Identification of Simple Sequence Repeat Markers Linked to Sudden Death Syndrome Resistance in Soybean

Jirawat Sanitchon,^a Apichart Vanavichit,^a Sontichai Chanprame,^a Theerayut Toojinda,^bKanokporn Triwitayakorn,^c Victor N. Njiti^d and Peerasak Srinives^a,*

ABSTRACT: Sudden Death Syndrome (SDS) caused by the soil borne fungus Fusarium solani is a major soybean disease. Resistance to this fungus is controlled by quantitative trait loci (QTLs). This study was aimed at identifying simple sequence repeat (SSR) markers linked to the QTLs conditioning SDS resistance. A mapping population was constructed by crossing the resistant soybean line GC87018-12-2B-1 with the susceptible line GC89045-13-1. One hundred and four recombinant inbred lines (RILS) were obtained via the single seed descent technique. Fifteen-linkage groups were constructed from data derived from 106 SSR markers. Inoculation was accomplished by the infested soil technique in the greenhouse conditions and phenotypic data were recorded. Broad-sense heritability of disease severity was 56% of the total variation. A QTL with LOD score of 2.53 was identified to locate on linkage group J as a cluster of four SSR markers. This QTL was previously unidentified for conferring resistance to the SDS.

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a Department of Agronomy, Kasetsart University, Kamphaeng Saen, Nakhon Pathom 73140, Thailand.
b National Center for Genetic Engineering and Biotechnology, Klong Luang, Pathum Thani 12120, Thailand.
c Institute of Molecular Biology and Genetics, Mahidol University, Salaya, Nakhon Pathom 73170,Thailand.
d Department of Plant, Soil and General Agriculture, Southern Illinois University, Carbondale, IL 62901- 4415, USA.

* Corresponding author, E-mail: agrpss@ku.ac.th

Received 5 Aug 2003, Accepted 25 Feb 2004