Tolerant varieties and exogenous application of nutrients can effectively manage drought stress in rice

Abstract

Common abiotic stresses in rainfed rice areas like drought can occur at any phase of crop growth and may occur periodically. Variation in intensity and severity of drought requires the use of different rice varieties and different nutrient management strategies. This study evaluated the morphological and physiological response of contrasting rice cultivars (Rajalaxmi, IR64, and Sahbhagidhan) to various nutrient combinations under water sufficience and scarce conditions. Drought stress at vegetative stage significantly reduced tiller formation, dry matter remobilization,and photosynthesis, leading to around 41.6% yield reduction. The effect of drought stress was more evident in Rajlaxmi and IR64 by a yield reduction of 57.4% and 43.2% as against only 24.3% in Sahbhagidhan. The combined application of nutrients resulted in higher proline accumulation, chlorophyll and carbohydrate concentrations, and photosynthesis and antioxidant enzymes, ultimately better tolerance to drought. This is reflected in higher values of tolerance indices and low scores of leaf drying and leaf rolling, especially for Sahbhagidhan. The combined application of P, K, Ca, Zn, and Fe resulted in 52.9, 53.3, 48.9% higher yield over P or K application. Rice drought tolerance can be managed by combining breeding of drought tolerant high yielding varieties with proper application of fertilizer nutrients.