Effectiveness of Pseudomonas fluorescens and L-tryptophan to improve seedlings growth of onion (Alium cepa L.)

摘要

Onion (Alium cepa L.) is an important vegetable crop of the world. In Pakistan, its yield is considerably low as compared to other onion producing countries. Plant growth promoting rhizobacteria (PGPR) and plant growth regulators (PGR) can be used as an effective tool to increase the growth and productivity of crop plants. In present study, different treatments of L - tryptophan and Pseudomonas fluorescens (S20) were applied to study the effect of their combined application on productivity of onion nursery. The experiment was laid out with three replications in Randomized Complete Block Design (RCBD) under field conditions. Results showed that application of L - tryptophan at different levels and P. fluorescens alone and in combination significantly increased growth of onion seedlings . The combined use of P . fluorescens and L - tryptophan at 40 mg kg - 1 resulted in maximum increase in shoot length (61%), root length (76%), shoot fresh weight (77%), root fresh weight (69%), shoot dry weight (80%), N (30%), P (3 2 %) and total bioma ss (65%) of onion seedlings as compared to control plots . However, dual application of L - tryptophan and P. fluorescens showed non - significant effect regarding relative water contents and K + concentration in seedlings. It is concluded that combined applicat ion of P . fluorescens and L - tryptophan at 40 mg kg - 1 is more effective to get higher productivity of onion nursery and should be recommended to farmers.