Improve tolerance of elite mutation derived rice breeding lines to vegetative stage submergence stress under field condition
2019
Buluran, R.D. | Conception, J.S. | Desamero, N.V.
Addressing the emerging concerns of climate-change aggravated risks of flash-flooding in submergence prone areas, fast-paced development of tolerant varieties Jepun, Y Dam Do, and popular rice variety NSIC Rc 222 to increase yield, improve agronomic traits, improve eating quality and improve abiotic stress tolerance. A total of 34 elite mutation derived breeding lines, and its progenitors Jepun, Y Dam Do, and NSIC Rc222 were developed, and evaluated for tolerance to submergence stress at vegetative stage Lines were completely submerged under murky irrigation water for 7 days at an average of 83 cm, pH 9.10, 27 deg C water temperature, and 121.19 mV oxidative reduction potential. All the thirteen elite NSIC Rc 222-derived mutant lines showed higher percent plant survival compared to its progenitor (43%) by 7 - 36%. Similarly, all of the five Y Dam Do-derived mutant lines had higher percent survival than its progenitor (8%) by 7% to 43%. However, the lines were phenotyped as susceptible. Of the 16 Jepun-derived mutant lines, five (31%) had higher percent plant survival than its progenitor (63%) by 2 - 16%. Overall, the mutant lines had an average percent plant survival of 53%. Eight mutant lines derived from Japun and NSIC Rc 222 were phenotyped as moderately tolerant to submergence stress at vegetative stage based on comparative survival with tolerant check FR13A (92% survival). Excellent seedling vigor and growth response was observed in the mutant lines in terms of tiller number and plant height, with significant correlation with increasing plant survival percentage. Identified tolerant lines are potential new sources of tolerance to submergence stress for rice varietal improvement. The lines warrant field performance trial under submergence stress to validate performance of identified tolerant lines.
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