Effect of Different Priming Methods on Seed Viability and Seedling Growth of Upland Rice under Drought Stress

Abstract

This study aims to determine the effect of different priming methods on the viability and early growth of upland rice under drought stress.  Priming is an important approach to improve the resistance of upland rice plants to drought stress from the germination phase to growth, especially on sub-optimal land. There are several efficient priming methods as seed pretreatment to increase germination and tolerance to drought stress. An effective priming method is needed to increase the germination and growth of upland rice seedlings for application in dryland agriculture. Therefore, an experiment was conducted at the Seed laboratory of Pangkep State Polytechnic of Agriculture, Indonesia, from September to October of 2022 to investigate the effect of several priming methods on the germination and growth of upland rice seedlings under drought stress. The experiment consisted of 2 stages, germination testing and seedling growth phase testing with the addition of water stress treatment. Experiment 1 was conducted in a completely randomized design (CRD) with four replications, including Control (no priming), Osmopriming with 15% and 20% PEG solution, Redox Priming with 3% and 6% H2O2 solution, and Organic Priming using 50% and 75% Moringa leaf extract. Experiment 2 was conducted using a two-factor of factorial in Randomized Block design (RBD) with three replications. The first factor is the Seedling results of stage 1 experiments (selected the best of each priming method) includes 4 treatments each Control treatment, Osmopriming with 15% PEG solution, Redox Priming with 3% H2O2 solution, and Organic Priming with 50% Moringa Leaf Extract.  The second factor is the level of Drought Stress conducted by 100%, 60%, and 30% of Field Capacity. The results showed that the priming method with Osmopriming 15% PEG solution gave the best results on Seed germination percentage (87.5%) followed by Organic priming with 50% Moringa Leaf Extract (SGP 85%). Under drought stress conditions with 30% field capacity, the highest increase in proline levels was observed with H2O2 redox priming 3%  (10.3 µ-mol. g-1 ), while the average root growth of all primed seedlings showed better root growth than seeds without priming treatment. Seed priming gives better results on the growth and physiological activities of upland rice at several levels of drought stress, in the early growth phase of seedlings