Effects of different soil moisture levels on the germination and early vegetative stage of drought-susceptible and droughttolerant varieties of rice (Oryza sativa l.)

Abstract

Drought occurrences brought about by climate change are a major threat to rice production as rice thrives best in waterlogged conditions. Thus, “climate-change-ready” rice was developed by PhilRice and IRRI to ensure food security in a scenario of decreasing soil water levels. This study provides the first detailed evaluation on the germination and early vegetative growth responses of “climate-change-ready” rice varieties (NSIC Rc274, NSIC Rc288, NSIC Rc346, NSIC Rc348) and one droughtsusceptible (PSB Rc82) variety subjected to decreasing soil water levels. Results showed high germination percentage of each rice variety across all water levels except for NSIC Rc288 and NSIC Rc348. No significant differences were found across soil water levels in the mean root lengths, mean root-shoot dry weight ratios, mean leaf areas, and mean leaf counts in the early vegetative stage of the three remaining rice varieties. Among the growth parameters tested, mean shoot length was the best indicator of water stress for the drought-tolerant NSIC Rc274 (R=0.815) and NSIC Rc346 (R=0.847) rice. At germination and early vegetative stage, PSB Rc82, NSIC Rc274 and NSIC Rc346 rice varieties showed drought tolerance. Thus, these may be utilized to mitigate the projected future scarcity of rice production.