Direct seeding is increasingly being practiced by rice farmers under both rainfed and irrigated conditions. The trend is the outcome of a scarcity of labour required for transplanting, simplicity and additional benefits associated with direct seeding. Flooding slows seed germination, imposes fatalities and delays seedling establishment in direct-seeded rice. This study describes responses of contrasting rice genotypes subjected to flooding or low oxygen stress during germination and discusses of tolernace shown by certain cultivars. In expt, two tolerant('Khao Hlan On', 'Khaiyan') and two intolerant('IR 42', 'IR 64') genotypes were used for growth and survival measurements. To compare effects of priming, pre-germination and germination on anaerobic tolerant and intolerant lines. Length of the longest shoot was measured in seedlings grown under either a control or in flooded soil, and plant survival was calculated based on the number of seedlings that emerged from floodwater. All measurements were 21 d after sowing. Tolerant and intolerant genotypes had the same seeding survival under normal soil conditions. But survival of intolerant genotypes were lower than tolerant genotypes. Growth of tolerant genotypes were faster than intolerant genotypes. Among the treatment, treatment 3 was greater. Because treatment 3 emerged first from water. Among the after days 1, 3, 5, survival was highest in after day 1. The other side, To late seeding over time, survival decreased.

• Jaeyong Woo(Department of agronomy Graduate School, Chungbuk National University)
• Abelbagi M. Ismail(Internation Rice Research Insititute)
• Chulwon Lee(Department of agronomy Graduate School, Chungbuk National University) Corresponding author