Genetic variation among the salinity tolerant breeding lines identified from two multi‐parent advanced generation introgression line populations in rice (Oryza sativa)

Abstract

AbstractSalinity is a major environmental constraint affecting rice production in both irrigated and non‐irrigated areas and threatening global food security. Development of salt‐tolerant rice varieties with desirable agronomic traits is a logical approach to maintain high yield in saline areas. Here, we report development of two multi‐parent advanced generation introgression line (MAGIL) rice populations in two US cultivar backgrounds and their physiological and morphological evaluation under salinity stress at germination and seedling stages. From the initial screening of 180 MAGILs in sand culture, 36 tolerant‐to‐moderately salt‐tolerant lines were selected and further confirmed in hydroponics experiment. The selected MAGILs showed lower root and shoot Na+/K+ ratio compared with the recurrent parents. The principal component and cluster‐based analysis using 12 morphophysiological traits revealed grouping of the selected lines with tolerant donors. Genotyping results with 100 polymorphic SSR markers indicated a low level of genetic diversity among these lines. Clustering based on molecular marker data separated the MAGILs from the salt tolerance donors in both populations but were grouped with the recurrent parents, suggesting genetic similarity of MAGILs with recurrent parents. The salt‐tolerant MAGILs identified in this study are useful resource for investigating molecular and physiological bases of salt‐tolerant mechanisms as well as for evaluating their yield potential for release as salt‐tolerant rice varieties.