PRIMING OF RICE SEEDS FOR IMPROVEMENT IN GERMINATION AND ADAPTATION TO DROUGHT STRESS
Rice demand keeps increasing drastically due to the current global population growth. Rice production is not keeping pace with the increase in population due to several factors, including drought stress which affects plant growth and development. At the national level, available rice varieties have low to moderate tolerance to drought stress. The application of seed priming can improve this level of tolerance. However, interaction of seed priming with popular and locally grown varieties in response to drought stress has not been explored yet. This study aimed at i) determining how priming improves seedling establishment, ii) assessing the effect of priming on rice agro morphological traits under water deficit, and iii) evaluating the effect of primed seeds grown under water deficit on vigour of the progenies. Two different concentrations each of ascorbic acid (20 ppm and 10 ppm) and salicylic acid (10 ppm and 5 ppm), hydro-priming for 48 hrs, and dry control seeds were used. Agra and Jasmine rice varieties were planted in pots containing 4kg Vertisol soils where water heads were created on all the pots. Water stress conditions were imposed on the plants at two different growth stages viz. vegetative and booting. The stress was done by not watering the plants for ten days, after which they were watered and pounded to the required water head. The results showed that water stress during the vegetative stage did not have a significant effect on the yield as compared to water stress at the booting stage. Seed priming with plant growth regulators and distilled water improved the germination and vigour index of the two varieties over the dry control treatment. Treatment of the seeds with ascorbic acid and salicylic acid reduced drought stress in rice production. Seeds primed with salicylic were the most efficient in improving germination, seedling vigour and reducing drought stress. The study, therefore, highlighted the need to treat rice seeds with ascorbic acid and salicylic acid in order to enhance seed germination and vigour and reduce drought stress. This would intend to increase rice productivity in drought-prone areas in Ghana.