Elsayed A. Abdelraouf, Damanhour University, Etay Elbaroud, Egypt, Vijaya Joshi, University of Minnesota, St. Paul, MN, Axel Garcia y Garcia, 747, Road 9, University of Minnesota, Lamberton, MN and Breno B.B. Almeida, University of Sao Paulo, Piracicaba, BC, Brazil
Water is one of the most important factors limiting crop productivity. Its effects vary as a function of several factors, including timing and intensity. Because of declining water supply for agricultural use, limited irrigation is becoming an important irrigation practice worldwide. To better manage available water for sunflower production, information on its response to water is needed. Field experiments were conducted at the University of Wyoming Research and Extension Center in Powell, WY during 2010, 2011, and 2012 growing seasons to investigate the effect of limited irrigation strategies on yield and quality of confectionary sunflower. Information on growth, development, and yield, soil moisture, canopy temperature, and photosynthesis were obtained. Results showed significant differences between irrigation treatments on total seed yield and seed quality (7.94 mm sieve seed yield). The crop growth rate (CGR) of all irrigation treatments decreased at 74 days after planting and the higher CGR was observed at 116 days after planting. The higher relative growth rate of all irrigation treatments was observed at 36 days after planting. Significant differences in water use and water use efficiency between irrigation treatments were found. Relationships between canopy temperature and soil water content and between canopy temperature and photosynthesis were used to explain the effect of limited irrigation on yield and quality of confectionary sunflower.