Fotosíntesis y calidad fisiológica de genotipos de maíz criollo mejorado

Abstract

In Mexico, the melioration of native corns has benefited of hybridization, selection and recombination as methods for breeding. However, a good option for the melioration of native corns is taking advantage of heterosis for performance. In this assay the photosynthetic performance, and the physiological quality of seven native meliorated corn genotypes, obtained under different strategies of selection, and genetic improvement, were evaluated. The work took effect under greenhouse conditions in Saltillo, Coah., Mexico. The evaluated variables were: CO2assimilation rate, stomatal con ductance, intercellularCO2, transpiration and intercellular CO2relation, environmental CO2; plumule and radicle length, emergency speed rate as a vigor proof, percent of emergency as an essay of viability, and fresh and dry weight. Statistical differences for the CO2assimilation rate, and for perspiration, were found, but it was not so for the rest of the variables. The native materials showed a capacity in the mesophyll to fix CO2higher than the meliorated ones. The native populations had a higher length of plumule and radical, as well as a content of dry matter higher than the meliorated ones, due to the fact that the improved genotypes are adapted to better breeding conditions, as are irriga tions, and application of all agricultural inputs, while the native ones resist adverse environments as is persistent rain during several days, in addition to its efficiency in the production of dry matter, and in the fixing of CO2.