Evaluating Waxy Maize Grain Quality

The waxy maize grains were collected at late R3 stages for determining fresh grain quality using the method described by Huang et al. (2022) (link) in the 2019 and 2020 seasons. The soluble sugar content (determined with the anthrone colorimetric method), starch content (with the anthrone-sulfuric acid method), total protein content (with the total nitrogen content method, total protein content = total nitrogen content × 6.25), and lysine content (with the ninhydrin chromogenic method) of waxy maize grains were measured for each sample. The contents of amylopectin, amylose, gliadin, gluten, albumin, and globulin were measured by the Sanshu Bio-Tech company in China. The amylose content of starch was determined using a colorimetric amylose content assay (Knutson and Grove, 1994 ). The amylose content was analyzed using the GPC-RI-MALLs system developed by Park et al. (2007) (link). Glutenins and gliadins were extracted and quantitated subsequently from two biological replicates by reverse-phase ultra-performance liquid chromatography (RP-UPLC) according to a method described by Han et al. (2015) (link), and the sample size was modified in minor ways according to the protein concentration of waxy maize grain. The albumin and globulin content was analyzed using an automatic microplate reader (Multiskan GO, Thermo, USA).