Study On The Technology Of Maize Induced Wheat Double Haploid Breeding

The distant hybridization between wheat and corn can induce the production of haploid plants in wheat.Through this method,the hybrid genotype of wheat hybrid offspring can be homozygous in the short term,shorten breeding years,improve breeding efficiency,and also create a permanent genetic population for genetic research.For a long time,many researchers have conducted in-depth research on the technical system of this method.However,due to reasons such as technical operation,the frequency of haploid embryo production,the germination and seedling formation of haploid immature embryos,and the success rate of doubling treatment in wheat have been low,which limits the application of this technology in wheat breeding practice.Further research is still needed for practical double haploid cultivation of wheat and its application in breeding.This study aims to compare the technical systems suitable for maize induced wheat haploid production in Shaanxi region through flowering regulation experiments,genotype experiments,hormone treatment experiments,culture condition experiments,and plant doubling experiments,and obtain DH line populations for subsequent genetic map construction experiments.The research results of the paper are as follows:(1)The pollen of different varieties of corn during the fifth sowing period(January 23,2022)and the sixth sowing period(January 30,2022)all met the flowering period of wheat planted in the field,with the flowering period concentrated around April 19 to April 26,with a difference of 88 to 102 days between wheat and corn sowing periods.(2)Corn pollen obtained through both ultra-low temperature and greenhouse methods can induce wheat to produce haploid embryos,but the induction rate of fresh pollen obtained through flowering regulation is significantly higher than that of corn pollen stored at ultra-low temperature.(3)Different maize genotypes can induce haploid embryos in wheat,but there are significant differences in induction rates.The induction rates are as follows: sweet glutinous y21-11-311(14.44%)>Shaanxi white glutinous 11(9.14%)>super sweet y21-10-208(5.54%).In addition,there are significant differences in induction rates among different varieties within the same corn type.The sweet and glutinous type is characterized by sweet and glutinous peach flowers>sweet and glutinous y21-11-311,while the performance of glutinous corn is different between the two wheat varieties.(4)Different hormone treatments have a significant impact on the embryo yield of wheat maize hybrid,with an average embryo yield of 8.88% after 100 mg/L 2,4-D treatment significantly higher than that of 5.84% after 213 mg/L 2,4-D treatment.(5)There are significant differences in the embryo yield rate of pollinated panicles under different culture conditions.The average embryo yield rate(7.22%)under in vitro culture conditions of cutting panicles is significantly higher than the average embryo yield rate(3.93%)in the field natural environment,which is nearly twice as high.(6)Different wheat genotypes also have a significant impact on embryo yield.In experiments with different maize genotypes,hormone treatments,and culture conditions,there were significant differences in embryo yield among different wheat genotypes.In experiments with different maize genotypes,22F1-196 had the highest average embryo yield(17.00%);In different hormone treatment experiments,the average embryo yield of 22F1-393 was the highest(12.87%);In experiments under different culture conditions,the average embryo yield of 22F1-306 was the highest(13.45%).(7)There are significant differences in the germination and seedling rate of haploid immature embryos among different culture media.The germination rate and seedling rate are as follows: 1/2 MS>improved B5>1/2 MS+2 mg/L 2,4 D>1/2 MS+0.1 mg/L BAP+0.1 mg/L NAA.In addition,wheat genotypes also have a certain impact on the germination and seedling formation of haploid immature embryos.(8)A study was conducted on the doubling method of haploid wheat plants,and the results showed that the doubling efficiency of the treatment method with 0.2% colchicine for3 hours and oxygen supply throughout the process was the highest(35.3%),followed by the treatment with 8 g/L colchicine added to the surface of the culture medium for 16 hours(15.8%).The above research indicates that in the maize induced wheat double haploid technology system,selecting the appropriate maize genotype and wheat combination is the most fundamental guarantee.In addition,selecting the best treatment method for pollination ears,in vitro culture of immature embryos,and doubling of haploid plants is beneficial for improving the embryo yield and seedling rate.The comparative experimental results of various treatments in this study provide technical reference for the technology system,And create DH line populations for subsequent genetic analysis.