Improvement of high yielding inbred rice with better grain quality: variety Ld376 for general cultivation in Sri Lanka

Aiming at yield increase through plant type improvement, pest and disease tolerance, and wide adaptability, the locally developed high-yielding rice variety At362 was hybridized with Milyang23, a high-yielding Korean rice variety. From the resulting cross, a line, Ld8-13-4, was selected based on better yield and agronomic characters and was crossed again with IR79200-65-2-2, a bacterial leaf blight-resistant line with proven phenotypic acceptability. The study was conducted at the Rice Research Station, Labuduwa, Sri Lanka, from 2009–2015. Generation advancements from F1 to F8 were carried out from the Yala – 2010 to 2013/14 Maha seasons. From the preliminary evaluation of the 2013/14 Maha and 2014 Yala trials, six lines were selected for the major yield trials and evaluated in a Randomized Complete Block Design with standard check varieties and three replicates during the 2014/15 Maha and 2015 Yala seasons. The long slender line, Ld12-6-22-1-2, performed better in yield and had acceptable grain qualities. It was nominated to National Coordinated Rice Variety Test (NCRVT) and tested with Bg94-1 from the 2017 Yala to 2018 Yala seasons. The line was tested at different farmer fields during the 2019 Yala and 2019/20 Maha in Variety Adaptability Trials (VAT). Ld12-6-22-1-2 recorded better yields than the standard check variety Bg94-1, was superior in both Dry and Wet Zones, and ranked first for both variance component and rank method. Ld12-6-22-1-2 recorded more than 10 t/ha in four locations in the farmer fields, resembling the potential for high yield. The line showed an acceptable tolerance level to brown plant hopper, rice gall midge, bacterial leaf blight, and rice blast, with quality milled rice and good taste. It was the first long, slender white rice in the 3.5-month age category.