Studies on competition in plants VII. Effect on competition of a varying number, of competing and non-competing individuals

Summary

Using races of barley or rice differing in. competitive ability, three experiments were conducted in order to find the effect of varying number of competing and non-competing individuals on the increment or decrement in a few quantitative characters. The experiments were designed so that six plants of both competing and non-competing genotypes surrounded a plant in the centre. The number of competing and non-competing individuals among the six surrounding plants varied from zero to six, either planted in two separate groups or interspersed at random. It was found in these experiments that the increment or decrement in the characters of the central plants due to competition exerted by the surrounding competitors was linearly proportional to the number of competing individuals. Consideration is given briefly to what will occur if a very few but strongly competing plants are mixed with a population of plants with weak competitive ability.