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Families of two indiangrass [Sorghastrum nutans (L.) Nash] populations were used in this study with a family plot consisting of a parental clone and four half-sib progeny_ The experimental design was a randomized complete block with two replications. The regression of offspring on the parent in the same plot was used to obtain heritability estimates in which environmental covariances might be expected to inflate the parent-offspring covariance. The regression of offspring in one replication with its parent in another replication, and vice versa, was used to obtain heritability estimates whereby environmental covariances should be minimized. Heritability estimates for heading date and plant height, which had high heritabilities, were similar for the two estimation techniques. Heritability estimates for forage yield and in vitro dry matter digestibility (IVDMD) appeared to be influenced by environmental covariances. Mean heritability estimates for forage yield and IVDMD for the three sets of data analyzed were 0.64 and 0.94 respectively, when parents and offspring in the same plot were used in the regression analyses and 0.28 and 0.42 respectively, when parents and offspring in different plots were used. Heritability estimates for forage protein content averaged 0.49 and were similar for both methods of estimation.