[Behaviour of three groups of wheat (Triticum aestivum L.) under water stress. I Midsummer drought]

anglais. The behavior of three groups of wheat genotypes with adaptation for dry land, irrigation and for both conditions were contrasted. The aim of the study was to determine the efficiency of some characters related to drought resistance. The evaluation was made at Chapingo, Mex., under condition of midsummer drought. The outstanding varieties were Temporalera M87 and Galvez M-87 for dryland, and Pavon F-76 for dry and irrigated lands. Their advantages were higher yield and its component early maturity, higher intensity of green leaf coloration and higher content of leaf waxy. After the midsummer drought, the varieties Temporalera M-87 and Mexico M-82 for dry land, together with Oasis F-86 for irrigated lands, showed faster recuperation of their water potential and slower recuperation of their osmotic potencial, involving higher turgency. The characteristic pointed out before, indicated that in dryland conditions, the dry land varieties have more adaptative advantages under drought in relation to the remaining gruops.

espagnol; castillan. Se contrasto el comportamiento de tres grupos de variedades de trigo con adaptacion a secano, a riego y a ambas condiciones, para estudiar el funcionamiento de algunos caracteres relacionados con la resistencia a sequia. La evaluacion se hizo en Chapingo, Mex. bajo sequia intraestival. Las variedades Temporalera M-87 y Galvez M-87, de secano y Pavon F-76 de riego y secano, sobresalieron en rendimiento y sus componentes, en precocidad, y en forma conjunta en intensidad de la coloracion verde y cerosidad de la hoja. Despues de la sequia intraestival las variedades de secano de Temporalera M-87 y Mexico M-82, junto con Oasis F-86 de riego, mostraron rapida recuperacion del potencial hidrico, y lenta, del osmotico, redundando en mayoro turgencia. De lo anterior se infiere que las variedades seleccionadas bajo deficits hidricos tienen mayores ventajas adaptivas a secano en relacion al resto de los grupos.