Latin America is the center of domestication and diversity of maize, the second most cultivated crop worldwide. In this region, maize landraces are fundamental for food security, livelihoods, and culture. Nevertheless, genetic erosion (i.e., the loss of genetic diversity and variation in a crop) threatens the continued cultivation and in situ conservation of landrace diversity that is crucial to climate change adaptation and diverse uses of maize. We provide an overview of maize diversity in Latin America before discussing factors associated with persistence of large in situ maize diversity, causes for maize landrace abandonment by farmers, and strategies to enhance the cultivation of landraces. Among other factors, maize diversity is linked with: (1) small-holder farming, (2) the production of traditional food products, (3) traditional cropping systems, (4) cultivation in marginal areas, and (5) retention of control over the production system by the farmers. On the other hand, genetic erosion is associated with substitution of landraces with hybrid varieties or cash crops, and partial (off-farm labor) or complete migration to urban areas. Continued cultivation, and therefore on-farm conservation of genetic diversity held in maize landraces, can be encouraged by creating or strengthening market opportunities that make the cultivation of landraces and open pollinated varieties (OPVs) more profitable for farmers, supporting breeding programs that prioritize improvement of landraces and their special traits, and increasing the access to quality germplasm of landraces and landrace-derived OPVs.

An optimized gluten-free healthy snack (OGFHS) was developed from a mixture of protein quality maize/tepary bean (70:30), applying extrusion-cooking. The extrusion conditions were obtained from the axial combination of process variables (feed moisture content [FMC = 15%-25%]/extrusion temperature [ET = 120 °C-170 °C]/screw speed [SS = 50 rpm-240 rpm]). The desirability function response surface methodology was applied as an optimization technique in three response variables (expansion index [EI]/apparent density [AD]/hardness [H]) to obtain maximum EI and minimum AD and H. The best combination to produce OGFHS was FMC = 16.4%/ET = 137 °C/VT = 237 rpm. The optimized conditions to obtain OGFHS caused little change in the nutritional and nutraceutical properties of the unprocessed grains mixture. OGFHS (50 g) was compared with two commercial snacks (CheetosMR, TotisMR), showing better protein content, total dietary fiber and AoxA, as well as high acceptability and lower energy content than commercial snacks. Due to its great nutritional properties and AoxA,OGFHS could be used for health promotion and as an alternative to commercial snacks with low nutritional value and high energy content.

Development of non-conventional hybrids responds to the demand for the Elotes Occidentales land-race for production of pozole. The effect of growing cycle (2019, 2020, and 2021) on physical characteristics, flowered grain quality, and phytochemical content of two non-conventional hybrids of pozolero maize, as well as the effect of the presence or absence of pedicel, type of pollination (open and controlled, 2019), and parents (female and male, 2020) on flowered grain quality and content of phytochemical compounds, were evaluated. Size, hardness, color, total phenols, and anthocyanins in unprocessed grain were determined. Yield, volume, and puncture force were measured in flowered grain. Results were analyzed with a factorial arrangement in a completely randomized design. There were significant differences (p ≤ 0.05) in most of the variables studied by effect of crop cycle and hybrid. Non-conventional hybrids had large grains (40 g 100 grains⁻¹), soft endosperm (flotation index > 60), pink-purple color, and phenol and anthocyanin contents similar to those reported for the Elotes Occidentales land-race. The presence or absence of the pedicel did not affect flowered grain quality. Controlled pollination favored anthocyanin synthesis. The female parent determined the anthocyanin content of non-conventional hybrids. Thermal processing reduced anthocyanins by 60%; however, they leached into the flowering broth, so that the pozole made from non-conventional hybrids can have improved nutraceutical value, relative to that of pozole made with Cacahuacintle land-race.

México cuenta con amplia diversidad genética de maíz (Zea mays L.), una de las características que presenta esta diversidad es el color del grano, con una gama de tonalidades, que van desde el negro, azul, morado y rojo, que son los más comunes (Salinas et al., 2010), hasta el salmón y rosa pálido. Los compuestos responsables de los colores en los granos son las antocianinas, las cuales poseen capacidad antioxidante, antimutagénica y anticancerígena (López-Martínez et al., 2009; Zhao et al., 2009). Salinas et al. (2012; 2013) informaron que en poblaciones de maíz de grano azul los pigmentos se localizan en la capa de aleurona, en tanto que en los maíces granate y rojo el pigmento está localizado principalmente en el pericarpio; en los maíces magenta se encuentra en ambas estructuras (pericarpio y capa de aleurona).

En las regiones subtropicales de México, el mejoramiento genético del maíz (Zea mays L.) se ha enfocado tradicionalmente hacia la obtención de híbridos de alto rendimiento; sin embargo, las necesidades nutrimentales e industriales han reorientado los programas de mejoramiento para incluir aspectos de calidad nutricional e industrial del grano (Ortiz-Monasterio et al., 2007), donde el maíz con alto contenido de aceite (ACA) es de gran importancia para las industrias aceitera y de alimentos balanceados. Un maíz ACA contiene más del 6 % de aceite, en comparación con el maíz normal que tiene entre 2.0 y 5.0 %. El maíz ACA tiene valor nutricional adicional por su energía metabolizable, con un efecto significativo en raciones para animales, y puede sustituir grasas, harina de soya o aminoácidos esenciales sintéticos, lo que mejora la dieta (Alexander, 1988; Lambert, 2000). Una serie de estudios revisados por Lambert (2000) con cerdos, aves, ovejas y vacas lecheras, alimentados con raciones de maíz ACA mostraron en ellos mayor crecimiento, eficiencia alimenticia y calidad de sus productos.

La producción de maíz de grano amarillo en México es deficitaria, durante 2016 se importaron 12.2 millones de t (FIRA, 2016) para satisfacer la demanda anual, que es superior a 15.3 millones de t, de las cuales 75.7 % del maíz amarillo que se utiliza en México es de uso pecuario, principalmente como fuente de energía para la elaboración de alimentos balanceados. Partiendo de que el aceite del grano de maíz aporta 2.25 veces más energía que el almidón (Alexander, 1988), la utilización de maíz amarillo con alto contenido de aceite (ACA) podría tener impacto significativo en la alimentación pecuaria de rumiantes y monogástricos (bovinos, caprinos, porcinos, aves, entre otros). De acuerdo con Lambert (2000), un maíz ACA debe tener más del 6 % de aceite total en el grano, mientras que un maíz normal tiene de 2.0 a 5.0 %.