Identification of Major Locus Conferring Resistance to Urdbean Leaf Crinkle Disease in Black Gram [Vigna mungo (L.) Hepper]

Urdbean leaf crinkle disease (ULCD) is a major factor causing severe yield loss in black gram production. The identification of quantitative trait loci (QTL) linked to ULCD resistance is highly useful in breeding programmes. A mapping population was developed from a cross between the resistant parent CO 5 and the susceptible parent TU 68. ULCD screening was carried out through the artificial sap inoculation method. In the F_2:3 population, the ULCD score was assessed 60 days after infection. Composite interval mapping was carried out with a 1000-run permutation. Another mapping population, VBN(Bg) 4 × CO 5 in F_2:3 generation was used to validate the identified QTL. A single locus, qULCD3.1 was identified in linkage group 3. It explains 17.98% of the variation in ULCD resistance. Markers VR086 and CEDG 305 flanked the QTL region. The marker CEDG 305 explains 20.5% of the phenotypic variation for ULCD resistance in the validation population VBN(Bg) 4 × CO 5. This is the first report to identify a QTL for ULCD disease resistance. The identified markers can be used to incorporate ULCD resistance in black gram through marker-assisted selection.