Studies On Heterotic Performances And Genetic Characteristics Of Improved-Line Maize P Groups

The corn new idioplasm 78599 the application time are short in our country corn breeding, through to the hybrid combination genetic analysis which domestic nurtures at present,78599 and the derivation department is a relatively independent complete new idioplasm heredity class group,for domestic corn new 5 kind of heterosis use apattern.The P78599 idioplasm has the strong heterosis with the domestic 5 big idioplasm class group,in fact forms a new idioplasm class group outside our country original independent idioplasm class group,namely 78599 class groups.The corn inbred line department's selective breeding is the hybrid selective breeding premise, had the fine inbred line department,can the matched stack leave the fine hybrid,but the inbred line department's selective breeding besides looked that its agronomic characters fine,the combining ability question,had the high combining ability inbred line is more importantly can the matched stack become the strong superiority hybrid,therefore grasps the inbred line is the combining ability is the matched stack hybrid's key is.This experiment 4 which nurtures in recent years on the Jilin Agricultural college corn breeding faculty working office is carries on various characters including P crowd of idioplasm resources corn improvement the combining ability determination and the analysis,provides certain theory basis for these inbred line department's further use.The materials include improved-lines maize containing PN blood and basic maize inbred lines of the temperate four systems in my study.Two augemented NCⅡdesigns and two generation mean analysis designs were adoptend in this experiment.Studies on the heterotic performances and genetic characteristics of the important chatacters in PN improved lines,such as yield,plant height,growth period,kernel length,100-grain weight,etc.The result of my study is as follows:(1) The results of two incomplete diallel cross experiment showed that the grain weight per plant namely ear kernel weight was the highest in heterosis of all characters.The heterosis of two experiments was 106.8%,97.7%respectively.(2) In aspect of combining albility and tester selection of PN improved inbred,in these PN improved lines,J1782,J1881 had higher general combining ability in yielding character,other PN improved lines had lower GCA.Many PN improved lines had higher GCA in eat length and grain number per row of PN improved lines.The inbred that coming from Lvdahonggu and Tangsipingtou is the first selection tester in breeding.(3) Yield of the SCA in Group 1 of the J1881×Ji 853 up to 30.02,J1782×8415,J5918×B73 are higher,respectively,20.88 and 15.18,J5918×8415 minimum;Group 2 J1782×1324 up to 17.53,J1881×C8605-2,J1981×C8605-2,J1782×Dan 340 higher,respectively 17.53,14.59,13.62,13.53 effect,we elected the three GCA high portfolio,J1881×Kyrgyzstan 853,J1782×8415,J1782×1324.(4) In aspect of heterortic pattern,we regard PN improved inbred line group×Ldahonggu group,PN improved group×Tangsipingtou as two heterotic patterns.In breeding it is even more practicality and according with the breeding fact.(5) In aspect of genetic relationships,according to the result of two group incomplete diallel cross experiment and former studies and breeding practice that we judged the PN improved group has far genetic relationships with Lvdahonggu group and Tangsipingtou group.(6) In aspect of utilization and breeding inbred line,we advise using PN improved lines to improve inbred lines of Reid andLancaster groups then crossing with inbred lines of Lvdahonggu or Tandgsipingtou group.It did had very high value in maize breeding.(7) In aspect of heritability,the results of two incomplete diallel cross experiment showed that the narrow heritabilitiy of ear row number were over 90%,and the narrow heritabilities of plant height,ear height,ear width,100-grain weight were over 50 %,Which indicated that it was feasible on selection in the earlier generations.The narrow heritabilities of ear kernel weight and ear length were higher in two experiment but lower in another,which indicated that it can not be select in the earlier generations.The narrow heritabilities of seeding ration and kernel length were lower,so we should select them in late generation.