Agronomic Evaluation and MGDI-Based Multi-Trait Selection of S4 Sweet Corn Inbred Lines

Abstract

Sweet corn is a high-value commodity whose productivity can be improved through hybrid variety development. The development of superior hybrids depends on establishing inbred lines with superior agronomic performance and broad phenotypic variability as the basis for parental selection. This study aimed to evaluate agronomic traits and phenotypic variability, analyze correlations among traits, perform principal component analysis (PCA), and apply the Multi-Trait Genotype–Ideotype Distance Index (MGIDI) for multi-trait selection in S4 sweet corn inbred lines. The experiment was conducted at the Experimental Farm of Universitas Andalas from January to April 2025. An Augmented II design consisting of two blocks was used with 36 S4 inbred lines, comprising 33 test lines and 3 check lines. Results revealed wide phenotypic variability for most agronomic traits, except ear diameter and total soluble solids. Yield exhibited positive correlations with plant height, ear length, and ear diameter, but negative correlations with flowering and harvest traits. In contrast, total soluble solids were not significantly correlated with the other agronomic traits. Principal component analysis (PCA) showed that most agronomic traits contributed to the variation among inbred lines, whereas total soluble solids had a relatively small contribution. Based on multi-trait selection using MGIDI, seven inbred lines, i.e. CD3, MM1, AG2, PN1, CD2, IN2, and SL1, were identified as the closest to the ideotype. These lines have the potential to be prioritized as parental lines and should be further evaluated in the S5 generation and subjected to combining-ability evaluations in hybrid sweet corn breeding.