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Modeling light and temperature effects on leaf emergence in wheat and barley.

Phenological development affects canopy structure, radiation interception, and dry matter production; most crop simulation models therefore incorporate leaf emergence rate as a basic parameter. A recent study examined leaf emergence rate as a function of temperature and daylength among wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) cultivars. Leaf emergence rate and phyllochron were modeled as functions of temperature alone, daylength alone, and the interaction between temperature and daylength. The resulting equations contained an unwieldy number of constants. Here we simplify by reducing the constants by > 70%, and show leaf emergence rate as a single response surface with temperature and daylength. In addition, we incorporate the effect of photosynthetic photon flux into the model. Generic fits for wheat and barley show cultivar differences less than +/- 5% for wheat and less than +/- 10% for barley. Barley is more sensitive to daylength changes than wheat for common environmental values of daylength, which may be related to the difference in sensitivity to daylength between spring and winter cultivars. Differences in leaf emergence rate between cultivars can be incorporated into the model by means of a single, nondimensional factor for each cultivar.

Hordeum↗

PubMed1991

Poisoning of Canada geese in Texas by parathion sprayed for control of Russian wheat aphid.

Approximately 200 Canada geese (Branta canadensis) died at a playa lake in the Texas Panhandle shortly after a winter wheat field in the basin adjacent to the lake was treated with parathion to control newly invading Russian wheat aphids (Diuraphis noxia). No evidence of infectious disease was diagnosed during necropsies of geese. Brain ChE activities were depressed up to 77% below normal. Parathion residues in GI tract contents of geese ranged from 4 to 34 ppm. Based on this evidence, parathion was responsible for the goose mortalities. Parathion applications to winter wheat will undoubtedly increase if parathion is applied for control of both Russian wheat aphids and greenbugs (Schizaphis graminum). Geese may potentially be exposed to widespread applications of parathion from fall to spring, essentially their entire wintering period.

Aerosols↗

PubMed2002

[Development of Triticum aestivum-Leymus racemosus translocation lines NAU601 and NAU618 and their test-cross analysis with double ditelosomic].

Two Triticum aestivum-Leymus racemosus disomic translocation lines were selected and identified from irradiated progenies of T. aestivum-L. racemosus addition lines Lr. 2 and Lr. 7 by somotic chromosome C-banding and fluorescence in situ hybridization by using L. racemosus genomic DNA as probe. NAU618 (MS142-3), 2n = 44, is a disomic addition translocation line with a pair of translocated chromosome consisting of 5/6 length of L. racemosus chromosome Lr. 7 (including centromere) and 1/3 distal part of wheat chromosome 1A short arm. The alien segment is about 4/5 of the length of translocated chromosome. NAU601 (MS101-4), 2n = 42, is a disomic translocation lines with a pair of translocated chromosome consisting of 4B short arm, interstitial 1/3 part of 4BL and almost Lr. 2S, the alien segment is a half of the long arm of translocated chromosome. The results of test-cross analysis with T. aestivum c. v Chinese Spring double ditelosomic combine meiotic chromosomes C-banding indicated that the translocated chromosomes in these two translocation lines were involved in chromosome 1A and 4B respectively. Their resistance to wheat scab was identified using single floret inoculation in three successive years and showed that the resistance of NAU618(MS142-3) was similar to that of resistant check variety Sumai 3, and NAU601(MS101-4) was lower than Sumai 3 but much higher than susceptible parent Chinese Spring.

Crosses, Genetic↗

PubMed2001

Candidate-gene cloning and targeted marker enrichment of wheat chromosomal regions using RNA fingerprinting-differential display.

