Inheritance of Avirulence in Sclerospora graminicola(Schroet) and Resistance in Pearl Millet to the Pathogen

Chandramani Raj, . (2017) Inheritance of Avirulence in Sclerospora graminicola(Schroet) and Resistance in Pearl Millet to the Pathogen. PHD thesis, Professor Jayashankar Telangana State Agricultural University.

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Supervisors NameSupervisors ID
Pushpavathi, BPJTSAU (Hyderabad)
Sharma, RICRISAT (Patancheru)
Sokka Reddy, SAgrl Polytech (Siddipet)
Radhika, KAPGC LAM (Guntur)


Studies on development of simple sequence repeat markers and its validation, inheritance and molecular mapping of avirulence and inheritance and allelic study of resistance genes in pearl millet to the isolates of S. graminicola were undertaken at International Crops Research Institute for Semi-Arid Tropics (ICRISAT), Patancheru, Telangana, India. A total of 14481 sequences spanning 215561828 bp were screened using a microsatellite search tool, MISA, that identified 7453 SSRs from 3912 SSR containing sequences, of which 235 (3.3%) SSRs were of compound type and remaining 7218 (96.7%) were of perfect type. The overall relative abundance and density of SSRs in whole genome were 34.57 /Mb and 459.67 bp/Mb, respectively. A total of 2702 Simple sequence repeat primers were developed. Out of 2702 markers, 106 were custom synthesized and screened for diversity analysis on 60 isolates of S. graminicola. The gel electrophoresis result showed 22 scorable polymorphic markers. Allele frequencies i.e 57 alleles with an average of 2.59 alleles per locus were detected. The frequency of major alleles (MAF) per locus was 0.47-0.94, with an average of 0.72. In addition, the HO values were 0.00-0.76 with an average of 0.26, and HE values were 0.12- 0.62 with an average of 0.39. The polymorphic index content values were 0.11- 0.60, with an average of 0.33. The PCR product sizes were ranged from 110-320 bp. Analysis of molecular variance revealed 56.21% of the variance over 22 SSRs loci due to the differences among the isolates within states, 35.28 % due to within isolates and 8.51% was due to differences among the states. Dendrogram analysis revealed five major clusters across all isolates. Genetic analysis of 60 S. graminicola isolates at high delta K value provided evidence for the presence of two genetically distinct population structures with six admixtures. However, unstable graph of delta K verses K, suggested that there could be more differentiation of S. graminicola populations. Besides, S. graminicola primer pairs also amplified the fragments from other oomycetes P. sorghi (67.9%) and Phytophthora species (52.7%).

Item Type: Thesis (PHD)
Divisions: RP-Dryland Cereals
Uncontrolled Keywords: Inheritance of Avirulence, Pearl Millet, Pathogen, Molecular mapping
Subjects: Mandate crops > Millets > Pearl Millet
Depositing User: Mr T L Gautham
Date Deposited: 31 Jul 2017 10:14
Last Modified: 31 Jul 2017 10:15
Acknowledgement: UNSPECIFIED
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