Multiplication Method of Capsicum annuum L. by Soilless Culture : Effects of Planting Density of Mother Plants and the Substrates on Yield of Shoots

Abstract

Cultural conditions of mother plants were investigated to establish a vegetative propagation method for sweet pepper (Capsicum annuum L.). Planting densities of mother plants ranging from 30 m^-2 to 180 m^-2 in a deep flow hydroponic system revealed that the lower the density, the higher was the yield per mother plant, but conversely, the higher the density, the higher the yield was per unit planting area. When the mother plants were cultivated in the same hydroponic system, the roots of some plants turned brown, causing the plants to wilt and die, indicating a shortage of dissolved oxygen in the solution. Therefore, three kinds of synthetic root-anchoring substrates were examined and compared with hydroponics. Two types of transplants, cuttings and grafts, were used as mother test plants. The appearance and spread of the wilting symptoms were much slower with three anchorages than they were in the hydroponic culture. More than 80% of the grafted plants survived over a 10-month period on all substrates, whereas in the hydroponic plots, the grafts died within eight months. The yield of shoots was about the same among the three anchorages examined. Grafted mother plants yielded about twice the shoots than did the cuttings during 10-month cultivation period. By this method, 90 shoots can be harvested every week from one square meter of planting area continuously for one or more years.