DUS characterization of bread wheat (Triticum aestivum L. em. Thell.) genotypes by morphological and molecular markers
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Date
2012-08
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The present study was carried out on 28 wheat genotypes with the objectives: (i) To provide a detailed description of morphological DUS descriptors for wheat varieties over two years as per the DUS guidelines of PPV & FR Authority. (ii) To determine the relative extent of distinctiveness, uniformity and stability of morphological DUS descriptors. (iii) Characterization of the varieties by molecular markers to supplement the morphological DUS descriptors. The field experiments were conducted in the Rabi seasons 2009-10 and 2010-11 at N. E. Borlaug Crop Research Center and Wheat Grain Quality Laboratory, at G. B. Pant University and Agriculture and Technology, Pantnagar. Among the 30 visually assessed DUS descriptors, each 4 were monomorphic and dimorphic and the rest 22 were polymorphic. Out of the 8 measurable characteristics, each 2 were monomorphic and dimorphic and the rest 8 were polymorphic. No intra varietal variation was observed for any of the visual characters in two consecutive years in different wheat genotypes confined the uniformity and stability of genotypes. COYD analysis was made on 8 measurable DUS descriptors of wheat. COYD analysis was complemented with Modified Joint Regression Analysis (MJRA). The slope of the MJRA curves in both the years and regression coefficient indicated that all the considered characters were not completely independent and they are interacting with each other as well as with environment. COYU analysis revealed that all the genotypes were more or less uniform for measurable characters. However seven genotypes crossed the acceptable limits, as the standard deviation for different characters was not yet acceptable after two yeas with the probability of 5%. PCV and GCV showed differences in their magnitude which indicates less stability of these characters. On the basis of eight grouping characteristics nine genotypes were distinguished but all genotypes were not discriminated. Thus to supplement the morphological descriptors, molecular marker analysis was conducted using SSR markers. UPGMA cluster analysis distinguished those genotypes which were not discriminated by the morphological DUS descriptors. The present investigation revealed that all twenty eight genotypes were distinguished with help of molecular and morphological markers. It is concluded that molecular markers may be used as additional descriptors for establishing distinctiveness of wheat genotypes. According to PPV & FR Act 2001, for plant variety protection varietal DUS description is essential. Thus the varieties satisfying the DUS criteria can be registered with PPV & FR authority.
Description
Thesis-PhD
Keywords
characterization, wheats, Triticum aestivum, genotypes, plant morphology, molecular markers, stability, regression analysis, DUS