Molecular marker-assisted selection for development of common bean lines resistant to angular leaf spot

The objective of this work was to develop homozygous common bean lines carrying angular leaf spot resistance genes derived from the cultivars 'Mexico 54', 'MAR 2' and 'BAT 332' through marker-assisted selection. Molecular markers SCAR OPN02(890), RAPD OPE04(500) and OPAO12(950) linked to the resistance genes of 'Mexico 54', 'MAR 2' and 'BAT 332', respectively, were used in segregating backcross-derived populations to selection. DNA fingerprinting was used to select homozygous BC2F3 and BC1F3 resistant plants genetically closer to the recurrent parent. Two homozygous BC2F2:3 and two and five BC1F2:3 families derived from 'Ruda' vs. 'Mexico 54' (RM), 'MAR 2' (RMA) and 'BAT 332' (RB) crosses were selected, respectively. After only one (RMA, RB) or two backcrosses (RM), five and eight BC1F3 lines derived from RMA and RB, respectively, and seven BC2F3 lines derived from RM, with 14.9-16.6, 16.9-18.6 and 9.3-11.1% of relative genetic distances to the recurrent parent were selected. This is the first report of lines resistant to angular leaf spot carrying genes of the cultivars 'Mexico 54', 'MAR 2' and 'BAT 332' developed with the aid of molecular markers.