Radiation induced mutagenesis, physio-biochemical profiling and field evaluation of mutants in sugarcane cv. CoM 0265

Abstract

Purpose

Sugarcane is an important cash crop and is affected by soil salinity. CoM 0265, a moderately salt-tolerant variety grown in the Maharashtra region (India), has low sugar content. The present study was aimed to employ gamma ray induced in vitro mutagenesis with repeated and step-wise selection in sugarcane for the isolation and physio-biochemical profiling of the selected salt-tolerant mutants for improved agronomic performance and sugar content.

Materials and methods

Embryogenic callus culture of CoM 0265 variety was subjected to different doses of gamma radiation (10, 20, 30, 40, 50, and 60 Gy) followed by selection on NaCl containing media (50, 100, 150, 200, and 250 mM NaCl). The regenerated plantlets were hardened and selected based on ground nursery field trial on normal soil and saline field trial, in augmented block design for the selected mutant clones. Different physio-biochemical changes and activity of antioxidant enzymes were analyzed in the salt selected in vitro cultures and field-grown mutant clones.

Results

Dose optimization showed 40 Gy as the LD₅₀ for gamma radiation and 150 mM NaCl as the dose for in vitro selection experiments. The selected mutant clones showed higher tissue water content (TWC), chlorophyll, and lower sodium content indicative of tolerance to salt stress. Catalase and peroxidase enzyme activities in the top visible dewlap (TVD) of the putative mutant clones were significantly higher than the control. The average yield and sucrose percent of the selected mutant clones were significantly higher than control checks in the saline field trial. Mutant clones M8457 and M8721 exhibited improved yield and commercial cane sugar over the parent control check varieties under saline field conditions. Catalase activity was strongly associated with TWC (r = 0.34) and chlorophyll content (r = 0.41) while it was negatively correlated with sodium ion content (r = –0.38). Peroxidase activity in TVD also showed a significant positive correlation with chlorophyll content (r = 0.42) and a negative correlation with sodium ion content (r=–0.39). The improvement in yield and CCS (t/ha) was strongly associated with the lower sodium ion content of the mutant clones (r=–0.54 and −0.53, respectively).

Conclusions

Gamma ray induced mutants were isolated for improved sucrose and high yield in sugarcane var. CoM 0265. The results suggest that gamma radiation induced mutations result in physiological and metabolomic alterations for better growth and adaptation under in vitro and field stress conditions in sugarcane. The improved mutants can be further useful for commercial cultivation in saline areas.

Keywords:

• Sugarcane
• soil salinity
• in vitro mutagenesis
• physio-biochemical
• agronomic performance

Acknowledgements

The authors are thankful to Director General and Director (AS&T), Vasantdada Sugar Institute, Pune, India for providing a research facility. Authors are also thankful to the Plant Breeding Section at Vasantdada Sugar Institute for their help in performing juice analysis and identification of variants and Mr. Mahadeo Shinde, Statistician, Vasantdada Sugar Institute for his help in statistical analysis of the field data.

Disclosure statement

All the authors declare that they do not have a conflict of interest.

Additional information

Funding

The project study has been partially funded by Bhabha Atomic Research Centre (DAE-BRNS project grant sanction number 2009/37/51/BRNS/3306).

Notes on contributors

Madhavi V. Purankar

Madhavi V. Purankar has obtained her Master of Science degree in Environmental Biotechnology, and is currently doing her PhD on sugarcane improvement through gamma radiation-induced mutagenesis.

Ashok A. Nikam

Dr. Ashok A. Nikam has obtained PhD in Biotechnology and has a remarkable contribution in developing mutant sugarcane clones with high salt tolerance and improved yield.

Rachayya M. Devarumath

Dr. Rachayya M. Devarumath is a Scientist at Vasantdada Sugar Institute. He has been working in the area of sugarcane improvement through molecular breeding, mutation breeding as well as molecular characterization of sugarcane germplasm using DNA markers.

Suprasanna Penna

Dr. Suprasanna Penna is the Former-Head of the Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai and Former- Professor, Homi Bhabha National Institute, Mumbai, India. He has made significant contributions to crop biotechnology research through radiation-induced mutagenesis, plant cell and tissue culture, genomics, and abiotic stress tolerance..