5 results on '"Dhaliwal, Harcharan S."'
Search Results
2. Fertility and Morphology of the Synthetic Amphiploids and the Origin of Tetraploid Wheats
- Author
-
Dhaliwal, Harcharan S.
- Published
- 1976
3. DNA repair and crossing over favor similar chromosome regions as discovered in radiation hybrid of Triticum.
- Author
-
Kumar, Ajay, Bassi, Filippo M., Paux, Etienne, Al-Azzam, Omar, Michalak de Jimenez, Monika, Denton, Anne M., Yong Q. Gu, Huttner, Eric, Kilian, Andrzej, Kumar, Sachin, Goyal, Aakash, Iqbal, Muhammad J., Tiwari, Vijay K., Dogramaci, Munevver, Balyan, Harindra S., Dhaliwal, Harcharan S., Gupta, Pushpendra K., Randhawa, Gursharn S., Feuillet, Catherine, and Pawlowski, Wojciech P.
- Subjects
DNA ,CHROMOSOMES ,WHEAT ,GENOMES ,SOMATIC cells ,WHEAT farming - Abstract
Background: The uneven distribution of recombination across the length of chromosomes results in inaccurate estimates of genetic to physical distances. In wheat (Triticum aestivum L.) chromosome 3B, it has been estimated that 90% of the cross over events occur in distal sub-telomeric regions representing 40% of the chromosome. Radiation hybrid (RH) mapping which does not rely on recombination is a strategy to map genomes and has been widely employed in animal species and more recently in some plants. RH maps have been proposed to provide i) higher and ii) more uniform resolution than genetic maps, and iii) to be independent of the distribution patterns observed for meiotic recombination. An in vivo RH panel was generated for mapping chromosome 3B of wheat in an attempt to provide a complete scaffold for this ~1 Gb segment of the genome and compare the resolution to previous genetic maps. Results: A high density RH map with 541 marker loci anchored to chromosome 3B spanning a total distance of 1871.9 cR was generated. Detailed comparisons with a genetic map of similar quality confirmed that i) the overall resolution of the RH map was 10.5 fold higher and ii) six fold more uniform. A significant interaction (r = 0.879 at p = 0.01) was observed between the DNA repair mechanism and the distribution of crossing-over events. This observation could be explained by accepting the possibility that the DNA repair mechanism in somatic cells is affected by the chromatin state in a way similar to the effect that chromatin state has on recombination frequencies in gametic cells. Conclusions: The RH data presented here support for the first time in vivo the hypothesis of non-casual interaction between recombination hot-spots and DNA repair. Further, two major hypotheses are presented on how chromatin compactness could affect the DNA repair mechanism. Since the initial RH application 37 years ago, we were able to show for the first time that the iii) third hypothesis of RH mapping might not be entirely correct. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
4. Random chromosome elimination in synthetic Triticum-Aegilops amphiploids leads to development of a stable partial amphiploid with high grain micro- and macronutrient content and powdery mildew resistance.
- Author
-
Tiwari, Vijay K., Rawat, Nidhi, Neelam, Kumari, Kumar, Sundip, Randhawa, Gursharn S., and Dhaliwal, Harcharan S.
