Climatic and water availability effects on water-use efficiency in wheat

• Published in: Crop science 2004-03, Vol.44 (2), p.474-483
• Main Authors: Abbate, P.E, Dardanelli, J.L, Cantarero, M.G, Maturano, M, Melchiori, R.J.M, Suero, E.E
• Format: Article
• Language: English
• Subjects: Adaptation to environment and cultivation conditions; Agronomy. Soil science and plant productions; Biological and medical sciences; Cereal crops; Climate; Climatic conditions; climatic factors; dryland farming; Evaporation; Fundamental and applied biological sciences. Psychology; Genetics and breeding of economic plants; geographical variation; grain yield; Humidity; irrigation; leaf conductance; mathematical models; Pan evaporation; Photosynthesis; Relative humidity; soil water content; stomatal movement; Transpiration; Triticum aestivum; Vapor pressure; vapor pressure deficit; Varietal selection. Specialized plant breeding, plant breeding aims; Water availability; Water supply; Water use; water use efficiency; Wheat
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2004.4740

In Argentina, wheat (Triticum aestivum L.) is cropped over a wide range of climatic conditions. Considerable variability in the ratio of dry weight produced per unit of transpired water, usually referred to as water-use efficiency (WUE), is expected as variation in climatic factors affects photosynthesis and transpiration in different ways. Also, previous studies have shown that water supply limitations may affect WUE in wheat. The objective of this study was to quantify the effects of climatic environment and water availability on WUE in wheat crops. Six experiments were conducted at different locations of the Argentine wheat belt and crop dry weight and water use were measured in periods when water use was dominated by transpiration. Three of the experiments included both irrigated and rainfed treatments. Mean daily values of (i) pan evaporation, (ii) relative humidity, (iii) potential water use, and (iv) vapor pressure deficit, were used to find a general relationship that explained effects of the climatic environment on WUE. For experiments with high water availability, daytime vapor pressure deficit was better related to WUE than the other climatic factors. WUE was greater for experiments with water limitation, probably because stomatal closure to restrict transpiration rate occurred around midday when vapor pressure deficit was highest. As a consequence, relative dry weight under water limitation was not linearly related to relative water use as proposed in previous studies. A quadratic relationship that better represented this response was derived.