Multi-omics Analyses Dissect The Genetic Basis Of Heterosis

Heterosis plays important roles in rice hybrid breeding,but the underlying genetic mechanism is still not clear.The present study employed genomics,transcriptomics analysis and several genetic segregating populations to dissect the genetic basis of heterosis.The main conclusions are as follows.1.Genomes of the super hybrid rice’s parents were assembled,structure variations between them were analyzed and identified.The PAV of elite alleles from both parents contributed to the heterosis of super hybrid rice.2.The expression pattern of super hybrid rice and hybrid mimic was similar.Down-regulation of genes participated in plant defense response contributed to biomass and heterosis in rice.3.Quantitative trait locus mapping were conducted using three testcross populations and chromosome segment substitution backcross population,many QTL intervals of heterosis have important elite alleles controlling agronomic traits.These alleles were important hybrid breeding target.The accumulation or pyramid of these elite alleles will contribute to heterosis of super hybrid rice.4.Accurate physical maps for three sets of chromosome segment substitution lines with different backgrounds were obtained,which provided a platform for basic genetic research and molecular rice breeding.Combining genome-wide association for grain length and transcriptome analysis of young panicle,we could fine mapped qGL1 to a 119kb region.It will provide new candidate genes for improving rice grain breeding.