Lines Of Rye Research Articles

Induction of small-segment-translocation between wheat and rye chromosomes

A new approach to produce wheat-rye translocation, based on the genetic instability caused by monosomic addition of rye chromosome in wheat, is described. 1 283 plants from the selfed progenies of monosomic addition lines with single chromosome of inbred rye line R12 and complete chromosome complement of wheat cultivar Mianyang 11 were cytologically analyzed on a plant-by-plant basis by the improved C-banding technique. 63 of the plants, with 2n = 42, were found containing wheat-rye translocation or substitution, with a frequency of 4.91%. Compared with the wheat parent, other 32 plants with 2n = 42 exhibited obvious phenotypic variation, but their component of rye chromosome could not be detected using the C-banding technique.In situ hybridization with a biotin-la-beled DNA probe was used to detect rye chromatin and to determine the insertion sites of rye segments in the wheat chromosomes. In 20 out of the 32 variant wheat plants, small segments of rye chromosomes were found being inserted into different wheat chromosomes and form small-segment-translocation (SS translocation). The physical mapping of the translocated small segments of rye chromosomes indicated that alien insertion could occur in both the terminal and intermediate regions of wheat chromosomes. The technique described appeared to be an effective means to induce SS translocation. The wide application of SS translocation in the study of molecular cytogenetics and plant breeding is also discussed.

A86 Potential effects of slower than expected recruitment and proposed changes in eligibility criteria on power in a randomized controlled trial

Rye (Secale cereale L.) plants have high tolerance to Al, and become unique tools to study Al-toxicity and tolerance mechanisms. To better understand if and how Al-induced root growth inhibition is related with root histological differentiation, nutrient balances and cell cycle dynamics, tolerant (AT6) and sensitive (AS6) rye lines were exposed for 24 h to 1.1 mM Al. After that period, half of plants were transferred to medium without Al, while the other group was maintained with Al for more 48 h. AS6 plants showed evident and irreversible root growth inhibition, decreases in water content, organic matter and carbohydrate reserves. Also, roots of this line showed greater increases in Ca levels and changes in anatomy (e.g. thickness). Data revealed that AS6 plants accumulate more Al in roots and leaves, suggesting more Al translocation to the shoots. The two lines responded differently to Al exposure in what concerns endodermis differentiation and cell cycle profile. The tolerant line shows a tendency to arrest in G0/G1 phase whereas the sensitive have a tendency to arrest in S phase. These data point to an arrest of cells in specific cell cycle phases, leading to eventual Al-induced cell cycle delay. Taken all together, data show that even short-term exposure to Al leads to root anatomical modifications that in combination with the cell cycle dynamic changes, may represent a plant strategy to cope with this stress.

B-chromosomes in inbred lines of rye (Secale cereale L.)

B chromosomes from an experimental population of the Japanese JNK strain of rye, isogenic for its Bs, have been backcrossed into twelve different inbred lines. The experiment is a way of studying the effects of the Bs against a range of different homozygous A chromosome backgrounds. This publication deals with pairing effects of both the As and the Bs, and their interactions, and with pollen mitosis. At meiosis there is a genotypic component to B effects, and they do not appear to act solely through a physical disturbance within the nucleus. In pollen the Bs are always present in more than 50% of the grains regardless of their pairing behaviour during meiosis; this result fits with a ‘parasitic’ model of the activity of rye Bs.

Variation in highly repetitive DNA composition of heterochromatin in rye studied by fluorescence in situ hybridization

The molecular characterization of heterochromatin in six lines of rye has been performed using fluorescence in situ hybridization (FISH). The highly repetitive rye DNA sequences pSc 119.2, pSc74, and pSc34, and the probes pTa71 and pSc794 containing the 25S-5.8S-18S rDNA (NOR) and the 5S rDNA multigene families, respectively, were used. This allowed the individual identification of all seven rye chromosomes and most chromosome arms in all lines. All varieties showed similar but not identical patterns. A standard in situ hybridization map was constructed following the nomenclature system recommended for C-bands. All FISH sites observed appeared to correspond well with C-band locations, but not all C-banding sites coincided with hybridization sites of the repetitive DNA probes used. Quantitative and qualitative differences between different varieties were found for in situ hybridization response at corresponding sites. Variation between plants and even between homologous chromosomes of the same plant was found in open-pollinated lines. In inbred lines, the in situ pattern of the homologues was practically identical and no variation between plants was detected. The observed quantitative and qualitative differences are consistent with a corresponding variation for C-bands detected both within and between cultivars.

