Determining the phyllochron and final leaf pair number in on-farm cut dahlia cultivars

Abstract Dahlia is an important ornamental crop and widely used as a garden plant in beds mixed borders well cut flower bouquets arrangements. Understanding the factors that support sustainable production essential for dahlia growers to increase their profits. Two key variables define leaf development during vegetative phase of are rate appearance leaves on main stem final number leaves. The objective this study was determine phyllochron pair (FLPN) dahlias cultivars grown different locations. Three farm experiments varying from two eight were conducted years (2021/2022) six locations Rio Grande do Sul State, Southern Brazil. unfolded pairs (NLP - assumed when foliolates edges not touching anymore) each counted once or twice week, depending farm, until last unfolded. NLP linearly regressed against TT (thermal time °C day-1) (oC day pair-1) calculated slope linear regression. results indicated varied between 45.7 95.6 leaves-1 8 14 first experiment, 27.2 97.4 6 15 second experiment 46.8 at 106.4 pair-1 13 third. Thus, there no significant difference sites NFP variables.