Absorption and accumulation characteristics of nitrogen in different wheat cultivars under irrigated and dryland conditions.

To investigate the N absorption and accumulation characteristics of different wheat cultivars, twelve wheat cultivars with different drought tolerance were planted under both irrigated and dryland conditions. Compared with the irrigated condition, wheat N accumulation was significantly decreased at each growth stage under dryland cultivation, with the maximum decline in weak drought-resistant cultivars (more sensitive) (SN129, SN9-1, 40081, and CZ9578), secondly the moderately-tolerant (40345, 40035, SN121, and ZM175) and then strong drought-resistant cultivars (040521-135, JM47, 9801-C, and ND189). Furthermore, dryland condition decreased the N absorption ratio at anthesis-maturity stage, post-anthesis N accumulation and its contribution to grain N content. On the contrary, the N absorption ratio at jointing-anthesis stage and the contribution of pre-anthesis N translocation to grain N content were increased. Therefore, under dryland condition, we suggest that strong drought-resistant wheat cultivars should be popularly cultivated. These cultivars could significantly improve pre-anthesis N absorption and the translocation from pre-anthesis vegetative organs to post-anthesis grain, resulting in higher N use efficiency and high wheat yield.