José Luis Arellano Vázquez

Variedades de maíz azul Chalqueño seleccionadas por múltiples caracteres y estabilidad del rendimiento

The objectives of this study were 1) to evaluate the agronomic traits and yield through multiple environments; 2) analyse the behaviour of the varieties through multiple characters; 3) determine the stability of yield; and 4) selecting varieties based on multiple characters and yield stability. An evaluation of 24 varieties was conducted of blue maize landrace Chalqueno and white grain hybrid H-139 as a control, in six locations in the Central Highlands of Mexico. The experiments were established under an experimental design of randomized complete block with four replications. Significant differences (p≤ 0.001) were recorded between locations, varieties and in the varieties x locations interaction for days to male and female flowering, interval of male-female flowering, plant height, flattened plant, pods per plant and yield. Among localities grain yield ranged from 3.7 to 6.7 t ha -1, the proportion of ears per plant was from 0.59 to 0.86 and the days to male flowering of 82.9 to 107.6 days, the highest values corresponded to localities at 2 400 m elevation. Among varieties yield ranged from 4.7 to 6.4 t ha -1 , the control H-139 yielded 6.5 t ha -1 , the proportion of ears per plant ranged from 0.6 to 0.8 and male flowering 90 to 102 days. The analysis of the varieties through multiple characters, detected the

Gacela H72: híbrido de maíz precoz para áreas de temporal y riego del Altiplano Central de México

Due to the climate change that is manifested in the irregular distribution of rainfall less than its incidence in temporary and higher temperatures, the problem of lack of early corn hybrids arises, especially for regions of low and medium productive potential of the central table of Mexico, which cover 1 200 000 ha of cultivated area. The hybrid of early corn Gacela H72, was generated to respond to the conditions of climate change, since it is a double hybrid of early cycle and great hardiness, presents growth and vigorous development in the initial vegetative stage, so it exceeds the size of plant to other maize hybrids during the 30 days after emergence, is tolerant to drought in the vegetative and reproductive stages and yields well in conditions of low chemical fertilization. Its yield has a range of 3 to 11 t ha-1 which surpasses the 50% and creole varieties and 20% private commercial hybrids. It has a period of steepness between 95 and 100 days at altitudes of 2 600 m where other hybrids and varieties reach it between 110 and 115 days. It is resistant to the charcoal of the spike (Sphaceloteca reiliana) and to the putrescence of the cob (Fusarium spp.) And has the quality of nixtamalera-tortillera. Gacela H72, being a double hybrid, has progenitors with higher productivity in the seed than other hybrids, its female parent renders 7.5 t ha-1 in the High Valleys, which gives it 25% more profitability in the production of the registered and certified seed with respect to other maize hybrids. Plant size facilitates intensive sowing with 70 000 plants ha-1 and with double-row planting to 100 000 plants ha-1 yields of 10 to 11 t ha-1 have been achieved. The harvest can be done at 150 days with a moisture content in grain 25%, so the cob must undergo a drying process to reduce the moisture content of the grain 14%. In areas of irrigation and good weather has potential for the production of forage. The main economic impact of the Gacela H72 is the difference of 3 to 4 t ha-1 over the yield of the creole variety, which represents 12 000.00 to 16 000.00 pesos per hectare, which makes corn production profitable.

Comparación molecular de la indentidad genética de genotipos de maíz de diferente edad

Con base en el ano de produccion de la semilla 1994, 1996 y 2000 se realizo la compaparacion molecular de cuatro lineas endogamicas de maiz, generadas por el Programa de maiz del INIFAP: L1, L2, L3 y L4. Para ello, se extrajo el ADN de los embriones de las semillas con el cual se efectuo la RAPD y se establecieron las relaciones filogeneticas entre los tratamientos mediante el programa LCDMV (calculation software of molecular distances between varieties). Se utilizaron los parametros: distancia de Seuil = 0, confiabilidad del 95%, el estimador de distancias de Nei y Li y el metodo del agrupamiento promedio (UPGMA). En la comparacion por edades los dendogramas agruparon genotipos iguales con sus respectivas edades, destacando la similitud alcanzada para la union de las edades de L2 (90%) y de L4 (80%); mientras que para L1 el valor de similitud fue del 70%. La capacidad genotipica de las lineas bajo estudio para preservar su genoma fue mayor en L2, siguiendole L4 y despues L1. Los resultados indicaron la efectividad de la RAPD para diferenciar edades y genotipos geneticamente relacionados, asi como para distinguir entre y dentro de las lineas de maiz independientemente de su edad.