ARS | Publication request: A major QTL is associated with resistance to curly top virus in common bean (Phaseolus vulgaris) landrace G122

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: April 24, 2008
Publication Date: June 1, 2008
Citation: Larsen, R.C., Miklas, P.N., Kurowski, C. 2008. A major QTL is associated with resistance to curly top virus in common bean (Phaseolus vulgaris) landrace G122. Phytopathology. 98:S87.

Technical Abstract: Curly top virus (CTV) is a devastating disease of common bean in the Western U.S. Genetic resistance provides effective control but can be difficult to discern in early generations. Two populations of F5:7 RILs were derived from separate F1 seeds from a cross between the G122 landrace from India known as ‘Jatu Rong’ (CTV-resistant) and Taylor Horticultural (CTV-susceptible). The A and B populations comprising 98 individuals in total were evaluated for reaction to CTV in two field experiments over two years, and were screened for potential markers linked to resistance using a population of RAPD primers. Five dominant RAPD markers derived from G122 and completely linked with each other were associated with a major effect QTL that exhibited stable expression across years and populations. The phenotypic variation explained by the QTL in Population A (43.8%) was greater than in Population B (21.9%). Three additional linked RAPD markers detected a QTL with minor effect but in Population A only. Two of the three markers were polymorphic in the common bean BAT/JALO core mapping population enabling integration of the QTL to linkage group B6. G122 appears to possess resistance independent of the Bct-1 gene conferring resistance to CTV as determined by allelism tests. These findings combined with location of the major QTL on B6, indicate that G122 possesses novel resistance to CTV.