Impact of Submergence1 (Sub1) Locus in Genetic Background of Modern Rice Varieties (Oryza sativa L.)

Aim: To improve submergence stress tolerance of modern rice varieties (ADT36 and ADT37) through selection of superior rice lines.

Study Design: Backcross method.

Place and Duration of Study: This effort was taken in Nethouse of Kandaswami Kandar’s College, Namakkal District, Tamil Nadu, India. This process was completed in four years from 2019 to 2022.

Methodology: Here, widely cultivated two short-term rice varieties (ADT36 and ADT37) were selected to improve submergence tolerance based on polymorphism at phenotypic and genotypic level. Then, they were improved through backcrossing with respective recurrent parent by selection of superior rice lines compared to parental lines under submergence condition. Likewise, this process was advanced up to BC3F2 generation.

Results: In this study, a number of two NILs for ADT36 rice variety (ADT36- F12-5-19.18 and ADT36- F15-2-5.17) and five NILs for ADT37 rice variety (ADT37- F113-27-5.2, ADT37- F113-27-5.5, ADT37- F115-2-1.10, ADT37- F115-2-1.14 and ADT37- F115-2-2.14) are selected as superior lines.Selected rice lines exhibited more than 60% submergence tolerance than donor parent. This result indicates the adaptation of Sub1 locus into new genetic background of ADT36 and ADT37 rice variety under submergence condition.

Conclusion: Improvement process of rice lines under stress condition results in identification of highly active rice lines. Thus, selected submergence tolerant rice lines would be a boon to the rice farmers who are facing crop lose due to frequently occurring cyclones in the Cauvery delta region.