Genotypic differences in nitrogen accumulation and distribution among different sweet maize varieties

In order to understand nitrogen (N) accumulation and distribution in sweet maize variety with high fresh ear and kernel yield, explain the genotypic differences of N accumulation and distribution at different growth-phases and their effects on yield formation and N utilization efficiency (NUE), 22 sweet maize (Zea mays L. saccharata Sturt) varieties released in recent years in China were planted and their N accumulation and distribution amount at jointing stage, silking stage and fresh stage under the same nitrogen level were studied. The results indicated that the N accumulation and distribution were significantly different among sweet maize varieties. With the advance of growth and development, plant N content gradually decreased, N accumulation amount gradually increased and the N accumulation amount was highest from jointing to silking stage among different stages. N was mainly distributed in leaf before silking stage and was translocated to ear in grain filling stage. At fresh stage, N distribution amount was highest in ear among various organs, and it accounted for 41.32% of the total N accumulation amount, second was grain, which accounted for 28.53% of the total N accumulation amount. The variety with high yield had high N accumulation amount from jointing stage to fresh consumption stage. The variety with high fresh ear yield had high N distribution amount in leaf and grain at fresh stage, the variety with high fresh grain yield had high N distribution amount in leaf and tassel and low N distribution amount in cob at fresh stage. The variety with high N use efficiency for fresh ear yield mainly reduced N accumulation amount from silking stage to fresh stage, and secondly reduced N accumulation amount from jointing stage to silking stage, and the N distribution amount in leaf, cob and sheath was low. No significant correlations were observed between fresh grain N use efficiency and N accumulation amount at various stages and N distribution amount in organs at fresh stage.