Effects of population source and node position on rhizome bud distribution in speargrass (Imperata cylindrica (L.) Raeuschel)

Abstract

The effect of population source (agro-ecozone) and node position on bud distribution in mature (determinate) rhizome of first- (from natural vegetati on) and second- (from screenhouse-grown plants) generation speargrass (Imperata cylindrica (L.) Raeuschel) from the derived savanna (DS), southern Guinea savanna (SGS) and northern Guinea savanna (NGS) agro-ecozone of Nigeria were investigated. Twenty-node sections of ten mature rhizomes were randomly selected from speargrass in each growth environment for assessment of bud occurrence (%) on successive five-node regions viz. proximal apical (1st-5th node), distal apical (6th-10th node), proximal sub-apical (11th-15th node), and distal sub-apical (16th-20th node) regions. Bud occurrence on first- and second- generation rhizomes varied significantly with agro-ecozone and node position. Regardless of speargrass growth environment, bud occurrence from the distal apical to distal sub-apical regions of NGS rhizomes, proximal and distal apical regions of SGS rhizomes, and proximal apical region of DS rhizomes were identical and significantly higher than on the proximal apical region of NGS rhizomes, proximal and distal sub-apical regions of SGS rhizomes, and from distal apical to distal sub-apical regions of DS rhizomes. Buds were most concentrated on the proximal sub-apical regions of NGS rhizomes and least on the distal sub-apical region of DS rhizomes. These differences highlight the need to prevent cross-infestation of rhizome materials among speargrass agro-ecozones.

Keywords: Imperata; bud distribution; determinate rhizomes; agro-ecozones; savanna

Moor Journal of Agricultural Research Vol. 6 (1&2) 2005 pp. 76-80