Analysis Of Combining Abilities For Improved Line Of Maize Core Inbred "TIE7922"

In this study, using140hybrids produced by crossing35improved inbred lines of the Chinese core inbred Tie7922with4testers Chang7-2, PH6WC, Dan340and B20with p x q(NCII) design as materials, studies on combining ability of improved lines of Tie7922and heterosis and heretibilites for their major agronomic traits were conducted. The results showed that,(1) combining abilities of grain yield of Tong1037, Tong465, Tong1615, Tong1619and Tong1623were highter, these germplasms revealed higher utilization potential,(2) characters of plant height and ear diameter revealed higher narrow sense heritability, these characters could be chosen in early generation. However, characters of ear height stem diameter ear length row number ear weight kernel per ear,100-kernel weight and grain yield showed lower narrow sense heritability,these characters did not fit to be chosen in early generation,(3) the combinations ranked the first five in yield special combining ability were Tong465xB20, Tonf1037xDan340, Tong1623xB20, T1619xChang7-2, Tong1031x B20.(4) Among140hybrids,139hybrids expressed the mid-parent heterosis (MPH) value for grain yield exceeding100%. Moreover, MPH values for38of140hybrids were over200%; among these, the combinations, Tong1172xChang7-2, Tong931x Chang7-2, Tong1237xChang7-2, Tong465xChang7-2, Tong1031xB20, Tong1658x B20and Tong1172xB20, expressed MPH values over250%.(5) In addition, for high-parent heterosis (HPH),135hybrids expressed HPH value for grain yield exceeding100%; and HPH values for25of140hybrids were over200%; among these, three combinations, Tong1172xChang7-2, Tong797xChang7-2, Tong465x Chang7-2, expressed MPH values over250%.(6) Larger genetic distances and genetic differences existed between improved lies of Tie7922and Dan340, improved lines and Chang7-2. In contrast, small genetic distance and less genetic difference existed between improved lieso of Tie7922and PH6WC.