Abstract
Unraveling the complex genetic bases and mechanisms underlying salt tolerance is of great importance for developing salt-tolerant varieties. In this study, we evaluated 42 chromosome segment substitution lines (CSSLs) carrying chromosome segments from IR64 on the genetic background of Koshihikari under salt stress. Two CSSLs, SL2007 and SL2038, produced higher plant dry weight and grain yield than did Koshihikari under the stress condition. These CSSLs also showed lower Na+ and Cl− accumulation in the leaf and whole plant at the full heading stage, which might be related to the higher grain yield and yield components. To understand the genetic control of its grain yield and yield components, a SL2007/Koshihikari F2 population was generated for quantitative trait locus (QTL) analysis. Six QTLs for grain yield and yield-related traits were detected on chromosome 2. Using near-isogenic lines (NILs) from a SL2007/Koshihikari F5 population, qSTGY2.2 was delimited to a 2.5 Mb region and novel qSTPN2 was delimited to a 0.6 Mb region. We also detected a novel QTL, qSTGF2, for grain filling, which was considered an important contributor to grain yield under salt stress in this CSSL. Our results provide insights into mechanisms conferring grain yield under salinity stress and new genetic resources for cloning and breeding.
Highlights
Rice is a staple crop feeding the largest number of people on Earth, and it provides approximately one-quarter of global energy consumption per capita [1]
In agreement with the above findings, our result suggests that the maintained grain yield and yield components in the salt-tolerant chromosome segment substitution lines (CSSLs) could be attributed to low Na+ and Cl− accumulations in the leaf and whole plant at the full heading stage
The results indicate that IR64 possesses potential genetic factors conferring salt tolerance at the vegetative and reproductive stages
Summary
Rice is a staple crop feeding the largest number of people on Earth, and it provides approximately one-quarter of global energy consumption per capita [1]. The situation is becoming more urgent as millions of hectares of suitable land areas used especially for rice production in South and Southeast Asia, responsible for 90% of rice production worldwide, have been left uncultivated [6,7,8]. This calls for breeding salt-tolerant varieties with high yields to ensure food security and reutilize the land made unproductive by salt accumulation. As grain yield and yield contributors are severely depressed, tolerance at the reproductive stage deserves special attention
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