Results of the First Breeding Cycle Using Maize Accessions from CIMMYT, Mexico

AGRISOST 1 AGRISOST ISSN-e 1025-0247 RNPS 1831 https://revistas.reduc.edu.cu/index.php/agrisost January-December 2025  Volume 31 e248 Agrisost  Vol. 31, January-December 2025: 1-8 ISSN-e: 1025-0247 Results of the First Breeding Cycle Using Maize Accessions from CIMMYT, Mexico Genry Hernández Carrillo1, Ibrahim Pérez Cantillo2 & Idania L. Yero Pino3 1ORCID https://orcid.org/0009-0001-6240-8277,Vertientes-based research facility, Genetic Breeding Department, Camagüey, Cuba, 2ORCID https://orcid.org/0009-0002-0797-3406, Institute for Grain Improvement Research, Genetic Improvement Department, Bauta, Artemisa, Cuba, 3ORCID https://orcid.org/0000-0003-1446-4677, Vertientes Campus, University of Camagüey, Cuba. Citation: Hernández Carrillo, G., Pérez Cantillo, I., & Yero Pino, I. L. (2025). Results of the First Breeding Cycle Using Maize Accessions from CIMMYT, Mexico. Agrisost, 31, 1-8. https://doi.org/10.5281/zenodo.17701890 Received: March 7th, 2025 Accepted: April 12, 2025 Published: June 3rd, 2025 Funding source: Not declared. Conflict of interest statement: Not declared. Email: [email protected] Abstract Context: Obtaining germplasm that expresses higher levels of yield, quality, and stress tolerance requires the development of improved maize varieties and hybrids. To this end, preliminary characterization and evaluation may yield useful results, making it necessary to identify the group of individuals that could serve as progenitors of the enhanced generation. Aim: To evaluate the performance of 21 maize accessions from CIMMYT, Mexico, under the edaphoclimatic conditions of the municipality of Vertientes, Cuba. Methods: A randomized block design with three replications was used, and the agronomic traits of 24 maize accessions were evaluated. The following traits were recorded: plant and ear height, male and female flowering, biological cycle, ear length, number of rows per ear, 1000-grain weight (g), and grain yield (t·ha⁻¹). Results: The vegetative traits—plant height and ear height—proved to be directly proportional, characterized by a short stature. The entries exhibited an early growth cycle, and male flowering occurred approximately ±1.22 days before female flowering. Conclusions: The entries that exhibited the best agronomic traits were numbers 14, 19, 18, 15, and 10, with an average grain yield of 4.39 t·ha⁻¹, respectively. Seeds were obtained from 19 entries for the next breeding cycle. Mass selection was applied in the first generation of the F1, enabling the continuation of the next selection cycle. Keywords: maize accessions, morpho-agronomic traits, breeding. Introduction Maize (Zea mays L.) forms the foundation of food and nutritional security (SAN, in Spanish) for the Mesoamerican population, accounting for 61% of total caloric intake and serving as a significant source of protein (Poole et al., 2020). It is the second most economically important cereal after rice in Cuba and is highly preferred by the population for consumption. Maize is cultivated throughout the island, covering an area of 150,000 hectares, with the eastern provinces standing out for having the largest planted surface (Hernández, 2022). The same author reports that in 2020, 130,000 hectares of maize were harvested in Cuba, yielding 250,000 tons and an average grain yield of 2.22 t·ha⁻¹. Maize with yellow kernels—either flint or dent types—is primarily cultivated for human consumption as fresh ears and for animal feed in its dry grain form. Despite the crop’s importance and the advances in genetic improvement over recent decades, low yields remain the main challenge for small-scale farmers in the region. To address future challenges associated with climate change and the rising demand for food driven by population growth, it is imperative to implement strategies that promote the sustainable production of this crop, enhance its contributions to food and nutritional security, and reduce the food vulnerability of