RECURRENT SELECTION FOR FLOWER COLOR IN THE DAVIS POPULATION OF GERBERA

Abstract

Flower color can be treated as a composite of three quantitative traits. The traits hue (H), chroma (C), and value (L), as described in the CIELAB (1976) color system, are continuous variables easily included into an index of a recurrent selection program. A Euclidian distance index was utilized to minimize the mean distance of a population to a color point (dark yellow). The index was: l= sqrt[0.5*(H-85)**2 + 0.25*(C-80)**2 + 0.25*(L-50)**2]The index was applied to generation 15 of the Davis Pop. of gerbera, and two cycles of selection were performed (sel. intensity = 2.3 and 2.0 respectively). Crosses were made via a 6×6 factorial mating design. The mean index score in gen. 15 was 38.57. Two cycles of selection changed the mean to 15.08. The N.S. heritabilities for H, C, and L in gen. 15 were 0.6, 0.7, and 1.0. Selection reduced the heritabilities to 0.2, 0.0, and 0.1, respectively. The add. genetic corr. between H & C, H & L, and L & C were 0.1, 0.8, and -0.5, respectively. After selection, the correlations were 0.7, 0.9, and 0.2, respectively.