Study On The Induction Rate And Doubling Rate Of Tropical Maize Haploid Induction Lines In Different Genetic Background Materials

Haploid breeding technology of maize is one of the core technologies in modern maize breeding.This technology can break the limitation of long traditional breeding cycles,and a homozygous inbred line can be obtained in only two generations,greatly accelerating the process of maize breeding.In this study,tropical induction lines and warm hybrid induction lines were used as the parental lines to induce and double the haploid maize materials of six multi-parent populations.The induction rates of the two induction lines were studied,and the effects of different induction lines and different genetic background materials on the induction and doubling rates were analyzed,as well as the differences in induction and doubling rates among different recombinant inbred lines of the same population,providing a reference for future research and application of maize haploid breeding technology.The main results and conclusions obtained are as follows:(1)Under the induction of the same induction line,the haploid induction rates of maize with different genetic backgrounds were different.The average induction rate of warm-hybrid materials(2.89%)was higher than that of temperate materials(2.61%).The induction rates of different hybrid combinations also varied,with the Ye107 × CML384population(3.41%)having a significantly higher induction rate than the Ye107 × Q11population(1.81%).There were also significant differences in induction rates among different recombinant inbred lines of the same population.The induction rates between different recombinant inbred lines of Ye107 × Q11 and Ye107 × YML32 populations were significantly different,while the induction rates between different recombinant inbred lines of Ye107 × YML46 and Ye107 × CML312 populations were extremely significant,indicating that there may be objective genetic variation among the recombinant inbred lines.(2)Using different induction lines to induce the same materials,it was found that the induction rates were different.The induction rate of Yunyou 2 × Gaoyou 5(3.05%)was higher and more stable than that of Yunyou 2(2.55%).Fully utilizing the hybrid advantages of induction lines can effectively improve the induction rate.(3)The induction population materials selected in this study have a high natural doubling ability,and natural doubling can be used to double other materials within the population.The natural doubling rate of each population is above 10%,and the average doubling rate of all recombinant inbred lines is 19.23%.When using the same induction lines to induce materials with different genetic backgrounds,the natural doubling rate of the resulting maize haploid materials varies,with the doubling rate of temperate materials being higher than that of warm-temperate materials.The natural doubling rate of maize haploid materials also varies among different populations,with Ye107 × CML384 population being significantly higher than Ye107 × TML418 population.There is also a significant difference in natural doubling rate between different recombinant inbred lines of the same population.(4)By using different induction systems to induce and double a single material,it was found that different induction systems may have a significant impact on the doubling rate of haploids,and the relevant mechanism needs to be further explored and studied.