Research progress on the Heading Date of rice in Northeast China

Rice heading date(HD) refers to the time from sowing to heading(flowering).HD is one of the most important factors determining rice distribution and grain yield.HD, as a complex quantitative trait, is controlled by a number of genes and diverse environmental factors.In this review, we introduce two conserved flowering pathway, and the complex interaction among various HD genes in rice.We mainly describe the major and minor effect HD genes which control the rice distribution in Northeast China, and diverse haplotypes of each HD gene.We highlight that combination of different haplotype of multiple HD genes determine the rice distribution in Northeast China.In addition, we describe a CRISPR/cas9-mediated breeding technique by which the HD of cultivar can be efficiently shortened by mutating the heading date repressors genes, and adapted growth region of elite cultivar can move northward and planting area will be increased, simultaneously.This technique will facilitate to introduce new rice germplasms from South China to Northeast China.Based on the current situation of rice breeding and production in Northeast China, we propose to strengthen improving rice quality and increasing growth area by combining molecular design breeding and conventional breeding in future.