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Relationships Between the Microstructure, Physical Features, and Chemical Composition of Different Maize Accessions from Latin America

¹Universidad Autónoma de Querétaro, Centro Universitario, Cerro de las Campanas S/N, Querétaro, Querétaro, México, CP 76010. ²Centro de Investigaciones y Estudios Avanzados del IPN, Unidad Querétaro, Libramiento Norponiente No. 2000 Fraccionamiento Real de Juriquilla, Querétaro, México, CP 76230. ³Corresponding author. E-mail: jfigueroa@qro.cinvestav.mx ⁴Centro Internacional de Mejoramiento de Maíz y Trigo, Carretera México-Veracruz km 45 El Batán, Texcoco, Estado de México, México, CP 56130. ⁵Universidad Autónoma Agraria Antonio Narro, Buenavista, Saltillo, Coahuila, México CP 25315.

Chemical composition (moisture, total lipids, protein, and apparent amylose) and some physical features (1,000 kernel weight, hardness, and anatomical composition) were determined in 71 accessions representing races of maize from Latin America. Their microstructural characteristics (size and compaction of endosperm cell bodies, pericarp thickness, horny-floury endosperm ratio, and morphology and size of starch granules) were also evaluated using environmental scanning electron microscopy (ESEM). Compaction was the most important microstructural feature of the maize kernels, representing kernel hardness. Highly compact kernels tended to be hard, with high protein, pericarp, and hard-endosperm content and high pericarp thickness, but with low moisture, amylose content, and kernel weight and size. The opposite was observed in the least compact kernels. Highly compact kernels tended to have small, polygonal starch granules (<10 μm), while the least compact kernels contained large, spherical granules (>10 μm). These results suggest that microstructure is responsible for the physical features of maize kernels and that microstructure is related to chemical composition.