Analysis of Submergence Tolerance Index in Selected Rice (Oryza sativa l.) Cultivars Grown in Kebbi State, Nigeria
Ja’afar Umar *
Department of Biological Sciences, Federal University Birnin Kebbi, Nigeria.
Kasimu Shehu
Department of Biological Sciences, Federal University Birnin Kebbi, Nigeria.
Adamu Aliyu Aliero
Department of Plant Science, Usmanu Danfodiyo University Sokoto, Nigeria.
Abubakar Muhammad Gumi
Department of Plant Science, Usmanu Danfodiyo University Sokoto, Nigeria.
Jamilu Danjumma Koko
Department of Biological Sciences, Federal University Birnin Kebbi, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Aims: Submergence is a major abiotic stress limiting rice production in flood-prone regions such as Kebbi State, Nigeria. This study evaluated the submergence tolerance of six rice cultivars (MAI HIJABI, CP 60, FARO, FARO 40, SWARNA-SUB1, and IR64) based on survival rate, shoot elongation, elongation rate, and Submergence Tolerance Index (STI).
Study Design: The experiment was laid down in a completely randomized design consisting of six cultivars and each replicated three times.
Methodology: The experiment was conducted using a completely randomized design in pots under controlled submergence (14 days), followed by a 7-day recovery period.
Results: Results showed that SWARNA-SUB1 exhibited the highest survival rate (100%), longest shoot elongation (53.76 cm), highest elongation rate (3.28 cm/day), and superior STI (66.67%), confirming its high tolerance due to the presence of the Sub1A gene. CP 60 and Faro 40 recorded moderate STI values (33.34%) and showed some submergence resilience. Conversely, Mai Hijabi, Faro, and IR64 recorded 0.00% STI and low survival, indicating high susceptibility. While shoot elongation contributed to tolerance, excessive elongation, as seen in Mai Hijabi, did not correlate with survival, suggesting energy depletion.
Conclusion: This study highlights the potential of Swarna-Sub1 for cultivation in flood-prone areas and recommends its use in breeding programs to improve rice resilience to submergence stress.
Keywords: Submergence, rice, tolerance, index, cultivars