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 DZ-O 1-354 and DZ-O 1-196, 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, Dz-01-096 responded better than 02-01-354 to inoculation. The study indicats a possible specific interaction between host cultivar and bactenal isolate that gov~ros plant yield.