Anatomical and Physiological Characteristics Associated with Corn Endosperm Texture

Abstract

Grain texture is an important trait in corn (Zea mays L.) grain quality, influencing grain shipping and processing characteristics, susceptibility to insects, and flour cooking properties. The objective of this study was to evaluate anatomical and physiological factors affecting corn grain texture for three corn types differing in endosperm texture (Dent corn with floury‐textured endosperm, and popcorn and sweet corn with vitreous‐textured endosperm). The endosperm cell number and size, diameter of starch granules and the distribution of starch granules and protein bodies during grain development were determined. The levels of protein, starch and soluble sugar, and the arrangement of starch granule in mature grains were evaluated. There were significant genotypic differences (P < 0.05), but no significant year effects (P > 0.05) on any of those parameters. At mature stage, a genotype × year interaction was detected only for protein content. The percentage of vitreous endosperm ranged from 39 to 100% in 2004 and from 41 to 100% in 2005. Grain texture was positively associated with the levels of protein (r = 0.684, P ≤ 0.134) and soluble sugar (r = 0.992, P ≤ 0.0001), and negatively associated with starch level (r = –0.627, P ≤ 0.182), endosperm cell number (r = –0.814, P ≤ 0.049), endosperm cell length (r = –0.971, P ≤ 0.001) and width (r = –0.967, P ≤ 0.002), starch granule diameter (r = –0.868, P ≤ 0.025). Our results indicated that the vitreous texture of corn grains was associated with the presence of sugar‐starch compound, protein bodies and proteinaceous matrix, and well‐organized starch granules in the endosperm.