The usefulness of the RNA fingerprinting-differential display technique in gene cloning and targeted marker enrichment in wheat is demonstrated. A small region of chromosome 5BL was targeted that contains Ph1, a chromosome-pairing regulator gene. The cultivar Chinese Spring (CS) and mutant ph1b are almost identical except for chromosome 5BL, which, in the mutant line, carries an interstitial deletion encompassing the Ph1 gene. Poly(A)+ RNA of the two lines from anthers at developmental stages ranging from pre-meiotic mitosis to anaphase II was PCR-amplified using 38 pairwise combinations of 19 primers. The 35S-labeled amplified products were size-separated on denaturing polyacrylamide-urea gels. A total of 3154 fragment bands were observed, of which 43 were present in CS but absent in the ph1b mutant. These 43 fragment bands were eluted, re-amplified, and used as probes in gel-blot DNA analyses of wheat group 5 nullisomic-tetrasomic lines and the ph1b mutant. Twenty-four of these 43 probes were single- or few-copy sequences. Eight of the 24 probes mapped to wheat group 5 and five mapped to the deletion of the ph1b mutant. Three of these five probes were further localized to the submicroscopic region containing the Ph1 gene, by using two deletion lines flanking the region. Northern-blot analysis revealed that the gene corresponding to one of these three probes expresses mainly during meiosis and is from the B genome.

Blotting, Northern↗

PubMed1976

Relationship of gliadin protein components to chromosomes in hexaploid wheats (Triticum aestivum L.).

The synthesis of the A-gliadin protein fraction derived from the endosperm of the grain of hexaploid bread wheats (Triticum aestivum L.), which is toxic in celiac disease, was associated with the alpha arm of the 6A chromosome through use of the substitution lines of "Cheyenne" chromosomes in "Chinese Spring". The association was made through the use of ditelocentric stocks of Chinese Spring. The synthesis of many other gliadin components in the gel electrophoretic patterns of these two varieties could be associated with particular chromosomes as well. All genes detected were located in the chromosomes of homoeologous groups 1 and 6. It is possible to remove some of the proteins toxic to people with celiac disease from wheat (flour) by chromosome manipulation. If the toxic factor is not widely distributed among the storage protein components, it may be possible to produce a wheat that would be safe for celiac patients to eat.

Journal Article↗

PubMed1987

Analyses of alpha/beta-type gliadin genes from diploid and hexaploid wheats.

The alpha/beta-gliadin genes isolated from both hexaploid wheat (cv. Yamhill) and the diploid A genome progenitor Triticum urartu had remarkably similar sequences and differ by only a few point mutations. Primer extension analysis indicated that the transcriptional start points for individual genes in the family cluster within a few nucleotides. Comparison of the promoter region of several alpha/beta-gliadin and B-hordein genes reveals two conserved regions at about -130 and -250 bp. DNA from the hexaploid cultivars, Cheyenne and Chinese Spring, and the diploid progenitors T. urartu and Aegilops squarrosa was analysed by Southern blotting. Restriction fragment lengths of the alpha/beta-gliadin genes varied only slightly between the various wheats, although the overall copy number varied significantly. A region between approx. -1700 and -700 bp upstream from the TATA box was highly repeated in all three wheat genomes. For the hexaploid-derived gene, over 1700 bp of sequence upstream from the TATA box was determined, revealing an additional open reading frame between approx. -1550 and -1250 bp relative to the gliadin TATA box. Northern blot analysis indicated that RNA homologous to this repeated sequence family was present only in developing seed and accumulated to a maximum at late stages of maturation.

Base Sequence↗

PubMed2004

[Effect of the 5R(5A) alien chromosome substitution on the growth habit and winter hardiness of wheat].

The growth habit, ear emergence time, and frost tolerance of wheat/rye substitution lines have been studied in cultivars Rang and Mironovskaya Krupnozernaya whose chromosome 5A is substituted with chromosome 5R of Onkhoyskaya rye. Hybrid analysis has demonstrated that the spring habit of the recipient cultivars Rang and Mironovskaya Krupnozernaya is controlled by dominant gene Vrn-A1 located in chromosome 5A. Onokhoyskaya rye has a dominant gene for the spring habit (Sp1) located in chromosome 5R. It has been found that the resultant 5R(5A) alien-substitution lines have a winter type of development and ears do not emerge during summer in plants sown in spring. The change in growth habit has been shown to be related to the absence of the rye Spl gene expression in the substitution lines. The winter hardiness of winter 5R(5A) alien-substitution lines has been studied under the environmental conditions of Novosibirsk. Testing the lines in the first winter demonstrated that their winter survival is 20-27%. The possible presence of the frost resistance gene homeoallelic to the known genes Fr1 and Fr2 of the common wheat located on chromosomes 5A and 5D, respectively, is discussed.

