Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/11/2023
Publication Date: N/A
Technical Abstract: Increasing ambient temperatures during growth and development of rice affect its grain yield and quality. Previous studies identified the rice variety TeQing (TQNG) as heat-stress tolerant and recent experiments have found that tropical japonica rice (TRJ) varieties such as Lemont (LMNT) are heat stress susceptible. The objective of this study was to identify thermotolerant quantitative trait loci (QTL) derived from TeQing for use in genetic improvement of the US tropical japonica rice varieties. A chromosome segment substitution line (CSSL) mapping population (N=121) derived from LMNT x TQNG was phenotyped for several traits, including percent floret sterility, grain yield and quality, using a replicated study with two planting dates, 30 days apart, over two years. Dense molecular marker data, previously obtained for this population via genotyping-by-sequencing (GBS), was used for QTL mapping. Several QTLs and candidate genes associated with grain yield, quality, and overall thermotolerance mechanisms were identified. Specifically, eight genetic loci on four different chromosomes and nine potential candidate genes were found to be strongly associated with superior performance under heat stress. Identified QTLs are novel targets for fine mapping, candidate gene verification, and marker-assisted breeding in future studies to incorporate heat stress tolerance in US rice varieties.