the regional population (Prasanna et al., 2021). Agrisost 2 AGRISOST ISSN-e 1025-0247 RNPS 1831 https://revistas.reduc.edu.cu/index.php/agrisost January-December 2025  Volume 31 e248 Hybrid maize was one of the earliest successful applications of genetic theory in food production. The foundation of commercial hybrid development lies in inbred lines with good combining ability; however, the success in obtaining outstanding lines depends on the level of genetic variability present in the segregating population and on the gene frequency of alleles of interest (Borroel et al., 2018). The use of hybrids may be a decisive factor in maize production in Cuba, as the limited availability of improved germplasm often leads to reliance on creole genotypes with undesirable agronomic traits and low yield potential (Hernández et al., 2018; Ruiz et al., 2022a). To maintain, conserve, and harness the genetic potential represented by maize landraces and their wild relatives, collections have been established and deposited in various international germplasm banks, such as the one at the International Maize and Wheat Improvement Center (CIMMYT) (Chassaigne, 2022). The evaluation and characterization of foreign germplasm collections is a fundamental step in genetic improvement programs; the exchange of germplasm among research institutions greatly aids in refining and organizing accessions, and above all, in identifying valuable genotypes for use in breeding programs. Therefore, it is vital to have available information on each material regarding qualitative and quantitative traits of current or future importance (Rosales & Sánchez, 2022). Maize in Cuba is one of the most important commodities for both human and animal consumption, making it essential to study the plant genetic resources available in the Caribbean region in order to strengthen the country’s germplasm bank with new accessions. Building on the Cuba–Mexico collaboration with CIMMYT, which holds a larger quantity of advanced genetic material geared toward hybrid development and improved varieties, these resources are being used by regional programs to boost agricultural yields (Ruiz et al., 2022b). The purpose of developing S1 lines from segregating populations is to exploit the effect of transgressive inheritance in agronomic traits, which would allow the selection of lines that exhibit greater phenotypic expression than their best parent, thereby enabling the identification of outstanding inbred lines (Rebolloza et al., 2020). The use of commercial hybrids, native varieties, and open-pollinated foreign-origin varieties can serve as a genetic source for obtaining pure lines, which may be used in breeding programs. Therefore, the objective of this research is to evaluate the performance of 21 maize accessions from CIMMYT Mexico under the edaphoclimatic conditions of the municipality of Vertientes, Camaguey province, Cuba Materials and methods The experimental trial was conducted at the Vertientes Scientific-Technological Base Unit, located in Camagüey Province at coordinates 21° 5′ 23″ North latitude and 78° 10′ 21″ West longitude, along Sexto Anillo Highway at kilometer 22½, at an elevation of 48 meters above sea level, on a gleyed dark plastic soil with a pH of 6.4 and an organic matter content of 2.67%, according to site cartographic sheets and corroborated by Hernández et al. (2015). A randomized block design with three replications was used, covering a total planting area of 419.8 m², where the S₀ generation of each accession was sown in two rows of 5 meters in length per entry. The planting distance was 0.70 × 0.20 meters. At flowering, self-pollination was performed on 720 F₁ plants, selecting those from each plot with the best agronomic and health traits, and applying a 10% selection pressure. The morpho-agronomic traits of 21 maize accessions—10 triple hybrids and 11 varieties from CIMMYT—were evaluated, using the openpollinated varieties (OPVs) MAIG-5461, MAIG5462, and Tuson as controls (see Annex 1). Planting was carried