Studies on the Stiffness of Culms in Barley Plants (Hordeum sativum, JESSEN) : 14. The interrelationship of planting density and culm strength.

Abstract

The aim of this study is to make clear the relationship of planting density and culm strength. A brittle culm variety, Sekitorisai-No.1, and a stiff culm variety, Haganemugi, Mitake, and Dorirumugi were used. Plots were 5 m long and 20, 40, 60, 80cm row width with three replicates. In field experiments, desired row width were obtained by thinning the 20 cm row by hand. In glasshouse experiments, plants were sown in 1/2000 a and 1/5000 a pots. These plants were used for the control of the number of ears per plant or the plant spacing. Therefore, in Haganemugi and Sekitorisai-No. 1, the number of ears per plant in the broad row width were more than the one of the narrow width. Culm strength of these two varieties is lowered by the increase of the number of ears per plant. On the other hand, in Dorirumugi and Mitake, the number of ears per plant were regarded as the same between the material of the broad row width and the one of the narrow row width. Culm strength of two varieties is raised by the increase of row width. In material that has been fixed the number of ears per plant, the culm strength is raised by broading the distance among the plants (pot experiments). The same results are obtained by broading the row width in the field experiments. The planting density and row width are related to the culm strength and culm growth. The response of tillering on planting density and planting row width is very important factor to decide upon the variety for cultivation.