Preliminary Studies On The Inducing Characteristics Of Two Doubled Haploid Inducer Linesin Brassica Napus L.

The doubled haploid(DH)plant is a homozygous individual plant,which is obtained by doubling the chromosome number of a haploid.Thedoubled haploid plant can quickly reach 100%genetic homozygocity,and has important roles in plant breeding and related researches.The procedure for DH production includes two major steps:haploid induction and chromosome doubling.There are few direct way to get the double haploid from hybrid plants.The Chengdu Academy of Agriculture and Forest Sciencessynthesized a kind of specialoctaploid rapeseed(AAAACCCC,2n=8x=76),when it as male parent to tetraploid Brassica napus(AACC,2n=4x=38)pollination can directly induce maternal plants produce homozygous double haploid offspring.We have temporarily named it the Brassica napus homozygous double haploid inducers,and called it DHI in short.The purpose of this study is to identify the induction characteristics of BHDHI Y3560 and Y3380.7 females(Nuclear male sterile line:3209AB,3304AB,3318AB,Cytoplasmic male sterile line:3321A,3323A,0068A,WLA)as induced materials to study the induction characteristic of Y3560.2 females(Cytoplasmic male sterile line:0068A,WLA)as induced materials to compare differences in induction characteristics between Y3560 and Y3380.The results are as follows:1.In the cross combination of B.napus × Y3560 or Y3380,not only to produce hybrid plants,also produced a large number of similar female homozygous double haploid offspring.Full description of DHI as male parent has the ability to induce normal B.napus to produce homozygous double haploid.2.The same DH inducer induction ability differences of different parent material.Y356.0 of 7 sterile lines of induction rate is between 34.18%～100.00%,from big to small in turn is:3323A>0068A>3321A>WLA>3118AB>3209AB>3304AB;Among them for cytoplasmic sterile lines induced rate is higher,the average is 96.75%,and of the nucleus sterile lines induced rate is low,an average of 41.24%.Compared with the maize haploid inducer or other haploid induction method,DH inducer induction rate is high and has a wide application range.And induction rate of high and low are greatly influenced by parental genotype interaction,its internal mechanism needs further research.3.By comparison,two DH lines induced no significant difference in the induction rate,but both induced offspring there are some differences in ploidy on.Y3560 induces the production of phenotype similar to the parental of all offspring are tetraploid,and Y3380 induces the production of offspring in addition to tetraploid,also found a handful of diploid and octoploid.The induction ability of Y3560 was more stable than that of Y3380,which may be related to the different breeding methods of the two.4.Currently inducing mechanism DH inducer is not clear.Based on the experimental results of this study,suggesting a possible mechanism for the induction is:inducer to pollinate the female,after the male gametes and egg fusion under certain induction mechanism of action,maternal chromosome doubling,after the during mitosis paternal chromosome loss,resulting in a double haploid homozygous offspring.