Head Smut Resistance Identification and Genetic Effect of Portion Maize Inbred Lines

The resistance of 72 maize inbred lines to head smut of maize was studied and assessed by using the artificial inoculation method.The results showed that 18 of these lines were highly resistant,15 lines were resistant and 12 were middle resistant,and the percentages were 25%,20.8% and 16.7%,respectively.With the fourth method of diallel design,this paper analyzed combining ability and estimated genetic parameter in resistance of 11 inbred lines.The results showed that GCA negative effect of 917-1,4F1 and Ji818 was bigger,Chang7-2,GCA effect of Huangzao4 and Chang3 was larger.Ji818 ×Huangzao4,917-1 ×Huangzao4,Ji818 ×Chang7-2 and KD-13 × Chang7-2 combinations had significant negative effect,Huangzao4×Chang7-2 and 917-1×Ji818 combination had significantly positive effects.The additive effect and dominant effect of maize head smut resistance existed at the same time,and additive effect is dominant.So,not only consider the general combining ability,but also pay attention to the special combining ability effect in the breeding of hybrid.In order to breed hybrid with middle or high resistance,one of the parents must be the high resistant line.