Assessment of some plant growth promoting rhizobacteria on the seedling vigor index, growth of kenaf (Hibiscus cannabinus l. Malvaceae) and soil chemical properties

A. O. Oyedele; J. A. Adetumbi; A. O. Ojo; E. Ezaka; I. O. Fademi; J. O. Fademi; L. B. Taiwo; J. A. Adediran

Authors

Oyedele A. O. Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, Ibadan, Nigeria.
J. A. Adetumbi Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, Ibadan, Nigeria.
Ojo A. O. Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, Ibadan, Nigeria.
E. Ezaka Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, Ibadan, Nigeria.
Fademi I. Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, Ibadan, Nigeria.
Fademi J. O. Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, Ibadan, Nigeria.
Taiwo L. B. Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, Ibadan, Nigeria.
Adediran J. A. Institute of Agricultural Research and Training, Obafemi Awolowo University, Moor Plantation, Ibadan, Nigeria.

Keywords:

Bacillus subtilis, Bio-fertilizer, crop performance, effective PGPR, germination percentage, Stenotrophomonas maltophilia

Abstract

A screen house study was carried out at the Institute of Agricultural Research and Training, Ibadan, Nigeria to evaluate the effect of plant growth promoting rhizobacteria (PGPR), as biofertilizers on the growth of kenaf and on the soil chemical status. A seed germination bioassay was carried out to screen ten PGPR isolates for their effects on the germination and growth of kenaf. Two most effective PGPR were further assessed by pot experiments at two different cropping cycles using two varieties of kenaf (IfeKen DI 400 and Cuba 108). The treatments used include Bacillus subtilis 1, Stenotrophomonas maltophilia, Bacillus subtilis 1 + Stenotrophomonas maltophilia, NPK fertilizer and the un-inoculated control. The seed germination bioassay showed that some of the PGPR significantly (P < 0.05) influenced the number of germinated seeds, length and vigour index of the seedlings when compared to the control. Bacillus subtilis 1 and Stenotrophomonas maltophiliahadthehighestvigourindex of1048.0and1049.6forCuba108and1074.6and1088.0forIfeken DI 400, respectively.

Inoculation of Cuba 108 and Ifeken DI 400 with PGPR showed enhanced plant heights with increase of 2.22 to 16.0% and 0.8 to 89.7% respectively when compared to the un-inoculated control during both cropping cycles. An increase of 2.1 to 35.3% and 2.2 to 47.5% in the stem girth was recorded for Cuba 108 and Ifeken DI 400, respectively over the un-inoculated control. The effects of the bio-fertilizers on soil micro and macro-nutrients showed significant differences (P < 0.05) between the cropping cycles, varieties and the treatments applied. During the first cropping cycle, the PGPR effectively enhanced the soil status for some of the macro and micronutrients but was not effective for most chemical parameters during the second cropping cycle. The application of the PGPR enhanced the growth of the two kenaf varieties as well as the availability of some micro and macro nutrients and thus can be seen as prospective bio-fertilizers which can be incorporated into kenaf production for enhanced growth.