Document Type

Thesis - University Access Only

Award Date

2006

Degree Name

Master of Science (MS)

Department / School

Agronomy

Abstract

The use of host plant resistance is a major component for managing stem rust caused by Puccinia graminis f. sp. tritici, in wheat (Triticum aestivum L.). In this study, a segregating population from a cross between 2137 and CR L-Sr35 was made to develop a molecular marker for the stem rust resistant gene Sr 35. Ninety-eight F2 plants were inoculated with a stem rust isolate of race QTH. Infection type and severity were evaluated 10 days after inoculation. Twenty-one microsatellite primer pairs developed previously from the long arm of chromosome 3A were used to determine polymorphism among parental lines and the F2 population. Chi square analysis indicated that resistance to stem rust was conferred by a dominant gene (J:=l.01, P=0.48). Only four primers (Xgwm155, Xgwm391, Xgwrn497 and Xfca2076) revealed polymorphism and they were used for linkage analysis. Primer pair Xgwm391 revealed a polymorphic fragment of 200 bp found only in the susceptible bulk and parent 2137. In contrast, primer pair Xcfa2076 amplified polymorphic fragments of 210 bp in the resistant bulk and CR L-Sr35 and 200 hp in the susceptible bulk and 2137. Chi square analysis revealed that the Xcfa2076 marker was associated with the Sr 35 resistance gene and no significant deviation from the expected ratio was observed (i=0.78; P=0.4). The microsatellite marker Xfca2076 can be exploited for selecting Sr35 in wheat cultivars using marker assisted selection and combining this gene with other resistance genes, such as Sr 2, Sr24 and Sr 31, which are considered among the primary sources of resistance in most of the Northern Plains wheat varieties.

Library of Congress Subject Headings

Wheat -- Disease and pest resistance -- Genetic aspects

Puccinia graminis

Wheat rusts

Microsatellites (Genetics)

Genetic markers

Format

application/pdf

Number of Pages

50

Publisher

South Dakota State University

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