Physical mapping of the 5S rRNA multigene family in 6x triticale and rye: identification of a new rye locus

In situ hybridization was used to physically map the 5S rRNA multigene family in three selected lines of hexaploid triticale and five lines of diploid rye. Using this technique, evidence for a new locus on the 3RS arm of the three triticale lines was first obtained, as well as confirmation of the presence of 5S rRNA loci on wheat and rye chromosomes of homoeologous groups 1 and 5. The new locus on the 3RS arm was confirmed in two lines of rye, Secale cereale L., although it was not present in the other rye varieties studied. We propose that the new 5S rRNA locus be referred to as 5SDna-R3.

Differential expression of two β‐amylase genes of rye during seed development

The expression of two β‐amylase loci was analysed in the developing seeds of two inbred lines of rye (Secale cereale L.), one of which was a β‐amylase deficient mutant. Enzymatic activity and the contents of enzymatic protein and mRNA specific for each of an endosperm‐characteristic and ubiquitous β‐amylase were determined throughout the course of caryopsis development. Both loci were expressed in the developing normal line caryopses according to different temporal and quantitative patterns. The ubiquitous enzyme‐specific locus β‐Amy 2 was expressed earlier; both mRNA and enzymatic protein accumulated to a maximum extent at 10 to 15 days after pollination. In contrast, the highest content of mRNA for endosperm β‐amylase (encoded by the β‐Amy I locus) was found 20 days after pollination, and the corresponding enzymatic protein accumulated throughout seed development. The expression of the β‐Amy I locus was 30‐ to 40‐fold higher than that of the β‐Amy 2 locus in terms of maximum specific mRNA accumulation. The expression product of only the β‐Amy 2 locus was found in the developing mutant line caryopses. The expression pattern of this locus was similar in the developing normal and mutant line seeds in terms of the temporal accumulation of mRNA and enzymatic protein. However, an approximately 4‐fold higher level of ubiquitous β‐amylase‐specific mRNA was found in the mutant than in the normal line caryopses, and the content of ubiquitous β‐amylase protein decreased to near zero at seed maturity in the mutant line, but not in the normal line, caryopses. The enzymatic activities of both β‐amylases appeared to be regulated at the level of accumulated enzymatic protein.

Erratum: Detection of rye chromosome 2R using the polymerase chain reaction and sequence-specific DNA primers

Sequences derived from a rye gamma secalin gene were used as primers in polymerase chain reactions using DNA obtained from a series of wheat and triticale genetic stocks. A 473-bp fragment, the predicted size based on the distance between the selected primers, was found only in rye, triticales, and wheat lines carrying rye chromosome 2RS. Use of triticale lines with various wheat chromosome substitutions confirmed the chromosomal origin of the rye-specific marker. The presence of the 473-bp PCR product was always associated with the production of 75K secalins in grain samples. Thus, the primer sequences, and the clone of origin (pSC503), were both derived from the SEC-2 locus of rye chromosome 2RS.Key words: wheat (Triticum aestivum), rye (Secale cereale), chromosomal translocations, chromosomal substitutions, DNA polymerase chain reaction, sequence-specific primers.

CMS in rye: comparative RFLP and transcript analyses of mitochondria from fertile and male-sterile plants

The mitochondrial (mt) genomes of rye (Secale cereale L.) lines with "normal" and cytoplasmic male sterility (CMS) inducing "Pampa" cytoplasm were compared by detailed restriction fragment length polymorphism (RFLP) and Northern analyses. RFLP analyses using several heterologous mt genes as probes revealed considerable differences in the overall structure of the two mt genomes. With cob and atpA, the data indicate intragenic recombination and/or different copy numbers of these genes in the two cytoplasms. In spite of this heterogeneity at DNA level, the transcriptional patterns of nine out of ten mitochondrial genes analysed are unaffected. The exception is in the "Pampa" cytoplasm which contains an additional cob-homologous transcript. Since this transcript is strongly reduced in the presence of restorer genes, it might causally be correlated to the CMS phenotype.

