Comparison of recurrent and congruity backcrossing for interracial hybridization in common bean

Abstract

Two common bean (Phaseolus vulgaris L.) cultivars were used for recurrent backcrossing (i.e., repeated backcrossing to one of the parents) to both parents independently and for congruity backcrossing (i.e., backcrossing alternately to both parents). One cultivar, ‘ICA Pijao’ of race Mesoamerica, was late maturing, with erect type II growth habit and small seeds. The other was ‘Pinto UI 114’ of race Durango, an early maturing cultivar with prostrate type III growth habit and medium seeds. One to three recurrent backcrosses (RBC) to both parents, and two rounds of congruity backcrosses (CBC), were made. Thirty-two random lines from each method along with two parents were compared in a reps-in-set design at two locations (Popayan and Quilichao) in Colombia in 1992–1993.