Monosomic Addition Lines Research Articles

Identification and evaluation of clubroot resistance of radish chromosome using a Brassica napus-Raphanus sativus monosomic addition line

Clubroot resistance (CR) against the Ano-01 isolate of the clubroot pathogen Plasmodiophora brassicae for individual radish chromosomes was evaluated using 9 types (a–i) of Brassica napus–Raphanus sativus monosomic addition lines (MALs) produced from the progenies of the hybridization of B. napus (2n = 38, AACC) and Raphanobrassica ‘Rb-63’ (2n = 36, RRCC). Among the 9 types of MAL, the c-type showed high resistance, although other types and reverted plants with somatic chromosomes like B. napus (2n = 38) were susceptible. This result suggested that a major CR gene against the Ano-01 isolate may be located on the radish c-chromosome. However, it was also assumed that there might be other CR gene(s) in radish because many c-type MAL plants showed slight disease symptoms.

Single Alien Chromosome Additions from Shallot (Allium cepa L. Aggregatum group) Increase Endogenous Polyphenol Contents in Japanese Bunching Onion

Eight members of the Allium fistulosum L. – shallot (Allium cepa L. Aggregatum group) monosomic addition line (2n = 17, FF + 1A–FF + 8A) proved to be very effective in revealing the effects of single alien chromosomes from A. cepa on the production of polyphenol in the green leaf tissues of A. fistulosum. The determination of polyphenol content in the green leaf tissue of these monosomic additions was carried out monthly from January 2002 to December 2003. Throughout the 2-year period, every monosomic addition accumulated polyphenols in green leaf tissues. Two-way ANOVA revealed significant differences, at the 1% level, in the polyphenol contents of the various monosomic addition types as well as in various months. Dunnett’s test showed that four monosomic additions (FF + 2A, FF + 5A, FF + 6A, and FF + 8A) caused a greater increase in the amount of polyphenol content than did A. fistulosum. The levels of polyphenol accumulation in the remaining four monosomic additions and A. fistulosum were almost the same. A phenylalanine ammonialyase gene of shallot was allocated to chromosome 2A using two sets of the monosomic additions. These results indicate that the genes related to polyphenol production may be located on the 2A, 5A, 6A, and 8A chromosomes of shallot.

Production of Raphanus sativus (C3)-Moricandia arvensis (C3-C4 intermediate) Monosomic and Disomic Addition Lines with Each Parentl Cytoplasmic Background and their Photorespiratory Characteristics

We are maintaining five Moricandia arvensis monosomic addition lines of Raphanus sativus carrying R. sativus cytoplasm (autoplasmic MALs) and twelve M. arvensis MALs of R. sativus carrying M. arvensis cytoplasm (alloplasmic MALs) from BC6 to BC8 generation, and newly produced five M. arvensis disomic addition lines of R. sativus (autoplasmic DALs) and seven M. arvensis DALs of R. sativus carrying M. arvensis cytoplasm (alloplasmic DALs) from selfing and sib-crossing of the MALs and DALs in S3BC5 and S2BC6 generations. The structural, biochemical and physiological characteristics related to photorespiration of these MALs and DALs were compared to study the genetic mechanisms of the C3-C4 intermediate photosynthesis in the individual chromosomes of M. arvensis. The CO2 compensation point of the autoplasmic and alloplasmic DALs (RMa-b and MaR-b DALs) with one pair of M. arvensis ‘b’ chromosome were 29.4 and 30.1 μmol mol-1, respectively, which were significantly lower than that of other DALs and MALs as well as R. sativus (34.5 𰂼mol mol-1). An immunogold electron microscopic study of the P-protein of glycine decarboxylase (GDC) in photosynthetic cells of the RMa-b DAL revealed that the bundle sheath cell (BSC) mitochondria were more intensively labeled for the protein than the mesophyll cell (MC) mitochondria. The ratio of the labeling density of the BSC mitochondria to that of the MC mitochondria was 1.13, which lies between values in M. arvensis (2.66) and R. sativus (0.76). These data suggest that the ‘b’ chromosome of M. arvensis genome controls the expression of C3-C4 intermediate characteristics.

