Interéaction of submergence tolerance and drought yield QTLs (Sub1 and qDTYs) enhances morpho‐physiological traits and survival of rice (Oryza sativa L.) under submergence

• Published in: Annals of applied biology 2021-03, Vol.178 (2), p.355-366
• Main Authors: Mohd Ikmal, Asmuni, Noraziyah, Abd Aziz Shamsudin, Wickneswari, Ratnam, Amira, Ismail, Puteri Dinie Ellina, Zulkafli
• Format: Article
• Language: English
• Subjects: Agricultural production; breeding; Carbohydrates; Chlorophyll; Climate change; Drought; Elongation; Environmental changes; Flooding; Gene mapping; non‐structural carbohydrate; Physiological effects; Physiology; Plant breeding; Populations; Quantitative trait loci; Rice; Sub1 introgression; Submergence; submergence tolerance; Survival; Yield
• ISSN: 0003-4746; 1744-7348
• DOI: 10.1111/aab.12664

Climate change has caused increasing incidences of the extreme flooding around the world, which has impacted rice production, especially in rainfed ecosystems. Breeding for submergence tolerant rice varieties has been conducted to mitigate the adverse effects and help farmers to reduce yield loss. The present study was carried out to introgress the submergence tolerance QTL (Sub1) from IR64‐Sub1 into drought‐tolerant lines; UKM5 and UKM91 possessing the drought yield quantitative trait loci (qDTYs), viz. qDTY12.1 and qDTY3.1, and to evaluate the effects of the combination of these QTLs in improving the morpho‐physiological traits and survival under submergence. UKM5 and UKM91 were selected as the recipient of the Sub1 locus because of the intermediate submergence tolerance they possessed even though they only have qDTY/s. Therefore, the introgression of Sub1 into these lines was hypothesised to enhance survival. Submergence stress was given for 14 days to BC1F4 lines from the two breeding populations. Lines with better survival than the tolerant check, IR64‐Sub1 were selected and evaluated under 18 days of submergence stress. Generally, lines with Sub1 and qDTYs from UKM5*/IR64‐Sub1 and UKM91*/IR64‐Sub1 populations had higher survival rate (SR) of 90–100%, lower shoot elongation percentage (EP) and a smaller percentage of chlorophyll content change (CCC) than IR64‐Sub1. The selected lines also showed a low percentage of non‐structural carbohydrate change (NSCC) which related to the ability to recover after submergence. In both populations, the interaction of qDTY3.1 with Sub1 proved to give the best improvement on EP and CCC. This experiment provides novel findings; that is, the combinations of Sub1 + qDTY12.1 + qDTY3.1 showed high survival rate in the population of UKM5*/IR64‐Sub1, while qDTY3.1 improved SR of the lines from UKM91*/IR64‐Sub1 population to 100%. These results proved that the action of Sub1, qDTY/s and their interaction differ in contrasting population or background. The QTL combinations showed a consistent effect in both submergence experiments and proved the effectiveness of Sub1 and qDTYs combinations in enhancing the morpho‐physiological traits and survival. Introgression of Sub1 from IR64‐Sub1 into drought‐tolerant lines; UKM5 and UKM91 possessing the qDTYs viz. qDTY12.1 and qDTY3.1 was carried out. The effects of the combination of these QTLs in improving the morpho‐physiological traits and survival under submergence were evaluated. B