Inducing potential mutants in rice using different doses of gamma-rays for improving agronomic traits

Heba A. Elsherbiny1, Mahmoud M. Gaballah1, Hassan Sh. Hamad1, Shimaa M. Sakr1, Osama A. Elbadawy1, Khairiah M. Alwutayd2*, Ridha Boudiar3, Elsayed Mansour4, and Eman M. Bleih1
Mutation breeding offers a simple, fast, and efficient way to rectify major defects without altering their original identity. The current research aimed to study interesting traits in a mutant population generated by gamma rays. Five gamma rays doses (100, 200, 300, 400, and 500 Gy) were applied to develop M1 and M2 mutant populations from the Egyptian rice (Oryza sativa L.) ‘Giza177’. Both populations were evaluated in the field during two successive years 2022 (M1) and 2023 (M2). Several traits related to growth and yield were recorded such as plant height, number of branches and panicles, panicle weight, grain yield, and harvest index. Significant differences were found among radiation treatments for most traits. Overall, low radiation doses (100, 200, and 300 Gy) promoted the growth and productivity of plants; however, high doses (400 and 500 Gy) decreased these traits and increased the number of sterile plants. The effect of radiation doses was different on some traits between M1 and M2. The mutant population M2 displayed several promising mutant lines with desirable traits; early flowering (4-7 d earlier), short plant height (< 95 cm), panicle length (> 23 cm), tiller number per plant (> 25), and grain yield per plant (> 43 g). Conclusively, low gamma rays doses (inferior to 300 Gy) are of interest in generating desirable traits and promising lines. The current promising mutant lines should be further evaluated in multi-year trials to validate their behavior across various field conditions.
Keywords: Agronomic traits, gamma rays, induced mutation, Oryza sativa, rice improvement.
1Field Crops Research Institute, Agriculture Research Center, Rice Research Department, Kafrelsheikh 33717, Egypt.
2Princess Nourah bint Abdulrahman University, College of Science, Department of Biology, Riyadh 11671, Saudi Arabia.
3Biotechnology Research Center-C.R.Bt Constantine, Constantine 25016, Algeria.
4Zagazig University, Faculty of Agriculture, Department of Crop Science, Zagazig 44519, Egypt.
*Corresponding author (kmalwateed@pnu.edu.sa).