out during the wet season (April 2020). The agronomic management of the experiment was carried out in accordance with the recommendations outlined in the Technical Guide for Maize Cultivation (Cantillo et al., 2020). Evaluations The following traits were recorded: plant and ear height, male and female flowering, biological cycle, ear length, number of rows per ear, weight of 1,000 grains (g), and grain yield per hectare in t·ha⁻¹ (IBPGR, 1991). Statistical analysis For the variables ear length, number of rows, weight of 1,000 grains, and grain yield, analysis of variance and mean comparison were performed using Duncan’s test (p ≤ 0.05). Statistical analysis of the data was performed using the SPSS Statistical Package, version 24.0. Results and discussion Statistically significant differences were found among the accessions subjected to the first improvement cycle in several of the evaluated traits: plant height, ear height, biological cycle, and days to male and female flowering (Table 1). AGRISOST 3 AGRISOST ISSN-e 1025-0247 RNPS 1831 https://revistas.reduc.edu.cu/index.php/agrisost January-December 2025  Volume 31 e248 The recorded average for the variable plant height was 161.4 cm, with a minimum value of 111.6 cm corresponding to entry number 22, and a maximum value of 197.0 cm belonging to entry number 14, one of the controls; the coefficient of variation was 8.59%, indicating significant differences across all entries and control varieties. Regarding this trait in the selection process, Vega (1972) and San Vicente (2022) noted that taller plants are more susceptible to lodging caused by wind and rain, resulting in crop losses. The selection of shorter plants has proven effective in terms of yield. According to Vargas & Castillo (2019), the variable plant height is a varietal trait determined by stem elongation resulting from the accumulation of photosynthates produced in the leaves, which are translocated to the grains; moreover, it is of great interest in relation to mechanized harvesting. Plant height can also be affected by the combined action of four fundamental factors: light, moisture, nutrients, and population density. Table 1. Functional analysis of five vegetative traits across the 21 entries and three controls Entry Plant height (cm) MZ Height (cm) Days to flowering (days) Cycle (days) Male Fema le 1 159.9d 77.1e 51b 52b 113b 2 164.9c 87.6c 50b 51b 117ab 3 170.4b 84.3d 51b 53b 118a 4 167.6c 91.0c 51b 52b 116ab 5 176.5b 95.3bc 50b 51b 118a 6 170.2b 97.2bc 51b 52b 119a 7 171.6b 103.9b 51b 52b 120a 8 171.7b 93.6bc 52a 53b 116ab 9 125.0f 71.0e 50b 51b 119a 10 175.0b 89.0c 49b 51b 116ab 11 169.8bc 99.3bc 51b 52b 121a 12 153.2d 81.8d 49b 50c 120a 13 197.0a 124.0a 51b 53b 123a 14 158.0d 85.7d 51b 52b 110c 15 168.4c 98.7bc 50b 51b 114b 16 158.1d 84.5d 50b 52b 119a 17 158.3d 83.4d 50b 52b 118a 18 175.3b 102.2b 50b 51b 119a 19 172.9b 91.6c 50b 51b 121a 20 146.1e 72.0e 54a 55a 120a 21 111.6g 53.4f 54a 55a 119a 22 150.8d 84.8d 55a 56a 117ab 23 157.4d 88.6c 52a 54a 120a 24 143.2e 78.9de 53a 54a 111c Mean 161.4 88.29 51.04 52.26 118 VC% 10.92 15.36 3.096 2.897 2.66 SE 7.218 2.249 0.318 0.309 0.654 *Different scripts within the same column indicate statistically significant differences (p ≤ 0.05). The average height measured from the base of the plant to the node of ear insertion was 88.29 cm (Table 1), with a minimum value of 53.4 cm observed in entry number 22 and a maximum value of 124.0 cm corresponding to entry number 14 (control), and a coefficient of variation of 15.36%. The results show consistency between plant height and ear height; in this regard, Gutiérrez et al. (2004) concluded that there is a strong phenotypic association between plant height and ear height; in other words, these variables are directly proportional, which supports the results obtained in this trial. De la Cruz (2007) considered it advisable to use low and medium-stature materials, as these tolerate high plant densities per hectare, without neglecting the positive relationship between plant