Growth and Development of Johnsongrass Ecotypes

Abstract

Studies were conducted on the growth and development of 55 morphologically distinct vegetative types of johnsongrass ( Sorghum halepense (L.) Pers.) collected throughout the United States and from several foreign countries. Observations were made also on the growth of sorghum almum ( Sorghum almum Parodi) from three foreign countries. Mature leaf-blades of the different johnsongrass ecotypes varied in length from 31 to 59 cm and in width from 1.7 to 3.4 cm. Plant height and culm density varied 2 to 4-fold for the different ecotypes. Floret production varied from 87 to 352 sessile spikelets for representative panicles of the different ecotypes. The number and arrangement of branchlets within panicles also varied as did the size of various spikelet components. Sorghum almum produced much taller plants than did johnsongrass although culm density and lateral growth were less than that of johnsongrass.