Drought tolerance (DT) or water-saving is becoming one of the most important target traits in rice breeding community under ever-increasing severe drought situation all over the world. The introgression line "PD29" with IR64 genetic background has promising yield performance under both drought (stress) and irrigation (control) conditions. In the present study, the physiological characteristics related to stress tolerance of the "PD29" were analysed with recurrent parent, 1R64, and upland rice cv. IRAT 109 as the control varieties under both drought and irrigation conditions. "PD29" not only had higher leaf relative water content (RWC) under stress but also could recover RWC to a fully turgid (hydrated) state 2 h after rewatering, which indicated that "PD29" has higher DT ability than the control cultivars at the tillering stage. Further analysis showed that "PD29" not only had higher maximum photochemical of ΦPS II efficiency (Fv/Fm), osmotic potential (Ψ), proline content (Pro), and antioxidant activity (AOA) than IR64 under drought condition but also presented less decrease in the Fv/Fm and RWC, and more decrease in net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) and more increase in Pro and AOA. Furthermore, compared to IRAT1O9, "PD29" had higher Pro and more increase in the AOA under drought condition. The promising DT-performance of "PD29" was related to the significant increase of AOA and proline under the drought. Moreover, the significant decrease of the Pn, Gs, and Tr under the drought condition indicated that "PD29" has strong plasticity in photosynthetic capacity, which can maintain high photosynthesis under the adaptive circumstance and decrease water loss through transpiration under stress conditions.

drought, drought resistance, irrigation, leaf conductance,osmosis, photosynthesis, plant water relations, proline, rice, stomata,transpiration, water stress, Oryza, Oryza sativa, Oryza, Poaceae,Cyperales, monocotyledons, angiosperms, Spermatophyta, plants,eukaryotes, carbon assimilation, carbon dioxide fixation, droughttolerance, paddy, watering, Field Crops (FF005) (New March 2000), PlantPhysiology and Biochemistry (FF060), Plant Water Relations (FF062), SoilWater Management (Irrigation and Drainage) (JJ800) (Revised June 2002)[formerly Soil Water Management]

• Journal Article

• Drought
• Irrigation Management