TITLE:
Morpho-Physiological and Biochemical Characterization of Soybean-Associated Rhizobia and Effect of Their Liquid Inoculant Formulation on Nodulation of Host Plants in the Cameroon Cotton Fields Zone
AUTHORS:
Gilbert Rongoumi, Souleymanou Adamou, Yoradi Nadjilom, Doloum Gomoung, Takoukam Steve Toukam, Albert Ngakou
KEYWORDS:
Isolation, Morphologic Characterization, Soybean-Associated Rhizobia, Nodulation, Cameroon Cotton Zone
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.14 No.7,
July
26,
2023
ABSTRACT: The aim of this research was to assess the diversity
of the Cameroon cotton zone in soybean associated rhizobia in order to
formulate the most efficient elite inoculant to boost both the cotton and
soybean production. Therefore, soybean associated rhizobia were isolated and
characterized morphologically, physiologically and biochemically on YEMA
culture media. For each of the two soybean varieties (Houla1 and TGX1910 14F)
used, the trials were laid out in two IRAD-fields of North Cameroon
(Sanguere-Paul) and Far-North (Soukoundou) respectively, under a complete
randomized complete block design, the isolate formulations representing the
treatments. The six isolated strains (IS1, IS2, IS3, IS4, IS5, IS6) from which
seven liquid inoculant were formulated were revealed to belong to the same slow
growing group of rhizobia, with a high level of tolerance to temperature, pH,
and salinity, with optimum growth at respectively 28˚C, pH (7 - 9), salt (1% - 5%).
Not surprisingly, root nodules were formed by both inoculated and uninoculated
soybean plants. However, the most efficient soybean-rhizobia symbiosis for nodulations
were isolate IS6 associated to TGX1910 14F variety, and isolate IS5 associated
to Houla1variety at Sanguere-Paul. Whereas isolate M was associated to TGX1910
14F variety, Houla 1 variety had affinity with native rhizobia isolates at
Soukoundou. The present results suggest the adaptability of rhizobia isolates
to a particular soybean variety at a particular cotton fields zone. These
findings should be taken into consideration for commercial inoculant
formulation.