ESTIMATION OF VARIANCE COMPONENTS AND HERITABILITY FOR FLOWERING TIME AND CUT-FLOWER YIELD FOR THE DAVIS POPULATION OF GERBERA USING RESTRICTED MAXIMUM LIKELIHOOD (REML)

Additive genetic components of variance and narrow-sense heritabilities were estimated for flowering time and cut-flower yield for generations 8-13 of the Davis population of gerbera, using the least squares (LS) and restricted maximum likelihood (REML) methods. Estimates of heritability for flowering time were 0.54 and 0.50 using REML and LS, respectively, indicating a close agreement between the two methods. However, estimates of heritability for cut-flower yield were 0.30 and 0.46 from REML and LS. This may result from the fact that cut-flower yield was selected in each generation; flowering time was not. Realized heritability for cut-flower yield was estimated to be 0.26 which agreeded more closely with the heritability estimated from REML. The advantages of REML, and its applications in the estimation of components of genetic variance and heritability of plant populations are discussed.