The Effect of Successive Selection on the Self and Backcrossing Progenies from Normal Corn × Popcorn Crosses

It is an effective method to use normal maize inbreds to improve popcorn germplasm. To evaluate the practical result, the expansion fold, popping rate, ear-kernel weight and 100- kernel weight of F3, F4, F5, BC1S1, BC1S2, BC1S3, BC2S1, BC2S2 and BC2S3 by successive selection on the F2, BC1 and BC2 progenies from four selected normal corn X popcorn crosses were measured and analyzed. The result showed that the average ear-kernel weight, 100- kernel weight and their variation range, variation coefficients and the plant numbers superior to their popcorn inbreds were all greatly different among various crosses for all progenies, but small for expansion fold and popping rate. Compared with direct successive self selection, one or two backcrosses with the popcorn inbred decreased the ear-kernel weight and 100- kernel weight, but the expansion fold and popping rate increased. There were great variations in all progenies for each character, of which ear-kernel weight were the biggest, and popping rate the smallest. As successive selections going on, ear-kernel weight and 100- kernel weight decreased greatly, but expansion fold and popping rate increased significantly. There were positively significance or greatly significant correlations between all progenies and their popcorn inbreds for expansion fold and popping rate, but almost all negatively significance or greatly significance for ear-kernel weight and 100-kernel weight.