Physical mapping of translocation breakpoints in rye by means of synaptonemal complex analysis

A physical map including 40 translocation breakpoints has been constructed in rye by means of synaptonemal complex (SC) analysis of well-paired pachytene quadrivalents. The chromosome arms involved in such translocations were previously identified either from mitotic C-banding analysis or from the meiotic configurations observed in the progenies of crosses with a rye line having multiple chromosome rearrangements. The synaptonemal complexes formed by some translocation homozygotes were also analyzed, the relative pachytene SC length of their translocated chromosomes being compared to that observed in the corresponding translocation heterozygotes. In the translocations in which the position of the breakpoint could be well defined from mitotic C-banding analysis, a good correspondence between the relative position of the point showing partner exchange in the pachytene quadrivalents and the actual location of the breakpoint was established. It is concluded that the mapping of translocation breakpoints by SC analysis of pachytene quadrivalents provides a more accurate estimate of the position of the breakpoints than that obtained from mitotic C-banding analysis, due to the lack of evenly-distributed interstitial C-bands in most rye chromosomes. The distribution of the breakpoints along the chromosomes in relation to their spontaneous or induced origin is also discussed.

A linkage map of rye

A linkage map of rye (Secale cereale L.) is presented which comprises 60 loci including RFLPs, RAPDs, isozyme, morphological and physiological markers. The genetics and linkage relationships of these markers were investigated in several inbred lines of rye. For the RFLP mapping a genomic library of PstI-digested DNA was constructed from which 50 size-selected clones were analysed. The portion of single-copy and multi-copy DNA and the frequency of polymorphic DNA was determined. The markers are unequally distributed over the seven chromosomes of rye. Many of them exhibit a distorted segregation. The main region of deviating segregation ratios could be localized near the self-incompatibility loci.

Evaluation of pre-harvest sprouting in triticale compared with wheat and rye using a line source rain gradient

Field grown triticales, wheats and ryes were subjected to an artificial rain gradient with the aim of discriminating among different genotypes on the basis of their tolerance to wetting, measured as change in falling number (FN) and alpha-amylase activity (AA). Below-canopy gravity irrigation throughout the growing cycle ensured stress-free conditions. The rain gradient was created by overhead irrigation from a central water line or line source. Plots were sown perpendicular to the line source and sampled for AA throughout the gradient and over sampling dates. The gradient was also analysed for FN 30 days post physiological maturity (PM+30). Based on change in AA over both the gradient and sampling dates and change in FN at PM+30, genotypes tolerant to wetting were identified. The factors rnost important in conferring tolerance to wetting among triticales were spike angle, thousand-grain weight and FN levels. Whilst the line source offered good discrimination among triticales on the basis of change in FN and AA, it was not effective in distinguishing between wheat and rye lines.

B-chromosomes in inbred lines of rye (Secale cereale L.)

B-chromosomes from an experimental population of the Japanese JNK strain of rye, isogenic for its Bs, have been backcrossed into twelve different inbred lines. The experiment provides a way to study the effects of the Bs against a range of homozygous A-chromosome backgrounds. This publication deals with vigour and fertility: it shows that the rye Bs fit a parasitic model, and that they interact in their effects with the A-chromosome background genotype.

