Physiological efficiency of the bean plant before a water deficit/Eficiencia fisiologica de la planta de frijol ante un deficit hidrico

The research was carried out under semi-controlled conditions from November to February of the years 2016, 2017 and 2018 in the Scientific Technological Unit of Base Los Palacios, Cuba, with the aim of evaluating the effect of the water deficit on the physiological efficiency of the bean (Phaseolus vulgaris L.) cv. "Delicia 364". 80 bean seeds were sown per 1.40 [m.sup.2] pot. A Completely Randomized Experimental Design was used, with three treatments and four repetitions: two with water deficit (beginning of wilting of the leaves and when the yellowing of the apex of the leaves began) and a control with irrigation at field capacity. The water deficit was applied when the plants had between three and four true leaves. After each period of stress, the foliar water potential was determined and at the time of harvest the dry mass, the agricultural yield and its components. It was found that the water deficit imposed in the vegetative phase at different intensities caused a state of water stress in the bean plant and after recovering from it, caused increases in the aerial dry mass, number of pods and agricultural yield. The water deficit in bean plants until the beginning of the yellowing of the apex of the leaves, during the vegetative phase, increases the physiological efficiency of the plant depending on irrigation, between 16-25 %, in terms of the aerial dry mass, the number of pods per plant and the agricultural yield. Key words: stress, physiology, legume, yield. La investigacion se realizo en condiciones semicontroladas de noviembre a febrero de los anos 2016, 2017 y 2018 en la Unidad Cientifico Tecnologica de Base Los Palacios, Cuba, con el objetivo de evaluar el efecto del deficit hidrico en la eficiencia fisiologica del frijol (Phaseolus vulgaris L.) cv. "Delicia 364". Se sembraron 80 semillas de frijol por macetero de 1,40 [m.sup.2]. Se utilizo un Diseno Experimental Completamente Aleatorizado, con tres tratamientos y cuatro repeticiones: dos con deficit hidrico (inicio de marchitamiento de las hojas y cuando se inicio el amarillamiento del apice de las hojas) y un testigo con riego a capacidad de campo. El deficit hidrico se aplico cuando las plantas tenian entre tres y cuatro hojas verdaderas. Despues de cada periodo de estres se determino el potencial hidrico foliar y en el momento de la cosecha la masa seca area, el rendimiento agricola y sus componentes. Se encontro que el deficit hidrico impuesto en la fase vegetativa a diferentes intensidade