Adaptation, Physiological↗

PubMed1989

Overberg Research Projects: III. A preventive worm control programme for sheep in the Rûens, in the winter rainfall region of South Africa.

The mass gains and internal parasite burdens of a flock of untreated ewes and lambs were compared with those of a similar flock of treated ewes and lambs. These data, combined with climatic data, were used to compile a nematode parasite control programme for sheep in the Rûens, a sub-region of the winter rainfall area of South Africa. Teladorsagia were the most numerous parasites in the ewes and later in the season, also in the lambs. From July onwards, the development of Teladorsagia was inhibited regardless of previous exposure to worms, the number of worms present or the age of the host. Initially, Nematodirus dominated in the lambs and its development was not inhibited. Low numbers of Nematodirus, mainly inhibited, were found in the ewes. Both parasites were rife in winter but disappeared from the pasture during spring, while Trichostronglus rugatus, the dominant species of Trichostronglus, infested the lambs in spring and persisted in them throughout summer. Anthelmintic treatments had no significant effect on the live mass gains of ewes and suckling lambs while they were on lush, but heavily infested lucerne pastures for 5.5 months, but after a further 6 months on safe wheat stubble pastures, the overall mean live mass gain of the treated lambs was a significant 4.7 kg more than that of the untreated lambs. The integrated, preventive worm control programme recommended consists of pre-winter, pre-spring and pre-summer treatments with broad spectrum anthelmintics, but transfer to safe pastures after each treatment is essential.

Animals↗

PubMed2004

Dissemination of the highly expressed Bx7 glutenin subunit (Glu-B1al allele) in wheat as revealed by novel PCR markers and RP-HPLC.

Increased expression of the high molecular weight glutenin subunit (HMW-GS) Bx7 is associated with improved dough strength of wheat (Triticum aestivum L.) flour. Several cultivars and landraces of widely different genetic backgrounds from around the world have now been found to contain this so-called 'over-expressing' allelic form of the Bx7 subunit encoded by Glu-B1al. Using three methods of identification, SDS-PAGE, RP-HPLC and PCR marker analysis, as well as pedigree information, we have traced the distribution and source of this allele from a Uruguayan landrace, Americano 44D, in the mid-nineteenth century. Results are supported by knowledge of the movement of wheat lines with migrants. All cultivars possessing the Glu-B1al allele can be identified by the following attributes: (1) the elution of the By sub-unit peak before the Dx sub-unit peak by RP-HPLC, (2) high expression levels of Bx7 (>39% Mol% Bx), (3) a 43 bp insertion in the matrix-attachment region (MAR) upstream of the gene promoter relative to Bx7 and an 18 bp nucleotide duplication in the coding region of the gene. Evidence is presented indicating that these 18 and 43 bp sequence insertions are not causal for the high expression levels of Bx7 as they were also found to be present in a small number of hexaploid species, including Chinese Spring, and species expressing Glu-B1ak and Glu-B1a alleles. In addition, these sequence inserts were found in different isolates of the tetraploid wheat, T. turgidum, indicating that these insertion/deletion events occurred prior to hexaploidization.

Base Sequence↗

PubMed2005

Arabinogalactans and arabinogalactan-proteins induce embryogenesis in wheat (Triticum aestivum L.) microspore culture.

The objective of this study was to improve induction of embryogenesis in wheat microspore culture in order to obtain a high number of regenerable embryos. The arabinogalactan (AG) Larcoll and the arabinogalactan-protein (AGP) from gum arabic were tested on two spring genotypes to see if they could increase microspore viability and induce embryogenesis in the microspore culture. Adding Larcoll significantly decreased microspore mortality in both genotypes regardless of the presence or absence of ovaries in the culture. Similarly, gum arabic had a strong effect on the number of embryos produced and regenerated green plants. In fact, by using only gum arabic we were able to obtain green plants from wheat microspore cultures without the presence of ovaries. In addition to preventing a high mortality rate of the cells, our results show that the induction of embryogenesis in wheat microspore cultures is strongly affected by the use of both AG or AGP.

