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The maintenance of maize (Zea mays L.) populations on traditional agricultural systems is based on the empirical mass selection principles. Detasseling is a method used for seed production and for maintenance. The objective of this work was to analyze strategies for selection and maintenance of maize populations under a seed production scheme. On a maize population named 'JAGUAN' a seed production scheme was applied, using rows of detasseled (H) individuals female and rows of open pollinated male plants (M), through two generations (G1 and G2). In each generation and pollination method, mass selection was applied with farmer participation, resulting in six sub-populations: H and M in the first generation (G1), and the combinations HH, HM, MH and MM in the second (G2). The agronomic evaluation of these sub-populations was carried out in 2008; the second generation sub-populations allowed analysis of population effects: Female (HH and HM) vs. Male (MM and MH), and production methods: Detasseling (HH and MH) vs. Open pollination (HM and MM). Results indicated differences (P ≤ 0.05) between H and M populations for grain yield in both generations with an increase of 6.3 and 6.4 % of M over the H population, respectively. Between production methods there was an average difference (P ≤ 0.01) of 7.8 % in grain yield of detasseling over open pollination. The highest grain yield of the male population in the two generations was attributed to selection effects when the first sub-populations were developed in the first generation, while in the production methods the difference was due to both selection and detasseling. Thus mass selection applied in populations obtained through seed production schemes (male and female rows) allows maintenance of population traits and increase of average grain yield in maize.

Hernandez H.R.,Antonio Narro Agrarian Autonomous University | Velazquez J.E.,Instituto Mexicano Del Maiz Dr Mario E Castro Gil | Garduno D.S.,Instituto Mexicano Del Maiz Dr Mario E Castro Gil | Zamora Villa V.M.,UAAAN
Revista Fitotecnia Mexicana | Year: 2011

In this work it is postulated that polyembryony (PE) occurring in two maize populations (Zea mays L.) is under the control of two epistatic loci, where a dominant allele at either gene pair produces the normal seedling trait (duplicate gene action), so that polyembryony is shown only by the double homozygous recessive genotype. The genetic analysis was based on the F1, F2 and BC1 progenies from crosses among the populations IMM-UAAAN-BAP (D) and IMM-UAAAN-NAP (C) with eight non related germplasm sources, which were six commercial hybrids, one experimental simple hybrid and a population from CIMMYT. The 16 F1 crosses were done in 2007 in Tepalcingo, Mor; the F2 during 2008, in Buenavista, Coah., and The back crosses (BC1) were generated in 2009, in Buenavista. The PE evaluation for F1 and F2 was done under both greenhouse and field conditions using a complete block design, with 4 or 5 replicates; the BC1 evaluations were performed only under greenhouse. The PE segregation in F2 was tested under the hypothesis of two recessive hypostatic loci, ratio 15:1 (No-PE vs PE progenies); for the BC1 the hypothesis was for the 12:4 ratio. As expected, the PE was not shown in F1 progenies, but it was observed in F2 and BC1, with proportions of 3 to 7 % and 13 to 22 %, respectively. These results are compatible with the proposed hypothesis, considering a joint effect with incomplete penetrance; this phenomenon was present in amounts of 10 to 50 %, varying according to the exotic germplasm in use. The applied χ2 tests to the two types of hypothesis support the proposed inheritance pattern for PE in the two studied maize populations.

Vergara-Pineda S.,Antonio Narro Agrarian Autonomous University | De Leon-Muzquiz H.,Servicios Periciales | Garcia-Martinez O.,Antonio Narro Agrarian Autonomous University | Cantu-Sifuentes M.,UAAAN | And 2 more authors.
Revista Colombiana de Entomologia | Year: 2012

This is the first study performed in Mexico that analyzes the spatial dispersion of postfeeding larvae using human carrion. The remains of a 70 years old Hispanic male were set in an open area the 8th of November 2008. A total of 77 traps were set at ground level separated 50 cm apart of each other and spread along an area of 4 x 4 m. The larvae were collected in the morning along nine days 12 days after the body was leaved in place. Most of the post-feeding larvae molt into adults. Both larvae and adults were identified to the species level. Lucilia sericata was the more common species with 6,844 specimens out of the 8,439 collected; Calliphora coloradensis was the second with just 718 larvae captured. Other species found were Cochliomyia macellaria, C. minima and Phormia regina. The dispersal pattern was aggregated and not homogeneous.