height and grain yield potential. Liu et al. (2016) stated that both plant height and ear insertion height are very important agronomic traits in maize genetic improvement, as they influence potential yield. On the other hand, Prasanna et al. (2021) stated that these traits, in addition to being correlated with each other, are also correlated with lodging. Therefore, the use of mediumor low-stature plants is recommended, with an approximate plant height of 233 cm and an ear height of 117 cm. The average number of days from sowing to the emergence of the tassel and noticeable pollen release was 51.4 days, with a maximum of 55 days observed in entry number 22, which did not differ significantly from entries 8, 20, 21, 23, and 24. These entries outperformed the three controls and the rest of the evaluated entries. A minimum of 49 days was reported for entry number 10. The number of days from sowing until 50% of the plants exhibited exposed stigmas at least two centimeters long ranged from a minimum of 50 days for the control MAIG5461 to a maximum of 56 days. No statistically significant differences were observed among entries 20, 21, 23, and 24. The average was 52.26 days, as shown in Table 1. These two quantitative variables were shown to be proportional. The results show a difference of ±1.22 days between both flowering events across all entries and controls, indicating good floral synchrony—an influential factor in production. Authors such as López (1968), Vega (1972), Ayala & Oñate (2007), and Chávez et al. (2022) reported that plant height and ear height are associated with flowering time, with shorter plants being the earliest to flower. The results obtained differ from those presented by Cao et al. (2017) in a study of hybrids, who reported that they took between 71 and 76 days to reach male and female flowering, respectively. Ruiz et al. (2022a) in their study confirmed that the materials had an average of 64.8 days, with a range between 62 and 66 days after germination. In this regard, Rebolloza et al. (2020) demonstrated that the average phenotypic response of the S1 lines Agrisost 4 AGRISOST ISSN-e 1025-0247 RNPS 1831 https://revistas.reduc.edu.cu/index.php/agrisost January-December 2025  Volume 31 e248 in the anthesis–silking interval was five days under drought conditions, while under irrigation the average was two days. An accession is considered late after 65 days and early between 42 and 45 days, according to Gutiérrez et al. (2020), which reveals that the evaluated accessions exhibited intermediate flowering, making them of great interest in the selection process. The biological cycle for all entries was relatively short, with an average of 117.5 days after sowing. The earliest cycle was observed in entry number 15, with 110 days, which differed statistically from the controls and the rest of the entries. The longest cycle was recorded in entry number 12 (control), with 123 days. The recorded values for the ear length variable ranged from 13.5 cm in entry number 2 (minimum) to 17.1 cm in entry number 19 (maximum), surpassing the controls and other entries. The average was 15.05 cm, with a coefficient of variation of 6.155%. (Table 2). Guacho (2014) concluded that plant height does not significantly influence ear length. Ayala & Oñate (2007) and Ortigoza et al. (2019) reported that ear length is a trait correlated with yield; however, it is also a low-heritability attribute (10–30%), meaning it is highly influenced by environmental factors. However, Vera (2024) explains that physical factors such as sowing depth and seed health influence this variable and may cause significant differences among accessions. Table 2. Functional Analysis of Quantitative Traits of Five Agronomic Characteristics in Maize from 21 Accessions and Three Controls Entry Ear Length (cm) Number of rows Number of kernels/MZ Total of 1000 kernels (g) Yield per t.ha-1 1 15.4a 16.2a 32b 305bc 3.54b 2 13.5bc 15.4a 29bc 309bc 2.27c 3 15.8a 15.6a 30bc 391ab 2.36c 4 13.8bc 16.2a 34ab 315b 2.63c 