Comparative proteomic analysis of apomictic monosomic addition line of Beta corolliflora and Beta vulgaris L. in sugar beet

Apomixis refers to a process in which plants produce seed without fertilization through female syngamy that produces embryos genetically identical to the maternal parent. In sugar beet, interspecific hybrids between diploid Beta vulgaris and tetraploid Beta corolliflora were established and monosomic addition line M14 was selected because of the apomictic phenotype. By using two-dimensional electrophoresis gels we identified the proteins which were differently expressed between the M14 and B. vulgaris. A total of 27 protein spots which varied expressed between lines were isolated and successfully identified with MALDI-TOF MS. Among them five protein spots were found to be only presented in M14 and two protein spots only expressed in Beta. According to their functional annotations described in Swissprot database, these proteins were, respectively, involved in important biological pathways, such as cell division, functionally classified using the KEGG functional classification system. The result may be useful for us to better understand the genetic mechanism of apomixes.

Development of Triticum aestivum-Leymus racemosus ditelosomic substitution line 7Lr#1S(7A) with resistance to wheat scab and its meiotic behavior analysis

Leymus racemosus is highly resistant to wheat scab (Fusarum head bright). The transfer of scab resistant gene from L. racemosus to Triticum aestivum is of great significance for broadening the base of wheat resistance. In the present study, the pollen of T. aestivum-L. racemosus monosomic addition line with scab resistance was treated by irradiation with 1200 R 60Co-γ-rays prior to pollinating to emasculated wheat cv. Mianyang 85–45. Nine plants with a telocentric chromosome 7Lr#1S were observed in M1, and one ditelosomic substitution line 7Lr#1S was selected from selfcrossing progenies and confirmed by chromosome C-banding and GISH. Furthermore, a co-dominant EST-SSR marker CINAU 31 was employed to identify this substitution line. A pair of chromosome 7A of common wheat were found to be replaced by a pair of telocentric chromosome 7Lr#1S, and further investigation showed that chromosome configuration of the substitution line at MI of PMCs after GISH was 17.50 W + 2.19 W + 0.42 7Lr#1S + 1.08 I7Lr#1S + 0.69 IW. Two telocentric chromosomes paired as a bivalent in 59.7% of PMCs. Abnormal chromosome behaviors of telocentric chromosomes were observed in part of PMCs at anaphase I and telophase I, including the moving of two telocentric chromosomes to the same pole, lagging and earlier separation of their sister chromatid. All these abnormal behaviors can be grouped into three distinct types of tetrads according to different numbers of 7Lr#1S in their daughter cells and various micronucleus in some tetrads. However, due to the high transmission frequency of the female and male gametes with a 7Lr#1S, 84% of the selfcrossing progeny plants had ditelosomic substitution. The substitution line showed high resistance to wheat scab in a successive two-year test both in the greenhouse and field; hence, the line will be particularly valuable for alien gene mapping, small fragment translocation induction and telosomic cytological behavior analysis.

Production and characterization of intergeneric somatic hybrids between Brassica napus and Orychophragmus violaceus and their backcrossing progenies

Alien chromosome addition lines have been widely used for identifying gene linkage groups, assigning species-specific characters to a particular chromosome and comparing gene synteny between related species. In plant breeding, their utilization lies in introgressing characters of agronomic value. The present investigation reports the production of intergeneric somatic hybrids Brassica napus (2n = 38) + Orychophragmus violaceus (2n = 24) through asymmetric fusions of mesophyll protoplasts and subsequent development of B. napus-O. violaceous chromosome addition lines. Somatic hybrids showed variations in morphology and fertility and were mixoploids (2n = 51-67) with a range of 19-28 O. violaceus chromosomes identified by genomic in situ hybridization (GISH). After pollinated with B. napus parent and following embryo rescue, 20 BC(1) plants were obtained from one hybrid. These exhibited typical serrated leaves of O. violaceus or B. napus-type leaves. All BC(1) plants were partially male fertile but female sterile because of abnormal ovules. These were mixoploids (2n = 41-54) with 9-16 chromosomes from O. violaceus. BC(2) plants showed segregations for female fertility, leaf shape and still some chromosome variation (2n = 39-43) with 2-5 O. violaceus chromosomes, but mainly containing the whole complement from B. napus. Among the selfed progenies of BC(2) plants, monosomic addition lines (2n = 39, AACC + 1O) with or without the serrated leaves of O. violaceus or female sterility were established. The complete set of additions is expected from this investigation. In addition, O. violaceus plants at diploid and tetraploid levels with some variations in morphology and chromosome numbers were regenerated from the pretreated protoplasts by iodoacetate and UV-irradiation.

