Evaluation of Different PGPR Strains for Yield Enhancement and Higher Zn Content in Different Genotypes of Rice (Oryza Sativa L.)

Rice, one of the most important staple food crops of the world, suffers a major setback nutritionally, because it is deficient in bioavailable zinc. In an attempt to answer this problem a field study was performed for two years during 2010 and 2011. Rice plants were treated with selected plant growth promoting rhizobacteria (PGPR; P. putida, P. fluorescens, A. lipoferum, B 15, B 17, B 19, BN 17, and BN 30) and plant growth, zinc (Zn) content in different plant parts and grains was analyzed. The data obtained showed enhancement in rice growth and hence, increased rice yield in response to PGPR application. All isolates resulted in almost 1.5- to 2-fold increase in Zn content in roots, shoots as well as grains in comparison to the control. The bacterial isolates B 17, B 19, and BN 17 were of particular interest as they induced the movement of Zn from roots to shoots as well as from husk to the grains, thus making grains enriched in Zn (around 25% higher Zn content). Therefore, it can be concluded that application of PGPR strains is an important strategy to combat the problem of zinc deficiency in rice and consecutively in human masses.