No abstract

Aiming to evaluate sowing densities and efficiency of radiation use, six corn genotypes, three from open pollination (“Amarillo Almoloya,” “Cacahuacintle,” and “Jiquipilco”) and three hybrids (“Z-60,” “Condor,” and “H-50”), were sown at densities of 6.9, 7.8, and 8.9 plants m−2, under a split plot design, within a factorial arrangement of treatments during three years (2008, 2009, and 2010). Evaluated variables were yield, harvest index, biomass production, attenuation coefficient, and radiation use efficiency. Results indicate that 2008 was the best year because yield, biomass, and radiation use efficiency were 1132.6, 3505 gm−2, and 0.79 g MJ−1, respectively. “Jiquipilco” was the genotype that exhibited the best adaptability to climatic conditions of the zone; thus, it is recommended to be grown on the studied zone.

No abstract

To know the dynamics of net assimilation rate and the agronomic efficiency of nitrogen in the Tartago crop, seeds of three accessions were collected in Teotitlán de Flores Magón, Oaxaca, Mexico. The treatments consisted of nitrogen fertilization of 0, 20, 40, 60, 80, 100, 120, and 140 kg (N) ha−1, evaluated under a completely randomized design. The experimental unit was constituted by a Tartago plant inside of a polyethylene bag with soil of the zone, and four repetitions were considered. The response variables were dry biomass, number of fruits per plant, agronomic yield, harvest index, nitrogen agronomic efficiency, SPAD units, and net assimilation rate. The results indicate that climatic conditions did not influence the growth and development of the crop. The maximum values for all of response variables were achieved with the application of nitrogen in a range of 60 to 140 kg ha−1. The net assimilation rate was adjusted to a quadratic model. It is concluded that the Tartago responds positively to the application of nitrogen and can be an alternative to be grown in dry climate.

No abstract

Fungi causeconsiderable losses in the faba bean crop in many regions of the world. The aim of the current research was to evaluate the susceptibility of faba bean to fungi, mainly chocolate spot, and its effect on yield, using seeds exposed to gamma irradiation. Faba bean seeds were cultivated in three regions: Hidalgo, Puebla and Tlaxcala, Mexico; the seeds were irradiated with a dose rate of 4.90 Gy·min-1using a Gammacell 220 irradiator. The irradiation doseswere 0, 20, 40, 60, 80, 160, 250 and 350 Gy of gamma rays with 60Co radioisotopes. The irradiated seeds showed acceptablegermination (75.70 %)without visible damages,and survival was 53.62 % until 118 days after sowing. When unirradiated seed was used, the susceptibility of the crop could reach 60 % and the disease severity up to 34 %, with a disease progress rate of 0.006 units·day-1. The 40 Gy dose offered the best response to control the disease; up to 58.80 g of dry weight was obtained for every 100 seeds and a production of 4,442 kg·ha-1. In faba bean crop, up to 77 % of the variation in yield was due toseverity of fungi, mainlythe chocolate spot.

Calla (Zantedeschia aethiopica (L.) K. Spreng), is a cut flower which had obtained importance in recent years, but postharvest handling is limited. Thus, in order to know the fluorescein concentration effect and pH of pulse solution on inflorescences calla postharvest, were evaluated in Teotitlan de Flores Magon, Oaxaca-Mexico, four fluorescein concentrations (0, 20, 40 and 60 %, respectively) and two pH levels (acid and alkaline) in a completely randomized design with factorial arrangement, having a total of 24 experimental units, which was established by vase life and calla inflorescence with white spathe color, immersed in a fluorescein solution adjusted as appropriate at acidic or alkaline pH, where response variables were as follows: vase life, water consumption, stem diameter, absorption fluorescein stem base and fluorescein vertical absorption by floral scape. Results indicates the increased vase life is achieved at alkaline pH by fluorescein addition of 20, 40 and 60 %, respectively. Likewise, the higher water consumption is achieved at this pH. From this research, we can conclude fluorescein can affect the calla physiology for increasing vase life.

Los bosques de galería son formaciones vegetales que se desarrollan de forma paralela a los cauces de los ríos, poseen gran diversidad vegetal; siendo sus especies arbóreas importantes indicadoras de la calidad del agua; por ello, se describieron las variables de la vegetación arbórea y su relación con la calidad del agua del río Xaltatempa, Puebla, México. Se establecieron seis unidades de muestreo de 1000 m2, distanciadas cada 2 km, en las que se midieron e identificaron todos los árboles y arbustos, para generar información acerca del: índice de valor de importancia (IVI), índice de valor forestal (IVF), índice de heterogeneidad de Shannon-Weaver (H') e índice de similitud de Sorensen (ÍSS); adicionalmente se tomaron muestras de agua del río, para determinar sus principales características químicas. Los resultados indicaron diferencia ente sitios (α≤0.05), donde la especie más importante por su dominancia, densidad y frecuencia fue Platanus mexicana (IVI=182.71); de la misma forma lo fue por su diámetro, altura y cobertura (IVF=300.00). Mientras que la riqueza específica (H'=0.54), se concentró en: Alnus acuminata, Ligustrum japonicum, Parathesis serrulata, Pinus patula, Platanus mexicana y Quercus rugosa; en cuanto al ÍSS la combinación pareada de los sitios 4 (1586 m snm) y 5 (1536 m snm), hizo coincidir a las especies: Alnus acuminata, Ligustrum japonicum y Platanus mexicana (ÍSS=1.00). La estructura (fragmentada) y la diversidad (muy baja) de la vegetación arbórea del bosque de galería, hacen evidentes los cambios en su composición; sin tener efectos negativos en la calidad del agua para su aprovechamiento.