Development of ammonium nitrate free nutrient media for aluminium toxicity tolerance screening of rice genotypes from North-Eastern India

Abstract

North-Eastern India is blessed with a vast diversity of rice genotypes with varying yielding abilities. However, the predominant strong soil acidity induced nutrient stresses from the toxicity of aluminum (Al³⁺) ions often causes sub-optimal rice productivity. The lack of suitable nutrient media for the screening of aluminum (Al) toxicity tolerance of rice genotypes is one of the limiting factors in Al tolerant varieties' development. Modified Magnavaca's solution has been the most recommended nutrient solution for this purpose where ammonium nitrate is the primary nitrogen source. However, strict regulations related to the handling and storage of ammonium nitrate in India limit the preparation of Modified Magnavaca’s solution for laboratory use. Here, a modified ammonium nitrate-free formulation based upon the Magnavaca's solution has been proposed. The modified formulation was found to have 160.9 µM of active Al³⁺ concentration when 550 µM of aluminum chloride hexahydrate (AlCl₃.6H₂O) was added at pH 4.1 to the solution. Through a plant growth screening experiment using ten diverse rice genotypes a significant difference in the response of various genotypes to differential Al toxicity levels on root growth performance indicators was observed. Based on the response, we could able to categorize the genotypes into tolerant and sensitive in relative terms. Thus, the present experiment provided an important nutrient formulation suitable for screening rice genotypes under Al toxicity conditions. Moreover, the selected tolerant and sensitive genotypes can further pave the way for studying the molecular mechanism of Al toxicity response in rice and their use in the breeding program.

Keywords:

• Aluminum toxicity
• Magnavaca
• soil acidity
• rice

Acknowledgements

The authors are grateful to all the Co-PIs of the project (Project Title: Genome-wide association study (GWAS) for Al toxicity tolerance in rice from NEHR; Institute Project Code: N/A) for conducting the current study as a preface pilot project without any conflict of interest. Moreover, the authors are highly thankful to the Director, ICAR RC for NEH Region, Umiam, Meghalaya 793103, India, for providing the study facilities.

Disclosure statement

No potential conflict of interest was reported by the authors.

Authors contribution

SJ, AK, BUC, and HV Conceived and designed the manuscript. SJ, NS, and AK conducted the experiment. TR performed the chemical analysis of the samples. Sampling and data collection were done by SJ, NS. Data analysis was performed by MKL and BUC. SJ, BUC, and RK wrote the first draft of the manuscript. While BB and VKV provided guidance and supervision. All authors have read and given their consent for manuscript publication.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.