Response of the Tomato to Population Pressure1

Abstract

Five tomato vine types (indeterminate, jointless, determinate, miniature, and dwarf) were grown in “equidistant” (on the square) arrangements at 5 population levels (3,000, 7,000, 17,000, 41,000 and 100,000 plants per acre) with multiple and single harvests. As populations were increased, yields per unit area asymptotically approached a common theoretical maximum yield regardless of vine types. With multiple harvests, maximum yields were approached at low populations for the large vine types and at intermediate populations for the small vine types. Higher populations were required to approach the maximum yields obtainable using a single harvest than were required to approach the maximum yields obtainable using multiple harvests. Earliness (1st harvest yield/total × 100 for multiple harvest) and yield concentration (marketable fruit yield/total fruit yield × 100 for single harvest) increased for all vine types as population increased. The relation between yield per plant (w) and plant population per unit area (p) was best described by the equation w −1 = Ap + B , where A and B are constants.