Evaluating Plant Growth Promoting Abilities of Rhizobium under Moisture Deficit Stress in Horse Gram (Macrotyloma uniflorum Lam. [Verdc.])

Author: Priyadharshini Aaradhana, Shobana Narayanasamy and Sivakumar Uthandi

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Abstract

The horse gram crop is an unexplored legume cultivated in arid and semi-arid regions of India and is well known for its potential to withstand environmental adversities. But it is considered a poor man's crop and is grossly underutilized owing to lower yields. Rhizobial cultures isolated from horse gram with plant-growth-promoting potential possess inherent drought tolerance capacity. They can be exploited as effective bio inoculants for horse gram growth and yield enhancement under varied climatic conditions. Five rhizobia isolates were obtained from the Biocatalysts Laboratory of the Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore. The isolates were tested for their inherent ability to grow under different levels of moisture deficit stress in PEG 6000. Their ability to promote growth under moisture-stress conditions was assessed through germination plate assay. The length of the seedlings, germination percentage, and proline content were estimated. The isolates were able to withstand and exhibit growth under lower osmotic potential of upto -1.17MPa. The germination percentage of the seeds treated with cultures also significantly increased over the control. The growth parameters were also enhanced compared to the untreated seeds. This study thus explores the five isolates in question and their ability to enhance drought stress tolerance and plant health promotion in horse gram. This can be used effectively for furthering sustainable cultivation systems of horse gram.

Keywords

Horse gram, drought tolerance, Rhizobium, plant growth

Conclusion

The five isolates were tested for their ability to tolerate and grow at lower osmotic potential, and out of the five, HR5 had the highest tolerance to induced drought stress under in vitro conditions. Furthermore, the isolate also exhibited an increase in plant growth parameters in horse gram seeds under varied moisture deficit stress. The isolate was observed to promote drought stress alleviation by facilitating an increase in the accumulation of proline. Thus the isolate HR5 (Rhizobium sp.) can be selected to alleviate drought stress and promote plant growth in horse gram. It has the potential to be a drought-alleviating PGP microbe for horse gram cultivation for exploitation in the future.

References

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How to cite this article

Priyadharshini Aaradhana, Shobana Narayanasamy and Sivakumar Uthandi (2023). Evaluating Plant Growth Promoting Abilities of Rhizobium under Moisture Deficit Stress in Horse Gram (Macrotyloma uniflorum Lam. [Verdc.]). Biological Forum – An International Journal, 15(10): 1017-1021.