Study On Doubling Technology For Haploid Mature Embryo Based On Tissue Culture In Maize

As a highly effective and rapid Breeding technology,haploid breeding have rapidly developed in recent years and are favored by a large number of breeding scholars.In this research,the experiment was carried out with YHI-1,a inducer line developed by Henan Agricultural University,as male and the different hybrids as female,three main steps including haploid production,haploid identification and haploid doubling were focused on for exploring the effective method of induction and doubling.The results were as follows:1.Four maize hybrids(Jing24×K12,Dan598×Zheng22,Tie7922×C8605-2 and Qin319×Tai8085)as female were crossed with inducer YHI-1 as the male to study on influence factors on inducing rate in 4 different sowing time.The results showed that inducing rate was significantly different among 4 different hybrids,the inducing rate of hybrid jing 24×K12 is the highest and reached 17.56%.Meanwhile,different sowing time also significantly affected the inducing rate,which is highest with 15.39% on the sowing time of July 3 2017 in Zhengzhou of Henan province,it implied that more haploids could be produced by proper late sowing in Zhengzhou.2.The haploids were obtained by making crosses between Xianyu 335 as female and YHI-1 as male.the mature embryos of the haploid seeds were used to be treated with cochincine based on tissue culture for doubling.At the same time,the test of haploid early identification were performed during the process of tissue culture.The result showed that root length,total root number,seedling height and stem diameter of the tissue culture seedlings existed extremely significant difference between haploids and diploids.The average stem diameter and seedling height of haploid seedlings were only about 2/3 those of diploid seedlings.Therefore,the diploids could be removed effectively from haploids based on these differences in tissue culture seedlings before transplanting into field.3.The haploid embryos from mature kernels of Xianyu335 induced by Yu High Inducer No.1(YHI-1),were treated with 0.005%,0.01%,0.02% and 0.03% colchicines for 12 hours,24 hours and 36 hours,respectively,and MS medium without colchicine as the control,the plantlet rate and the doubling rate of the haploid plant were investigate,at the same time,combining the results of flow cytometry to analyze the doubling effect.The results showed that as the level of recovery of tassel fertility in the haploid plants increased,the somatic cell's level of diploidization increased.The interaction between the treatment time and quality volume fraction of colchicine existed significantly.Combining the plantlet rate and doubling rate,the treatment of 0.005% colchicine with 24 hours is optimum,and the comprehensive efficiency was the highest with 57.61%.