to gliadin loci Gli-D1-4 and Gli-B1-3 and 0.78 +/- 0.45% for the cross between the varieties Yunnat and B-16.     

小麦耐盐种质的筛选鉴定和耐盐基因的标记

通过对 40 0份材料的芽期、苗期鉴定 ,筛选出 11份耐盐性较强的普通小麦 (TriticumaestivumL .)、小麦和黑麦 (SecalecerealeL .)、小麦和延安赖草 (Leymuschinensis (Trin .)Tzvel.)杂交后代材料 ,其中耐盐性突出的材料有 :普通小麦品种“红蚂蚱”、“科遗 2 6”、“希望”(Hope) ;小麦与黑麦杂交后代材料 98_46、98_113、98_131;小麦与延安赖草杂交后代材料 98_16 0、98_16 1、98_16 3。耐盐性表现最突出的材料是 98_113和 98_16 0。细胞学鉴定和原位杂交及醇溶蛋白酸性聚丙烯酰胺凝胶电泳 (A_PAGE)分析和低分子量谷蛋白SDS_PAGE分析 ,证明 98_113是稳定的小麦 黑麦二体附加系 ,但具体附加的是黑麦的哪条染色体还不清楚 ;98_131是小麦 黑麦 1B/ 1R易位系。结合其他 1B/ 1R材料的耐盐表现 ,提出了黑麦 1R染色体短臂上存在耐盐基因的可能性。对 (98_16 0×BanacakaMska)F2 代分离群体苗期抗盐鉴定分析 ,表明在这一杂交组合中的耐盐性状可能由一个主效基因控制。应用SSR标记技术 ,筛选到了与 98_16 0耐盐性状连锁的SSR标记WMS6 7和WMS2 13,它们与耐盐基因的遗传距离分别为 13.9cM (centMorgan)和 31.0cM。结合小麦SSR图谱分析 ,将该主效抗性基因定位在 5BL上。     

Isoenzyme variation in Aedes aegypti correlated with Dirofilaria immitis infectability

From the Vero Beach strain of the mosquito Aedes (Stegomyia) aegypti (L.) (Diptera: Culicidae), substrains were selected for susceptibility (SS) and refractoriness (RR) to the dog heartworm Dirofilaria immitis (Leidy) (Filarioidea: Onchocercidae). These two lines and their reciprocal F1 hybrids were analysed for genetic variation at 14 enzyme loci, using polyacrylamide gel electrophoresis. Six of the enzyme loci showed variation (sample size 48 alleles/locus/line). Three of these were monomorphic in the refractory line but polymorphic in the susceptible, i.e. aconitase hydratase (Acoh), isocitrate dehydrogenase-1 (Idh-1) and phosphoglucomutase (Pgm). The other three loci, glucose-6-phosphate isomerase (Gpi), hexokinase-1 (Hk-1) and isocitrate dehydrogenase-2 (Idh-2), were polymorphic in both SS and RR lines and their hybrids. At two loci (Hk-1, Pgm) three alleles were detected, whereas the other polymorphic loci had only two alleles. For Hk-1, the most frequent allele was Hk-1(80) (0.563) in refractory and Hk-1(100) in the susceptible (0.521) and F1 hybrids. For Pgm the most frequent alleles were Pgm125 in the susceptible line (0.646) and Pgm100 in the F1 hybrids (0.563 and 0.604) and refractory line (1.000). The mean observed heterozygosity (Ho), the mean Hardy-Weinberg expected heterozygosity (He) and the mean number of alleles per locus in the refractory line were lower, but not significantly so, than in the susceptible line and their reciprocal F1 hybrids; the proportion of polymorphic loci was significantly lower in the refractory than in the susceptible line and their F1 hybrids. Within both lines all polymorphisms were in Hardy-Weinberg equilibrium, whereas significant departures from predicted frequencies were observed in SS x RR hybrids at four polymorphic loci (Acoh, Gpi, Hk-1, Pgm) and at three polymorphic loci (Acoh, Hk-1, Pgm) in RR x SS hybrids. The average Nei's and modified Rogers' genetic distances between the lines were 0.024 and 0.139, respectively. These electrophoretic data show that the refractory line (putatively lacking fi allele) can be distinguished from the susceptible line (fi/fi) and their hybrids (heterozygous fi) by isozyme marker frequencies, but it remains to be seen whether this difference is causal or chance linkage. In any case, this model system of Ae. aegypti/D. immitis provides opportunities to better understand and manipulate the molecular biology of filariasis transmission.     