5 16.3a 13.6b 35ab 348b 2.3c 6 14.9b 13.6b 34ab 329b 3.15b 7 14.6b 14.6b 35ab 309bc 2.58c 8 14.2b 13.4b 31bc 250c 2.42c 9 14.1b 14.0b 30bc 249c 2.07c 10 15.9a 13.8b 32b 330b 4.11a 11 14.2b 14.2b 33b 301.5bc 4.54a 12 14.8b 15.2a 31bc 320b 3.69b 13 15.6ab 13.9b 33bc 429a 2.60c 14 14.6b 16.0a 34b 330b 4.61a 15 15.9a 14.0b 33bc 321b 4.15a 16 15.0ab 14.0b 36ab 358b 3.68b 17 15.7ab 14.0b 36ab 340b 3.46b 18 16.0a 12.0c 32bc 382ab 4.52a 19 17.1a 16.0a 39a 376.6ab 4.57a 20 13.8bc 14.0b 30c 305bc 3.42b 21 14.0b 12.0c 33b 328.5b 2.29c 22 15.0ab 14.0b 31c 308.5bc 2.18c 23 15.0ab 16.0a 32c 283.5cd 2.44c 24 15.9a 14.0b 30c 278c 2,12c Mean 15.05 14.4 32.71 324.86 3.15 VC% 6.155 8.29 7.295 12.94 14.46 SE 0.193 0.24 0.487 8.579 0.184 *Different scripts within the same column indicate significant differences (p ≤ 0.05). The number of rows per ear was recorded, with an average of 14.4 grain rows per ear. The maximum was 16.2 rows, observed in entries 1, 2, 3, 4, and 10, respectively, while the minimum was 13.4 rows, corresponding to entry 8. The number of grain rows per ear is strongly controlled by genotype and is minimally affected by variations in climatic conditions (Callava, 2020). The trait "number of grains per ear" showed an average value of 32.71 grains, ranging from 29 grains (entry 2) to 39 grains (entry 19), and a coefficient of variation of 7.295%, as shown in Table 2. It can therefore be deduced that the number of grains is directly related to ear length, with the longest ears (entry 19), measuring 17.1 cm, containing 39 grains per ear. The average value for the 1,000-grain weight component was 312.5 g, with a maximum of 391 g (entry 3) and a minimum of 249 g, corresponding to entry 9. The coefficient of variation was 12.86% (Table 2). These data were collected when the ears reached an average moisture content of 14.35%. Table 2 shows the average yield obtained in the performance trial was 3.09 t·ha⁻¹. The highest yield was 4.61 t·ha⁻¹ (entry 14), which did not differ statistically from entries 19, 11 (control), 18, 15, and 10, respectively. However, it did differ statistically from controls 12 and 13 and the rest of the entries. The lowest yield was recorded in entry 9, with 2.07 t·ha⁻¹. These results indicate a contribution among the variables ear length, number of rows, number of grains, and 1,000-grain weight, consistent with the findings reported by Borroel et al. (2018). Yield is a complex trait, and its expression depends on the functioning and interaction of various physiological components, whose limits vary according to the genotype and the environment in which it develops (De la Cruz, 2007; Pacheco et al., 2017; Clemente et al., 2022). It was confirmed that the yields of the maize accessions were low. According to Jurado (2022), the causes of low maize yield may be influenced by the climate in which it was grown, the short day length, the short vegetative cycle of the crop, and abiotic stress typical of tropical regions. Droughts and low soil fertility are also cited as limiting factors in crop yields. AGRISOST 5 AGRISOST ISSN-e 1025-0247 RNPS 1831 https://revistas.reduc.edu.cu/index.php/agrisost January-December 2025  Volume 31 e248 The variability present in the available germplasm is a fundamental requirement for identifying genotypes with specific traits. Traditionally, genetic diversity was estimated based on agro-morphological traits, with the limitation posed by the interaction of their expression with the environment (Rossi et al., 2019). In the selection process of the lines obtained for the next cycle, new materials are available from entries 1, 6, 10, 11, 12, 14, 15, 16, 17, 18, 19, and 20, which stood out in terms of yield, uniformity, plant height, ear height, days to male and female flowering, and certain agronomic traits such as number of rows, ear length, and ear diameter. Díaz et al. (2021) indicated that depending on the size of the base population, the evaluation of progenies, and the recombination method used, these variables influence the response