- Subjects
CHROMOSOMES ,WHEATGRASSES ,AEGILOPS ,PLANT nutrients ,MILDEW ,CROP evolution ,GENOMES - Abstract
Synthetic amphiploids are the immortal sources for studies on crop evolution, genome dissection, and introgression of useful variability from related species. Cytological analysis of synthetic decaploid wheat (Triticum aestivum L.) - Aegilops kotschyi Boiss. amphiploids (AABBDDU
k Uk Sk Sk ) showed some univalents from the C1 generation onward followed by chromosome elimination. Most of the univalents came to metaphase I plate after the reductional division of paired chromosomes and underwent equational division leading to their elimination through laggards and micronuclei. Substantial variation in the chromosome number of pollen mother cells from different tillers, spikelets, and anthers of some plants also indicated somatic chromosome elimination. Genomic in situ hybridization, fluorescence in situ hybridization, and simple sequence repeat markers analysis of two amphiploids with reduced chromosomes indicated random chromosome elimination of various genomes with higher sensitivity of D followed by the Sk and Uk genomes to elimination, whereas 1D chromosome was preferentially eliminated in both the amphiploids investigated. One of the partial amphiploids, C4 T. aestivum 'Chinese Spring' - Ae. kotschyi 396 (2n = 58), with 34 T. aestivum, 14 Uk , and 10 Sk had stable meiosis and high fertility. The partial amphiploids with white glumes, bold seeds, and tough rachis with high grain macro- and micronutrients and resistance to powdery mildew could be used for T. aestivum biofortification and transfer of powdery mildew resistance. Les amphiploïdes synthétiques constituent des ressources immortelles pour des études portant sur l'évolution des cultures, la dissection des génomes et l'introgression de variabilité utile provenant d'espèces apparentées. Une analyse cytogénétique d'amphiploïdes décaploïdes (Triticum aestivum L.) - Aegilops kotschyi Boiss. (AABBDDUk Uk Sk Sk ) a permis d'observer des univalents à compter de la génération C1 suivie d'élimination chromosomique. La plupart des univalents ont atteint la plaque de la métaphase I après la division réductionnelle des chromosomes appariés et ont subi la division équationnelle qui a mené à leur élimination sous forme de chromosomes retardataires ou de micronoyaux. Une variation substantielle du nombre de chromosomes observés chez les microsporocytes provenant de différents épis, épillets et anthères chez certaines plantes suggère qu'il se produirait également de l'élimination chromosomique au niveau somatique. Des analyses GISH, FISH et de marqueurs SSR sur deux amphiploïdes avec un nombre réduit de chromosomes a indiqué que l'élimination chromosomique était aléatoire au sein des différents génomes. Globalement, le génome D, suivi des génomes Sk et Uk , était le plus souvent sujet à élimination et le chromosome 1D avait été préférentiellement perdu chez les deux amphiploïdes examinés. Un des amphiploïdes partiels de génération C4 , 'Chinese Spring' - Ae. kotschyi 396 (2n = 58), comptait 34 chromosomes du T. aestivum, 14 du génome Uk et 10 du génome Sk et il présentait une méiose stable ainsi qu'une fécondité élevée. Les amphiploïdes partiels à glumes blanches, gros grains, rachis résistant, forte teneur en micro- et macronutriments ainsi que résistants à l'oïdium pourraient s'avérer utiles pour l'amélioration de la valeur nutritive du T. aestivum et le transfert de résistance à l'oïdium. [ABSTRACT FROM AUTHOR]- Published
- 2010
5. Molecular mapping of cereal cyst nematode resistance in Triticum monococcum L. and its transfer to the genetic background of cultivated wheat.
- Author
-
Singh, Kuldeep, Chhuneja, Parveen, Singh, Inderjit, Sharma, S. K., Garg, Tosh, Garg, Monika, Keller, Beat, and Dhaliwal, Harcharan S.
- Subjects
HETERODERA avenae ,WHEAT ,GENOMES ,HETERODERIDAE ,CULTIVARS - Abstract
Triticum monococcum, the diploid A genome species, harbours enormous variability for resistance to biotic stresses. A spring type T. monococcum acc. 14087 was found to be resistant to Heterodera avenae (cereal cyst nematode, CCN). A recombinant inbred line population (RIL) developed by crossing this accession with a CCN susceptible T. boeoticum acc. 5088 was used for studying the inheritance and map location of the CCN resistance. Based on composite interval mapping two QTL, one each on chromosome 1AS and 2AS, were detected. The QTL on 1A, designated as Qcre.pau- 1A, appeared to be a major gene with 26% contribution to the overall phenotypic variance whereas the QTL on 2A designated as Qcre.pau- 2A contributed 13% to total phenotypic variation. Qcre.pau- 1A is novel, being the only CCN resistance gene mapped in any 'A' genome species and none of the other known genes have been mapped on chromosome 1A. The QTL Qcre.pau- 2A might be allelic to Cre5, a CCN resistance gene transferred from Ae. ventricosa and mapped on 2AS. The Qcre.pau- 1A was transferred to cultivated wheat using T. durum cv. PBW114 as the bridging species. Selected CCN resistant F lines showed introgression for the molecular markers identified to be linked with CCN resistance locus Qcre.pau-1A. Thus, this gene alone could impart complete resistance against CCN. These introgression lines can be used for marker-assisted transfer of Qcre.pau- 1A to elite wheat cultivars. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.