Evaluating Rye Inbred Lines Per Se and in Euplasmic and Alloplasmic Crosses for Triticale Suitability

The production of primary triticales (× Triticosecale Wittmack) is laborious and the performance of the resulting amphidiploids has been mostly unsatisfactory. It is, therefore, desirable to have criteria to assess wheat and rye lines as suitable triticale parents. This study investigated the genotypic variation and covariation caused by 15 rye (Secale cereale L.) inbred lines per se and as parents of testcrosses, euplasmic and alloplasmic (Triticum turgidum L. and T. aestivum L. cytoplasm) rye F2 populations, and hexaploid and octoploid primary triticales in order to assess rye lines for their “triticale suitability.” All materials were evaluated in drilled yield trials at two locations and in 2 yr. Genotypic variances between rye lines were generally greater than those due to rye parents in testcrosses, F2 populations, and primary triticales. The variances of hexaploid and octoploid triticales, when significant, were of similar magnitude. Correlations between the two ploidy levels were moderate to high for all traits. Relationships between triticales and corresponding rye materials were inconsistent and frequently negative for yield and yield component traits. The prediction of triticale performance based on rye line and cross performance was possible for days to heading, but was without prospect for the yield complex. Rye lines which proved favorable as parents of hexaploid triticales were superior at the octoploid level as well.

Variability for grain extract viscosity in inbred lines and an F2 population of rye (Secale cereale L.)

Variability in grain viscosity attributed to pentosans was investigated in 28 inbred lines of spring rye and in an F2 population derived by crossing lines with high and low viscosity. Variability in viscosity was not related to the level of total soluble pentosans but was highly correlated (r2 = 0.83) with the level of high molecular weight (> 500 KDa) soluble pentosans. Variability in the level of high molecular weight pentosans did not appear to be related to seed characteristics such as colour, plumpness, or starch content. It appears that there is variability for viscosity within rye germplasm and thus it should be possible to breed ryes which produce grain with either high or low viscosity. Rye with low grain viscosity may be preferred for animal feed. Key words: Rye, Secale cereale, pentosans, feed value

Maternal induced haploids in rye (Secale cereale L.)

An inbred line of rye named P8 was found to possess haploid plants in their diploid stock. Phenomenon of spontaneous haploidy was examined in this line. Fifty families derived from this inbred line were screened to determine their ploidy level by mitotic chromosome count taking root tips. Seven families were found to contain haploid plants. Among these seven families, plants from two families which were diploid were crossed reciprocally with the standard out breeding cultivar Conrah. As all of the tested plants of P8 were found ‘aa’ allele for 6-Phosphogluconic dehydrogenase (6-PGD) isozyme, therefore, only those Conrah plants which have ‘bb’ alleles for the same isozyme were used in crossing programme. F1 seedlings were screened with the same isozyme marker and out of 1741 F1 seedlings tested, 51 were found to be non-hybrid phenotype for 6-PGD enzyme. Among these, only five plants were found haploid and the rest were diploid. Haploid plants were obtained only from those crosses where P8 was female which indicates that haploids in this line was maternally induced.

Test Systems for Evaluating Quantitative Resistance Against Fusarium Foot Rot in Inbred Lines of Winter Rye

AbstractThe first results of three test systems for evaluating the susceptibility of rye inbred lines to foot rot caused by Fusarium culmorum and F. graminearum are presented. The test systems were specifically designed for greenhouse, foliar tent and field experiments. The inbred lines, some of which are being used in commercial hybrids, showed significant variation for resistance. Significant interactions occurred between genotypes and test systems, and within the test systems between genotypes and years or growth stages. A significant correlation existed between susceptibility in the greenhouse and in the field (r = 0.84, P = 0.05), when inoculation in the greenhouse took place at the jointing stage (EC 31). In earlier growth stages, however, this correlation was not significant. In both greenhouse and foliar tent experiments, susceptibility to F. culmorum and F. graminearum was strongly correlated (r = 0.71, 0.87, resp., P = 0.01). In the field, F. culmorum alone was used for artificial inoculation. Genotypic variance and repeatability in the field were highest after inoculation in spring with conidia suspensions. It is concluded that, in inbreeding generations with limited seed quantities, the greenhouse and the foliar‐tent test systems offer good possibilities of indirectly improving foot‐rot resistance in rye.