to selection. Therefore, to avoid genetic drift, they suggest using 30 families if five or more selection cycles are to be carried out. They also mention that genetic drift is stronger when fewer than 10 families are used in recombination. In this study, 80 families were selected in the first cycle, which ensures the preservation of genetic variability. The results obtained in this study become a valuable tool for advancing the genetic improvement processes of the populations from which the evaluated lines were derived. However, this should be complemented with genetic diversity studies using molecular methods in order to gain deeper insight into the genetic distances among different population groups, aimed at obtaining lines for hybridization programs. This collection of 21 maize accessions from CIMMYT represents a valuable resource for driving future genetic gains in maize breeding programs being developed in Cuba. Conclusions Outstanding S1 lines were obtained, with some traits of interest for the next selection cycle. The best yield results were obtained from entries 10, 14, 15, 18, and 19, while entry 9 showed the lowest yield and was discarded for the next selection cycle. Recommendations Continue with the selection cycles to gradually enhance the desirable traits of these materials, with the aim of obtaining inbred lines for the development of new hybrids and improved varieties adapted to our agroclimatic conditions. Author contribution statement Genry Hernández Carrillo: Research conception and development , experimental design, data analysis, article writing, and final review. Ibrahim Pérez Cantillo: Research development and result analysis, final review. Idania L. Yero Pino: Research development and result analysis, final review. Conflict of interest statement The authors state there are no conflicts of interest whatsoever. References Ayala, D.A., & Oñate, J. L. (2007). Evaluación y caracterización morfoagronómica de 117 líneas de maíz negro y 42 líneas de maíz dulce provenientes del CIMMYT (México). (Previa a la obtención del título de: Ingeniero Agropecuario, Escuela Poitécnica del Ejercito) https://repositoriobe.espe.edu.ec/server/api/c ore/bitstreams/04dbda94-2c34-4ce3-8bed37673975c393/content Borroel, V.J., Salas, L., Ramírez, M.G., López, J.D., & Luna, J. (2018). Rendimiento y componentes de producción de híbridos de maíz en la Comarca Lagunera. Terra Latinoamericana, 36(4), 423-429. http://doi.org/10.28940/terra.v36i4.281 Callava, S., (2020). Caracterización morfológica y selección de diferentes genotipos de maíz (Zea mays L.). (Tesis de Grado. Ingeniero Agrónomo). Universidad Nacional del Sur. Argentina. Cantillo, I., Riverón, A., Rodríguez, E., Cabañas, M., Rivero, L. E., Toledo, D., & González, T. A. (2020). Guía Técnica para la Producción de maíz. Instituto de Investigaciones de Granos, IIG. MINAG; SEGRANOS; GAG; JICA. Cao, S., Loladze, A., Yuan, Y., Wu, Y., Zhang, A., Chen, J., Huestis, G., Cao, J., Chaikam, V., Olsen, M., Prasanna, B. M., San Vicente, F., & Zhang, X. (2017). Genome-wide analysis of tar spot complex resistance in maize using genotyping-by-sequencing SNPs and whole-genome prediction. The Plant Genome, 10(2). https://doi.org/10.3835/plantgenome2016.10 .0099 Chassaigne, A. A. (2022). Actualización en los Procedimientos para solicitar germoplasma de maíz del CIMMYT. En XXIV Reunión Latinoamericana de Maíz. Memorias de la XXIV Reunión Latinoamericana de Maíz. (pp. 41-42). Instituto Nacional de Innovación Agraria – INIA. Cajamarca. https://latam.maize.org/reunionesbianuales/xxiv-reunion-latinoamericana-demaiz-memoria/ Chávez, A., Guillén, W., & Escobal, F. (15-17 de junio, 2022). XXIV Reunión Latinoamericana de Maíz. Memorias de la Agrisost 6 AGRISOST ISSN-e 1025-0247 RNPS 1831 https://revistas.reduc.edu.cu/index.php/agrisost January-December 2025  Volume 31 e248 XXIV Reunión Latinoamericana de Maíz. Instituto Nacional de Innovación Agraria – INIA. Cajamarca. https://repositorio.inia.gob.pe/bitstreams/3b 34ddca-6e16-4424-91347f7f908d5d05/download