Chemical Seed Priming to Improve Salinity Tolerance in Rice

Abstract

A study was conducted at Rice Research Station, Vyttila to assess the effect of seed priming in improving the salinity tolerance of rice varieties. The study consisted of two parts. In the first part, screening of rice varieties for salinity tolerance was done and in the second experiment, the effect of priming on salinity tolerance was assessed. The first experiment was a laboratory study to screen three rice varieties, namely, Jyothi, Uma and Vyttila-10 at five salinity levels i.e., non-saline, 3 dS m-1, 6 dS m-1, 9 dS m-1 and 12 dS m-1. Results showed that Jyothi was susceptible to 6 dS m-1 salinity at 16 days after sowing (DAS). Uma was moderately tolerant and became susceptible to 6 dS m-1 at 21 DAS. Vyttila-10 was highly tolerant to 6 dS m-1 salinity but it was susceptible to the salinity level of 9 dS m-1 at 21 DAS. In the second experiment, seeds of these varieties were primed with three chemicals namely beta-amino butyric acid @ 1 mmol L-1, calcium chloride @ 2% and sodium nitroprusside @ 100 µM and with water as control. The seedlings of Jyothi and Uma were raised at salinity levels of 6 dS m-1 and 9 dS m-1, while seedlings of Vyttila-10 were raised at salinity levels of 9 dS m-1 and 12 dS m-1. The efficacy of each priming chemical was analyzed based on germination percentage, growth parameters and visual salt injury symptoms. Priming seeds with calcium chloride was found to improve the growth and salinity tolerance of rice seedlings and could be a reliable method to combat the salinity stress of rice in the initial stages of crop growth.