Progress on Transferring Elite Genes from Non-AA Genome Wild Rice into Oryza sativa through Interspecific Hybridization

The progress of research on transferring elite genes from non-AA genome wild rice into Oryza sativa through interspecific hybridization are in three respects, that is, breeding monosomic alien addition lines (MAALs), constructing introgression lines (ILs) and analyzing the heredity of the characters and mapping the related genes. There are serious reproductive barriers, mainly incrossability and hybrid sterility, in the interspecific hybridization of O. sativa with non-AA genome wild rice. These are the ‘bottleneck’ for transferring elite genes from wild rice to O. sativa. Combining traditional crossing method with biotechnique is a reliable way to overcome the reproductive barriers and to improve the utilizing efficiency of non-AA genome wild rice.

Monosomic Addition Lines of Flowering Chinese Cabbage ( B. campestris L. ssp. chinensis var. parachinensis L. H. Bailey)-Chinese Kale ( B. oleracea L. var. alboglabra L. H. Bailey)

Interspecific alien addition lines have played significant roles in gene mapping, intergenomic gene transfer and chromosomal homoeological identification between closely related species. Selection of alien addition lines was conducted by karyotype analysis and morphological observation with the reference of parents. Triploid interspecies hybrid (AAC, 2n = 3x = 29) was obtained from Brassica campestris ssp. chinensis var. parachinensis Qinglu 9601 (tetraploid, AAAA, 2n = 4x = 40) × B. oleracea var. alboglabra Baihua 9705 (diploid, CC, 2n = 2x = 18) by immature hybrid embryo culture in vitro. Five different alien monosomic addition lines (AA + C2, AA + C3, AA + C4, AA + C6, AA + C7) were obtained from the backcross progenies of AAC × AA. Each alien monosomic addition line has some specific morphological characters. It is feasible to obtain alien addition lines from the progenies of AAC × AA by karyotype analysis and morphological observation based on the reference of parents.

MOLECULAR APPROACHES TO CHARACTERIZING AND IMPROVING BULB COMPOSITION IN ONION

MOLECULAR APPROACHES TO CHARACTERIZING AND IMPROVING BULB COMPOSITION IN ONION

Production of Alien Addition Lines in Polyploid Bunching Onion (Allium fistulosum) Carrying 1A Chromosome(s) of Shallot (Allium cepa) and Their Application to Breeding for a New Vitamin C-Rich Vegetable

Eight Allium fistulosum L.–Allium cepa L. Aggregatum group (shallot) monosomic addition lines (2n = 17, FF+1A–FF+8A) have been useful in revealing the effects of single alien chromosomes from A. cepa on the production of l-ascorbic acid in the leaf tissue of A. fistulosum. In this study, the determination of ascorbic acid content revealed that the incorporation of alien chromosome 1A into a diploid background of A. fistulosum increased the internal ascorbic acid content of the leaf blade tissue. We produced a 1A disomic addition in the tetraploid of A. fistulosum (2n = 34) and demonstrated high-frequency transfer of the alien chromosome in crosses with A. fistulosum. Five plants of the 1A disomic additions were regenerated via apical meristem culture of the FF+1A on a Murashige and Skoog medium containing colchicine. These 1A disomic additions showed partial fertility for female and male gametes. Most of the progenies from selfing of the 1A disomic additions and reciprocal crossing with A. fistulosum possessed chromosome 1A. Interestingly, 64% (18 of 28) of the plants obtained from the reciprocal crosses were 1A monosomic additions in a triploid background of A. fistulosum. These monosomic additions were more vigorous and vitamin C-rich than euploid plants of A. fistulosum.

A BAC library of Beta vulgaris L. for the targeted isolation of centromeric DNA and molecular cytogenetics of Beta species

