IDENTIFYING RANDOMLY AMPLIFIED POLYMORPHIC DNA (RAPD) MARKERS LINKED TO MAJOR GENES FOR COMMON BACTERIAL-BLIGHT RESISTANCE IN TEPARY BEAN

Common bacterial blight (CBB), incited by Xanthomonas campestris pv. p haseoli (Xcp), is an important seed-transmitted disease of common bean (Phaseolus vulgaris L.), Tepary bean (Phaseolus acutifolius A. Gray) has high resistance to Xcp. The objective of this study was to identif y RAPD markers linked to genes controlling resistance to three isolate s of Xcp using bulked segregant analysis in an F-2 population from the tepary bean cross CIAT-G40005 (resistant to Xcp) xNebr;#4B (susceptib le to Xcp). Twelve RAPD markers were mapped in a coupling-phase linkag e with three genes for resistance to Xcp. The linkage group spanned a distance of 19.2 cM. A marker L7(750) was linked to the genes for resi stance to Xcp strains EK-11 and LB-2 at 8.4 cM and 2.4 cM, respectivel y. Markers U10(400) and Y14(600) were detected as flanking markers for the resistance gene to Xcp strain SC-IA at 2.4 cM and 7.2 cM, respect ively. The symbols Xcp-1, Xcp-2, and Xcp-3 were assigned for the genes for resistance to Xcp strains EK-11, LB-2, and SC-4A, respectively. R APD markers linked to the genes for resistance to Xcp could be used fo r transferring all of the resistance genes from P. acutifolius to a su sceptible P. vulgaris cultivar.