Jaganathan, D (2016) Fine mapping of the “QTL-hotspot” region for drought tolerance in Chickpea (Cicer arietinum L.). PHD thesis, Osmania University,Hyderabad.
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Supervisors
| Supervisors Name | Supervisors ID |
|---|---|
| Varshney, R K | ICRISAT(Patancheru) |
| Kavi Kishor, P B | Department of Genetics, Osmania University, Hyderabad |
Abstract
Chickpea (Cicer arietinum L.) is the third most important grain legume cultivated in the arid and semi-arid regions of the world. Drought is one of the major constraints leading up to 50% production losses in chickpea. In order to understand the basics of drought tolerance, two recombinant inbred line (RIL) mapping populations (ICC 4958 × ICC 1882 and ICC 283 × ICC 8261) segregating for root traits were developed and a promising “QTL-hotspot” region was reported on these populations. With an objective to fine map this region, two approaches were adopted, i) genotyping-by sequencing (GBS) and ii) skim sequencing. GBS approach enabled identification of 828 single nucleotide polymorphism (SNP) markers. A high-density genetic map was developed, comprising 1,007 marker loci including 49 SNP markers in the “QTL-hotspot” region and spanning a distance of 727.29 cM. QTL analysis using the extended genetic map along with precise phenotyping data generated earlier, re-estimated the “QTL-hotspot” from 29 cM to 14 cM. In addition, these 49 SNPs were converted into cleaved amplified polymorphic sequence (CAPS)/derived CAPS (dCAPS) markers which can be used in marker assisted breeding. An ultra-high-density bin map was developed using 53,223 SNPs obtained through skim sequencing approach and its analysis with the phenotyping data, split the “QTL-hotspot” region into two sub-regions namely “QTL-hotspot_a” of 139.22 kb with 15 genes and “QTL-hotspot_b” of 153.36 kb with 11 genes. To validate and find more recombination in these regions, a large mapping population was developed. Flanking SNP markers of the two regions were converted to KASPar assays and screened on 1,911 F2 lines. Progeny testing on F2:3 lines revealed the role of “QTL-hotspot_a” in controlling 100-SDW. A total of 15 candidate genes were reported in this region. In summary, the refined region will help in precise introgression of the “QTL-hotspot” in breeding program for yield improvement under drought conditions and the reported genes can be used for further cloning studies to dissect the molecular basis of drought tolerance in chickpea.
| Item Type: | Thesis (PHD) |
|---|---|
| Divisions: | RP-Grain Legumes |
| CRP: | CGIAR Research Program on Grain Legumes |
| Uncontrolled Keywords: | Chickpea, Drought, Production,Tolerance, Phenotyping |
| Subjects: | Mandate crops > Chickpea |
| Depositing User: | Mr T L Gautham |
| Date Deposited: | 14 Oct 2016 09:45 |
| Last Modified: | 14 Oct 2016 09:45 |
| URI: | http://oar.icrisat.org/id/eprint/9724 |
| Acknowledgement: | UNSPECIFIED |
| Links: | |
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