We constructed a sugar beet (Beta vulgaris) bacterial artificial chromosome (BAC) library of the monosomic addition line PAT2. This chromosomal mutant carries a single additional chromosome fragment (minichromosome) derived from the wild beet Beta patellaris. Restriction analysis of the mutant line by pulsed-field gel electrophoresis was used to determine HindIII as a suitable enzyme for partial digestion of genomic DNA to generate large-insert fragments which were cloned into the vector pCC1. The library consists of 36,096 clones with an average insert size of 120 kb, and 2.2% of the clones contain mitochondrial or chloroplast DNA. Based on a haploid genome size of 758 Mbp, the library represents 5.7 genome equivalents providing the probability of 99.67% that any sequence of the PAT2 genome can be found in the library. Hybridization to high-density filters was used to isolate 89 BACs containing arrays of the centromere-associated satellite repeats pTS5 and pTS4.1. Using the identified BAC clones in fluorescent in situ hybridization experiments with PAT2 and Beta patellaris chromosome spreads their wild beet origin and centromeric localization was demonstrated. Multi-colour FISH with differently labelled satellite repeats pTS5 and pTS4.1 was used to investigate the large-scale organization of the centromere of the PAT2 minichromosome in detail. FISH studies showed that the centromeric satellite pTS5 is flanked on both sides by pTS4.1 arrays and the arms of the minichromosome are terminated by the Arabidopsis-type telomeric sequences. FISH with a BAC, selected from high-density filters after hybridization with an RFLP marker of the genetic linkage group I, demonstrated that it is feasible to correlate genetic linkage groups with chromosomes. Therefore, the PAT2 BAC library provides a useful tool for the characterization of Beta centromeres and a valuable resource for sugar beet genome analysis.

Biochemical and Genetic Analysis of Carbohydrate Accumulation in Allium cepa L

Onion and shallot (Allium cepa L.) exhibit wide variation in bulb fructan content, and the Frc locus on chromosome 8 conditions much of this variation. To understand the biochemical basis of Frc, we conducted biochemical and genetic analyses of Allium fistulosum (FF)-shallot (A. cepa Aggregatum group) alien monosomic addition lines (AALs; FF+1A-FF+8A) and onion mapping populations. Sucrose and fructan levels in leaves of FF+2A were significantly lower than in FF throughout the year, and the springtime activity of acid invertase was also lower. FF+8A showed significantly higher winter sucrose accumulation and sucrose phosphate synthase (SPS) activity. Inbred high fructan (Frc_) lines from the 'W202Ax Texas Grano 438' onion population exhibited significantly higher sucrose levels prior to bulbing than low fructan (frcfrc) lines. Sucrose synthase (SuSy) activity in these lines was correlated with leaf hexose content but not with Frc phenotype. Markers for additional candidate genes for sucrose metabolism were obtained by cloning a major SPS expressed in onion leaf and exhaustively mining onion expressed sequence tag resources. SPS and SuSy loci were assigned to chromosome 8 and 6, respectively, using AALs and linkage mapping. Further loci were assigned, using AALs, to chromosomes 1 (sucrose phosphate phosphatase), 2 (SuSy and three invertases) and 8 (neutral invertase). The concordance between chromosome 8 localization of SPS and elevated leaf sucrose levels conditioned by high fructan alleles at the Frc locus in bulb onion or alien monosomic additions of chromosome 8 in A. fistulosum suggest that the Frc locus may condition variation in SPS activity.

Neocentric activity in chromosome 5R of rye revealed by haploidy

Schlegel, R. 1987. Neocentric activity in chromosome 5R of rye revealed by haploidy. - Hereditas 107: 1–6. Lund, Sweden. ISSN 0018–0661. Received October 2, 1986 In metaphase I and anaphase I of haploid ‘Petka’ rye a particular univalent chromosome with a proximal constriction can be observed in most of the pollen mother cells. A similarly shaped chromosome was also found in polyhaploid wheat-rye hybrids, triticale × wheat hybrids. and in a monosomic wheat-rye addition line derived from several rye genotypes. This chromosome behaves as a dicentric since co-orientation of the ordinary centromere and a second centromere-like structure is evident. However, the neocentric activity does not originate in the telomeres, but is confined to the proximal region of the long arm of this submeta-centric chromosome, which has been identified as chromosome 5R by the C-banding pattern (5Rq21).

Monosomic alien addition lines: a new tool for studying and using plant genomics

Interspecies hybridization and backcrossing is a means to transfer desirable genes from one species to another in breeding programs of higher plants. Monosomic alien addition lines (MAALs) can be produced via addition of single chromosome of an alien donor species to the entire chromosome complement of the recipient species. MAALs are powerful tools for elucidating genome structure and transferring genes. Backcrossing of MAALs to the recipient parent results in plants containing short overlapping introgressions, which cover the entire donor genome. These introgression lines can be used as vectors of alien genomic libraries in a recipient genetic background. In addition, a complete set of MAALs also serves as a library of the donor genome dissected into individual chromosome entities, which facilitates high-throughput marker allocation to individual donor chromosomes, and marker assignments and syntenic relationships can be compared between the donor chromosomes and the respective orthologous recipient chromosomes. Meanwhile, MAALs can be used to study the introgression mechanism and the pairing status of homologous chromosomes. In this review, we presented the production and properties of MAALs and highlighted their advantages for genetic breeding and fundamental researches.

