Objective Agronomy and quality of early generation progenies of 39 early-maturing sweet corn lines were evaluated for breeding high-yield, high-quality fresh-eating varieties.

Methods Growth periods of 192 sweet corn germplasms were investigated, and 39 representative inbred lines were selected. Using North Carolina Design II (NCDII), the selected lines were crossed with 3 testers (B1, B2, B3) to produce 117 hybrid combinations. Systematic phenotypic evaluation was conducted, and statistical analysis, principal component analysis (PCA) and combining ability analysis were jointly performed to comprehensively assess breeding potential of the materials.

Results Cluster analysis showed that the 39 materials fell into distinct groups with obvious genetic divergence. The distribution of traits indicated that key indices including plant height, ear height, growth period and sugar content followed normal distributions. Most combinations were within elite ranges and could be further improved. Three principal components were extracted via PCA, representing yield, quality and plant architecture, respectively. A trade-off between yield and sugar content was observed, offering a theoretical basis for synchronous multi-trait selection. Combining ability analysis revealed that additive genetic effects were predominant, with a high ratio of general combining ability (GCA) variance to specific combining ability (SCA) variance. Elite high-yield inbred lines A233 and A74, and high-quality inbred lines A859 and A837 were identifie.

Conclusion By comprehensively analyzing the distribution, principal components, and combining ability on agronomic traits of the early generation progenies of 39 early-maturing sweet corn lines, a trade-off between yield and quality seemed existed for the breeding program. A233 and A859 appeared to be the choice candidates for breeding desirable new varieties.