Improved Management Options for Submergence-Tolerant (Sub1) Rice Genotype in Flood-Prone Rainfed Lowlands of West Bengal

Abstract

Flash flood or submergence is a common phenomenon in rice growing rainfed lowland areas that seriously af-fects crop establishment leading to severe yield losses. A few submergence-tolerant rice varieties have been de-veloped by introgressing SUB1 gene into mega rice varieties of South Asia. Two of these, Swarna-Sub1 and Sambha Mahsuri-Sub1, are already released in India for the commercial cultivation. Performance of these va-rieties can be further enhanced through adoption of appropriate management practices both in nursery and in main field. Two on-station field experiments were conducted using Swarna-Sub1 during the wet season (kharif) of 2011 at Rice Research Station, Chinsurah, Hooghly, West Bengal (India). Results of these experiments re-vealed that the use of lower seeding density (25 g m −2), application of balanced doses of N-P 2 O 5 -K 2 O @ 80-40-40 kg ha −1 in nursery and transplanting of aged seedlings (44 days) significantly improved plant survival, yield attributing traits and grain yield. An additional N-dose of 20 kg ha −1 at 7 days after receding of flood water re-sulted in better post-submergence recovery and maximum grain yield. In the on-farm trials conducted at three different locations in West Bengal, nursery raising of seedlings with the application of N-P 2 O 5 -K 2 O @ 80-40-40 kg ha −1 , transplanting them at an optimum age (35 days) and application of 20 kg·N ha −1 after 7 days of de-submergence produced maximum grain yield of Swarna-Sub1.