Mutation induction in aromatic Joha rice of Assam for improvement of morpho-agronomic traits through M₁ to M₃ generation

Abstract

Purpose

The popular Joha rice cultivar Kon Joha, cultivated throughout the state, was used to induce mutations. Kon Joha is short-grain aromatic rice with excellent cooking quality. The cultivar is tall and late maturing with an average yield of less than 2 tons ha⁻¹ and is susceptible to lodging

Materials and methods

The investigation through M₁ to M₃ generation aimed at improving the morpho-agronomic traits of the popular Joha rice cultivar Kon Joha. The experiments were carried out during the Sali season (winter rice) from 2017 to 2019 at Instruction-cum-Research (ICR) Farm of Assam Agricultural University, Jorhat (Assam). Dry uniform seeds of Kon Joha were subject to irradiation with 100–400 Gy of gamma rays from a ⁶⁰Co source. The M₁ generation used a randomized complete block design with four replications during Sali 2017. A total of 5998 M₁ plant progenies were subject to screening in the M₂ during Sali 2018. The M₃ included 662 morpho-agronomic variants raised in the plant rows during Sali 2019, and 66 mutants were confirmed.

Results

The M₁ of Kon Joha registered a reduction in germination, seedling height, pollen/spikelet fertility and plant survival at 400 Gy. All the traits showed highly significant differences among the doses in the M₂ generation. The shift in trait means was in both directions as influenced by the genotype and mutagen dose. The 66 mutants exhibited significant differences for all traits in the M₃ generation. Fifty mutants were shorter than the parent Kon Joha. The GCV and PCV estimates were high (>20%) for grain yield, biological yield, productive tillers, filled grains, and average panicle weight. All the traits except panicle length exhibited high heritability coupled with high genetic advance, suggesting the predominance of additive gene action and the effectiveness of simple selection. Grain yield showed a significant positive correlation with plant height, panicle length, filled grains, spikelet fertility, the average panicle weight and harvest index in the mutant population.

Conclusions

Thus, mutation induction in Kon Joha proved useful in inducing desirable changes in plant architectural traits. The study further emphasized the short stature high yielding mutants with strong aroma for wide-scale testing in the state.

Keywords:

• Joha rice
• gamma radiation
• mutant
• heritability
• mutation induction

Author contributions

Research concept and design: Debojit Sarma, Nagendra Sarma Barua and Bikram Kishore Das; collection of data: Dibosh Bordoloi; data analysis and interpretation: Debojit Sarma and Dibosh Bordoloi; writing the article: Dibosh Bordoloi; critical revision of the article: Debojit Sarma and Bikram Kishore Das; finally approved by all authors.

Disclosure statement

No potential conflicts of interest are reported by the authors.

Additional information

Funding

This research was financially supported by Directorate of Post Graduate Studies, Department of Plant Breeding and Genetics, Faculty of Agriculture, Assam Agricultural University, Assam and Board of Research in Nuclear Science (BRNS), Department of Atomic Energy, Government of India, Mumbai. The authors gratefully acknowledge Bidhan Chandra Krishi Viswavidyalaya, West Bengal for providing irradiation facilities.

Notes on contributors

Dibosh Bordoloi

Dibosh Bordoloi, PhD, Subject Matter Specialist at Krishi Vigyan Kendra, Karimganj, Assam Agricultural University, Assam, India

Debojit Sarma

Debojit Sarma, PhD, Professor of Department of Plant Breeding and Genetics, Assam Agricultural University, Jorhat, Assam, India

Nagendra Sarma Barua

Nagendra Sarma Barua, Professor of Department of Plant Breeding and Genetics, Assam Agricultural University, Jorhat, Assam, India

Bikram Kishore Das

Bikram Kishore Das, Scientific Officer of Nuclear Agriculture & Biotechnology Division, Bhabha Atomic Research Center, Mumbai, India