Genetic Potentiality Using Yugoslavia Maize Inbred Lines To Improve Chinese Elite Hybrids

Exotic germplasms have been playing an important role in corn breeding and production in China.Systematical introduction and utilization of the exotic germplasms is useful to improve breeding level and promote maize output steadily. But this depends on our knowledge about their genetic tendency and the appropriate ways to be used in practical breeding.In this study,Dudley's method was used to analyse the genetic potentiality of 9 Yugoslavia maize lines to improve ear-kernal and plant characters of 9 Chinese elite hybrids and their suitable ways to be used in practical breeding in summer in 2003,and spring and summer in 2004.101 and 149 crosses were made between 9 indroduced lines and 18 Chinese inbreds,which were the parents of 9 Chinese elite hybrids.Meantime,NC II mating design was adopted to study the combining ability,over-check heterosis,genetic distance(GD) with SSR markers between 9 indroduced lines and 8 Chinese inbreds,representing different heterotic groups,in 2004.And the correlations among SCA,GD, over-check heterosis and the performance of F₁ crosses were calculated to study whether GD could be used to predict SCA, over-check heterosis and F₁'s performance,and their relationships with the result of Dudley's method for hybrid improvement were analysed also.Through correlations among all characters,the elite characters of hybrids with high yield and the potentiality for their simultineous improvement were analysed.The main results are as follows:(1) Nine Yugoslavia lines had different potentiality and suitable ways to improve all charachers of 9 Chinese elite hybrids.For the ear-kernel weight of Nongdal08, ZPL01 could improve HuangC, ZPL02 and ZPL06 improve Xul78,ZP05, ZPL09 and ZPL10 improve Xul78 or Huang C.For the ear-kernel weight of Yuyu33, ZPL01 , ZPL02, ZPL06 and ZPL09 could improve Zheng58 through different ways, ZPL03 and ZPL05 improve Zheng58 or Chang7-2. For the ear-kernel weight of Yuyu22, ZPL01, ZPL02, ZPL09 and ZPL10 could improve Yu87-1, ZPL05 improve Zong3.For the ear-kernel weight ofNongda3138 ,ZPL07 may improve Zong31 and ZPL09 improve P138.For the ear-kernel weight of Yuyu24, ZPLOK ZPL05, ZPL09 and ZPL10 could improve 246 or Chang7-2 by different ways, ZPL(^ ZPL03 and ZPL06 improve 246 by different ways, ZPL07 improve Chang7-2.To the ear-kernel weight of Yuyu23, ZPLOK ZPL(^ ZPL09 and ZPL10 could improve Ye478 by different ways, ZPL05 improve Chang7-2, ZPL06 improve Ye478.To improve the ear-kernel weight of Yuyu20, ZPLOKZPL03 and ZPL05 could improve Gai3, ZPL02> ZPL06, ZPL09 and ZPL10 improve Ye478.For the ear-kernel weight of ShendanlO, ZPLOK ZPL06 and ZPL09 could improve Shenl37, ZPL02 and ZPL05 improve Q1261.To the ear-kernel weight of Yuyul5, ZPL07 and ZPL10 could improve Ye478, ZPL01 and ZPL05 improve Yu374.(2)Every Yugoslavia maize lines had different potentiality to improve otherear-kernel or plant character of Chinese 9 elite hybrids,but this was not consistant withear-kernel weight for their tendency and suitable utilization methods.For example,thesuitable ways to use ZPL01 to improve ear-kernel weight of Nongdal08 was (ZPL01 XHuang C ) X Huang C ,the same was for ear length,but (ZPL01 X Huang C ) X ZPL01 and(ZPLOlXHuang C) XZPL01 or (ZPL01 XXul78) selfing directly was suitable forkernels per row and kernal rate respectly.The suitable ways to use ZPL02 for ear-kernelweight, ear length, kernels per row and kernal rate were (ZPL02 X Xul78) X ZPL02 or(ZPL02XXul78, (ZPL02XHuangC) XZPL02 or (ZPL02 X HuangC) XHuangC,( ZPL02 X HuangC ) selfing directly, (ZPL02 X HuangC ) respectly.The same was forother introduced lines and the improvement of other hybrids.(3) Combining ability analysis showed that there were significant difference amongintroduced lines for GCAs and their SCAs with Chinese inbreds for different characters.High yield crosses meight be easily made using ZPL02 or ZPL03 with Chinese inbreds belonging to different heterotic groups through ear length,kernel number and 100-kernel-weight.The performance of crosses with ZPL01,ZPL04, ZPL07,ZPL09 and ZPL10 meight be influenced easily by different environments.All ear-kernel characters were usually poor for crosses with ZPL05 and ZPL06The SCAs of ear weight for 72 crosses was greatly different, from -0.069 to 0.154, and the SCAs for the same cross were also different.The SCAs between ZPLOland Zheng653, ZPL02 and Zong3s Zheng653> 8085T ^0 Luyuan92, ZPL03and HuangC, Yu87-K ZPL04and HuangC,Zong3, ZPL06and Zong3,8085T, ZPL07and HuangC,...