Abstract:
Abstract: Starch accumulation in wheat is a physiological process of transportation and conversion of photosynthetic assimilates into starch that determines grain yield and quality. The process of starch accumulation cannot only be affected by genetic factors, but also be regulated by environmental conditions. Sprinkler irrigation is one of the most advanced irrigation methods used worldwide and plays a vital role in wheat production in China. However, little is known about the starch accumulation characteristics and its quality variation of wheat grains under sprinkler irrigation. The objectives of this study were to quantify the difference between sprinkler irrigation and surface irrigation in starch accumulation and starch quality properties of wheat grains. In order to achieve the objectives, field experiments were conducted during 2012-2013 and 2013-2014 winter wheat growing seasons with medium-gluten wheat cultivar Bainong AK58 as a test material and surface irrigation as control. The experiment was carried out in Experimental Field of Henan Institute of Science and Technology (35°17'N, 113°56'E) located in Hongmen town of Xinxiang city, Henan, China. Content of starch and its component were determined according to the method of double-wave length. Starch pasting properties were measured by using the Rapid Visco Analyser. The accumulation courses of total starch, amylose and amylopectin were simulated by Logistics equation and then characteristic parameters of the curves were calculated.The results showed that: 1) Compared with surface irrigation, sprinkler irrigation improved the total starch content and the content of amylopectin in wheat grains, and decreased the amylase content and amylose/amylopectin ratio; 2)The accumulated total starch content and amylopectin content each grain under sprinkler irrigation were significantly increased by 7.8%-8.0% and 12.2%-12.5% (P<0.05); 3)The accumulated amylose content each grain under sprinkler irrigation was significantly decreased by 8.3%-11.4%(P<0.05); 4) The accumulation courses of starch could be well fitted to the logistic equations by relating starch contents against days after anthesis with R2 of 0.995-0.999 (P<0.05); Logistic simulation revealed that the higher total starch and amylopectin accumulation in a single grain under sprinkler irrigation resulted from the higher maximum and average accumulation rate while the lower amylose accumulation in a single grain under sprinkler irrigation resulted from the smaller maximum and average accumulation rate; 5) Compared with surface irrigation, the peak of viscosity, through viscosity, breakdown value and final viscosity of wheat flour under sprinkler irrigation were increased (P<0.05) by 0.169-0.186, 0.053-0.062, 0.116-0.124 and 0.155-0.171 Pa·s, respectively; However sprinkler irrigation had no significant effect on the pasting time and pasting temperature of wheat flour. The results suggested that sprinkler irrigation improved starch accumulation and starch quality of medium-gluten wheat grain. This study may provide valuable information for the high-yield and good-quality cultivation of winter wheat.