Abstract:

Many researches have shown that the absorption, translocation and utilization of nitrogen varied markedly in different genotypes of common corn. However, there are few reports on waxy corn is this field. In this study, 31 cultivars of waxy corn (Zea mays L. ceratina Kulesh) released recently within China were employed to evaluate their nitrogen use efficiencies (NUE) by indices of agronomic efficiency (AE), recovery efficiency (RE), physiological efficiency (PE), and partial factor productivity (PFP). The field experiment was split plot design with nitrogen treatment (225 kg N/ha) or control (0 kg N/ha) as main factor, and the 31 cultivars were planted randomly in each plot. Five plants of each cultivar were sampled at anthesis, fresh ear harvest (21 days after anthesis) and physiological maturity stages, respectively for measuring nitrogen contents in different organs of leaf, leaf sheath, culm, tassel, bracteal leaf, ear axis and kernel. Results showed that there were significant genotype differences of N use efficiencies among the 31 cultivars in terms of AE, RE, PE, and PFP (Table 2–4). Cluster analysis revealed that the cultivars with high yield potential and NUE for whatever product of fresh ear, fresh kernel or maturity kernel were FN 2146, JKN 267, JKN 218, YBN 1, SW42 and SAUWX02 (Fig.1). Compared with other cultivars, their average yields of the fresh ear, fresh kernel and maturity kernel were higher by 17.9%, 18.1% and 28.6%, the average AEs of the fresh ear, fresh kernel and maturity kernel were higher by 45.2%, 50.2% and 64.7%, the average REs of the fresh ear, fresh kernel and maturity kernel were higher by 35.1%, 35.1% and 36.7%, the average PEs of the fresh ear, fresh kernel and maturity kernel were higher by 4.5%, 9.7% and 20.3%, and the average PFPs of the fresh ear, fresh kernel and maturity kernel were higher by 17.9%, 18.1% and 28.6%, respectively. It is confirmed by correlation analysis that increasing the N harvest index and N translocation rate may promote NUE in waxy corn.

Key words: Waxy corn, Yield, Nitrogen use efficiency, Genotype difference