Culture Media↗

PubMed1993

Body and carcass composition of Angus and Charolais steers as affected by age and nutrition.

The objectives of this study were to examine the effects of a low vs moderate rate of gain during the growing phase on empty body and carcass composition during finishing of Angus and Charolais steers of two ages. Forty-eight Angus and 48 Charolais steers that were either spring-born (OLDER) or fall-born (YOUNGER) were fed two diets (alfalfa pellets [CON] or cubed grass-alfalfa hay, wheat straw, cottonseed hulls, and soybean meal [RES]) for a growing period followed by a conventional feedlot period. The feedlot period started when the YOUNGER-CON steers weighed the same as the OLDER-RES steers. At that time, an interaction of age x diet occurred in empty body fat content (P < .10), whereas breed and age x diet affected carcass fat content (P < .01). OLDER-CON steers were larger (average 378 kg empty BW) and fatter than the other, smaller groups (average 222 kg). Angus carcasses were fatter than Charolais carcasses (P < .01). At the end of the finishing phase, compensating steers (OLDER-RES) had fatter carcasses than OLDER-CON steers. Empty body fat content was affected by a breed x age x diet interaction (P < .10). Allometric regressions (Y = aXb) of fat on empty BW indicated that empty body fat accretion was greater in Angus than in Charolais and in YOUNGER than in OLDER steers. A breed x age x diet interaction (P < .10) indicated that OLDER-Angus had higher fat accretive rates than YOUNGER-Angus, whereas OLDER-CON-Charolais steers deposited fat more slowly than the remaining groups. These data suggest that steers receiving feedlot diets at light weights, whether young in age or previously restricted, accumulate fat more rapidly than do larger steers. This feeding strategy may be an advantage in late-maturing types, but moderate growth through approximately 75% of slaughter weight is recommended for early-maturing types.

Adipose Tissue↗

PubMed1989

[Is it necessary to test children having summer respiratory problems with cereal pollens?].

We tested 100 children with clinical signs that occurred in spring or summer. Prick tests were made with extracts of wild grass pollens (Dactylis, Phleum, Lolium) and with separate cereal pollens (Wheat, oats, Sweet-corn Barley and Rye). In 20 children whose test was negative for wild grass pollen, we saw no sensitization to cereals. In 80 children with grass pollenosis, Barley and Rye are the cereals that gave the most positive prick tests, whilst sweet corn is the cereal with most negative tests.

Allergens↗

PubMed2001

Genetic and physical characterization of chromosome 4DL in wheat.

The long arm of chromosome 4D in wheat (Triticum aestivum L.) has been shown in previous studies to harbor genes of agronomic importance. A major dominant gene conferring Aluminum (Al) tolerance (Alt2 in 'Chinese Spring' and AltBH in 'BH 1146'), and the Knal locus controlling the K+/Na+ discrimination in saline environments have been mapped to this chromosome arm. However, accurate information on the genetic and physical location of markers related to any of these genes is not available and would be useful for map-based cloning and marker-assisted plant breeding. In the present study, using a population of 91 recombinant inbred lines segregating for Al tolerance, we provide a more extensive genetic linkage map of the chromosome arm 4DL based on RFLP, SSR, and AFLP markers, delimiting the AltBH gene to a 5.9-cM interval between markers Xgdm125 and Xpsr914. In addition, utilizing a set of wheat deletion lines for chromosome arm 4DL, the AltBH gene was physically mapped to the distal region of the chromosome, between deletion breakpoints 0.70 and 0.86, where the kilobase/centimorgan ratio is assumed to be low, making the map-based cloning of the gene a more realistic goal. The polymorphism rates in chromosome arm 4DL for the different types of markers used were extremely low, as confirmed by the physical mapping of AFLPs. Finally, analysis of 1 Mb of contiguous sequence of Arabidopsis chromosome 5 flanking the gene homologous to the BCD1230 clone (a cosegregating marker in our population coding for a ribulose-5-phosphate-3-epimerase gene), revealed a previously identified region of stress-related and disease-resistance genes. This could explain the collinearity observed in comparative mapping studies among different species and the low level of polymorphism detected in the chromosome arm 4DL in hexaploid wheat.

