Variability of kernel carbohydrate components on commercial waxy corn hybrids in Thailand

Abstract

Importance of the work: A specialty waxy corn with sweet kernels has been developed through hybrid breeding, focusing on palatability improvement to fulfill consumer preference. However, information on the kernel carbohydrate components of waxy corn
hybrids is still lacking.
Objectives: (1) To investigate the carbohydrate composition of fresh kernels harvested at milk stage among 10 commercial waxy corn hybrids based on the contents of total starch, amylopectin, total sugar and phytoglycogen; (2) to assess the seasonal effect on given traits; and (3) to classify all test hybrids and rank them regarding kernel carbohydrate components.
Materials & Methods: Ten waxy corn hybrid cultivars currently available in the Thai markets were evaluated under field condition in the 2017/2018 dry season and in the 2018 rainy season. The fresh kernels harvested at the milk stage were analyzed for the contents
of total starch, amylopectin, total sugar, and phytoglycogen.
Results: The seasonal effect on the given traits were assessed and the phenotypic variabilities of test genotypes on given traits were visualized using a dendrogram based on Ward’s hierarchical clustering method. Additionally, the data were subjected to unweighted
selection indexing to rank the promising genotypes regarding their kernel carbohydrate components. Growing season, genotype and their interactions significantly altered the contents of total starch, amylopectin, total sugar and phytoglycogen with varied responses.
Despite a large variation in the carbohydrate profiles among varieties, the fresh kernels carbohydrate of tested waxy corn hybrids were generally composed predominantly of total starch and amylopectin, with a small portion of sugar and phytoglycogen.
Main finding: Considering the divergence in both the carbohydrate profiles and market targets, a proper waxy corn ideotype for a specific market target is imperative.