Principal Scientist ICAR-IARi,New Delhi-110012 New Delhi, Delhi, India
Body of Abstract: Malini MK, Sudhir Kumar, and Madan Pal Singh*
ICAR-Indian Agriculture Research Institute, New Delhi, India
*Correspondence: madanpal@yahoo.com
Abstract
Photosynthesis is an important anabolic process that produces energy for the cellular activities and contributes to the yield potential of the crop plants. Though it is light-dependent but is highly sensitive to rising temperature. Exploring the natural diversity for photosynthetic capacity in rice would facilitate its genetic improvement for changing future climate conditions. A study was conducted to phenotype a panel of rice accessions for reproductive stage high temperature stress tolerance and to identify single nucleotide polymorphisms (SNPs) associated with gas exchange and yield-associated traits through a genome-wide association study (GWAS) and analysing the relationships among these traits in rice accessions. A set of 140 Indian rice accessions were raised in pots under ambient field conditions (Ambient temperature, 32/28°C) till booting stage and exposed to high temperature stress (38/28°C) under controlled conditions till maturity. Rate of photosynthesis and related gas-exchange traits were estimated under both the environment at post anthesis stage and yield-associated traits were measured at maturity in all the rice accessions. The findings of the study showed large variability in all gas-exchange and yield and related traits under ambient and high temperature environment. In majority of the accessions, rate of photosynthesis and yield traits decreased due to high temperature stress but some of the accessions showed no significant changes and few of them exhibited significant increase for all the traits analysed under high temperature. The associated novel QTNs and candidate genes were elucidated from SNP associations identified from GWAS. This study has identified donors with high temperature tolerance which can be further analysed in future studies and selected as source for developing climate resilient rice genotypes.