Aluminum↗

PubMed2002

Identification of chromosome arms influencing expression of the HMW glutenins in wheat.

The high-molecular-weight (HMW) glutenin genes, located on the group 1L chromosome arms, are a major determinant for baking quality in wheat ( Triticum aestivum L.). In addition, the HMW glutenin genes provide a valuable model system for studying the evolution and regulation of orthologous and paralogous genes in polyploid species. The goal of this study was to identify loci that modify the expression of the HMW glutenins, and to map them to specific chromosome arms. Comparisons were made between endosperms with zero versus three (or three versus six) doses for each of the 42 chromosome arms of wheat. SDS-PAGE and scanning densitometry were used to quantify the protein expression levels of the four HMW glutenin genes in cv. Chinese Spring, for each of the dosage comparisons. Fifteen chromosome arms were found to have significant effects on Glu-B1-1, excluding the structural gene dosage effect: eight positive effects on 1AL, 2AS, 2BL, 2DS, 5DS, 6AL, 6DL, and 7AL and seven negative effects on 1BS, 1DS, 1DL, 4DL, 6BS, 6DS, and 7AS. Nineteen chromosome arms had significant effects on Glu-B1-2, excluding the structural gene dosage effect: eight positive effects on 1AL, 2AS, 2BS, 3AL, 4BL, 6DS, 7BL and 7DS and 11 negative effects on 1AS, 1BS, 1DS, 1DL, 2AL, 2BL, 3DS, 4BS, 4DL, 5BL, and 6BS. Twenty chromosome arms had significant effects on Glu-D1-1, excluding the structural gene dosage effect: 11 positive effects on 1AL, 1BL, 2BS, 2DS, 5BS, 5DS, 6AL, 6DS, 6DL, 7AL, and 7BL and nine negative effects on 1AS, 1BS, 1DS, 2BL, 4DL, 5BL, 5DL, 6BL, and 7DS. Twenty-five chromosome arms had significant effects on Glu-D1-2, excluding the structural gene dosage effect: 17 positive effects on 1BL, 2AS, 2BS, 2DS, 2DL, 3AS, 3AL, 3BS, 5AS, 5BS, 5DL, 6AL, 6DL, 7AL, 7BS, 7BL, and 7DL and eight negative effects on 1DS, 4DL, 5AL, 5BL, 6BS, 6BL, 6DS and 7DS. Of the 164 gene-chromosome arm tests performed, about 52% (85/164) showed no significant effects, and 48% (79/164) showed significant effects, excluding the structural gene dosage effects. Of the significant effects, 56% (44/79) were positive effects, and 44% (35/79) were negative effects. Comparisons of dosage effects on orthologous loci (both x-type or both y-type HMW glutenins) showed that orthologous HMW glutenin genes are largely influenced by the same regulatory systems. Less correlation was found for comparisons between paralogous genes, although considerable conservation was observed at this level as well. These observations suggest that after polyploidization, many of the duplicated orthologous regulatory loci were inactivated by mutation, thus consolidating control over the HMW glutenin genes. Possible candidates for orthologous regulatory genes were identified in maize and barley. This study represents the first comprehensive search of the wheat genome for regulators of the HMW glutenins.

Chromosome Mapping↗

PubMed2005

Allelic variation at the linked AP1 and PhyC loci in hexaploid wheat is associated but not perfectly correlated with vernalization response.

Vernalization requirement is an important trait in temperate crop plants such as wheat and must be considered when selecting varieties for cultivation under different climatic conditions. To determine the growth habit of wheat varieties, plants need to be grown under different vernalization regimes, a lengthy but necessary process for breeders involved in crossing winter with spring germplasm. If haplotypes can be associated with growth habit, then molecular marker assays that are reliable, cheap, and quick can be developed to assist in the selection of plants with the desired phenotype. We have analyzed 81 accessions that have different vernalization requirements and putative different origins of spring habit for sequence variation at the Apetala1 (AP1) locus, which underlies Vrn-1, and at the linked Phytochrome C (PhyC) locus. Good correspondence was found between the AP1 genotype and the PhyC haplotype for 77 of the 81 accessions. Two varieties displayed a recombination event between the AP1 and PhyC loci, and one variety carried a recombinant PhyC gene. In addition, one variety carried an apparent AP1 winter allele, but displayed the Vrn-A1 spring habit. The PhyC haplotype for this variety also indicated the presence of a Vrn-A1 spring allele. Our data suggest that both the AP1 promoter region and PhyC SNPs can be used as diagnostic markers for vernalization response at the vrn-A1 locus, but that neither are perfect tags.

