Effect of nitrogen reduction on the remobilization of post‐anthesis assimilates to grain and grain‐filling characteristics in a drip‐irrigated spring wheat system

Abstract

AbstractDrip‐irrigation is a cultivation mode that uses water and fertilizer efficiently and is the main cultivation technique for wheat (Triticum aestivum L.) production in the Xinjiang Uyghur Autonomous Region, China. The amount of nitrogen (N) fertilizer used in drip‐irrigated wheat production is strongly connected to land productivity. However, the effect of reduced N application on the translocation of assimilates to grains and grain‐filling in wheat under drip irrigation is unknown. A 2‐yr field experiment (2018–2019) was conducted in the Xinjiang Uygur Autonomous Region with two varieties of spring wheat (Xinchun 38 [XC38] and Xinchun 49 [XC49]) and five N application levels (300 [N1], 275 [N2], 250 [N3], 225 [N4], and 0 [N0] kg hm−2). The results showed that N application significantly affected the dry matter accumulation, transport amount, transport rate, and the contribution rate of wheat (stem sheaths, leaves, and spikes). The maximum values of the above parameters of XC38 and XC49 were observed in response to N3 and N4, respectively. In addition, N affected the dry weight and grain‐filling characteristic parameters. Nitrogen affected the rate of grain‐filling during the three periods, with N3 and N4 being the best treatments for XC38 and XC49, respectively. The results of this study provide an understanding of the translocation of assimilates and the grain‐filling characteristics of spring wheat, and the optimum N application levels were different for XC38 and XC49. Among the N treatments in this study, the optimum nitrogen levels were 250 and 225 kg hm−2 for XC38 and XC49, respectively.