Genetic dissection of stage-dependent dry matter accumulation in Maize (Zea mays L.) kernel

Abstract Dry matter accumulation (DMA) in kernels is a fundamental requirement for high grain yield maize breeding and harvesting. However, the genetic mechanism underlying how DMA promotes the grain weight at different grain-filling stages is poorly understood. Here, with a recombinant inbred line (RIL) population, we performed a quantitative trait locus (QTL) analysis of DMA during the early and late grain-filling stages under three environmental conditions. Taking 0-45 days after pollination (DAP) as a minimum period to physiological maturity, we investigated the DMA before 45 DAP, designated DMA0-45, and found that 13 DMA QTLs are responsible for DMA0-45 and each could explain 7.11 to 23.64% of the total phenotypic variation. Of them, four QTLs, qDMA5.2, qDMA6.4, qDMA7.2, and qDMA9.2 were consistently detected in at least two of three field trials. For the DMA after 45 DAP, 18 QTLs were detected and they could account for 8.49 to 28.66% of the total phenotypic variation and only qDMA1.2 was consistently detected at Shandong for two years continuously. Since no common DMA QTL was found between the early (0-45 DAP) and the later (after 45 DAP) stage, it is speculated that the genetic control of DMA acts in a stage-dependent manner. Our results will be helpful to further decipher the genetic basis of grain yield formation and provide a sight for grain yield improvement in maize.