Clemente, A., Meneses, M.H., & Pardey, K. (2022). Evaluación del rendimiento de híbridos provenientes de líneas endocriadas de maíz criollo (Zea mays) del departamento del Magdalena, Caribe colombiano. Intropica, 17(1), 88-96. https://doi.org/10.21676/23897864.4039 De la Cruz, M. (2007). Efecto de diferentes niveles de N-P-K y dos densidades de siembra sobre el rendimiento y características agronómicas de las cuatro líneas parentales endogámicas del hibrido de maíz HB-83 mejorado, en Guatemala. (Tesis de grado). Universidad Rafael Landivar. Guatemala. Díaz, G., De León, C., Nieto, D., & Mendoza, M.C. (2021). Ganancia en ciclos de selección recurrente para rendimiento y resistencia a carbón de la espiga en maíz. Mexican Journal of Phytopathology, 39(1), 61-74. https://doi.org/10.18781/R.MEX.FIT.20081 Guacho, E. (2014). Caracterización agromorfológica del maíz (Zea mays L.) de la localidad San José de Chazo. (Tesis de Grado. Ingeniero Agrónomo). Escuela Superior Politécnica de Chimborazo. Riobamba, Ecuador. Gutiérrez, E., Espinosa, A., Palomo, A., Lozano, J. J., & Antuna, O. (2004). Aptitud combinatoria de híbridos de maíz para la comarca lagunera. Nota Científica Revista Fitotecnia Mexicana, 27(Número Especial 1), 7-11. https://doi.org/10.35196/rfm.2004.Especial_ 1.7 Gutiérrez, L. M., Pérez, L. del S., Gómez, A., Jerónimo, M., Brenes, G., & Cajina, N. (2020). Caracterización y evaluación de 20 accesiones de maíz (Zea mays L.) procedente del banco nacional de germoplasma del Instituto Nicaragüense de Tecnología Agropecuaria INTA. (Tesis en opción al título de Ingeniero Agrónomo). Universidad Nacional Agraria. Managua, Nicaragua. Hernández, G. (15-17 de junio de 2022). Estado actual del maíz en Cuba. Presentación en la XXIV Reunión Latinoamericana de Maíz. Cajamarca, Perú. https://latam.maize.org/?wpdmdl=1212 Hernández, G., I. Vargas, Y. Hurtado, P., Castro, E. Rodríguez, I., et al. (2018). Ensayo comparativo de rendimiento de híbridos con endospermo blanco y amarillo procedentes del CIMMYT de México. Revista Cubana de Arroz. 20(2), 32-41. Hernández, A., Pérez, J. M., Bosch, D., & Castro, N. (2015). Clasificación de los suelos de Cuba. Mayabeque, INCA, 93. https://ediciones.inca.edu.cu/files/libros/clas ificacionsueloscuba_%202015.pdf International Board for Plant Genetic Resources (IBPGR). (1991). Descriptors for Maize. International Board for Plant Genetic Resources, Rome. https://cgspace.cgiar.org/server/api/core/bits treams/afe74e02-40fb-4643-8960bbd42c9a07cf/content Jurado, J. (2022). Comportamiento agronómico y rentabilidad de progenies de maíz en el cantón ventanas, provincia los ríos, Ecuador. (Proyecto de Investigación presentado previo a la obtención del Título de Ingeniero Agrónomo). Universidad Técnica de Cotopaxi. La Maná, Ecuador. https://repositorio.utc.edu.ec/server/api/core /bitstreams/3baf65a8-ffe6-4630-b65143ecca1b5818/content Liu, L., Zhang Y. D., Li H. Y., Bi Y. Q., Yu L. J., Fan X. M., Tan J., Jefferrs, D. P., & Kang M. S. (2016). QTL Mapping for gray leaf spot resistance in a tropical maize population. Plant Dis. 100(2), 304-312. https://doi.org/10.1094/PDIS-08-14-0825RE López, L. (1968). Modificación de la Variedad Sintética 2 (VS2) de maíz, mediante Selección Masal. (Tesis de Ingeniería). Universidad Técnica de Manabí. Facultad de Agronomía, Manabí, Ecuador. https://repositorio.iniap.gob.ec/bitstream/41 000/370/1/iniapsctL864m.pdf Ortigoza, J., López, C. A., & Gonzalez, J. D. (2019). Guía técnica cultivo de maíz. San Lorenzo, Paraguay: (J. Ortigoza Guerreño, Ed.). https://www.jica.go.jp/Resource/paraguay/e spanol/office/others/c8h0vm0000ad5gkeatt/gt_04.pdf Pacheco Fernández, M., Landa de Saá, Y., Santana Castro, C. L., Hernández Morales, A., Brutau Proenza, K., Vinci, M., Fajardo Nuñez, D. G., Méndez Gallo, Y., Alonso Esquivel, M., & Lopetegui Moreno, C. M. (2017). La cadena de valor del maíz como alimento animal en Cuba. Estudio de su situación en seis municipios de las provincias de Santiago de Cuba y