Alleles↗

PubMed2004

High levels of genetic diversity throughout the range of the Portuguese wheat landrace 'Barbela'.

BACKGROUND AND AIMS: Landrace populations represent an important intra-crop reservoir of biodiversity and source of novel gene alleles for use in breeding programmes. Here the aim was to measure the diversity of a wheat landrace, 'Barbela', from the north of Portugal. METHODS: DNA was extracted from 59 accessions of Barbela collected across its geographical range. Diversity was measured by microsatellite length polymorphisms using 27 primer pairs amplifying 34 polymorphic microsatellite loci. KEY RESULTS: High levels of polymorphism were found, with an average polymorphism information content of 0.52; an average of 4.77 alleles (range 2-11) were present at each locus, and half of these loci showed an additional allele in the reference variety 'Chinese Spring'. CONCLUSIONS: 'Barbela' is maintained from seeds collected by farmers, but it maintains high allelic variation, and no groupings of accessions were detected when analysed by geographical region, farm or climate, indicating that the wheat landrace is a homogeneous entity. The diversity within the farmer-maintained landrace demonstrates the importance of characterization and maintenance of landrace collections before valuable genetic combinations are lost as uniform commercial crops are introduced.

Alleles↗

PubMed2002

Fertilizer management in watersheds of two Ramsar wetlands and effects on quality of inflowing water.

Two field experiments were carried out in the watersheds of two Ramsar wetland areas, Lakes Koronia and Volvi (area A) and Lakes Mikri and Megali Prespa (area B), to study the effect of application of N fertilizer on wheat yields, the quality of runoff water, and the quality of stream water. The treatments were a combination of two methods of fertilizer application (total amount in fall, and 2/3 in fall + 1/3 in spring) at three rates (0, 100, and 200 kg N/ha) with four replications. Concentrations of NH4+, NO3-, NO2-, P, and Cl- and pH were determined in all water samples. Runoff water quality was not influenced by fertilizer application in either area. Chemical parameters for water did not differ along the selected watercourses in area B, while in area A they were higher in the samples taken near Lake Koronia than in the samples taken upstream, indicating that the watercourses are polluted downstream by nonagricultural sources. The differences in wheat yields between the 100 and 200 kg N/ha application rates were not high. These results call for better fertilizer management in order to achieve better yields and to diminish the possibility to have negative effects to the environment.

Agriculture↗

PubMed2005

Molecular characterization and mapping of ALMT1, the aluminium-tolerance gene of bread wheat (Triticum aestivum L.).

The major aluminum (Al) tolerance gene in wheat ALMT1 confers. An Al-activated efflux of malate from root apices. We determined the genomic structure of the ALMT1 gene and found it consists of 6 exons interrupted by 5 introns. Sequencing a range of wheat genotypes identified 3 alleles for ALMT1, 1 of which was identical to the ALMT1 gene from an Aegilops tauschii accession. The ALMT1 gene was mapped to chromosome 4DL using 'Chinese Spring' deletion lines, and loss of ALMT1 coincided with the loss of both Al tolerance and Al-activated malate efflux. Aluminium tolerance in each of 5 different doubled-haploid populations was found to be conditioned by a single major gene. When ALMT1 was polymorphic between the parental lines, QTL and linkage analyses indicated that ALMT1 mapped to chromosome 4DL and cosegregated with Al tolerance. In 2 populations examined, Al tolerance also segregated with a greater capacity for Al-activated malate efflux. Aluminium tolerance was not associated with a particular coding allele for ALMT1, but was significantly correlated with the relative level of ALMT1 expression. These findings suggest that the Al tolerance in a diverse range of wheat genotypes is primarily conditioned by ALMT1.

Alleles↗