Development Of Molecular Markers For Glutinous Rice And New Alleles Creation Of Rice Quality

While China’s rapid socio-economic development and people’s quality of life continue to improve,the demand for high-quality and specialized rice is rising rapidly.Due to its excellent quality traits,glutinous rice is widely used in food care,brewing,making cakes,cold drinks and medicinal purposes,and is very popular among people.Glutinous is a recessive trait,and in actual production,it can easily lead to loss or even deterioration of glutinousness due to crossbreeding and string pollination,which seriously affects the preservation of the seed.In the breeding of glutinous rice,most of the glutinous traits of the cross progeny are heterozygous,and the presence or absence of glutinous traits cannot be accurately reflected by the straight-chain starch content,which must wait until the cross progeny strains are stable to be accurately analyzed,which greatly increases the breeding workload.The biosynthesis of rice starch is mainly regulated by a starch synthase(GBSS I)encoded by the waxy gene(Wx).However,Wx genes are differentially expressed in different backgrounds and are susceptible to environmental temperature and other factors,so the creation of new rice quality alleles is of great importance for breeding high-quality rice.In this study,we developed glutinous allele-specific molecular markers for sequence differences on the second exon of the glutinous rice waxy gene,established an efficient selection technology system for glutinous rice,and provided technical support for breeding new varieties of excellent glutinous rice.Creating new rice quality alleles through mutagenesis to provide new resources for breeding excellent new japonica rice varieties.The main research results are as follows:1.Using the sequencing analysis and the insertion region of the second exon 23 bp of the glutinous rice waxy gene,we developed the waxy gene-specific functional markers wx-1 and wx-2,and established the glutinous rice specific discriminant system through the optimization of the reaction system and reaction procedure to efficiently identify whether the waxy gene is contained and the heterozygous or pure alleles of the contained waxy gene.2.Use the established glutinous rice specific discriminant system to assist in selecting the waxy gene and purify the core germplasm of the excellent glutinous rice variety Hefeng Glutinous 331.It was also applied in the auxiliary selection of "Zhong Japonica Glutinous919" variety.3.The excellent japonica rice variety Green Fragrant Japonica 28 was mutagenized by60Co-Y rays,and 17 effective mutants were screened based on field agronomic trait observation,background analysis and rice quality determination,among which there were 4mutants with lower straight chain amylose content than Green Fragrant Japonica 28 and 13 mutants with better appearance quality than Green Fragrant Japonica 28.4.The sequencing results of Wx gene showed that 17 mutants did not differ from Green Japonica 28,and it was initially speculated that the change of straight-chain amylose content of the mutants was not related to Wx gene,but was caused by mutation of new loci,which laid the material foundation for breeding new varieties of high-quality rice.