1991 Volume 36 Issue 2 Pages 148-152
The effect of past record of plant density on the growth and seed production of large crabgrass and common purslane was investigated. Both species were grown under two different plant density conditions, i. e., 5 plants per 1/2, 000a pot as low density in both weeds, 100 plants per pot in large crabgrass and 65 plants per pot in common purslane as high density. Cultivationu nder such conditions was continued for 4 years with one generation a year. Seeds were obtained under the above conditions, i. e., seeds of the 5th generation were grown under low or high plant density conditions.
1) Effect of past record of plant density on the growth parameters was not observed in the case of low plant density conditions in the test for the 5th generation, except for the plant length of large crabgrass (Fig. 1, Table 1).
2) When large crabgrass with different past records of plant density was grown under high plant density conditions, the number of green leaves, the leaf area and seed weight of the plants with a past record of low density were greater than those of the plants with a part record of density. These differences were not observed in common purslane (Fig. 1, Table 2).
3) There were different kinds of individual variations in the past record of growth conditions between both weeds. Although individuals with different reactions to plant density were observed in each plot, the effect of the actual plant density on the growth parameters in the 5th generation was more pronounced than that of the past record of plant density, except for several growth parameters of large crabgrass in all the plots (Fig. 2).
