Dry matter and nitrogen accumulation, partitioning, and translocation in synthetic-derived wheat cultivars under nitrogen deficiency at the post-jointing stage

Abstract

Synthetic hexaploid wheat-derived cultivars (SDCs) show substantially improved yield potential compared with that of nonsynthetic-derived cultivars (NSCs) developed by conventional breeding. However, the relationship between the high-yielding traits of SDCs and nitrogen (N) use efficiency, especially their performance under N deficiency, is unclear. A field experiment was conducted in two successive seasons examining the responses of six genotypes (three SDCs and three NSCs) under two N treatments: N+ (N sufficiency, N nutrition index ≥ 1) and N− (N deficiency, N nutrition index < 1). N deficiency had a significantly negative effect on grain yield (GY) and yield-related traits. Compared with that of NSCs, SDCs showed 14% (N+) and 16% (N−) higher GY. This yield gain was mainly attributable to the higher total dry matter (DM) and post-anthesis DM accumulation of SDCs under both N treatments. On average, SDCs showed higher chlorophyll content than NSCs in the three upper leaves from 0 to 32 days post-anthesis, which was highly positively correlated with GY under both N treatments. Total and fertilizer N accumulation were significantly decreased under N deficiency. Compared with that of NSCs, SDCs showed lower grain protein concentrations under both N treatments, which was negatively correlated with GY. In addition, SDCs showed significantly higher N use efficiency and N utilization efficiency (NUtE) than NSCs, and a positive correlation was detected between NUtE and GY. The results indicated that SDCs show advantages over NSCs in GY, DM accumulation, and NUtE under N deficiency, and thus cultivation of SDCs shows potential to reduce N waste and environmental contamination.