Selecting sweet corn lines carrying the super sweet sh2 gene based on phenotypes and molecular markers

Abstract

This study aimed to identify the lines carrying the super sweet sh2 gene to serve the selection and creation of high-quality sweet corn varieties for the Vietnamese fresh eating market. Four markers viz., umc2276, umc1320, bnlg1257 and umc1273 were used to screen sh2 gene on five sweet corn inbred lines along with a check line. The results showed that the umc1273 is an optimum marker to identify the sh2 gene in sweet corn lines. Using this marker screen on 20 inbred sweet corn lines selfing at 6 generations had identified 9 lines carrying the sh2sh2 recessive homozygous gene viz., S3, S4, S5, S10, S11, S14, S16, S17, S21. Genetic diversity analysis of 20 6th generation inbred sweet corn lines originating from China, Taiwan, India, America and the Philippines based on phenotypes under Spring 2023 crop conditions using NTSYS software showed that 20 sweet corn lines were divided into 13 groups, one group had 3 lines, 01 group had two lines and 11 groups had one line at a difference of 38%. Using a routine biostatistics program with phenotypic traits, 6 elite lines were selected S16, S10, S5, S17, S14, S11. These sweet corn lines belong to the short-term group (from 81 - 92 days), average plant height is from 137.6 ± 2 to 162.8 ± 3 cm, average seed coat thickness (50.81 - 58.57 µm), dry grain yield reached (from 588.05 - 663.62 kg/ha), Brix level reached over 18%. These lines can be used in high-quality sweet corn breeding programs.