Development of Salinity and Submergence Tolerant Rice Lines

Paddy fields of coastal belt of Wet Zone of Sri Lanka are subjected to submergence during rainy period and saline water intrusions during dry spell. These fields require rice varieties with both salinity and submergence tolerance. To incorporate submergence and salinity tolerance, two crosses At 354/Bg 455 and Ld 12-2-22-2-1-1 / Ld13-5-7 were made during 2014 Yala and segregating populations were evaluated at Rice Research Station (RRS), Labuduwa under plant house conditions (by submerging 5 days old seedlings for 10 days and surviving plants subjecting to 12 dS m^-1 NaCl solutions) at RRS, Bentota and in selected farmer fields under natural conditions. IRRI 119 x Bg 369 and IRRI 64(Sub1) x Bg 369 crosses were made during 2015/16 Maha and subjected to artificial screening at RRS Labuduwa for both submergence and salinity. From the four crosses 10 lines were selected and screened for salinity and submergence tolerances. Best performing lines were evaluated for yields at RRS Labuduwa during 2018/19 Maha, 2019 Yala and 2019/20 Maha, and at Thunduwa and Rathgama farmer fields in 2019/20 Maha. SS₄- 4, S₂ B₇ (red), C₁ - 33, C₂ - 20, and SS₃-26-1 were identified as tolerant to salinity. S₂B₇ (red), S₂B₇ (white) and N₁ F₂ 1 were identified as submergence tolerant lines. S₂B₇ (red) identified as the variety consisting of both salinity and submergence tolerance and better yields.