Identification And Genome-wide Association Analysis Of Cold Tolerance In Japonica Rice At The Germination Stage

In recent years,direct seeding rice has attracted much attention due to its low labor intensity,saving rice field and high efficiency.It has developed rapidly around the world and has become an important cultivation method.The cold tolerance of rice during the germination period directly affects the seed germination rate of rice direct seeding and seedling establishment,which in turn affects rice yield.Therefore,studying the genetic mechanism of cold tolerance at the germination stage of rice,discovering and using cold-tolerance related genes,and cultivating new rice varieties suitable for direct seeding in low-temperature areas are of great significance for improving rice productivity.In this study,295 japonica rice varieties were used as test materials to identify cold tolerance at the germination stage of rice,and 788,396 high-quality SNPs obtained by resequencing were used for GWAS analysis to obtain QTL sites related to cold tolerance at the germination stage of japonica rice.The selection of direct seeding varieties in low tem perature areas and the use of molecular breeding to improve the cold tolerance of japonica rice provide a theoretical basis.The main results of this article are as follows:（1）Under the conditions of low temperature treatment（14℃）and control（26℃）,a statistical analysis of the germination rate of 295 japonica rice at the germination stage found that there were extensive phenotypes in both relative germination potential（LTGP）and relative germination index（LTGI）The difference is that there are 32 copies of materials with LTGP≥80%,35 copies of materials with LTGI≥80%,and 27 copies of strong cold-tolerant materials with both≥80%,respectively Ju Dapei,Wan Dalu,Lu Weidao,Hong Mao,Jin Gou,Lu Yu and so on.（2）The mixed linear model（MLM）of TASSLE5.0 software was used to analyze the correlation of cold-tolerance traits in japonica rice during germination.Under the condition of P≤5.46×10^-6,a total of 9 QTL loci significantly correlated with cold-tolerance were detected on rice chromosomes 1,4,6,8 and 10.Among them,6 QTLS or adjacent sites can retrieve the known function of the cold tolerance gene.