Response of 1-Aminocyclopropane-1-carboxylic Acid Containing Pseudomonas fluorescens for Rhizobial Population and Yield of Maize (Zea mays L.)

Pseudomonas (P) fluorescens promote plant growth by lowering the endogenous ethylene synthesis in the roots through their 1-aminocylopropane-1-carboxylate-deaminase (ACCD) activity. However, in the environs of the roots may decrease the efficiency of these P. fluorescens by stimulating ACC- oxidase activity resulting in greater ethylene production by the roots. So this study was designed to assess the performance of P. fluorescens containing ACC-deaminase for improving rhizobial population and yield of maize. The results revealed that the rhizobial population, irrespective of treatments, was maximum at 55 days after sowing followed by a reduction at harvest. The treatment T28+pH 7.2 (Temperature 28°C + pH 7.2) enhanced the maximum population of P. fluorescens in rhizoshpere at 35, 55 and 75 days after sowing (DAS) was with 1.69, 1.59 and 1.87 log fold increase over fertilized un-inoculated FUI [(3.7089 log cfu/g = 5.80 x103 cfu g-1 soil), (5.8673 log cfu/g = (7.53x105 cfu g-1 soil) and (4.676 log cfu/g 5.55x104 cfu g-1 soil)]. Similar treatment T28+pH 7.2 recorded maximum number of cob plant-1, cob length-1, number of grains line-1 and number of grains cob-1 at harvest were with T28+pH 7.2 by 30.6, 32.1, 29.7 and 37.7% over the control FUI (2.1, 15.2 cm, 35.0 and 503), respectively. While the treatment T31+pH 7.2 (Temperature 31°C + pH 7.2) enhanced the cob girth and maximum grains line cob-1 at harvest were with 26.0 and 31.3% response over FUI (13.3 cm cob-1 and 13.9), respectively. The treatment T28+pH 7.2 significantly increased the seed and stover yields of maize by 24.9 and 31.6% over the control (2914 and 7133 kg ha-1), respectively.