Narrow sense heritability for individual traits was estimatedusing parent-offspring regression (Nyquist and Baker, 1991), bytaking account of how lines in F4 progeny row test performedrelative to the F3SPS generation. The estimation was done for individual families, across families and adjusted by an inbreedingcoefficient of self-generation (Nyquist and Baker, 1991). Bootstrap was implemented in R to obtain the standard error and 95% confi-dence interval of the estimate (R Development Core Team, 2011).As SPS and their derived lines were tested in different seasons,when genotype x season interaction affected trait performance,their estimates may be distorted (Nyquist and Baker, 1991).