Rakesh K
International Rice Research Institute, Philippines
Title: QTL Identification for Reproductive-Stage Salinity Tolerance in Rice using Novel Phenotyping Technique
Biography
Biography: Rakesh K
Abstract
Rice responds differentially at different stages of development. The seedling and reproductive stages are the most sensitive growth stages with very weak association, suggesting that they are regulated by different processes and sets of genes/QTLs. There are hardly any studies exist on reproductive-stage salinity tolerance mainly because of the lack of reliable reproductive-stage-specific phenotyping techniques and incomplete knowledge of the stage-specific mechanisms of salinity tolerance.Two major challenges for screening exclusively for the reproductive stage are, 1) how to stress plants at the reproductive stage without stressing them at the seedling or late vegetative stage; and 2) how to impose the stress on different genotypes or mapping populations at equivalent growth stages of development because of the variability in the progression of growth rate through developmental stages. We standardise a methodology that allows salt translocation to the reproductive organs such as the flag leaf (the largest source for the sink) and panicle as quickly as possible just at the initiation of booting when the genotypes are at the same stage of tissue/organ development rather depending on age of the plant. A mapping population derived from CSR28/Sadri was used QTL identification using the novel phenotyping technique and 6K illumina SNP platform. Salt stress equivalent to EC 10 dSm-1 was imposed on rice plants with trimmed leaves starting from boot leaf emergence up to 20 days in an experiment. Stage-specific effect of salt stress was verified by observing salt-sensitive and salt-tolerant genotypes. Details will be presented.