Abstract:
Rice (Oryza sativa) supplies the staple food for nearly 50% of the global population. Higher rice
production for increasing population is achieved through intensive agricultural practices
including the use of chemical fertilizer. Excessive use of chemical fertilizers has adverse effects
on human health and the environment. Plant Growth Promoting Bacteria (PGPB) are an
alternative to the chemical fertilizer. Determination of the efficient PGPB for selected crops is
essential for improvement of their productivity. The objective of this study was to determine the
effect of two selected bacteria isolates of rice (I-1 and I-2) on the crop duration and yield of three
improved rice varieties under greenhouse condition. The Experiment was conducted at Faculty
of Agriculture, University of Ruhuna, Mapalana (in ecological zone WL2), from August to
December 2018 at average monthly temperatures of 33.23 ℃±1.59, 34.16 ℃±3.79, 35.26
℃±3.26, 33.8 ℃±1.6 and 32.4℃±1.79. Surface sterilized seeds of three improved rice varieties
Bg 300, At 308 and Bg 379/2were inoculated using the two bacteria isolates, I-1 and I-2. The
treatments were laid in a completely randomized design (CRD) with five replicates. The days to
flowering (DF) of each treatment were recorded and the number of grains per first panicle (GP)
was measured as a yield component. Data was analyzed using SAS software for ANOVA and
Duncun’s Multiple Range Test (DMRT) for mean separation. The plants of Bg 300 and Bg379/2,
inoculated with I-1, reported significant low DF as 114.5±1.25 and 112.5±0.86 in contrast to
those of control plants of 117.5±0.5 and 118.5±1.22 DF, respectively. The Bg379/2 plants
inoculated with I-2 (of 114.5±0.25 DF) also flowered early in contrast to control plants. Plants of
Bg 300 and Bg 379/2 with I-1, produced the highest GP as 134±7.35 and 157±11.2, respectively
over those of the control plants of Bg 300 and Bg 379/2 (105.75±6.98 and 132±2.94
respectively). Bacteria inoculation did not affect DF and GP in the variety At 308 indicating the
differences in varietal responses on the inoculation. Variety and location interaction must be
investigated for I-1 under field conditions for its utilization as a bio-fertilizer for rice in the
future.
