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Copyright of Revista Mexicana de Ciencias Agrícolas is the property of Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In spite of the advantages of barley when compared to other cereals, in México there are few studies on whole-plant barley used as forage and its nutritive value for dairy cows. Twenty six (26) advanced awnless forage barley lines plus commercial varieties of oat (cv. Cuauhtémoc), triticale (cv. Eronga 83), grain barley (cv. Cerro Prieto) and one awnless experimental line of bread wheat (AN-266-99), were evaluated during 2005-2006 and 2006-2007, fall/winter cycles at the "Las Vegas" Ranch ocated in Francisco I. Madero municipality, Coahuila, México. Dry matter production and other agronomic variables were measured on two sampling dates in each cycle using a randomized complete block design with three replications and forage nutritive value in each sampling was determined also. Results indicated that wheat, oat and triticale were the high nutritive value genotypes in the first sampling due to their energy and protein contents together with less ADF and NDF concentrations, but yielding less dry matter than awnless barley genotypes. In the second sampling awnless barley genotypes kept an adequate nutritive value at later than milky - dough stages through increased energy (NEl and NEm) and decreased fiber (ADF and NDF) contents. These data allows lengthening the period of use of awnless forage barley without losing quality, with the additional advantage that being awnless it will avoid animal damage in delayed grazing. [ABSTRACT FROM AUTHOR]

Dry matter yield and its fractions (stems, leaves and spikes), leaf/stem ratio, plant height and phenological stage of 36 awnless barley F7 lines, plus two commercial controls (triticale cv Eronga 83 and barley cv Cerro prieto), were evaluated in three environments (Torreón, Coahuila; Navidad, Nuevo León; and Celaya, Guanajuato) in central and northern Mexico. Experimental design was a randomly complete block design with three replicates. Data generated by locations and cycles (i.e. environments) were analyzed as a randomly block combined over environments. The genotype averages were used in a principal components analysis and a cluster analysis. The genotype x environment interaction had no effect on dry matter yield, and was different (P<0.05) between genotypes. The multivariate analyses effectively separated the awnless from the awned genotypes mainly based on dry matter yield and precocity, which favored the barleys. The awnless barley genotypes were clustered into three groups with potential for forage production, with genotypes 33, 19, 10 and 34 outyielding others with production greater than 12 t ha-1. The evaluated new awnless forage barley genotypes constitute a feasible alternative for winter forage production. Their precocity and productivity are important in areas with restricted water use, and allow barley to be included in annual forage crop rotation schemes. [ABSTRACT FROM AUTHOR]

Infrared technology is a practical, fast, non-destructive method that helps in forecasting plant development and can be used to select physiological traits, instead of other methodologies that require more time and breeding efforts. According to the statistical analyses and the relationship between the direct and indirect effects of the variables, this technology could serve as the basis for implementing a genotype selection methodology. Awnless barley was assessed in a randomized block design with three replicates in two crop seasons at Mexico's northeastern region. Two samplings were carried out during crop development: at 75 and 90 days after sowing. The infrared and stomatal sensors were used to identify the direct and indirect effects of stomata's traits on dry forage yield. The data were analyzed in a subdivided plot design, using mean comparison tests, correlation coefficients and path analyses, finding significant differences (p < 0.05) among localities and among samplings. Dry forage yield was significant and positively correlated with plant height (r = 0.578) and canopy temperature (r = 0.724), and negatively correlated with the leaf upper side stomatal width (r = −0.409) and the leaf lower side stomatal width (r = −0.641), chlorophyll content and vegetation index. Temperature, chlorophyll, density and leaf lower side stomatal index had the strongest direct effects on yield. Therefore, the infrared technology appears as a way to select high yielding awnless forage barley, to obtain the correlation, the positive direct effect of temperature and the negative effect of chlorophyll. Due to their direct effects, low density and low leaf underside stomatal indexes can also help in the indirect selection of higher yielding forage barley genotypes. [ABSTRACT FROM AUTHOR]