Rice seedling establishment as affected by cultivar, seed coating with calcium peroxide, sowing depth, and water level

Abstract

Inconsistent seedling establishment is a constraint to the adoption of direct seeding of lowland rice ( Oryza sativa L.) in the tropics. Rice cultivars with superior seedling establishment in flooded soil have been recently identified. The establishment of these tolerant cultivars was compared with a control cultivar with and without calcium peroxide-coated seed under various combinations of water level and sowing depth. Water level had little effect on seedling establishment when seed were sown on the soil surface, but establishment was reduced by raising the water level when seed were sown below the soil surface. Calcium peroxide-coated seed established better than the tolerant cultivars at 13- and 25-mm sowing depths, but their seedlings were shorter and less vigorous than those of tolerant cultivars. Tolerant cultivars and coated seed had longer mesocotyls than controls. Sowing tolerant cultivars beneath a flooded soil surface at less than 13 mm assists achievement of consistent seedling establishment in lowland rice production.