Effects of Row Width and Seedling Spacing on Yield and its Components in Grain Sorghum Grown under Dryland Conditions¹

Abstract

Two experiments were conducted under dryland conditions in Israel in 1960-61 to study the effects of population density and its distribution in the field on tillering, head weight, kernel weight, and yield of grain sorghum. Size of population and plant areas provided were found to be the major factors determining yield. Superior yields resulted from narrow rows combined with wide intrarow seedling spacing. Yield superiority was due primarily to increased number of heads per unit area, rather than to changes in head weight. Heads per unit area and the number of kernels per head were largely free of environmental effects. Kernel weight, on the other hand, was mainly affected by environmental conditions existing at the time of kernel maturation.

Interrelationships among yield components indicate that plant yields were inversely associated with the number of heads per unit area. Plot yields were equalized at the different seedling densities, mostly by changes in the number of kernels per head. Plot yields were directly associated with number of heads per unit area and inversely associated with head weights. Highest yields were obtained from 20,000 to 70,000 plants per acre, especially when planted in narrower rows.