INHERITANCE OF FLOWERING TIME AND ITS APPLICATION FOR INDIRECT SELECTION IN THE DAVIS POPULATION OF GERBERA

Genetic components of variance and heritability of flowering time were estimated for five generations of the Davis Populationof Gerbera hybrids, Composite, Estimates of narrow-sense heritability averaged 0.50 and broad-sense heritability averaged 0.77 using the NCII design. Narrow-sense heritability was also estimated with two models of parent-offspring regression, resulting in average heritability of 0.49 and 0.51. Estimates of components of variance indicated that the major genetic effect controlling flowering time is additive. However, the dominance component accounted for 28% of the total variance; the environmental component was only 23%. Flowering time is negatively correlated with cut-flower yield. The phenotypic coefficient was –0.34; genetic correlations were –0.47 when estimated from the NCII design, and –0.72 when estimated from the parent-off-spring method. A practical model was constructed to assess the efficiency of indirect selection for cut-flower yield using flowering time as a marker trait. The advantages of indirect selection accruing from increased population size and reduced generation time are discussed.