Effects of Different Concentrations of Paclobutrazul and Plantlet Density on Minituber Production in Potato cv. Sante

Effects of different Paclobutrazol concentrations (0, 250, 350 and 450 mgL-1) and plantlet density (80, 100 and 120 plantlet/m2) on minituber production per plantlet in potato cultivar ‘Sante’ were investigated in a factorial experiment based upon a randomized complete block design of 4 replications. Paclobutrazol (Cultar with 250 g/L of active ingredient) was used as foliar application at early stolon initiation. The results indicted that Paclobutrazol increased chlorophyll a and b contents of the leaf tissue as well the ratio of the tuber fresh mass to shoot fresh mass. Paclobutrazol significantly reduced the internode,s, stem and stolon length, also reduced stem diameter. While plantlet density increased internode, stem and stolon length, yet reduced tuber fresh mass to shoot fresh mass ratio. The interaction between the two factors was significant on internode, stem and stolon lengths. The study clearly showed that Paclobutrazole is effective in suppressing excessive vegetative growth in high plantlet densities. It could also improve the minituber average weight through an increase of assimilation to the minituber and as well an increase of chlorophyll a and b contents of the leaf tissue. Means related to weight and number of minituber production were recorded as 3.27, 3.74 and 5.69, 6.16 in control and Paclobutrazol treatments, respectively. In total, for producing the highest numbers of minituber of higher weights, it is recommended to apply higher plantlet densities along with lower concentrations of Paclobutrazol