Using Allium alien monosomic addition lines to study chlorophyll degradation in stored Japanese bunching onion

SummaryChlorophyll (Chl) degradation and the formation of Chl derivatives in stored leaves of Japanese bunching onion (JBO; Allium fistulosum L., genome FF) were determined to elucidate the mechanism of Chl degradation by using alien monosomic addition lines (AMALs; FF+1A to FF+8A) of JBO from shallot (A. cepa L. Aggregatum group, genome AA). Year-round changes in Chl content in JBO and in the AMALs were also detected over 2 years. The Chl content in FF was significantly influenced by the alien chromosomes from shallot. In particular, the Chl contents of FF+4A or FF+5A, were higher in Winter than in FF, which suggests that chromosomes 4A and 5A from shallot had a larger influence on the formation of Chl than the other chromosomes. Chl contents in FF+3A and FF+5A decreased greatly in the leaves of AMALs and JBO during storage at 25°C, whereas in FF+4A the Chl content was the lowest compared to the control, FF. Chlorophyllide (Chlide) a, C132-hydroxychlorophyll (OHChl) a, pheophorbide a, and pheophytin (Phy) a, as derivatives of Chl a, were present mainly during storage of JBO and the AMALs. Phy alevels increased with Chl degradation, especially in FF+3A, while OHChl alevels in FF and FF+3A showed a decline during storage. In addition, Chlide alevels in all lines diminished during storage.Thus, Chl amay be degraded, in part, through Phy a, as well as Chlide aand OHChl a, in JBO and the AMALs during storage.

Conversion of chromosome-specific RAPDs into SCAR-based anchor markers for onion linkage maps and its application to genetic analyses in other Allium species

Integration of previously developed Allium cepa linkage maps requires the availability of anchor markers for each of the eight chromosomes of shallot ( A. cepa L. common group Aggregatum). To this end, eight RAPD markers originating from our previous research were converted into SCAR markers via cloning and sequencing of RAPD amplicons and designing of 24-mer oligonucleotide primers. Of the eight pairs of SCAR primers, seven resulted in the amplification of single bands of the original RAPDs, and the remaining primer set amplified an additional band. The results of Southern hybridization using RAPD amplicons from genomic DNA of Japanese bunching onion ( Allium fistulosum L.)—shallot monosomic addition lines indicated that five SCAR markers were single shallot chromosome-specific markers and were not detected in genomic DNA of A. fistulosum. The eight SCAR primer pairs were applied to other Allium species and exhibited three types of amplification profiles, namely RAPD amplicons observed only in shallot, in shallot and Allium vavilovii, and in several Allium species. A mapping study using 65 F 2 plants generated by the selfing of one interspecific cross A. cepa × Allium roylei individual integrated the SCAR marker SAOE17 500 into chromosome 5 as expected. The results of the present study show that the eight SCAR primer sets specific to shallot can facilitate the mapping in A. cepa and can also serve as anchor points between maps of different Allium species.

Cytogenetic analysis of F1, F2 and BC1 plants from intergeneric sexual hybridization between Sinapis alba and Brassica oleracea by genomic in situ hybridization

AbstractBy intergeneric sexual hybridization between Sinapis alba and Brassica oleracea, F1, F2 and BC1 progeny plants were produced. S. alba plants (genome SS, 2n = 24) were pollinated with B. oleracea (genome CC, 2n = 18), and the fertile F1 plants were pollinated with B. oleracea to obtain BC1 plants. GISH analysis showed that 10 out of 12 F1 plants had 12 S. alba chromosomes (one full S chromosome set) and nine B. oleracea chromosomes (one C chromosome sets), representing the expected hybrids. However, two F1 plants had 12 S chromosomes and 18 C chromosomes (two C chromosome sets), indicating unexpected hybrids. A maximum of three trivalents between C and S chromosomes were identified at metaphase I of semi‐fertile F1 pollen mother cells (PMCs), which indicates homology and chromosome pairing between these two genomes. The C genome had obviously been doubled in two F2 plants from selfed semi‐fertile F1 plants. BC1 plants consisted of 18 C chromosomes and different numbers of one, five and six additional S chromosomes, respectively. Monosomic alien addition lines developed in the present study can be used for B. oleracea breeding and Sinapis alba gene mapping.

