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20111
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Subject: Molecular Biology and Biotechnology × Author: Admas Berhanu × Start date: 2010 × Type: Thesis ×
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    ThesisItemOpen Access
    Molecular characterization of stripe rust resistance in wheat (Triticum aestivum L.) using DNA markers
    (CCSHAU, 2011) Admas Berhanu; Boora, Khazan Singh
    Triticum aestivum L., commonly called bread wheat, is the most common staple crop throughout the world. India is the second largest producer, next to china. Wheat is highly affected by rust diseases. Despite the natural resistance of wheat varieties to most stripe rust races, the highly variable nature of the pathogen and their time to time arise as a new strains put a major threat in wheat production. Hence, it becomes a major point of breeding interest in most part of the world. The present study was undertaken to study SSR polymorphism among 26 wheat genotypes using PCR. The 26 genotypes consisted of equal number of resistant and susceptible genotypes. Using 40 SSR primers, a total of 140 clear and reproducible bands were observed. For the genotypes studied, up to 9 bands (WMC 11) were produced with an average of 3.5 bands per primer. The size of amplified bands ranged from 100- 1517 bp. The similarity coefficients between different genotypes ranged from 0.46 to 0.88 with an average similarity value of 0.66. At an arbitrary cut-off at 27 per cent similarity level on a dendrogram, the wheat genotypes were categorized into two major clusters. PBW 590 and WH 896 were found to be genetically most divergent, while genotype Bijiga Yellow and WL 711 were least divergent. One unique band was selected for identification of resistant varieties for stripe rust. The size of unique band was around 400 bp. This marker WMC 206 has been found to have a tight linkage with resistant gene and present on chromosome 4D. Similar studies on gene identification by different researchers have revealed that chromosome 4D is a host for Yr 28 and Yr 32 genes, which are resistant to yellow rust. The unique band can be developed into Sequence Characterized Amplified Region (SCAR) marker after cloning and sequencing. The developed SCAR can be used for identification of yellow rust resistant genotypes from the susceptible ones. The present study successfully distinguishes yellow rust resistant genotypes from the susceptible ones using SSR Markers. The present study is of special value as it can play a key role in the introgression of a yellow rust resistant gene to the breeding programs.