Abstract

Background: Genetic variability assessment is essential for breeding programs aimed at improving desirable traits. This research aimed i) to evaluate the genetic variability, correlations and path coefficients of agronomic traits and yield components in Thai sweet corn and ii) to identify cultivars best suited to the climate of Nakhon Si Thammarat in Southern Thailand. Methods: Ten cultivars of Thai commercial sweet corn were evaluated for genetic variability using three blocks of a completely randomized block design. Analyses included genetic variability, correlation coefficients and path analysis. Result: The findings indicated significant differences in most agronomic traits and yield components among the cultivars. The genetic variability analysis revealed that all traits had higher phenotypic coefficient of variation than genotypic coefficient of variation. Stem height, days to male and female flowering and rows per ear demonstrated moderate heritability, with stem diameter and rows per ear showing moderate heritability and genetic advance as a percentage of the mean. The correlation coefficient and path analysis revealed that stem height, leaf width, ear length and diameter and kernels per row had a positive direct effect on ear weight, with or without husk. These traits are suggested as key factors for enhancing ear weight in breeding programs. Based on yield components, the cultivars Hi-Brix 59 and Dr Pek 1351 are recommended for Nakhon Si Thammarat due to their adaptability to the local climate.