PHENOTYPIC CHARACTERIZATION OF MULTI-PARENT ADVANCED BREEDING LINES FOR SUBMERGENCE TOLERANCE IN RICE (ORYZA SATIVA L.)

Abstract

Submergence is one of the major abiotic stresses limiting rice production in flood-prone ecosystems, causing substantial yield losses. The present study was undertaken to assess genetic variability and identify submergence tolerant, high-yielding rice genotypes among multiparent advanced generation intercross (MAGIC) lines. A field experiment was conducted during kharif 2023 at the Zonal Agricultural and Horticultural Research Station (ZAHRS), Shivamogga, using 50 MAGIC lines along with eight check varieties in a randomized complete block design with two replications. Analysis of variance revealed significant differences among genotypes for all the traits under both submergence and non-submergence conditions, indicating the presence of considerable genetic variability. Submergence tolerance screening was performed by subjecting the genotypes to complete submergence for 14 days, including the national tolerant check Swarna Sub1, the local tolerant check Hemavathi, and the susceptible check Jyothi. Survival percentage and stem elongation percentage were recorded seven days after de-submergence, and genotypes were evaluated according to the International Rice Research Institute (IRRI) standard evaluation system. Genetic variability and character association analyses revealed substantial variation among the genotypes and significant positive associations of grain yield with several yield-contributing traits. Two MAGIC lines exhibited consistent superiority under both submergence and normal conditions by recording higher grain yield and survival percentage than the check varieties. These promising genotypes can be utilized in future breeding programmes and subjected to multi-location trials and genomic selection for the development of submergence-tolerant, high-yielding rice cultivars.