Granma. MINAG; COSUDE; AGROCADENAS; PNUD. https://www.undp.org/sites/g/files/zskgke32 6/files/migration/cu/73b578d49cec192bbfb7 f5c4c5b0dd12229a354a31f913a54de3b3bf4 c9c39bb.pdf AGRISOST 7 AGRISOST ISSN-e 1025-0247 RNPS 1831 https://revistas.reduc.edu.cu/index.php/agrisost January-December 2025  Volume 31 e248 Poole, N., Donovan, J., & Erenstein, O. (2020). Agrinutrition research: Revisiting the contribution of maize and wheat to human nutrition and health. Food Policy, 100, 101976. https://doi.org/10.1016/j.foodpol.2020.1019 76 Prasanna, B. M., Cairns, J. E., Zaidi, P. H. et al. (2021). Beat the stress: breeding for climate resilience in maize for the tropical rainfed environments. Theor Appl Genet 134, 1729– 1752. https://doi.org/10.1007/s00122-02103773-7 Rebolloza, H., Cervantes, Y. F., Broa, E., Bahena, G., & Olvera, A. (2020). Fenotipeo y selección de líneas S1 segregantes de maíz tolerantes a estrés hídrico. Revista Biotecnia, 22(3), 20-28. http://doi.org/10.18633/biotecnia.v22i3.113 0 Rosales, G. P., & Sánchez, D. (2022). Caracterización morfológica de 25 variedades de maíz amiláceo evaluadas en dos localidades de la provincia de Tayacaja, Huancavelica. Llamkasun, 3(2), 15-29. http://doi.org/10.47797/llamkasun.v3i2.103 Rossi, E.A., Ruiz, M., Di Renzo, M., & Bonamico, N.C. (2019). Diversidad genotípica de 291 líneas de maíz de CIMMYT y caracterización fenotípica en el Sur de Córdoba, Argentina. BAG, Journal of Basic and Applied Genetics XXX (1), 25-33. http://www.scielo.org.ar/scielo.php?scipt=sc i_arttext&pid=S185262332019000100004&Ing=es Ruiz, A., Cantillo, I., Rodríguez, E., & Pérez, E. (2022a). Obtención y evaluación de nuevos híbridos simples de maíz (Zea mays L.). Revista Cubana del Arroz, 24(1), 1-6. Ruiz, A., Cantillo, I., Rodríguez, E., & Pérez, E. (2022b). Evaluación de la aptitud combinatoria general de líneas endogámicas de maíz (Zea mays L.) mediante una prueba de mestizos. Revista Cubana del Arroz, 24(1), 12-16. San Vicente, F. (15-17 de junio de 2022). Contribución del CIMMYT al Mejoramiento Genético de Maíz en América Latina. Presentación en la XXIV Reunión Latinoamericana de Maíz. Cajamarca, Perú. Vargas, J. P., & Castillo, E. A. (2019). Evaluación de 20 híbridos de maíz, en Tisma, Masaya. (Tesis Doctoral). Universidad Nacional Agraria, Managua, Nicaragua. Vera, Ch. G. (2024). Evaluación del comportamiento agronómico de dos genotipos de maíz frente al estrés hídrico en la comuna Colonche, provincia de Santa Elena. (Tesis en opción al título de Ingeniero Agropecuario). https://repositorio.upse.edu.ec/handle/46000 /10912 Vega, P. (1972). Efecto del medio ambiente sobre la relación altura de mazorca/altura de planta en maíz (Zea mays L.). Agronomía Tropical 22(5), 461-474. Agrisost 8 AGRISOST ISSN-e 1025-0247 RNPS 1831 https://revistas.reduc.edu.cu/index.php/agrisost January-December 2025  Volume 31 e248 Appendix Appendix I Genetic material used in the study, its origin, and grain color Entry Accessions Material Origin Kernel color 1 (CLRCY017/CL02450)// CML451 Triple hybrid CIMMYT White 2 (CLRCY016/CL02450)// L02720 Triple hybrid CIMMYT White 3 (CLRCY017/CL02450)// CLYN205 Triple hybrid CIMMYT White 4 (CLRCY017/CL02450)// CLYN214 Triple hybrid CIMMYT Yellow 5 (CLRCY040/CLYN206)// CLRCY017 Triple hybrid CIMMYT Yellow 6 (CLRCY017/CL02450)// CLRCY040 Triple hybrid CIMMYT Yellow 7 (CL02720/CML451)// CLRCY016 Triple hybrid CIMMYT Yellow 8 (CL02450/CLRCY041)// CLYN214 Triple hybrid CIMMYT Yellow 9 (CL02450/CLRCY041)// CML451 Triple hybrid CIMMYT Yellow 10 (CLRCY044/CLRCY039)// CL02450 Triple hybrid CIMMYT Yellow 11 MAIG-5462 (Control) VPL IIG Yellow 12 MAIG-5462 (Control) VPL IIG Yellow 13 Tuson (Control) VPL IIG Yellow 14 S11TLWNHGAB03 VPL CIMMYT Yellow 15 S11TLWNHGAB05 VPL CIMMYT Yellow 16 S11TLWNHGAB06 VPL CIMMYT Yellow 17 S11TLWNHGAB08 VPL CIMMYT Yellow 18 S11TLYNHGAB01 VPL CIMMYT Yellow 19 S11TLYNHGAB02 VPL CIMMYT Yellow 20 S11TLYNHGAB03 VPL CIMMYT Yellow 21 S11TLYNHGAB04 VPL CIMMYT Yellow 22 S03TLW3HGB VPL CIMMYT Yellow 23 S06TLWQHGAB02 VPL CIMMYT Yellow 24 S07TLYNHGAB01 VPL CIMMYT Yellow