The heterosis phenomena has been exploited in hybrid maize field production. Theoretically, heterosis was depending on genetic distance of inbred lines. Meanwhile, different from field corn breeding, sweet corn does not have well defined heterotic group. The objective of this study was to determine genetic similarity (GS) of eight selected inbred lines of sweet corn based on morphological traits and its correlation with specific combining ability (SCA) and heterosis. The eight inbred lines were characterized and crossed in full diallel design. Then, the lines, F1 and its reciprocal, were evaluated by using the Randomized Complete Block Design in three replications. The result showed positive heterosis and SCA effect in most of the hybrids which indicated the heterosis effect in the hybrids performance. Based on the morphological traits, the genetic similarity between the inbred lines was 62.2-82.4%. The inbred lines with 70% similarity coefficient were grouped into three. There was significant correlation between the genetic similarity and heterosis in all traits, except in the plant height. Meanwhile, only SCA of days to maturity and TSS showed significant correlation to genetic similarity. This indicated the usefullness of genetic similarity to identify the potential inbred lines for parental hybrid.

The genetic diversity is basic need of plant breeding. The experiment aimed to evaluate the genetic diversity of twenty sweet corn inbred lines, to estimate broad sense heritability, genetic correlation and path analysis, and grouping the sweet corn inbred lines. Randomized complete block design was used with three replications. ANOVA, genetic correlations, and cluster analysis were used to analysis the data. The genetic diversity coefficients was indicate the high genetic diversity, that was potential for hybrid sweet corn breeding programs. Most characters had high broad sense heritability. The ear weight has a significantly positive correlation with plant height, ear height, number of seed rows, ear length and ear diameter. The ear length and ear diameter have a high direct influence on the ear weight. Cluster analysis grouped the inbred lines into three groups at 70% similarity coefficient level. The group which have the lowest similarity coefficient level indicated wide genetic distance. The wide genetic distance groups can be used as a parents for composing of hybrids with high level of heterosis.