A Mutant with Expression Deletion of Gene Sec-1 in a 1RS.1BL Line and Its Effect on Production Quality of Wheat

The chromosome arm 1RS of rye (Secale cereal L.) has been used worldwide as a source of genes for agronomic and resistant improvement. However, the 1RS arm in wheat has end-use quality defects that are partially attributable to the presence of ω-secalins, which are encoded by genes at the Sec-1 locus. Various attempts in removing the Sec-1 genes from the 1RS.1BL translocation chromosome have been made. In the present study, two new primary 1RS.1BL translocation lines, T917-26 and T917-15, were developed from a cross between wheat variety “{"type":"entrez-nucleotide","attrs":{"text":"A42912","term_id":"2298361"}}A42912” and Chinese local rye “Weining.” The lines T917-15 and T917-26 carried a pair of intact and homogeneous 1RS.1BL chromosomes. The line T917-26 also harbored an expression deletion of some genes at the Sec-1 locus, which originated from a mutation that occurred simultaneously with wheat-rye chromosome translocations. These results suggest that the accompanying mutations of the evolutionarily significant translocations are remarkable resources for plant improvement. Comparison of translocation lines with its wheat parent showed improvements in the end-use quality parameters, which included protein content (PC), water absorption (WA), sodium dodecyl sulfate sedimentation (SDSS), wet gluten (WG), dry gluten (DG) and dough stickiness (DS), whereas significant reduction in gluten index (GI) and stability time (ST) were observed. These findings indicate that 1RS in wheat has produced a higher amount of protein, although these comprised worse compositions. However, in the T917-26 line that harbored an expression deletion mutation in the Sec-1 genes, the quality parameters were markedly improved relative to its sister line, T917-15, especially for GI and DS (P < 0.05). These results indicated that expression deletion of Sec-1 genes significantly improves the end-use quality of wheat cultivars harboring the 1RS.1BL translocation. Strategies to remove the Sec-1 genes from the 1RS.1BL translocation in wheat improvement are discussed.     

Genotypic variation in tetraploid wheat affecting homoeologous pairing in hybrids with Aegilops peregrina.

The Ph1 gene has long been considered the main factor responsible for the diploid-like meiotic behavior of polyploid wheat. This dominant gene, located on the long arm of chromosome 5B (5BL), suppresses pairing of homoeologous chromosomes in polyploid wheat and in their hybrids with related species. Here we report on the discovery of genotypic variation among tetraploid wheats in the control of homoeologous pairing. Compared with the level of homoeologous pairing in hybrids between Aegilops peregrina and the bread wheat cultivar Chinese Spring (CS), significantly higher levels of homoeologous pairing were obtained in hybrids between Ae. peregrina and CS substitution lines in which chromosome 5B of CS was replaced by either 5B of Triticum turgidum ssp. dicoccoides line 09 (TTD09) or 5G of Triticum timopheevii ssp. timopheevii line 01 (TIMO1). Similarly, a higher level of homoeologous pairing was found in the hybrid between Ae. peregrina and a substitution line of CS in which chromosome arm 5BL of line TTD140 substituted for 5BL of CS. It appears that the observed effect on the level of pairing is exerted by chromosome arm 5BL of T turgidum ssp. dicoccoides, most probably by an allele of Ph1. Searching for variation in the control of homoeologous pairing among lines of wild tetraploid wheat, either T turgidum ssp. dicoccoides or T timopheevii ssp. armeniacum, showed that hybrids between Ae. peregrina and lines of these two wild wheats exhibited three different levels of homoeologous pairing: low, low intermediate, and high intermediate. The low-intermediate and high-intermediate genotypes may possess weak alleles of Ph1. The three different T turgidum ssp. dicoccoides pairing genotypes were collected from different geographical regions in Israel, indicating that this trait may have an adaptive value. The availability of allelic variation at the Ph1 locus may facilitate the mapping, tagging, and eventually the isolation of this important gene.     

几类异质小麦雄性不育系育性恢复性的细胞遗传学研究

系统调查了4类异质(粘果、易变、偏凸、二角山羊草细胞质)1BL/lRS、非1BL/1RS小麦雄性不育系与其恢复系杂种F减数分裂中期Ⅰ出现单价体细胞频率,以及后期Ⅰ出现落后染色体和染色体桥细胞频率,并对中、后期染色体变异率与杂种F自交结实率进行了相关分析.结果表明(1)1BL/1RS型杂种在中期Ⅰ、后期Ⅰ染色体变异率要明显高于非1BL/1RS杂种;(2)4类异源细胞质在非1BL/1RS杂种中有着明显提高单价体细胞频率的作用;(3)在1BL/1RS杂种中,1B@1BL/1RS杂合核型染色体联会松弛,对单价体频率的影响远大于异源细胞质的影响;(4)1BL/1RS型杂种自交结实率与中期出现单价体细胞频率不直接相关,而与后期出现落后染色体和染色体桥细胞的频率呈高度负相关;(5)非1BL/1RS型杂种在减数分裂中、后期染色体行为相对稳定,易恢复且恢复度高,很有实际利用价值.     

