Estimates of heritability allow breeders to calculate expected progress from selection relative to germplasm sources, the type of breeding procedure used to improve the germplasm, and the amount of testing of genetic material. The objective of this study was to compare estimates of heritability and other genetic parameters for yield of maize (Zea mays L.) by using variances among progenies for 121 selection experiments from seven recurrent selection programs. The seven recurrent selection methods included full-sib (FS), half-sib (HS), S 1 per se progeny (S 1 ), S2 per se progeny (S2), testcrosses with an inbred tester (TCI), testcrosses with an broad-base tester (TC-B), and full-sib reciprocal recurrent selection (FR). The estimates of the heritabilities from the pooled analyses were 68.00/o (FS), 58.50/o (HS), 79.80/o (Sl), 77.30/o (S2), 53.30/o (TC-I), 62.70/o (TC-B), and 54.90/o (FR). The estimate of heritability was unexpectedly smaller for S2 when compared with S1 selection. The hypothesis was developed that the small relative value of heritability for S2 selection was due to the importance of dominance effects in the individual populations undergoing selection. The effects of machine versus hand harvesting were to increase the error variance 2.5 times and the genetic variance 2 times. Heritabilities were similar for hand and machine harvesting.