Impact of introduced inbred lines on maize tolerance to acidic soils

A total of 66 half diallel hybrids from 12 lines of maize and 16 top cross hybrids from four IRAD lines and four composites were evaluated on acid soils in Cameroon at Nkoemvone in 2004. The 12 lines consisted of five from IRAD, one from IITA, four from CIMMYTColombia and two from CIMMYT Mexico. The objectives of the study were to evaluate the genetic potential of introduced maize inbred lines for yield improvement to identify high yielding crosses under high Al toxicity (O) conditions and to study the gene effect. The trials were conducted under native acidic soils with high Al toxicity (O) and a control (T). Among the best 20 single cross hybrids on acid soils, 70% had at least one introduced parent while only 30% had locally adapted parents. One top cross hybrid was the best performer (5.01 t/ha) compared to the best open pollinated variety under stress environment (O).The study revealed that maize tolerance to acidic soils was controlled by non-additive gene action.