Effect of the 1BL.1RS translocation on the wheat endosperm, as revealed by proteomic analysis

The introduction of the 1RS chromosome of rye into wheat made wheat more resistant to several pathogens. Today, this resistance has been overcome but the 1BL.1RS translocation remains interesting because of the improved yield and despite the lower rheological properties it produces. Nothing has been reported yet on the impact of rye chromatin introgression on the grain proteome of wheat. The comparison of the 2-DE profiles of 16 doubled haploid lines, with or without the 1BL.1RS translocation, revealed quantitative and qualitative proteic variations in prolamins and other endosperm proteins. Eight spots were found specifically in lines having the 1BL.1RS translocation; 16 other spots disappeared from the same lines. Twelve spots, present in both genotypes, met the criteria for up- or down-regulated spots. In translocated genotypes, a highly overexpressed spot, identified as a gamma-gliadin with nine cysteine residues, suggests that the lack of LMW-GS induced by 1BL.1RS is counterbalanced by an overexpression of a relatively similar prolamin. Moreover, a spot that was absent from 1BL.1RS genotypes was identified as a dimeric alpha-amylase inhibitor. It was considered to be a valuable candidate to explain the sticky dough associated with translocated cultivars.     

Partial resistance to powdery mildew in German spring wheat ‘Naxos’ is based on multiple genes with stable effects in diverse environments

Powdery mildew is one of the most important wheat diseases in temperate regions of the world. Resistance breeding is considered to be an economical and environmentally benign way to control this disease. The German spring wheat cv. 'Naxos' exhibits high levels of partial and race non-specific resistance to powdery mildew in the field and is a valuable source in resistance breeding. The main objective of the present study was to map the genetic factors behind the resistance in Naxos, based on a population of recombinant inbred lines (RIL) from a cross with the susceptible CIMMYT breeding line SHA3/CBRD. Powdery mildew severity was evaluated in six field trials in Norway and four field trials in China. The major quantitative trait locus (QTL) with resistance from Naxos was detected close to the Pm3 locus on 1AS in all environments, and explained up to 35% of the phenotypic variation. Naxos was shown to carry another major QTL on 2DL and minor ones on 2BL and 7DS. QTL with resistance from SHA3/CBRD were detected on 1RS, 2DLc, 6BL and 7AL. The QTL on the 1B/1R translocation showed highly variable effects across environments corresponding to known virulence differences against Pm8. SHA3/CBRD was shown to possess the Pm3 haplotype on 1AS, but none of the known Pm3a-g alleles. The RIL population did not provide any evidence to suggest that the Pm3 allele of SHA3/CBRD acted as a suppressor of Pm8.     

Identification of the 1RS rye chromosomal segment in wheat by RAPD analysis

The introgression of rye DNA into the wheat genome was studied using random decamer and specific primers with the polymerase chain reaction (PCR). DNA from paired near-isolines in Chisholm and Arkan backgrounds differing with respect to the presence of a 1 RS.1 BL translocation was amplified with 120 arbitrary sequence primers. Two of the primers (OPR 19 and OPJ07) amplified rye-specific DNA fragments. The OPR19 primer amplified a 1.35-kb fragment that appeared to be specific to the 1 RS.1 BL translocation, based on its presence only in lines carrying the 1 RS. 1 BL translocation. A fragment of the same size was also amplified in 1 RS.1 AL translocation lines. This 1 RS. 1 BL marker locus was designated Ximc 1. The other primer, OPJ07, amplified a 1.2-kb DNA sequence, that was designated Ximc 2, specific to the wheat-rye translocation in various wheat backgrounds. The sequences of the two marker loci were found to be different from each other. The Ximc 1 locus was a low-copy sequence which was also present in Balboa rye genomic DNA. Through the use of specific primers, the presence of the rye-specific marker was confirmed in hexaploid as well as in tetraploid wheat backgrounds. The use of RAPDs for the study of smaller alien introgressions into wheat is discussed.