Chavez E.C.,Antonio Narro Agrarian Autonomous University | Fuentes Y.M.O.,UAAAN | Ocampo S.P.,UAAAN | Flores J.L.,UAAAN | Flores J.L.,Monterrey Institute of Technology
Interciencia | Year: 2014

The red flour beetle Tribolium castaneum is the main pest in stored grains and foods. Its control is based on the use of insecticides and fumigants, causing resistance problems. In order to determine and quantify the enzymatic mechanisms involved in resistance, biochemical tests for α and ß esterases, oxidases, glutathione s-transferases, acetylcholinesterase and insensitive acetylcholinesterase were performed in four Tribolium castaneum populations collected from flour mills in Northern Mexico (Coahuila, Nuevo León, Tamaulipas and Aguascalientes), using a susceptible line of T. castaneum as a reference. Results showed that α and ß esterases, as well as oxidases, are the enzymes with the greater presence within the studied populations. These findings suggest that α and ß esterases, and oxidases, are involved in the resistance to insecticides of the populations of T. castaneum under study.

Juarez-Maldonado A.,UAAAN | De-Alba-Romenus K.,UAAAN | Ramirez-Sosa M.I.M.,ITESM Campus Saltillo | Benavides-Mendoza A.,UAAAN | Robledo-Torres V.,UAAAN
Program and Abstract Book - 2010 7th International Conference on Electrical Engineering, Computing Science and Automatic Control, CCE 2010 | Year: 2010

An experiment was developed to validate the NICOLET B3 model. This model has two state variables: carbon content in the vacuoles and carbon content in the cell structure. Carbon dioxide, temperature and radiation taken inside a greenhouse were used as inputs to the model; the model gave out fresh and dry matter of lettuce aerial part. The model dynamic simulation was carried out using MatLab Simulink R2009a. A lettuce crop growth was developed under greenhouse conditions in soilless system, with a set of data loggers to record data. Results have shown that the data obtained from experiment are accurately predicted with this model. © 2010 IEEE.

Mellado M.,Antonio Narro Agrarian Autonomous University | Lara L.M.,Antonio Narro Agrarian Autonomous University | Veliz F.G.,UAAAN | de Santiago M.A.,UAAAN | And 3 more authors.
Pesquisa Agropecuaria Brasileira | Year: 2015

The objective of this work was to obtain prevalence estimates of cloudy vaginal mucus in artificially inseminated Holstein cows raised under intense heat, in order to assess the effect of meteorological conditions on its occurrence during estrus and to determine its effect on conception rate. In a first study, an association was established between the occurrence of cloudy vaginal mucus during estrus and the conception rate of inseminated cows (18,620 services), raised under intense heat (mean annual temperature of 22°C), at highly technified farms, in the arid region of northern Mexico. In a second study, data from these large dairy operations were used to assess the effect of meteorological conditions throughout the year on the occurrence of cloudy vaginal mucus during artificial insemination (76,899 estruses). The overall rate of estruses with cloudy vaginal mucus was 21.4% (16,470/76,899; 95% confidence interval = 21.1-21.7%). The conception rate of cows with clean vaginal mucus was higher than that of cows with abnormal mucus (30.6 vs. 22%). Prevalence of estruses with cloudy vaginal mucus was strongly dependent on high ambient temperature and markedly higher in May and June. Acceptable conception rates in high milk-yielding Holstein cows can only be obtained with cows showing clear and translucid mucus at artificial insemination.

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