Abstract
Plants of Gypsophila paniculata L. ‘Bristol Fairy’ were grown in boxes at nine different shoot densities to know how the number of florets per shoot, a basis of flower quality, was determined during plant growth and development. Four components were defined to analyze the number of florets per shoot (FN): number of nodes (NN), primary branches (PB), secondary branches (SB), and units (= dichasia: UN). NN, PB, SB, UN, and FN were considered to be determined in this order during plant growth and development. Fresh weight, stem diameter (SD), PB, SB, UN, and FN of cut flowers decreased as shoot density increased. Total weight of cut flowers and total number of florets per box were almost equal, except in three low-density plots. Days to visible bud and days to flowering tended to decrease as the number of shoots per plant decreased. Path analysis was used to estimate the interrelationship among components. Stem diameter was defined as an outer variable. Path coefficients of stem diameter for NN, PB, SB, UN, and FN were −0.520, 0.686, 0.725, 0.589, and 0.408, respectively. Path analysis indicated that stem diameter had strong direct effects on each component. The correlation coefficient between SD and FN was 0.985. Stem diameter has a strong indirect influence on the number of florets per shoot and can be used as an index to predict FN.
