INHERITANCE OF RESISTANCE TO ERWINIA-STEWARTII IN 4 INBRED LINES OF DENT CORN - QUALITATIVE AND QUANTITATIVE-ANALYSES

The inheritance to resistance to Stewart's bacterial leaf blight of co rn (BLB) was studied in four resistant dent corn inbred lines, Pa419P, Pa70, Pa83, and Pa887P, each crossed with the susceptible inbred line RB14AHt. Parents, F1, F2 and backcrosses to the resistant (BCr) and s usceptible (BCs) parents in each of the four families were evaluated i n 1977 and 1979 under artificial inoculation in the field. Estimates o f degree of dominance ranged from 0.8 for Pa419P in 1977 to 1.2 for Pa 83 in 1979. Broad sense heritability estimates ranged from 89.3% to 94 .1% in 1977. Estimates were slightly lower in 1979 due to less disease pressure. Estimates of the number of genes conditioning resistance ba sed on Wright's formula varied from 1.1 to 3.2 in 1977 and from 2.0 to 4.1 in 1979. Mendelian genetic sis indicated a single dominant gene m odel best fit the 1977 data, with only the Pa70 family deviating signi ficantly. The 1979 data did not fit any one or two gene model tested. Generation mean analysis indicated significant additive and dominance genetic effects in all families in both years. Most of the variation a mong generations was attributable to additive gene action. Pa887P woul d be an excellent source of resistance to BLB to use in a breeding pro gram.