Effect of Azospirillum isolates on the growth and nitrogen content of tef [Eragrostis tef (Zucc.) Trotter]

Abstract

Two dizotrophi bacteria, coded as A31 and A32, were isolated from the rhizosphere of two tef varieties DZB01B354 and DZB01-196, respectively. Different morphological, biochemical, and physiological comparisons with type cultures Azospirillum lipoferum, ATCC 29707, and Azospirillum brasiliense, ATCC 29145 showed that the isolates belong to A. lipoferum. Inoculation studies of isolates on pot-grown tef plants showed marked increases in height, grain yield, total shoot and root weight, root-shoot ratio and total grain nitrogen. An increase in grain yield up to 12% over uninoculated controls was observed. The bacterial isolate A32 was found to perform better than A31 in promoting growth and yield on both homologous and heterologous tef varieties. Of the two tef varieties, DZB01B096 responded better than DZB01B354 to inoculation. The study indicats a possible specific interaction between host cultivar and bacterial isolate that governs plant yield.

SINET: Ethiopian Journal of Science Vol. 23, No. 2 (December 2000), pp. 247-262



Key words/phrases: Azospirillum lipoferum, yield increase, Eragrostis tef