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Texcoco de Mora, Mexico

Yang E.-N.,CAS Chengdu Institute of Biology | Rosewarne G.M.,CAS Chengdu Institute of Biology | Rosewarne G.M.,International Maize and Wheat Improvement Center | Herrera-Foessel S.A.,International Maize and Wheat Improvement Center | And 5 more authors.
Theoretical and Applied Genetics

Chapio is a spring wheat developed by CIMMYT in Mexico by a breeding program that focused on multigenic resistances to leaf rust and stripe rust. A population consisting of 277 recombinant inbred lines (RILs) was developed by crossing Chapio with Avocet. The RILs were genotyped with DArT markers (137 randomly selected RILs) and bulked segregant analysis conducted to supplement the map with informative SSR markers. The final map consisted of 264 markers. Phenotyping against stripe rust was conducted for three seasons in Toluca, Mexico and at three sites over two seasons (total of four environments) in Sichuan Province, China. Significant loci across the two inter-continental regions included Lr34/Yr18 on 7DS, Sr2/Yr30 on 3BS, and a QTL on 3D. There were significant genotype × environment interactions with resistance gene Yr31 on 2BS being effective in most of the Toluca environments; however, a late incursion of a virulent pathotype in 2009 rendered this gene ineffective. This locus also had no effect in China. Conversely, a 5BL locus was only effective in the Chinese environments. There were also complex additive interactions. In the Mexican environments, Yr31 suppressed the additive effect of Yr30 and the 3D locus, but not of Lr34/Yr18, while in China, the 3D and 5BL loci were generally not additive with each other, but were additive when combined with other loci. These results indicate the importance of maintaining diverse, multi-genic resistances as Chapio had stable inter-continental resistance despite the fact that there were QTLs that were not effective in either one or the other region. © Springer-Verlag Berlin Heidelberg 2013. Source

Albino-Garduno R.,University of San Francisco | Turrent-Fernandez A.,Campo Experimental Valle de Mexico | Isabel Cortes-Flores J.,Colegio de Mexico | Livera-Munoz M.,Colegio de Mexico | Carmen Mendoza-Castillo M.,Colegio de Mexico

Intercropping systems of maize with common bean (Phaseolus vulgaris L.) have increased species performance compared with simple crops and this advantage would be due to physiological complementarity of this species and the efficiency in the use resources usage. Therefore, the objective of this study was to analyze the effect of the spatial arrangement of maize and beans regard its distribution of aerial biomass and roots, photosynthetically active radiation in the canopy and grain production of both species. This research was carried out in the year 2012; at the experimental field "Valley de Mexico" Zea mays L. ('H-155') and P. vulgaris L. ('Negro 8025') were intercropped. The arrangement was maize (MM) and bean (FF) in simple cultures, two furrows of maize intercropped with two of bean (MMFF) and an alternate with each species (MFMF). An ANOVA and means comparison (DMS; p≤0.05) were assessed from the resulting data using SAS® software version 9.00. The highest maize yield (p=0.014) arose when it was intercropped, the MFMF treatment had more exploration area with root presence (7861 cm2) and lateral roots (186 cm2). The MM treatments had less maize grain yield (p≤0.05) compared to the intercropping arrangements, as they had the lowest photosynthetically active radiation at the ground level (RFAts) and their roots had less side soil exploration. Beans in MFMF had 38 % less area with root presence and high RFAts values respect to the simple crops, which decreased the biomass since the pre-flowering, the leaf area index in grain filling and yield grain. The beans at the MMFF treatments increased its biomass and yield grain, as the basal leaves got more RFA. The soil relative efficiency was 1.12 in the MMFF treatment and 1.07 in the MFMF. Source

Sharma R.C.,ICARDA | Crossa J.,CIMMYT | Velu G.,CIMMYT | Huerta-Espino J.,Campo Experimental Valle de Mexico | And 3 more authors.
Crop Science

