Effect of temperature-tolerant rhizobial isolates as PGPR on nodulation, growth and yield of Pigeonpea [Cajanus cajan(L) Milsp.]
2013
Kaur, Simranjit | Khanna, Veena
Plant-growth promoting rhizobacteria in conjuction with efficient Rhizobium, can affect the growth and nitrogen fixation in pigeonpea (Cajanus cajan (L) Milsp.) by inducing efficient symbiosis and plant growth. In this study out of 15 rhizobial isolates, isolated from different pigeonpea growing fields, four isolates i.e LAR-2, LAR-3. LAR-4 and LAR-8 were found to grow upto 45°C. Similarly, PGP traits such as IAA and Psolubilizing ability were evaluated at 35°C and 40°C and based on these results LAR-2, LAR-3, LAR-4, LAR-8 were selected as co-inoculant with recommended Rhizobium LAR-6 for studying their efficacy under field condition for symbiotic parameters and growth of pigeonpea. The seeds were treated with Rhizobium alone or in combination with selected temperature tolerant rhizobial isolates (as PGPR). The rhizobial isolates showed positive synergistic effect with recommended Rhizobium (LAR6) in dual-inoculation, which resulted in a significant increase in number and dry weight of nodules over Rhizobium alone and un-inoculated control. Maximum number and dry weight of nodules was recorded with treatment LAR-6+LAR-2 (37.4 no and 50mg/plant) followed by LAR-6+LAR-8 (30 no, & 48.7 mg/plant) as compared to Rhizobium LAR-6 alone (20.4 no, 31.4/plant) and control (8 no, 10.8 mg/plant). The same trend was evident with yield attributing traits and N–content in seeds, The positive interaction between co-inoculants was subsequently reflected in grain yield, LAR-6+LAR-2 inoculation exhibited 12.1% increase over control whereas with Rhizobium alone it was 8.3%. Thus dual inoculation regime significantly enhanced all symbiotic and growth parameters and also affected yield.
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