Influence of selected wheat and rye genotypes on the direct synthesis of hexaploid triticale

In the synthesis of primary hexaploid triticale, a cross-incompatibility barrier exists when tetraploid wheat (4X) is crossed with diploid (2X) rye. Fertilization may occur, however, abnormal endosperm development usually leads to premature embryo death. Four selected tetraploid wheat lines were crossed as females with seven open-pollinated rye lines and the resulting embryos were rescued in vitro 13–16 days after pollination. The wheat genotypes showed a major influence on crossability (seed set), embryo development and plant recovery. The highest efficiency of amphihaploid plant recovery (18.3 plants per 100 pollinated florets) was obtained from one 4X wheat line originally selected from the cross T. carthlicum × T. dicoccoides. Some of the 3X amphihaploid plants (ABR) derived from two wheat lines showed relatively high level of partial fertility presumably as a result of meiotic restitution. Correlation analysis showed that crossability (seed set), normal hybrid embryo development in vivo and embryo culturability were independent of each other.

Characterization of cDNA clones for rye endosperm β-amylase and analysis of β-amylase deficiency in rye mutant lines

In order to characterize a β-amylase deficiency in the endosperm of mutant rye lines, homologous cDNA probes were prepared. A rye cDNA library was constructed from a normal line and screened with a barley β-amylase probe. Three partial cDNA clones specific for endosperm β-amylase in rye were isolated and characterized. The largest of these clones was used to investigate the expression of endosperm β-amylase in mutant and normal lines by Northern hybridization. These experiments, as well as in vitro translation experiments, demonstrate the absence of endosperm β-amylase mRNA in mutant lines. Sequencing of three different cDNA clones revealed a single nucleotide difference, which suggests that two genes encoding endosperm β-amylase genes might exist in rye. From Southern blots we anticipate that these two genes are tightly linked. Results of these experiments and previous data indicating that the mutation was located within the β-amylase locus on chromosome 5 are consistent with the hypothesis that the mutation results from a deletion simultaneously affecting the two genes. However, due to extensive polymorphism within normal lines used as control, additional experiments will be required to further substantiate this conclusion. The deduced amino acid sequence reveals the occurrence of three short glycine-rich repeats containing 11 or 12 residues close to the carboxyl terminus of the protein. A comparison of the nucleotide sequence between rye and previously described barley cDNA clones revealed ca. 90% homology at the amino acid level, except in this C-terminal repeated part, where it drops to 45%.

A New Greenbug Virulent to E‐Biotype Resistant Sorghum

Sorghum [Sorghum bicolor (L.) Moench] hybrids resistant to Biotype E greenbug [Schizaphis graminum (Rondani)] had more damage than expected when heavily infested with greenbugs daring August, 1990. Greenbugs isolated from severely damaged plants of resistant sorghum in Stevens County, Kansas, were tested for virulence to Biotype‐E resistant cultivars and lines of sorghum, wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), oat (Arena sativa L.), and rye (Secale cereale L.). Greenhouse tests involving seedling plants indicated that the sorghum fines with resistance to Biotype E were susceptible to the greenbug isolate from Stevens County. The only sorghum germplasm fine that appeared resistant to this isolate was PI 266965. Small grains with resistance to Biotype‐E greenbug retained their resistance to the new isolate. Because no previously designated biotypes have shown virulence to Biotype‐E resistant sorghum, the greenbug isolate from Stevens County was designated Biotype I. If Biotype I replaces Biotype E in the field, in a similar fashion to the replacement of Biotype C by Biotype E during the 1980s, greenbug resistance now available in sorghum will be compromised and sorghum production will be vulnerable to the new biotype.

Gene Localization of Aspartate Aminotransferase and Endopeptidase Isozymes in Wheat and Rye Using Developmental and Organ-Specific Patterns

Wheat, rye and wheat-rye addition lines have been investigated regarding their developmental and organ-specific isozyme patterns of aspartate amino-transferase (AAT) and endopeptidase (EP). Evidence is given, that development-specific isozymes of AAT are encoded by chromosomes 3R and 4R of ‘Imperial’ rye which can be used as biochemical markers up to leaf age of 14 days. Organ-specific increase of intensity of bands for AAT in stems could be assigned to genes or alleles of chromosome 3A of ‘Chinese Spring’ wheat. For EP new markers were localized on chromosomes 4R and 6R of ‘Imperial’ rye showing variability. Utilization of these markers is possible at all developmental stages of the leaves. Mechanisms of gene regulation are discussed.