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Author: Gurpreet Kaur × End date: 2016 × Start date: 2000 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    CHARACTERIZATION OF Ustilago segetum (Pers.) Roussel tritici Jensen CAUSING LOOSE SMUT OF WHEAT
    (Punjab Agricultural University, Ludhiana, 2010) Gurpreet Kaur
    Thirty five isolates of the Ustilago segetum (Pers.) Roussel tritici Jensen were characterized on the basis of pathogenicity using Nielsen’s Canadian differential set and other cultivated wheat varieties. The isolates could fall in 6 and 23 categories on the individual basis of their reaction on Canadian differentials and cultivated wheat varieties, respectively. However, 35 isolates could fall into 29 groups on the basis of their reaction collectively on Canadian differential set and cultivated wheat varieties. Grouping of races in most of the cases could not be attributed to the area from where they were collected and also the type of wheat from which initially collected. Only some of the isolates, LS11, LS13, LS16, LS18, LS32 and LS35 collected from Triticum aestivum from Himachal Pradesh, Uttar Pradesh, Dhaulakuan, Rajasthan, Jalandhar and Ludhiana (from Triticosecale) fell in different individual groups indicating geographical diversity in the pathogen. Random Amplified Polymorphic DNA (RAPD) and Inter Simple Sequence Repeats (ISSR) profiling were evaluated for assessing the extent of genetic variation among the isolates of Ustilago segetum (Pers.) Roussel tritici Jensen which causes loose smut disease of wheat. Eight random decamer primers and eight ISSR primers were used to characterize twenty four isolates of the pathogen. These isolates were collected from wheat cultivars grown at various locations of North-Western India (Punjab, Haryana, U.P. and Rajasthan). The RAPD and ISSR primers generated a total of 206 scorable bands collectively. All the isolates could be precisely differentiated from each other employing these primers and initially grouped into two distinct clusters. The molecular classification did not correspond with the geographical distribution, host origin of the isolates and groups categorized based on pathogenicity test. ISSR profiling was found superior to RAPD and can be effectively utilized for further characterization of the loose smut pathogen.