| A total of 11 inbred lines of sweet corn which with greet genetic diversity was used selectively as parents to make complete diallel crossing in accordance with the Griffing method 4 in order to study F1 hybrids, backcrossing generations and parental materials. Quantitative analysis of 11 main characters of sweet corn was studied as follows:heterosis analysis, broad sense heritability, narrow sense heritability, general combining ability, specific combining ability, reciprocal effect, correlation and path analysis. According to analysis, conclusions are evaluated as follows:(1)The heterosis of F1 hybrids are ubiquitous in sweet corn and the positive heterosis are higher than negative parts universally (except Rare ear length, Starch content, Stem diameter, Soluble protein content). It shows that there are some superiority combinations in the 30 Hybridized combinations which are made by 11 parent inbred lines in this experiment.The order of variation coefficients of heterosis indexes is:Rare ear length> Soluble protein content> Ear height>Grain yield> Single ear weight> Grain number per row>100-grain weight>Starch content> Soluble sugar content> Stem diameter> Ear row number>Plant height> Ear length> Ear width. So in these 14 traits, Soluble protein content, Grain yield, Single ear weight, Starch content,100-grain weight, Ear height, Soluble protein content, Grain number per row, Ear length have more margin to select and the margin of others are narrow.(2) Broad sense heritability from strong to weak is:Starch content> Soluble protein content> Ear row number> Plant height> Ear height> Ear width> Soluble sugar content> Grain yield> Ear length> Grain number per row> 100-grain weight> Single ear weight> Stem diameter>Rare ear length. Narrow sense heritability from strong to weak is:Ear row number>Soluble sugar content> Ear height> Ear length> Single ear weight> Grain yield> Stem diameter> Starch content> Plant height> Soluble protein content> Grain number per row> Ear width>Rare ear length>100-grain weight. It can be selected in early generations if broad sense and narrow sense heritability are both high, such as Ear height, Stem diameter, Ear row number, Ear length, Soluble protein content, Soluble sugar content, but if not, it is easy to be influenced by environment, so it is better to select in later generations, such as 100-grain weight, Rare ear length.(3) The general combining abilities of 11 parents inbred lines in 14 main traits present very significant difference and the specific combining abilities of Hybridized combinations are also present significant or very significant difference.The positive effect value of parent inbred linesJiT314,JiT043and JiT203are generally higher and the general combining abilities in grain yield and soluble sugar content of them are also higher. So parent inbred lines JiT02 and JiT03 can be used as good parents in the selection of good sweet corn. The hybrid combinations JiT314×JiT203, JiT310×JiT043, JiT314×JiT091, JiT308×JiT315 are good combinations for high yield and high quality breeding. The high yield and high quality breeding need high general combining ability in two parents or at least one parent. But it is possible that the hybrid has high specific combining ability while its two parents' general abilities are low.(4) In various combining abilities, the correlation extent between yield (or sugar content) and total combining ability are most close than others. The correlativity between F1 generation and female parent in yield is higher than male parent significantly. So the high yielding inbred line must be selected as female parent. While the correlativity between F1 generation and male parent in sugar content is higher than female parent significantly. So the high sugar content inbred line must be selected as male parent.(5) The correlation coefficients between grain yield and main traits from strong to weak are:Single ear weight> Ear length> Soluble protein content> Ear row number>Ear width> Plant height> Stem diameter>Grain number per row> Ear height> Rare ear length>100-grain weight> Starch content>Soluble sugar content. Single ear weight, Ear length, Ear width, Grain number per row, Grain number per row, Plant height have very significant or significant positive correlation with grain yield. In order to obtain high yield sweet corn, it must priority select them which influent grain yield most greatly. The direct path coefficients from strong to weak are:Ear length> Single ear weight>Ear width> 100-grain weight> Grain number per row>Plant height> Rare ear length> Stem diameter> Ear height>Ear row number.(6) The correlation coefficients between soluble sugar content and main traits from strong to weak are: Grain yield> Ear height>Ear width> Rare ear length> Plant height>100-grain weight> Stem diameter> Soluble protein content> Ear length>Starch content> Grain number per row>Ear row number> Single ear weigh. Ear width, 100-grain weight, Rare ear length, Soluble protein content have positive correlation with soluble sugar content, although the coefficients are not significant, the positive values are fairly big. So, In order to obtain high sugar content sweet corn, it must priority select them which influent sugar content most greatly. The direct path coefficients from strong to weak are: Ear height>Grain yield> Ear width>100-grain weight>Soluble protein content>Rare ear length> Stem diameter>Plant height>Grain number per row>Starch content>Ear row number> Ear length>Single ear weight.
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