Soil Matters More than Genes for Red Gram Growth: UoH Study

 Hyderabad: The soil type has a greater influence than plant genetics in the manner in which microbes colonise red gram root nodules, a study by the University of Hyderabad (UoH) has found. Research suggests that even well-developed crop varieties may underperform if the soil lacked the right microbial communities — an insight that could reshape how pulses are cultivated in India and elsewhere.

Red gram, or pigeon pea, is a vital crop in semi-arid regions and a major protein source for millions of people, especially in vegetarian diets. The crop is known for its ability to fix atmospheric nitrogen through nodules on its roots, which house beneficial bacteria—particularly Bradyrhizobium. This natural process helps farmers reduce dependence on chemical fertilisers.

The study led by Prof. Appa Rao Podile found that these nodules also host other microbes, and the soil — and not the plant variety — determined which ones thrived. Using metagenomic analysis, the team compared cultivated varieties like Asha, Durga and Mannem Konda Kandi with a wild relative, across three soil types — alfisol, vertisol and inceptisol.

The wild type mostly housed Bradyrhizobium, while the cultivated ones had more microbial diversity, possibly due to domestication weakening traditional symbiotic ties. The team noted that although nodule microbial diversity was lower than that of the surrounding soil, it was more selective—suggesting a targeted interaction between plants and certain microbes.

“Even though we assume nodules as homes for nitrogen-fixing bacteria, their microbial population is shaped more by soil than by the plant,” the study said. The findings show that seed genetics alone cannot ensure strong crop performance. Soil health—and the microbes it supports—are equally crucial. Poor soil, heavy chemical use or seed breeding that ignores microbial partnerships can all affect yields.

The study, supported by the Science and Engineering Research Board (now Anusandhan National Research Foundation), was published in Environmental Microbiome. Co-authors include Dr Anirban Basu, Dr Chalasani Danteswari and Dr P.V.S.R.N. Sarma from the UoH department of plant sciences.

For millions who cultivate red gram, the message is clear: nurturing soil health is as vital as choosing the right seed.