The Global Wheat Program of the International Maize and Wheat Improvement Center (CIMMYT) develops and distributes improved germplasm targeted toward various wheat growing regions of developing world. The objective of our study was to quantify the genetic yield gains in CIMMYT's spring bread wheat (Triticum aestivum L.) in the Elite Spring Wheat Yield Trial (ESWYT) distributed over the past 15 yr (1995-2009) as determined by the performance of entries across 919 environments in 69 countries. To determine the annual genetic gains, differences in mean yields of the five highest yielding entries from mean trial yield and mean yield of the widely grown international check 'Attila' were regressed over 15 yr of ESWYT testing. Across locations in all countries, mean yields of the five highest yielding entries showed an annual gain of 27.8 kg ha-1 (0.65%) compared to Attila. Annual yield gains in megaenvironment 1 (ME1) (optimally irrigated), ME2 (high rainfall), Egypt, India, and Pakistan were 27.4 (0.55%), 21.4 (0.62%), 111.6 (1.13%), 32.5 (0.83%), and 18.5 kg ha-1 (0.5%), respectively. These results demonstrate continuous genetic yield gains in the elite spring bread wheat lines developed and distributed by CIMMYT and the positive outcomes achieved through breeding and the international exchange of elite spring wheat germplasm that have benefited national programs throughout the world. © Crop Science Society of America. Source

Ramirez-Diaz J.L.,Instituto Nacional de Investigaciones Nucleares | Ledesma-Miramontes A.,Instituto Nacional de Investigaciones Nucleares | Vidal-Martinez V.A.,Campo Experimental Santiago Ixcuintla | Gomez-Montiel N.O.,Campo Experimental Iguala | And 5 more authors.
Revista Fitotecnia Mexicana

México is center of origin of maize (Zea mays L.), and as a species it has broad genetic diversity. However, this diversity has been scarcely used by Mexican maize breeding public programs that develop commercial hybrids. It is partly so because current methodologies do not use improved heterotic patterns. This research presents a breeding protocol proposal for incorporation of outstanding native maize germplasm into improved maize heterotic patterns for commercial maize hybrid development, and shows effects of application of this protocol on grain yield and grain size of test-crosses. The proposed protocol has three stages: 1) selection of candidate, improved heterotic patterns, 2) selection and incorporation of native germplasm into improved material, and 3) application of reciprocal recurrent selection method (RRS) with familiar selection modification. Evaluation of this methodology employed a subtropical single-cross from progenitors that incorporated 25 % of germplasm of races of Ancho and Tabloncillo maize. S1 lines and testcrosses were evaluated in four locations. The proposed protocol effectively incorporated native germplasm into improved germplasm: testcrosses with similar grain yield to the original single cross were identified from both race groups. This protocol was also effective for increasing grain size. This protocol allows incorporation of native maize or improved germplasm to current heterotic patterns or outstanding single crosses. Source

Perez-Ruiz J.A.,Colegio de Mexico | Zamora-Diaz M.,Campo Experimental Valle de Mexico | Mejia-Contreras J.A.,Colegio de Mexico | Hernandez-Livera A.,Colegio de Mexico | Solano-Hernandez S.,Campo experimental Bajio

The objective of this study was to evaluate agronomic characteristics, grain yield, and physical grain quality in malting barley (Hordeum vulgare L.) genotypes cultivated under irrigation. The study was carried out at the El Bajío region of Mexico. The variables evaluated were number of tillers (NM), number of nodes on the main stem (NN), plant height (AP), hectoliter weight (PHL), weight of one thousand grains (PMG) and grain yield (REN). The experimental design was randomized complete blocks with a 10×5×2 factorial arrangemen of treatments: ten genotypes, five sowing dates and two agricultural cycles. The sowing dates were November 15 and 30, December 15 and 30 and January 15. The agricultural cycles were 2012-2013 and 2013-2014. The data were analyzed with an ANOVA, means were compared with Tukey test (p≤0.05) and correlations. The genotypes expressed higher NM, NN, AP, PHL, PMG and REN when sowing was at the end of autumn, while those established at the beginning of winter had lower values. The varieties Alina and Armida produced higher yields and better grain physical quality. Source

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