Agronomic performance and genetic diversity of newly developed S4 temperate and tropical sweet corn lines

Abstract

This study aims to evaluate agronomic traits and genetic diversity through correlation analysis, principal component
analysis, and cluster analysis on 20 agronomic traits of 16 S4 tropical sweet corn lines (NG01-NGO16) and 4 S4 temperate
lines (NGO17-NGO20) developed from varieties imported from Thailand, China, Japan, and the USA along with 3 inbred
check lines viz., SW1 (sweet, yellow), D181 (sweet, white) and UV10 (sweet, purple). The field experiment was arranged
in a randomised complete block design with 3 replicates in Hanoi, in the autumn-winter crop 2022 to evaluate twenty
agronomic traits, divided into 4 groups viz., 5 growth traits, 7 morphological traits, 7 yield traits, and 1 quality trait.
Correlation analysis showed that the single plant yield was positively correlated at p<0.01 with the number of kernels per row 0.61, the number of kernel rows per ear 0.57, and positively correlated at p<0.05 with ear diameter 0.47 and ear length 0.45. Twenty traits were dimensionally reduced to 3 main principal components contributing 66.8% of total phenotypic variation in which growth duration, plant height, ear height, leaf angle, number of kernels row per ear, number of kernels per row, 1000-grain weight, single plant yield and total soluble solids can be used to evaluate the differences of sweet corn lines. Cluster analysis based on principal components on 20 agronomic traits classified 20 sweetcorn lines into 3 main groups. This study provided useful information on phenotypic diversity and valuable sweetcorn genetic resources for breeding programs on speciality corn in Vietnam.