Cytogenetic characterization of Solanum lycopersicoides Dun. Alien chromosome additions in cultured tomato

Cytogenetic analysis of five Solanum lycopersicoides monosomic alien addition lines of tomato was carried out. Meiotic analysis showed that additional chromosomes caused serious abnormalities. It was demonstrated that different chromosomes of S. lycopersicoides had different effects on chromosome pairing. For instance, associations formed between chromosomes II and IV of S. lycopersicoides and chromosomes of cultured tomato were trivalents, while chromosome XI in all cells was present as a univalent. Pachytene analysis showed that chromosomes of homeologous group II paired at their long arms, and their nucleolus organizer regions were of different sizes. The use of molecular markers provided accelerated identification of the introgression of S. lyvcopersicoides genetic material.

GISH and BAC-FISH study of apomictic Beta M14

Apomixis is a means of asexual reproduction by which plants produce embryos without fertilization and meiosis, therefore the embryo is of clonal and maternal origin. Interspecific hybrids between diploid B. vulgaris (2n=2x=18) and tetraploid B. corolliflora (2n=4x=36) were established, and then back-crossed with B. vulgaris. Among their offspring, monosomic addition line M14 (2n=2x=18+1) was selected because of the apomictic phenotype. We documented chromosome transmission from B. corolliflora into M14 by using genomic in situ hybridization (GISH). Suppression of cross-hybridization by blocking DNA was not necessary, indicating that the investigated Beta genome contains sufficient species-specific DNA, thus enabling the determination of genomic composition of the hybrids. We analyzed BAC microarrays of B. corolliflora chromosome 9 by using fluorescence-specific mRNA of B. vulgaris and Beta M14. BAC clones 16-M11 and 26-L15 were detected as fluorescence-specifics of BAC DNA of Beta M14. Then both BAC clones 16-M11 and 26-L15 were in situ hybridized to M14 chromosomes. The two hybridized BAC clones were located close to the telomere region of the long arm of a single chromosome 9, and showed hemizygosity. The results of BAC microarrays showed that these developments of embryo and endosperm have conservative expression patterns, indicating that sexual reproduction and apomixis have an interrelated pathway with common regulatory components and that the induction of a modified sexual reproduction program may enable the manifestation of apomixis in Beta species. It would be sufficient for the expression of apomixes with those apomictic-specific genes on chromosome 9 of B. corolliflora.

Negative effect of chromosome 1A on dough strength shown by modification of 1D addition in durum wheat (Triticum durum)

A monosomic addition line of Aegilops tauschii chromosome 1D in Triticum durum cv. PBW114 was produced in 1990. This line was self-pollinated and maintained for several generations while following the presence of chromosome 1D carrying the gene for red glume color. Cytological analysis indicated that two of the three derivative lines had substitution of chromosome 1D for 1A and another had substitution of chromosome 1D for 1B. One of these lines carried a pair of small chromosomes in addition to the 1D chromosome. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the derived lines showed the presence of high-molecular-weight (HMW) glutenin encoded by the Glu-D1 locus. The small chromosome found in one of the lines had nearly regular pairing and transmission to daughter nuclei. Fluorescent in situ hybridization (FISH) and analysis of molecular markers indicated that the small chromosome was derived from the short arm of chromosome 1A and carried the Glu-A3 locus. Microsatellite mapping based on the deletion bin map revealed that the small chromosome had terminal deletions on both the terminal and centromeric sides. The line with the small chromosome showed improvement of the sodium dodecyl sulfate (SDS)-sedimentation value as compared to parent durum. However, the increase in SDS-sedimentation value was more significant in the substitution line of chromosome 1D for 1A without the small chromosome. These facts suggest a negative effect of the Glu-A3 locus on dough strength. The sequence of the Glu-D1 locus from these lines showed that the HMW glutenin subunits were Ae. tauschii specific 2(t) + T2, which were previously found to be associated with poor rheological properties and bread loaf volume in synthetic hexaploid wheat by other workers. Thus, the significant improvement in the SDS-sedimentation value of the substitution line of 1D for 1A suggests that the absence of the negative effect of chromosome 1A on quality is more important than the presence of Glu-D1 of Ae. tauschii.