The phyllochron, defined as the time interval between the appearance of successives leaves, can be used to simulate leaf appearance in plants. The number of leaves affects the leaf area index of the plant and is considered an excellent measure of physiological time. The objective of this work was estimate the phyllochron in potato plants cultivated in hydroponic system with substrate in different plant densities. The experiment was carried out in a protected environment at the Department of Fitotecnia, UFSM, RS, from 03/09/2004 to 26/10/2004. The experimental design was a completely randomized, with three repititions. The treatments were the densities of 5x5, 10x10, 15x15 and 20x20cm between hills. The phyllochron values for each density were related to the number of hills m-2 and stems m-2. The estimated phyllochron values varied according to plant density. Phyllochron increased with plant density, showing that plant density affects the leaf appearance rate in potato, and this response should be taken into account in the simulation models of the number of leaves in this crop.
Solanum tuberosum L.; thermal time; leaf emergence; intra-specific competition
