PJB-2021-534
PRECURSOR (L-TRYPTOPHAN)-INOCULUM (RHIZOBIA) INTERACTIONS FOR IMPROVING GROWTH, YIELD AND NODULATION OF MUNG BEAN (VIGNA RADIATA L.).
Muhammad Ashfaq Anjum
Abstract
Auxin producing rhizobia are capable of improving growth and yield of legumes. Addition of L-Tryptophan (L-TRP) to the inoculation media may further improve its effectiveness as a result of precursor-inoculum interactions resulting into microbial biosynthesis of auxins in the rhizosphere. Rhizobial strains were isolated from the mung bean root nodules using dilution plate technique. Auxins production by rhizobia were assayed with and without L-TRP (a physiological precursor of auxins) supplementation to the growth media. There was a large variation in auxins biosynthesis capabilities of these rhizobial isolates and three rhizobial i.e. A23, N12 and N42 being most prolific in auxin biosynthesis were further tested alone and in combination with different conc. of L-TRP (10-3, 10-4 and 10-5 M) for improving the growth, nodulation and yield of mung bean (Vigna radiata L.) in a pot trial conducted at the Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan. Mung bean seeds were inoculated with peat-based rhizobial inocula and sown in complete randomized design (CRD) with six repeats. NPK fertilizers were applied @ 30-25-0 mg kg-1 soil as urea and single super phosphate (SSP) in all pots. Results depicted that rhizobial inoculation significantly improved the growth and yield of mung bean. Combined application of rhizobia and 10-5 M L-TRP was however more efficient than their single application in improving the growth and yield of mung bean. Results revealed that fresh biomass, seed yield, number of pods plant-1, number of grains pod-1, number of nodules plant-1, nodular mass plant-1, N and P contents in mung bean seeds were significantly increased compared to un-inoculated and untreated control. These results imply that supplementation of rhizobia with L-TRP could be a successful approach for improving growth, nodulation and yield of mung bean. ¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬
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