Diallel analysis of maize inbred lines with emphasis on resistance to leaf diseases

The objective of this work was to identify the predominant type of gene action for resistance to Exserohilum turcicum, Phaeosphaeria maydis, Physopella zeae and Puccinia polysora, and to determine the genetic potential of maize (Zea mays) inbred lines in order to obtain hybrids with high agronomic performance and resistance to leaf diseases. Forty-one F-1 hybrids from the diallel crosses between ten endogamic lines, and the controls P3069, P30F90, BG7060, Balu761, and Dow2A120 were evaluated in four places, using a randomized block experimental design, with three replicates. The hybrids LGS(3)xLGS(9), LGS(2)xLGS(6), LGS(2)xLGS(4) and LGS(2)xLGS(3) showed an excellent performance in comparison with the controls, for the different characters evaluated. The lines with higher frequency of favorable alleles were LGS(2), LGS(9), LGS(4) and LGS(3). The additive genetic effects are the most important for the resistance to P. maydis and for ear height, while nonadditive genetic effects are more important for yield, plant height, resistance to E. turcicum, P. zeae and P. polysora.