The QTL Preliminary Mapping Of Corn’s Tassel Branch Mutations

Tassel,an important organ of maize, has a heavy effect on yield. A large tassel would cost much nutrition and reduce the number of pollens, which further effects the setting percentage. The size of tassel is influenced by its number of branches. The long-time planting experience reveals that the tassel is evolving more and more small. The breeders can select individuals with their hoped size of tassel through the number of branches. The branching program is one of important procedures for tassel’s development. The study on tassel’s branches is helpful to clarify the genetic mechanism about maize’s tassel development and breed new varieties.This study position the QTL of tassel mutant gene (Tassel branch number, tbn) in the mutant inbred line3237. This study constructed the backcross population and backcross inbred lines population of inbred line3237and inbred line1212, which the former has no any tassel branch and the latter has6-7branches. This study created the genetic linkage map by SSR marker. The map contents114markers with1486.4cM whole length and13.04cM mean distance between markers. This study confirmed7QTL involved with number of tassel branches in total,4of which were located respectively in the second, third, fifth, seventh chromosome in the BC1population. The other3QTL were also located in above chromosomes without the seventh in the backcross inbred lines population. The results from two times QTL positioning together revealed that the QTLs in second, third, fifth chromosome are all located between markers umc1026-umc2247, umc2169-bnlg1779, umc1966-umc2164. But the LOD value in third and fifth chromosome were not stationary, which the former varied between10.96%and24.75%, the latter varied between16.78%and33.18%There are in all136QTLs involved with number of tassel branches in maize in published papers and this study. All the data were mapped to IBM22008Neighbors through BioMercator2.1and analysed by element analysis method.16coincident QTLs were obtained and distributed all10chromosomes. Among which, the confidence interval of Q2, Q3, Q5, Q10lower than10cM.